siemens · 2015. 1. 21. · inference and defuzzification method ..... 2 . 57 dfuz weighting...

SIEMENS

SIMATIC S5

SIFLOC S5 Basics of Fuzzy Control

SIFLOC S5 Configuration System

Design and Implementation of Fuzzy Controller

User's Guide Hardware Requirements and Software Installation

Table of Contents

Table of Contents

1 Basics of Fuzzy Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . 1

. 1 . 1 Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1

. Basics of Fuzzy Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 3

Fuzzy Sets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . 4 Linguistic Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . 4

. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Membership Functions 1 5 Truth Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . 5

Function Components of a Fuzzy Controller . . . . . . . . . . . . . . . . . 1 . 7

. . . . . . . . . . . . . . . . . . . . . . Typical Functions of a Fuzzy Controller 1 7 Fuuification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . 10

. Linguistic Set of Rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 11

. Defuuification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 14

2 SIFLOC S5 Configuring System . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . 1

2.1 General Description and Operator Desktop . . . . . . . . . . . . . . . . . 2 . 1

2.2 Getting Started with SIFLOC S5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 7

2.3 Defining the Fuzzy Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . 11

2.3.1 Defining Structure Names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 12 2.3.2 Defining Inputs and FUZ Blocks . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 14 2.3.3 Defining Outputs and DFUZ Blocks . . . . . . . . . . . . . . . . . . . . . . . . 2 - 16 2.3.4 Modifying a Configured Controller . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 21

2.4 Defining the Membership Functions . . . . . . . . . . . . . . . . . . . . . . . . 2 . 26

2.4.1 Selecting Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 28

Table of Contents

Defining the Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . 30 Number of Membership Functions . . . . . . . . . . . . . . . . . . . . . . . . . 2 . 32 Individual Names for Linguistic Values . . . . . . . . . . . . . . . . . . . . . . 2 . 34 Modifying the Samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . 36

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Defining the Rule Basis 2 . 42

Entering Rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . 45 Editing. Deleting. and Printing Rules . . . . . . . . . . . . . . . . . . . . . . . 2 . 51

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Implicit Zero Rule 2 . 53

Inference and Defuzzification Method . . . . . . . . . . . . . . . . . . . . . . . 2 . 57

DFUZ Weighting Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . 58

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fuzzy Data File Management 2 . 61

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Off-line Analysis 2 . 68

Instantaneous Value Monitoring of the Fuzzy Structure . . . . . . . 2 . 70 Family of Graphs of the Fuzzy Structure . . . . . . . . . . . . . . . . . . . . 2 . 75

On-line Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . 2 . 80

Link Parameter Setting Functions . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . 80 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . On-line Monitoring 2 . 84

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Exiting SIFLOC S5 2 . 92

Design and Implementation of Fuzzy Controllers . . . . . . . . . . 3 . 1

. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Overview 3 1

. Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3

Analyzing the Control Engineering Task . . . . . . . . . . . . . . . . . . . . . 3 . 3 Assessment Criteria for Employing a Fuzzy Controller . . . . . . . . 3 . 3 Analyzing the Previous Control Response . . . . . . . . . . . . . . . . . . . 3 . 4

Definition and Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 . 5

Table of Contents

Defining the Process Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 . 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Setting up the Rule Basis 3 . 6

. . . . . . . . . . . . . . . . . . . . . . . . . From Configuration to Optimization 3 7

Configuration with SlFLOC S5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 . 7 . . . . . . . . . . . . . . . . . . . . . . . . . . Off-line Analysis with SlFLOC S5 3 . 7

. . . . . . . . . . . . . . Loading and Commissioning a Fuzzy Controller 3 8 Correcting and Optimizing a Fuzzy Controller . . . . . . . . . . . . . . . 3 . 9

Hardware Requirements and Software Installation . . . . . . . . 4 . 1

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hardware Requirements 4 . 1

How can SIFLOC S5 be installed and invoked? . . . . . . . . . . . . . . 4 . 2

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 1

Application SlMATlC S5 Basics of Fuzzy Control

1 Basics of Fuzzy Control

1 .l Application

Continuous automatic operation is a major goal in the procedure Automatic of controlling a technical process. In a linear system, or in a Operation system that can be linearized in the proximity of the operating point, this goal can be reached by using closed-loop control circuits that are equipped with PI, or PID controllers. Using fuzzy control is expedient if solving an automation task with conventional controllers is either not possible or requires high expenditure, and additional corrective interventions of an operator who is familiar with the process. The technical processes are then characterized by multi-variable control or non-linear and time-variant control systems which can only inadequately be described by mathematical models.

Fuzzy controllers may be employed either in addition to or Empirical instead of conventional regulators. The SlMATlC fuzzy compo- process nents have been developed to complement the existing modular expertise control system. Adequate empirical knowledge, however, is a prerequisite for performing complete automation by fuzzy control. This knowledge permits manual intervention to be used for bringing the process concerned into the desired state.

Typical applications are: Typical applications - Process control including the coordination of subordinate

control activities - Controlling non-linear single- and multi-variable systems

- Quality control

- Feedforward control

- Parameter adaptation

- Logic structures in control procedures

Function Com~onents Basics of FUG Logic SlMATlC S5

FuuY Fuzzy controllers are used for implementing statistical non-li- Control near transfer functions. These provide the following benefit for

the user:

- Direct know-how input - Directed influence on the effect

- Improved control quality - Robust against changes in the process

- Advantageous utilization in non-linear processes

Fuuy Control

Setpoint

Controlling technical processes may employ a fuzzy control structure (for one manipulated variable) that looks like the one shown in Fig. 1 .l. Generating an output variable Y (manipulated variable) from conditioned input variables (measured values) is the task of the fuzzy controller. Its function is based on empirical process expertise that has been formulated as qualitative IF-THEN rules.

Controlled Variable Y Variable X

Fig. 1.1 Basic Structure of a fuzzy control

Measured 7 Value - Conditioning - Process

"

Fuzzy Controller -

A . . m m .

Measured values

Fuzzy Logic SlMATlC S5 Basics of Fuzzy Control

1.2 Basics of Fuzzy Logic

Fuzzy logic permits vague information, empirically gained Fuzzy knowledge, and verbally described control strategies of a plant Logic operator to be integrated realistically into process automation.

Degree of Membership

A Crisp value

Fig. 1.2 Difference between "crisp value" and "fuzzy value"

1 -

Degree of Membership Fuzzy value

"average velocity"

Velocity

1.0-

0.5-

0.0

0 20 40 60 80 100 'kmlh

"average velocity"

Velocity

0 20 40 60 80 100 *km/h

Funy Logic Basics of Fuzzy Control SlMATlC S5

1.2.1 Fuzzy Sets

Set theory The fuzzy logic presented by Lotfi A. Zadeh in 1965, an enhancement of the classic set theory, is used for describing and combining "fuzzy sets". Distinction is made by referring to the usual sets as "crisp sets". The classic (crisp) logic defines the elements of these sets as correct/incorrect, truelfalse, 110.

In contrast to these definitions, fuzzy logic describes fuzzy sets by a continuous membership function that may assume any value between 0 and 1. Fuzzy sets include the linguistic values that have been formulated for fuzzy controllers. Fuzzy logic is the general theory. It includes binary logic as an "exception".

1.2.2 Linguistic Values

Colloquial Linguistic values use colloquial terms for describing physical terms quantities that cannot clearly be discriminated from one another,

dealing with qualitative features rather than with concrete numericvalues. In fuzzy control, linguistic values refer to process variables that may either be input variables (measured values from the process or reference variables) or output variable (manipulated variables).

Applying to Typical linguistic values are "cold", "warm", or "hot" for measured process temperature values or "slightly open" or "nearly open" for an variables output variable to a control valve. Uniform terms that may be

applied to all process variables (such as "very small", "small", "medium", "large", and "very large") are better. Such terms may also be signed. At least two linguistic values are required for the entire range of a process variable. These are "small" and "large" for unsigned process variables, and "negative" and "positive" for signed variables.

Funy Logic Basics of F u w Control

1.2.3 Membership Functions

Each linguisticvalue of a process variable corresponds to afuuy set that is defined by a membership function. Fig. 1.3 shows the possible membership function characteristics of three typical linguistic values (L = low, M = medium, H = high).

1.2.4 Truth Values

A membership function employs a truth value to quantify the Degree of qualitative statement of a linguistic value. This truth value is membership allocated to the actual numeric value of a process variable, thus representing a degree of membership of a fuzzy set. The degree of membership may assume a value between 0 and 1.

As membership functions typically overlap, several membership functions may, for a given instantaneous value of a process variable, supply a truth value that is different from zero. The abscissa of Fig. 1.3 shows the instantaneous value of a process variable. The membership functions MF1 and MF2 assign the truth values TV1 and TV2 to the process variable.

Fuzzy Logic Basics of Fuuy Control SlMATlC S5

L i n g u i s t i c v a l u e s L ( low)

Membership f u n c t i o n s MF

T r u t h v a l u e s

M (medium)

ME 2

H ( h i g h )

MF 3

100 % Process variables

Range of the process variable

Fig. 1.3 Typical membership functions of a process variable with three linguistic values

Function Components Basics of Fuzzy Control

1.3 Function Components of a Fuuy Controller

A fuzzy controller consists of the following components (see Configuration Fig. 1.4): of a fuzzy

controller

Fuzzification of the input variables

Linguistic set of rules

Generating the manipulated variable by defuzzification

1.3.1 Typical Functions of a Fuzzy Controller

A given fuzzy controller is characterized by the following Parameters parameters:

Input variables: X1 and X2

Output variable: Y

Linguistic values: - N = negative and P = positive for X1

- L = low, M = medium, and H = high for X2 and Y

Fig. 1.5 shows the functions of this fuzzy controller. The subsequent description of the function components refers to this example.

Function Components Basics of Fuzzy Control SlMATlC S5

Input variables

Xp I t t

functions of the Determining Fuuification truth values

Truth values of the input variables

Linguistic Set of Rules

THEN parts of

functions of the the rules:

output variables Delimitations

I Composing the I rule basis I

Membership function of the rule basis

I Calculating the I I i

areas' center of I aravitv H Defuzzification I I Y1

Output variables m yq

Fig. 1.4 Basic structure of the function components of a fuzzy controller

1 - 8

Function Components SlMATlC S5 Basics of Fuuy Control

ANDing is implemented as a minimum operation. ORing is implemented as a maximum operation.

Input variables: X1 and X2 Output variable: Y Linguistic values: - N = negative and P = positive for X1 - L = low, M = medium and H = high for X2 and Y Center of gravity: C

IF (X1 = "positive") AND (X2 = "medium") THEN (Y = "medium")

Fig. 1.5 Typical functions of a fuzzy controller

Function Components Basics of Fuzzy Control SlMATlC S5

1.3.2 Fuzzification

Determining The "fuzzification" function component starts processing the XI, truth values ... Xp input variables of afuzzy controller by converting the instan-

taneous values of the variables via appropriate membership functions into truth values. The Nl ,... N k truth values result for a given input variable X and the MF1, ... MFk membership functions that have been defined for this variable. The example in Fig. 1.3 with three membership functions (k=3) yields 0 as the truth value of N 3 , while the truth values of TV1 and W 2 are not equal to zero. Correspondingly, this also applies to the truth values that, according to Fig. 1.5, are calculated via three membership functions from the X2 input variable.

Function Components SlMATlC S5 Basics of Fuzzy Control

1.3.3 Linguistic Set of Rules

The "linguistic set of rules" function component implements a linguistic rule, also known as "fuzzy rule".

A fuuy rule is of the form:

IF <condition> THEN <consequence>

It describes a sub-strategy of a fuuy controller that is decisive for the controller response.

The fuuy rule implemented by the linguistic set of rules corresponds to the IF part (conditional part) of a rule. This produces a resulting truth value from all truth values of the "fuuification" function component. The THEN part of the rule is performed by the subsequent function component "Defining the rule basis".

A linguistic rule may consist of several truth values that are combined by AND and OR functions of any complexity. Parentheses define the sequence of several consecutive operations. Combinations without parentheses are executed in the sequence "AND before OR".

Colloquial formulation of linguistic rules

For the example in Fig. 1.5, the following can be a formulation of two selected rules that is based on linguistic values:

1 st rule: I F (X1 = "positive") AND (X2 = "medium") THEN (Y = "medium")

Linguistic rule

Fuuy rule

IF-THEN rule

Resulting truth value

2nd rule: IF (X1 = "negative") OR (X2 = "small") THEN (Y = "small")

Function Components Basics of Fuuv Control

Minimum operation, mavimum operation

Inference

Membership function of a rule

Implementing linguistic rules

The linguistic set of rules uses minimum and maximum operations for calculating the resulting degrees of membership.

- ANDing is implemented as a minimum operation. Analogous with binary logic, ANDing only produces a truth value > 0 if all truth values of the conditional part (IF part of the rule) are different from zero. lmplementation is thus done by a minimum operation that yields the smallest truth value.

- ORing is implemented as a maximum operation. Analogous with binary logic, ORing produces a truth value that corresponds to the truth value that is different from zero if at least one truth value is different from zero. Implementation is thus done by a maximum operation that yields the largest truth value.

Defining the Rule Basis

The resulting membership function of the rule basis is the goal of the composition. The procedure required to reach this goal is known as "inference."

Determining the rules' membership functions

The membership functions of an output variable Y that corres- pond to the THEN parts of rules and are represented at the right- hand side of Fig. 1.5 form the base from which the procedure starts. To determine the membership function of a rule, the associated membership function of the THEN part is limited to the resulting truth value of the rule's IF part. There are the methods of minimum inference and product inference for this purpose. The- se methods are compared in Fig.l.6.

Function Components SlMATlC S5 Basics of Fuuy Control

The membership functions of both rules in Fig. 1 .S are characterized by theTHEN part of the first rule being delimited to the resulting truth value of an AND function, and the THEN part of the 2nd rule being delimited to the resulting truth value of an OR function. Minimum inference is implemented there.

/ Methods of minimum and maximum inference for determining the membership function of a rule J

A

Example: The three linguistic values L = low, M = medium, and H = high have been assigned to the output variable. The rule's truth value is 0.8.

0

Minimum inference

Fig. 1.6 Minimum and product inference methods

- Minimum inference The membership function of a rule results from delimiting the THEN part's membership function to the current truth value of the IF part.

Product inference

- Product inference The membership function of a rule results from multiplying the THEN part's membership function by the current truth value of the IF part.

Function Components Basics of Fuuy Control SlMATlC S5

Determining the membership function of the rule basis

Membership The composition of a rule basis is performed by overlaying the function of a rules' membership functions. As many membership functions rule basis are involved in this process as there are linguistic values allo-

cated to the output variable. In order to allow the effective components of all rules to produce the required result, the membership function of the rule basis is determined by performing a maximum interconnection of the membership functions of the individual rules. The result is a polygon that forms an enveloping curve of the limited membership functions. The right-hand part of Fig. 1.5 shows how the membership function of the two rules is com- posed to form the membership function of the rule basis.

1.3.4 Defuzzification

Calculating The "defuuification" function component calculates the output the output variable Y (manipulated variable) that corresponds to the variable abscissa value of the area center of gravity of the rule basis's

membership function. The original center-of-gravity method that may always be used for this purpose is shown at the right-hand side of Fig. 1 .S.

General Description and Operator Desktop SlMATlC S5 SlFLOC S5

SIFLOC S5 Configuring System

2.1 General Description and Operator Desktop

The SIFLOC S5 program provides you with a configuration tool that permits convenient configuration, parameter selection, analysis, and operator communication and visualization of fuzzy controllers in the SlMATlC S5 process control system. Its graphic desktop makes it easy to learn and handle SIFLOC S5.

Definition of terms

This description employs the terms "dialog section" and "dialog step".

- "Dialog section" describes a contiguous function within fuzzy Dialog configuration, such as "defining the fuzzy structure", or "de- section fining the rule basis", etc.

- "Dialog step" describes the part of the dialog section that is Dialog step required for executing a function (such as "defining input"). Each dialog step may have its own desk-top representation (e.g. different key sets). Its representation takes the changes from previous steps into account (such as entering the previously allocated structure name into the corresponding graphic image).

General Description and Operator Desktop SlFLOC S5

Keys

Representation conventions used in this description

- Keys of the operator input keyboard are shown in angle brackets within the description (e.g. <F1 > or <RETURN>).

Colors - Technical reasons do not allow the screen contents to be represented in its original colors. Colored fields are therefore represented by different shades of gray.

Lines - The difference in the colors of lines and polylines is shown by different line types.

Characters - The different color of characters is not taken into consider- ation.

Marginal - The marginal headers in the margins of a page provide a headers quick overview of the topics discussed in the text.

General Description and Operator Desktop SIFLOC S5

Desktop elements

The desktop layout always shows: Desktop layout

- A banner line that contains the name of the currently selected control dialog is displayed at the top screen margin. For example:

- The keys that are accessible on the keyboard during this dialog step are at the bottom of the screen. The labels below these keys show the key functions in plaintext.

Accep tance C o n t i n u e Menu s e l e c t i o n b a r s

The different colors of the labels improve the legibility.

- At the center, the work area contains option menus, input fields, graphic fields, etc. For example:

20 .00 INPUT 1 8 0 . 0 0

Here too, legibility is increased by using different colors for graphic elements and labels.


Alternative Most dialog steps offer an alternative key input to be performed. key input To select a menu, for example, either:

- Use the cursor keys (arrow upldown) to select the menu selector bar (the selected bar then has a colored background), )I and press <RETURN> to enter the selected function.

Or:

- Press the function key that corresponds to the selected menu item to enter (execute) the function directly. For example: 2nd menu item = function key cF2> 3rd menu item = function key cF3>, etc.

Pressing the <ESC> key takes you back to the previous dialog step. This means that you will have the previous desktop re-displayed. This key enables you to move backward, step by step, through the configuration dialog.

The assignments of the function keys <F1 > through <F9>

. . . change as the dialog steps change. These function keys are not only used for selecting a menu function but also for selecting input fields of specific execution functions.

Example: Defining the fuzzy structure (see Fig. 2.7) Keys <F1 > 1 cF2> = define input 1 output Keys cF5> 1 cF6> = delete input l output

The <F10> key is used in the current dialog section for selecting the "Central function menu" (Fig. 2.1). This menu permits direct selection of the required function. This means that you may skip certain dialog sections or steps during configuration.

General Description and Operator Deskto SIMATIC S5 SIFLOC &

W The use of the "Central function menu" for a new configu- Central func- ration is limited. As the configuration sequence must be tion menu adhered to, jumps are neither expedient nor permitted.

1. Defining the fuzzy structure

2. Defining the membership functions

3. Defining the rule basis

4. Inference and defuzzification method

5. DFUZ weighting factors

6. Fuzzy data file and documentation

7. Off-line analysis

10. End of program

Fig. 2.1 Central function menu

Each option menu has one default function that is highlighted by Default se- an underlying colored bar when the menu is activated. The high- lection of the lighted function is activated when you press the <RETURN> key menu function (see Fig. 2.1, selector bar, line no. 9).

Select "H" to activate the help function. The help function displays explanations of the currently displayed desktop. Pressing the <ESC> key returns you to the current desktop.


The "R" key on the central function menu desktop activates and displays the README file that contains some user information. Note: The README file may also be output by means of DOS commands (TYPEIPRINT).

Input and Input and output fields are used on the desktop. output fields An output field shows, for example, the numeric value of a

graphic representation. This value cannot be edited (see Section 2.4.5, "Modifying the Samples", Fig. 2.31). The output field has a blue background.

An input field is displayed instead of a key set. It has a yellow background, can be edited, and contains a default value. The <RETURN> key is displayed to the right of the input field (see Fig. 2.6).

Decimal - A point (.) must be used as the decimal separator when deci- separator mal values with a fractional part are entered.

Fractionalpart - The digits to the right of the decimal point of a decimal value need not be entered if you only use integer values. SIFLOC S5 automatically inserts the fractional digits (.00).

Getting Started SIFLOC S5

2.2 Getting Started with SIFLOC S5

To start the SIFLOC FUZZY configuration tool, enter the following commands on operating system level:

C:\> CD SIFLOC <ENTER> SIFLOC S5 <ENTER> SIFLOC S5 SX <ENTER> with PG 730 SX only

"C:" stands for the drive that contains the SIFLOC directory. If your SIFLOC directory is installed on another drive - enter the correct drive name.

W PG 730 SX knows only a few gray levels. Setting and visibi- lity may therefore reduce contrast and readability. Adjust slide potentiometer, or screen inclination, andlor select in- verted display (press <CONTROL> + <ALT> + <I> on the keyboard) to improve readability.

These entries start SIFLOC S5 and display the SIFLOC S5 presentation image. ESC> and <RETURN> keys are displayed below the copyright line and version number. Pressing <ESC> on your keyboard deletes the start menu from the screen and returns you to the operating system level. Pressing <RETURN> or <ENTER> deletes the start menu from the screen and displays the first operator input menu with two options (Fig. 2.2).

Activate SlFLOC S5

Getting Started SlFLOC S5

Fig. 2.2 Desktop "Supporting Animation Texts"

3

Option menu Select from the option menu whether or not animation text will be displayed before the next dialog steps. Animation text is usually employed for presentation purposes, not during a normal configuration session. That is why the first menu line "are not required" is the default selection. Pressing the <RETURN> key enters the default selection; the function keys are used for selecting either the first (<F1 >) or the second (<F2>) menu function.

s r m o ~ : $5 SZEMENS

a n d m o r ... R e t u r n Menu s e l e c t o r b a r Acceptance D l r e c t selection Help

Supparting animation texts

Getting Started SlMATlC S5 SlFLOC S5

The desktop of the dialog section "Defining the fuzzy structure" is No animation displayed if you have selected "Animation texts are not required" text (see Section 2.3, Fig. 2.5).

If you have selected "Animation texts are to be displayed", the With anima- first image (Fig. 2.3) will show you an overview in large letters, the tion texts second image a list of the four "Fuzzy control" configuration steps, and the third image (Fig. 2.4) the headline of the subsequent dialog step.

Qverview

PC software functions

* Configuring

* Set parameters

* Operator input

* Monitoring

of fuzzy control in SIEMENS systems

a Cont lnue

Fig. 2.3 Animation text "Overview"

Getting Started SIFLOC S5

Step 1 :

Defining the fuzzy structure

~efining the fuzzy st~ucture

Fig. 2.4 Animation text of the "Defining the funy structure" dialog step

SZFLOC S5 3

Continue

Fuzzy Structure SlMATlC S5 SlFLOC S5

2.3 Defining the Fuzzy Structure

Defining the fuzzy structure is the first dialog step in a fuzzy con- Defining the figuration session. fuzzy structure Fig. 2.5 shows the displayed screen contents.

Fig 2.5 "Defining the funy structure" desktop

,.,.:.:: ............... ,.:., :,: :,.,.: ...... ,:,,,,, ..; .;.,, ,:,:,:,:,:,:,

:i;.iigi$g$&g$ . . . . . . jjl~j:j : :.:.:.. . :... .: : ....... :. ..:.::..,.:::::.::

In this dialog step, we distinguish between two types of configuration:

- Creating a new fuzzy structure (from Section 2.3.1 onwards).

.......................... . . . . . . . . . . .,:., . , . . . . ) ,.: ............................ ,:;. ... : : . . . . . . . . . . . . . . . . . . . . . . . . . ....................... I::: :. :.. . . . : . .

;;iiii.,:i:.::'. \,: j:; ,: i;: .: ::.;.ji ,, i;:~j$Ui;g$;. ,:&$ c;g$$it;';ij-:e*;;.;ge'f:$$ :::::.:. . . ...;...; :j: ,: :: :. :.: ...".'......::. :.. ....................... , , , , , , , , , ......... . . . . . . . . , ............. .:.: ....:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

- Editing an existing fuzzy structure (Section 2.3.4).

I N P U T S (I) O U T P U T S ( 0 )

R e t u r n S t r u c t u r e name Read f i l e DB/DX S e l e c t i o n Menu C o n t i n u e H e l p

Fuzzy structure: name SIFLOC S5

2.3.1 Defining Structure Names

When you create a new fuzzy structure, you first assign this structure a name. Pressing the <F1 > function key displays an input

S t r u c t u r e name field instead of the previously displayed key row (Fig. 2.6).

P r o c e s s - r e l a t e d fuzzy s t r u c t u r e name (up t o 1 6 c h a r a c t e r s ) Im Fig. 2.6 input field of the process-related structure name

Entering the Enter the name (up to 16 characters) and press <RETURN>. name

Once you have entered the name of the structure (e.g. "TEMP- KORR"), the following text is briefly displayed at the bottom of the screen:

"New fuzzy s t r u c t u r e i s c r ea t ed ! '

It is assumed that DB data blocks are consistently used for data storage. Change this default selection if you wish to use DX data

V D 1 U A blocks instead.

s e l e c t i o n After you have pressed the <F3> function key, the system will, in an additional input field (Fig. 2.6 a), inquire whether you wish to use DX or DB data blocks for data storage.

Implement f u z z y c o n t r o l w i t h DX i n s t e a d o f DB d a t a blocks?

Fig. 2.6 a Input field for data storage in OX or D6 data blocks.

Select cN> if you wish to use DBs for data storage.

Funy structure: name SlMATlC S5 SIFLOC S5

Next, the desktop with a new key set (Fig. 2.7) and the name of the structure inserted above the fuzzy control representation is displayed.

. . . , .: .. . . . , . , ..7- ,.,., . . .. . .,.. ,...: :.:.:.: ,. ..,(.. . ,: .... .. . .. ... : ::. ... :.:.:::::: ::,: ,L$i:g$$$$&y :; j,:;4<$s$2

; .. .. . .: . .:.. , .. : . . . , , : .: .::::.,,:.:: ;:::;:;:::;.:.

TEMPKORR I N P U T S ( I ) O U T P U T S ( 0 )

DB no. DB no.

F a p m II' R e t u r n I d e f i n e 0 I e d i t 0 I d e l e t e 0 Menu Con t inue Help

Fig. 2.7 Desktop after the structure name has been entered.

The inputs and outputs are defined in the next step. There is no specific definition sequence required.

Funy structure: Inputs SlFLOC S5

2.3.2 Defining Inputs and FUZ Blocks

W Only the cF1> and cF2> keys of <F1 > to cF6> are active at the beginning when a new function is created, and a name has not yet been assigned.

lnput names

Press the <F1 > key to define the input. The input names input field (Fig. 2.8) is displayed instead of the key set.

I n p u t name (up t o 1 6 c h a r a c t e r s ) : ID Fig. 2.8 lnput name input field

Defining the Enter a name (up to 16 characters), and press <RETURN>. The input names name (e.g. "OUTLET1 ") is entered in the graphic image for the

inputs and linked with "Fuzzy control" via an arrow (see Fig. 2.12). A new input field is inserted instead of the key set (Fig. 2.9).

FUZZY structure: inputs SlMATlC S5 SlFLOC S5

FUZ data block

Number of FUZ data block for "OUTLET 1" (3-255):101 IH I I

Fig. 2.9 FUZ data block input field

Select a number between 3 and 255 that has not yet been alloca- Number of ted in your target CPU ("101" in our example). Press FUZ data <RETURN> to enter the selected number. The number will be block entered to the right of the input arrowhead in the "Fuzzy control" graphic image (see Fig. 2.12).

Subsequently, you may define further inputs and the associated FUZ data blocks or the output names and DFUZ data blocks.

Fuzzy structure: Outputs SlFLOC S5

2.3.3 Defining Outputs and DFUZ Blocks

v Only the <F1 > and <F2> keys of <F1 > to <F6> are active at the beginning when a new function is created, and a name has not yet been assigned.

Output names

Defining Defining the output is similar to defining the input. output names

Pressing the <F2> key replaces the key set on the display with the output name input field. Type a name of up to 16 characters ("INLET1" in our example), and press <RETURN> to enter this name.

I I

Fig. 2.70 Output name input field

Output name (up t o 16 characters):

An arrow appears between the "Fuzzy control" symbol and the list of outputs. The entered output name is displayed next to this arrow (see Fig. 2.1 2). The input field of the DFUZ data block name is displayed at the same time.

Fuzzy structure: Outputs SIFLOC S5

DFUZ data block

Select a number ("201" in our example). Press <RETURN> to Numberof enter the selected number. The number will be entered to the left DFUZ data of the output arrowhead in the "Fuzzy control" graphic image block (see Fig. 2.12)

Fig. 2.11 DFUZ block inpui field

Number of DFUZ data block for "INLET1" (3 - 255) : 201

Subsequently, you may define further outputs and the asso- Further inputs ciated DFUZ data blocks, or further input names and FUZ data and outputs blocks.

You may define inputs and outputs in any sequence. For example, you may define all inputs before you define all outputs. Or you may define an output after each input.

Fuzzy structure: Outputs SlFLOC S5 SiMATlC S5

Fig. 2.12 User interface with a defined fuzzy structure (example)

.. . : .... : ...... :...:...::. .: ' .. ... ............................................... . . " ' :.:.:.;:,.:: ..... ::::j:.: ,: :,:, :,.:.,.::. :::.,.:::.:;,;.,. ' ' . . . '. ' . .'. .' . . . ., ............................ ;,,.:,:.: . . . . . . . . . . . . . . . . . . . . . . . . , , : : : : : , , . , ,.... , . . , .,.,.,,, , , . . . ..... ........... , :..:..:. : .:.:: :;, . :: . .:.:: .: :::::: :::. : . . . , i : ; : i , $ i i : ~ ~ ~ ~ $ y # ~ ~ ~ ~ ~ ~ ~ ~ & $ ~ ~ f : $ $ $ ~ ~ ~ n : ~ : j j : : j : ~ . . . . . . ............ . ,,,.,.,., , , , , , , , ,.,.,,,,,,, , .... . . :. (.:.. :... :.. . .. .. . ..................... . . , , . . . ..... ....... .: ... ;;I; .,. : :,:...: :<:I :: :. , ...,..,. . . . . . . . . . . . . . . . . . . . . , , , . . . . . . . . . . . . . . . . . . . . , . . . . . . .

Pressing <RETURN> takes you to the next dialog section. Here you may specify the function block and the data block numbers (Fig. 2.12 a).

.....,: ........................... ... :....:.:.: : : : ::,:: . ................................ " ' ' ,

$F@nljiQc .. ......................................................... ',m;:, TEMPKORR

I N P U T S ( I ) O U T P U T S ( 0 )

R e t u r n I d e f i n e O I e d i t O I d e l e t e O Menu Con t inue Help

Fuuy structure: Outputs SlMATlC S5 SlFLOC S5

Fig 2.12 a Block number menu

Block number input SIPLOG $5

2 . Number of t h e DFUZ f u n c t i o n b l o c k

3. Number o f t h e APP f u n c t i o n b l o c k

4 . Number of t h e RULE f u n c t l o n b l o c k

5. Number of t h e RULE d a t a b l o c k

6 . A c t i v a t e c e n t r a l menu

a n d m o r ...m R e t u r n Menu s e l e c t o r bar Accep tance D l r e c t selection Help

Funy structure: Outputs SIFLOC S5

Select < F1 > or <RETURN> to display an input field that permits the DFUZfunction block number to be entered ( Fig. 2.12 b).

Fig. 2.12 b FUZ function block number input field

Either press <RETURN> to confirm the default value (1 13), or enter a different function block number (that must still be unallo- cated in your target CPU). Proceed in the same manner if you wish to allocate further block numbers.

W You must define all block numbers before you can leave the screen. The message

I n c o r r e c t SIMATIC b l o c k number!

will be displayed if the definition is incomplete.

Press <F7> to terminate this dialog step.

Further configuration sequence

Next dialog Once you have defined inputs and outputs, you have terminated section the "Defining the fuzzy structure" dialog step in the normal confi-

guration sequence. Press <RETURN> to move to the next dialog section (Section 2.4; Defining the Membership Functions).

Editing the The dialog steps "Edit inputs/outputs" and "Delete inputslout- structure puts" are available. If, for example, you wish to rename or delete

an input of the structure that you have just finished, you may do it now. Section 2.3.4 tells you how you can do this.

Funy structure: Modification SlFLOC S5

2.3.4 Modifying a Configured Controller

Before you can edit a completely parameterized fuzzy structure, you must read it from a file. The first user interface of this dialog section forms the initial situation of this procedure (see Fig. 2.5).

Reading the structure

Pressing the cF2> key replaces the key set with the file name input field. The default setting of this field is "*.FUZn (Fig. 2.13).

Specify f i l e name (ptessb.1 for menu) : * . FUZ

Fig. 2.13 File name input field

You may now either enter the required file name or display the list Activating the of the existing files with a ".FUZ" extension. To do the latter, mere- file list ly press the <RETURN> key. The file list will then be displayed as an option menu inside the "Fuzzy control" symbol (Fig. 2.14).

Funy structure: Modification SIFLOC S5

;:;:> ... :::.::.,:.::.:.: ........................ .> .;:::; 2.;: ,.,., ........................................................ . . . . . . . . . . . . . . . . , . , . , , ... ...................... y,, , :: .::::..;. ::::;:;:;~;;;i:jjjj~~:jji:,jj:,;:j:::;:::::::::~:~:~:::.:~~ : : : ; : : : : ; : ; ; : ; : ; ; ; ; ; : : : > : : ; : ; . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..: ........................ c,:.::>: :::;:~'rFL;.j~~jli$g$ z : ; , : ; ; @ : : : ' . ' : i . . . . . . . . . . . . . . . . . . . . . . . . . j:.:i:.:,;$;;;:' . . . . . :::$ , . ::,:: . . , , ;;,:,;;:,::I:,,;,:::;.;::::,:::2;;::&::::;jl . , . . . . . . . . . . . . .

I N P U T S (I) O U T P U T S ( 0 )

Return Menu s e l e c t o r bar Acceptance Help

Fig. 2.14 User interface with FUZ file option menu

Use the cursor keys to select the required file, and press <RETURN> to enter it. The text

Fuzzy s t r u c t u r e i s r e a d f rom f i l e !

appears briefly before the user interface with the symbol of the selected structure is displayed (see Fig. 2.12).

Entering the As you type the structure name, you overwrite the default name file name "*.FUZ". You need not enter the ".FUZ" extension, it will automati-

cally be assigned to the file. Once you have pressed <RETURN>

Funy structure: Modification SlMATlC S5 SIFLOC S5

to enter the selected name, the symbol of the selected structure will be displayed according to Fig. 2.12.

Changing DBIDX data storage

Press <ESC> after you have read a structure if you wish to change the data blocks (DB or DX) used in that structure. This takes you to the desktop shown in Fig. 2.5 where you may toggle (<F3> function key) between data storage in DB or DX data blocks.

W Ensure that none of the new block numbers has been allocated elsewhere. Note that an alteration only becomes effective after the modified data has been transferred to the PLC. Make sure that FUZ file, SEQ file (if applicable), and the data in the PLC are of the same version.

Editing input/output

Use the <F3> and <F4> function keys to edit the names of inputs and outputs. Pressing <F3> replaces the key set with an input field (Fig. 2.15). If necessary, overtype the default value 0, and enter the number of the input whose name you wish to edit. I e d i t o

Number of t h e newly named i n p u t v a r i a b l e : O Im

Fig. 2.15 Input field for selecting the input name

Type, for example, "2" and press <RETURN>. You will now ob- Editing an tain a new input field (Fig. 2.16) that contains the old input name input as the default entry.

Fuzzy structure: Modification SIFLOC S5

New name for "OUTLET2"(up to 16 chars.):OUTLET2 Im I I

Fig. 2.16 lnput field for the new input name

W Accept the default value if you wish to retain the input name, and merely want to edit the FUZ data block name.

Type the new name (here: "RDIFF") and press <RETURN> to enter. The input field changes (Fig. 2.1 7), and SIFLOC S5 expects a FUZ data block number to be entered. You may now leave the old number (default) unchanged, or enter a new number.

New FUZ DB no. f o r "RDIFF" ( 3 - 255) : 102 1H Fig. 2.17 lnput field for a new FUZ block number

Pressing <RETURN> takes you back to the current user interface (Fig. 2.12).

Editing an Editing an input or a DFUZ data block is identical to editing an output input (see above). The only difference is in the annotation of the

input fields.

Fuzzy structure: Modification SlMATlC S5 SIFLOC S5

Deleting inputloutput

Use the <F5> and <F6> function keys to delete inputs or outputs. It must be observed that the set of rules of completely configured structures will become incorrect and must be adapted. A warning will be displayed (Fig. 2.18), asking you whether you I delete o wish to continue (<Y> key) or return to the current desktop (< N > key).

Fig. 2.18 Warning with acknowledgment options

When you select <Y>, an input field will be displayed in which Entering the you must enter the number of the inputloutput that you wish to number delete (Fig. 2.15).

The specified inputloutput will be deleted when you press Deleting <RETURN>, and an updated version of the screen is displayed.

W Deleting an inputloutput also deletes the allocation of the related FUZ data block number (DFUZ data block number). The integration into the rest of the STEP 5 program must also be corrected.

Membership Functions SIFLOC S5 SlMATlC S5

2.4 Defining the Membership Functions

General This dialog section permits the input and output variables to be defined and, for these variables - range specifications to be made - the default names of the linguistic values to be replaced with

individual names - the number of membership functions to be determined - the samples of the membership functions to be modified

It also permits the graphic representation of the membership functions to be printed at any time.

First of all, we want to explain the terms that are used here: - Range:

This term stands for the process related range of an input variable, and is defined by its minimum and maximum value. Default setting: 0.00 - 100.00

- Linguistic values: Two to seven linguistic values are possible. For example: Very very low (WL), very low (VL), low (L), medium (M), high (H), very high (VH), very very high (WH). Default setting (3 values): L, M, H

- Membership function: The membership function is a polygon with four samples. As the second and third sample may coincide, such a polygon seems to be represented by 3 samples. Each membership function represents a linguistic value (such as "small"). Default setting: 3 polygons

- Truth value: Each membership function has a certain number of truth values. The truth value range goes from 0 through 1.

Procedure The following procedure is recommended for setting the membership function parameters: - Determine the variable (input of the FUZ block)

Membership Functions SlMATlC S5 SIFLOC S5

- Define the range (i.e. determine minimum and maximum values)

- Define the required number of membership functions - Set the sample parameters individually

The "Defining the membership functions" screen is displayed

- after the "Defining the fuzzy structure" menu has been completed and the <RETURN> key pressed

or - after the "Defining the membership functions" function has

been selected from the "Central function menu" that has been opened by the <F10> function key.

Fig. 2.19 User interface after the fuzzy structure has been defined

C79030-88576-C900-Q2

$IFLUG 35 SIEMENS DeEinidg $he membership function$

L M H

Member- s h i p d e g r e e

0

- * \ //'"',

. /

* \ // " ' / /

* \ ,R0' ' /

H\ ''9 / ",

0' * \ / ' /'

* \ * / / "

:,/H' '

0.00 OUTLET1 100.00 ~~~~~~~ R e t u r n V a r i a b l e Range Number Names P o l n t s Hardcopy Menu Con t inue Help

Membership Functions: Variable SIFLOC S5

2.4.1 Selecting Variables

Pressing the <F1 > key selects the "Selecting a variable of the fuzzy structure" menu (Fig. 2.20).

V a r i a b l e

. . . .......

. . . . . . . . . . . . . . . . . . . . . . . .

TEMPKORR I N P U T S ( I ) O U T P U T S ( 0 )

R e t u r n S e l e c t I S e l e c t 0 Menu Con t inue Help

Fig. 2.20 Screen for selecting a variable

Membership Functions: Variable SIFLOC S5

Select input

The <F1 > key is used for selecting the input. Pressing this key replaces the key set with an input field (Fig. 2.21) that shows input "1 " as the default selection. Select I

Number of t h e r equ i r ed input v a r i a b l e : llla Fig. 2.21 Select input" input field

Press <RETURN> to accept the default value, or enter a new number and press <RETURN>. The current screen (Fig. 2.19) is re-displayed. All further parameter selections refer to this input.

Select output

The <F2> key is used for selecting the output. The procedure is the same as for selecting an input.

Select 0

Membership Functions: Range SlFLOC S5

2.4.2 Defining the Range

Range

The input variable range is defined in the next dialog step. Press cF2> to obtain the screen form that is used for specifying the range of values, and a new key set (Fig. 2.22).

Fig. 2.22 User interface for specifying the range of value

Defining the kahge z3f a variabLe

Determining the minimum value

First of all, specify the minimum value. Pressing <F1 > replaces Minimum v a l u e the key set with an input field (Fig. 2.23).

SIFLOC SS

L M H

1

i * \ H

H'-'' \ /

8 * \ 0' '\ /

Member- /' '' I

/ s h i p \(' '\ / , d e g r e e

" \ A' I / * \ / / '\

/' / "

* \ * / ' i '\

0 I-' '

0.00 OUTLET1 100.00

m m m R e t u r n Minimum v a l u e Maximum v a l u e Menu C o n t i n u e Help

Membership Functions: Range SlMATlC S5 SIFLOC S5

Once you have typed the required value and pressed <RETURN> to enter it, the following text appears briefly:

Membership functions are converted!

Subsequently, the value (e.g. "10.00") is entered in the image, and the current key set re-displayed.

Fig. 2.23 Input field of range minimum

Range minimum = 0.00

Determining the maximum value

The <F2> key is used for selecting the range maximum (e.g. "80.00"). The procedure is the same as for selecting the range

Maximum value

minimum.

D

Press <RETURN> to select the next dialog step after you have defined the range.

C o n t i n u e

Membership Functions: Number SIFLOC S5

2.4.3 Number of Membership Functions

To modify the default number of membership functions, press the <F3> key. This displays an input field (Fig. 2.24):

Number

[Required number o f membership f u n c t i o n s (2 - 1) : 51m

Fig. 2.24 Input field for the number of membership functions

Type the required number (here: 5) and press <RETURN> to enter the value. The screen with 5 polylines and the original key set is displayed (Fig. 2.25).

Membership Functions SlMATlC S5 SIFLOC S5

ng the inembership f u h ~ $ i ~ n $

VL M VH L H

1 0 . 0 0 OUTLET1 8 0 . 0 0

~~~~~ R e t u r n V a r i a b l e Range Number Names P o l n t s Hardcopy Menu Con t lnue Help

Fig. 2.25 User interface with 5 membership functions

Proceed with assigning individual names (Section 2.4.4) if you do Next dialog not want to accept the default names of the linguistic values step (here: VL, L, M, H, VH). If you accept the default names, you may now start the dialog of modifying the samples (Section 2.4.5).

Press <RETURN> to select the next dialog step.

Cont inue

Membership Functions: Names SIFLOC S5 SlMATlC S5

2.4.4 Individual Names for Linguistic Values

Default names The linguistic values have default values assigned. The default names of the maximum of seven membership functions are:

- W L (very very low) - VL (very low) - L (low) - M (medium) - H (high) -VH (veryhigh) - W H (very very high)

Names

To replace these designations with individual names, press cF4> and a new key set will be displayed (Fig. 2.26). Depending on the current number of membership functions, function keys from <F1 > to (maximum) cF7> will be inserted. (In our example: 5 keys = <F1 > through cF5>.)

The individual names may not be longer than 16 characters; appropriate abbreviations are recommended.

Return Name1 Name2 Name3 Name4 Name5 Menu Continue Help

Fig. 2.26 Key set for editing names

Typical names and abbreviations are: - POSITIVE BIG (PB) - POSITIVE SMALL (PS) - ZERO (Z) - NEGATIVE SMALL (NS) - NEGATIVE BIG (NB)

Membership Functions: Names SIFLOC S5

The names may be edited in any sequence. Pressing <F1 > replaces the key set with the input field (Fig. 2.27). This field shows the previous name as the default entry. Once the name has been Namel edited and the <RETURN> key pressed, the new name will be entered in the image and the key set is re-displayed for further alterations of names (Fig. 2.26).

I New Dame of linguistic value 'VL" = VL I Fig. 2.27 Input field for new names

Proceed in the same manner with all names that are to be modified. Subsequently, you may press <RETURN> to proceed with the next dialog step, such as "Modifying the samples" (Section 2.4.5).

C o n t i n u e

Membership Functions: Samples SIFLOC S5

2.4.5 Modifying the Samples

To modify the samples, press the <F5> key (see Fig. 2.25). This displays a new key set (see Fig. 2.28).

P o i n t s

R e t u r n S e l e c t i o n o f o n e o f t h e 5 m e m b e r s h i p f u n c t i o n s M e n u C o n t i n u e H e l p

Fig. 2.28 User interface for selecting the membership functions

Selection Press the corresponding key (here: <F1 > through <F5>) to select the membership function. Pressing < F2>, for example, selects the 2nd membership function.

Membership Functions: Samples SlMATlC S5 SIFLOC S5

L

SIEMENS Defining t h e membership functions

VL M VH L H

1

Member- s h i p D e g r e e

0

10.00 OUTLET1 80.00

m m m a R e t u r n S e l e c t i o n o f p o l n t l t o 4 Menu C o n t i n u e H e l p

Fig. 2.29 User interface for selecting the samples

A user interface with a new key set and a colored area of the selected function is displayed (Fig. 2.29). The background color is the same as the color of polygon and name (here: "L').

The triangular form is the default representation of the member- Representation ship functions (polygon). This means that samples 2 and 3 coin- of the cide. They are equally distributed across the definition area membership (Fig -2.29). functions


These membership functions may be of different forms (see Fig. 2.30). You may allocate individual values by modifying (moving) the samples.

2 / 3 2 3 2 3 2 / 3 2 3 2 3 2 / 3 W

A

1 4 1 4 1 4 1 1 4 1 4 I Preferred for left Preferred for right range limit range limit

Fig. 2.30 Valid membership function shapes

Select sample In the next step you select the sample that you wish to modify (eg. with <F3>). The sample location is marked by a triangle on the screen, and represented by a blue output field below the graphic image that displays the precise value (here: 27.50) of this sample (Fig. 2.31).

There are two possibilities for modifying the selected sample:

- Use the cursor keys for horizontally moving the triangle to the Move left or right, thus directly altering the form of the polygon (the

decimal value in the output field is updated as the curve changes).

or Input - Press the "I" key in order to open an input field that permits the

value to be entered directly (Fig. 2.32). Once the decimal value has been typed in, and entered by pressing <RETURN>, the sample position is immediately updated and the function area modified accordingly.


Defining khe- membership fanctiona

VL M VH L H

1

Member- s h i p Degree

0

1 0 . 0 0 OUTLET1 8 0 . 0 0

F j ~ ~ p [ Q I ~ [ g p ~ ~ ~ Return Selection o f p o i n t 1 t o 4 Input Move MenuContlnue Help

Fig. 2.31 User interface for modifying samples


Value = 27.50 +1 I n R e t u r n S e l e c t i o n o f p o i n t 1 t o 4 I n p u t Move Menu C o n t i n u e Help

Fig. 2.32 Input field for direct input of the sample value

Plausibility During sample positioning, the system only permits values or Check curve alterations to be entered that do not cause the graphic re-

presentation to deviate from the permitted shapes (see Fig.2.30).

It is not possible, for example, to move sample 3 so far to the right that is is further to the right than sample 4.

Examples

Further steps

Example 1 : You enter "30" for sample 3, while sample 4 has been positioned at "25". The input field turns back into an output field and shows the highest possible value "25" when you press <RETURN>. The graphic image is updated accordingly.

Example 2: The polygon is of a triangular shape (i.e. samples 2 and 3 coincide). You select sample 2 and, with the cursor key, attempt to move it to the right. The polygon does not change as sample 2 cannot be moved beyond sample 3.

W The parameterized values will be lost if you alter the number of membership functions after you have set the sample parameters.

One by one, you select all samples that you wish to modify, thus defining the form of the membership function. Next, you press <RETURN> to return to the original user interface (Fig. 2.25).

Membership Functions: Samples SlMATlC S5 SlFLOC S5

- In order to process a further function, select cF5> "Points" and use the opened key set for selecting the required membership function. Proceed as described above.

- In order to process a new variable (such as a further input or output variable), press the <F1 > key "Variable" (Fig. 2-25), and proceed according to the description in Section 2.4.1.

- To proceed with configuring the fuzzy structure, press <RETURN> to activate the next dialog step "Defining the rule basis" (Section 2.5).

C o n t i n u e

Defining the Rule Basis SIFLOC S5

2.5 Defining the Rule Basis

General

The IF-THEN rules form the core of a fuzzy control structure. This means that the linguisticvalues that are defined by the membership functions are, according to the existing empirical knowledge, combined in rules of the form

IF "condition" THEN "consequence"

Using the rule editor, these rules may conveniently be entered (see Section 2.5.1).

For each logic dialog step, the system provides you with the corresponding menu. You may set up a maximum of 54 rules in each fuzzy structure. Plausibility checks performed during input pre- vent illegal rules.

Up to 70 statements of the type "input variable" = "attribute" can be combined by AND / OR.

Example: IF OUTLET1 - - L AND RDlFF - M - OR OUTLET1 - M - AND RDlFF - L -

("input variable" = "attribute")

Parentheses permit any priority sequence to be set up.

W ANDing has priority over ORing.

W An expression in parenthesis has highest priority.

Defining the Rule Basis SlFLOC S5

W Restrictions of parentheses: A parenthesis may not be used at the beginning of a rule. Example: (A OR B) AND (C OR D)

The parenthesis at the beginning of the rule is illegal. Remedy: Resolve the parentheses: A AND (C OR D) OR B AND (C OR D)

In the THEN part, you specify the required action in the form of a THEN simple statement "output variable" = "attribute".

Example: THEN INLET1 - VL - ("output variable" = "attribute")

W SIFLOC S5 rejects rules with identical THEN parts, as one rule per linguistic value of an output variable is always enough. Rules with identical THEN parts must be ORed such that they form a single rule.

Defining the Rule Basis SIFLOC S5

No rules

Entry

The work area of the 1 st menu of the entry into the dialog section "Defining the rule basis" is blank if rulesfor this structure have not yet been defined. The message

No rules available

and the key set below are displayed in response (Fig. 2.33).

R e t u r n Move d i s p l a y I n p u t E d i t D e l e t e P r i n t Menucon t inue Help

Fig. 2.33 User interface key set after "Defining the rule basis" has been entered

Rules exist Any existing rules of the selected structure will be displayed. There may not be sufficient space for accommodating all rules of a large set of rules on one screen. In this case, use the keys <"Ar- row up">, <"Arrow down">, cPgUp>, and <PgDn> to scroll through the display. Editing the rule basis is described in Section 2.5.2.

Rule Basis: IF- THEN Rule SIFLOC S5

2.5.1 Entering Rules

Press <F1 > in the entry menu to activate the screen for the "IF- THEN rule"

Next, the key set is replaced with

- an input field that permits the new rule to be selected Rule No.

and, after the number has been entered (default = 1) - an input field that permits the RULE name to be specified. Rule name

Type the rule name (e.g. RULI) in this field and press <RETURN> to enter it.

A new menu will be displayed for each of the following steps, en- abling you to perform the further entries in the correct sequence.

The first editing menu lists the input variables of the selected structure (Fig. 2.34).

An information box above the key set is updated after each step. Information It informs about the number of brackets (showing you immedi- box ately whether the number of opening brackets is identical to the number of closing brackets), and shows the current number of the rule line.

Rule Basis: IF- THEN Rule SlFLOC S5

Fig. 2.34 User interface for selecting the input variable

Selecting the Use the arrow keys to select the required input variable, and input variable press <RETURN> to enter the selected value. The further edit-

ing steps refer to this variable.

SIFEOC $5 -,

The next menu (Fig. 2.35) shows the associated linguistic values in an option box. The rule line is extended, it shows the name of the selected input variable (here: OUTLETI).

F

I n p u t v a r i a b l e s S e t u p o f new r u l e no . 1 (RULE name: RUL1)

1

I n f o

R u l e l i n e :

ReturnMenu s e l e c t o r b a r Accep tance Correction I n s e r t l i n e D e l e t e Help

fi I EMENS Enter an TF-THEN xule ( M D b e f o ~ e QR)


L i n g u i s t i c v a l u e s Setup o f new r u l e no . 1 (RULE name: RUL1) : . : . : i ,~~: : ; :~ : I j : : , ; ; ::::::, ':~.,,;::,:,~;,;:I'.:j,:';:;:Ij;:jl;;:j,Ij~j .:.:;.: , . .:::::., : :.o (. .. :..... ..: ..:.:,. .. ...................................

2 . L

3 . M

4 . H

5 . VH

6 . NOT VL

7 . NOT L

8 . NOT M

9 . NOT H

1 0 . NOT VH

Fig. 2.35 "Linguistic Valuesu option box

The field of the next entry is prepared (inserted) when the rule is being set up.

In the next step you select the required operator (Fig. 2.36), and Operators in the menu which follows you enter the number of open brackets (Fig. 2.37). The default value in this field is "0". This means that Open brackets you may press <RETURN> if the subsequent expression is not to be in parenthesis. Otherwise, enter the number of parentheses you wish to open.

Operators Setup o f new r u l e no. 1 (RULE name: RUL1)

3 . THEN B - Fig. 2.36 uOperators' option box

Rule Basis: IF- THEN Rule SIFLOC S5

Opening b r a c k e t s Setup o f new r u l e no . 1 (RULE name: RUL1)

7 VL l

Fig. 2.37 "Number of open brackets" input field

According to the specified number, the brackets will be inserted in the field provided in the rule. If you enter a number >8, the space provided proves insufficient, and a bracket with a multipli- er will show, for example: "( 9x) ['l.

Input variables Setup o f new r u l e no . 1 (RULE name: RUL1)

1. OVTLET2 I OUTLET1 # VL l 2 . R D I F F =I 1 1 rI 1 3. F I L L LEVEL

Fig. 2.38 "Input variables" option box

Proceed with the next steps accordingly, until your IF rule has completely been set up. The last operator is THEN. Select the "output variable" from the option box and, from the subsequently displayed box, the required "linguistic value". Now, the rule is complete. The subsequently displayed screen may, for example, look like the one in Fig. 2.39.

SIMATIC S5 Rule Basis: IF-THEN Rule

SlFLOC S5

bracket s :

bracket S :

Rule l i n e :

SIEMENS

Setup o f new r u l e no. 1 (RULE name: RUL1)

Fig. 2.39 Typical user interface with complete rule

This, and the previous key sets, contain the "C" (correction) key. The last input to have been made is canceled and the previous

board. dialog step resumed when you press the letter "C" on your key- Correction

1 [

OR I L

Press the "C" key again to display the key set shown in Fig.2.34. Pressing the "C" key repeatedly takes you further back in the dialog.

I n f o

Cont lnue Correction

OUTLET1 P: VL

R D I F F n L

F I L L LEVEL P H

I N L E T 1 P VL

Rule Basis: IF- THEN Rule SIFLOC S5 SlMATlC S5

This operation does not delete operands or operators. They are merely blanked out and will be re-activated when you press <RETURN>. Your entries always become valid jn the last white field of the rule. Here you may perform alterations or enter values.

Pressing the <RETURN> key either displays a new key set (Fig.2.41) or an error message (e.g. the one in Fig. 2.40):

Continue

Fig. 2.40 Message after a rule has completely been set up

The message remains on the screen for a while before the previous key set is re-displayed (Fig. 2.39).

The created rule is valid if the new key set (Fig. 2.41) is displayed instead of an error message.

Discard Accept Help I Fig. 2.41 Key set after a rule has completely been set up

Further procedures:

When you press < E X > , a warning (that must be acknowl- edged) appears that tells you that your data will be lost (Le, the

Discard entire rule you have been creating will be deleted).


Press the <RETURN> key if you wish to enter the rule you have just finished. The same screen and key set will now be displayed as upon the entry into the dialog section (Fig.2.33). All previously established rules will be output too (you may have to scroll the Accept

screen to view the entire set of rules). This key set enables you to

- enter further rules (Section 2.5.1)

- edit rules (Section 2.5.2)

- delete rules (Section 2.5.2) - print rules (Section 2.5.2)

- process the "implicit zero rule" (Section 2.5.3)

2.5.2 Editing, Deleting, and Printing Rules

Editing rules

Pressing <F2> displays an input field in which you enter the number of the rule that you wish to modify. The further procedure is described under "Entering rules". E d i t

Deleting a rule

Pressing cF3> displays an input field in which you enter the number of the rule that you wish to delete. The default value in

played when you enter the default value. this field is "0". Nothing is deleted and the previous key set is dis- ,,,,,,

Before a rule is deleted, SIFLOC S5 asks you whether you really want to delete rule X. Enter Y(es) or N(o) to acknowledge this prompt.

Printing a rule

Pressing <F4> displays the following input field (Fig. 2.42):

P r i n t

Rule Basis: IF- THEN Rule SIFLOC S5 SlMATlC S5

N o . o f r u l e t o be p r i n t e d ( 0 = a l l ) : O IH

I I

Fig. 2.42 Print job input field

Type the number of the rule that you wish to print. The default value in this field is "0". All existing rules of this structure will be printed if you press <RETURN> to accept the default setting. The report looks like this (Fig. 2.43; typical rule):

Fig. 2.43 Typical report: Printout of a rule

Rule Basis: Zero Rule SlMATlC S5 SIFLOC S5

2.5.3 Implicit Zero Rule

General

The linguistic values of the fuuy structure input variables subdi- Why "implicit vide the whole operation area into several smaller fuzzy work zero rule'? areas (sub-areas).

Normally, all sub-areas in which the fuzzy structure is expected to output "0" or another constant value must also be described. Selecting the "implicit zero rule" saves creating these "zero rules" which sometimes can be very long. In defuuification, the (approximately) same degree of membership becomes effective as in the case of an explicit description of the inactive response of the fuzzy structure.

Using the implicit zero rule

Pressing the <RETURN> key after the IF-THEN rules have Completing been completed takes you to the next dialog step that permits the by "implicit set of rules to be completed by the "implicit zero rules". The fol- zero rule" lowing key set is displayed (Fig. 2.44):

I R e t u r n I m p l i c i t z e r o r u l e s Menu C o n t i n u e Help I Fig. 2.44 Key set for completing the set of rules

Pressing <F1> displays a graphic representation of inputs, blocks, and outputs (see Fig. 2-46), and an input field (Fig. 2.45). Enter the output variable to which you want to apply the "implicit zero rule" in this input field.

Rule Basis: Zero Rule SlFLOC S5 SlMATlC S5

Implicit zero rules for output variable no. (0 - none) : 1 Fig. 2.45 Input field for defining the output variable

Selecting the The number of the first output variable that is to be edited is output shown as the default setting of the input field. You may either en- variable ter a different number if you do not wish to apply the "implicit zero

rule" to the suggested variable, or enter "0" if you want to skip the entire dialog step and to continue with inference and defuuification (Section 2.6).

Allocating by Once you have pressed <RETURN> to enter the number, an op- option menu tion menu is displayed on the desktop (Fig. 2.46). In addition to

the line "No implicit "zero rule" required", this menu contains a list of all linguisticvalues of the selected output in the form of selector bars. To apply the "implicit zero rule" to one of these values, either use the arrow keys to select one of the bars before you press <RETURN>, or perform an immediate selection via the function keys.

Rule Basis: Zero Rule SIFLOC S5

I I 1. I m p l i c i t " ze ro r u l e " f o r l i n g . v a l u e VL 2 . I m p l i c i t " z e r o r u l e " f o r l i n g . v a l u e L 3. I m p l i c i t " z e r o r u l e " f o r l i n g . v a l u e M 4. I m p l i c i t " z e r o r u l e w f o r l i n s . v a l u e H I I 5 . Imp l l c l : " zezz z c l e " f o z l ~ n g . v a l _ e VZ 6 . No i m p l i c i t Uzezz z c l e " req.~ired

SIFLVC SS S XEMENS

Fig. 2.46 User interface for selecting the "zero rule' menu

I n p u t s ( I ) DB no . R u l e s DB no. O u t p u t s ( 0 )

3 . F I L L L E E L

ando or^ .... R e t u r n Menu s e l e c t o r b a r Accep tance D l r e c t selection Help

Set of rules compXetion by "zero ru5eSn

Once you have selected the "implicit zero rule" for a linguisticvalue of the current output value (here: INLETI), the key set and the option menu disappear, and the input field required for defining the next output variable is re-displayed.

Proceed in the same manner for assigning the "implicit zero rule" Further output to further outputs. variables

Rule Basis: Zero Rule SIFLOC S5 SlMATlC S5

No further If you do not require a further "implicit zero rule", mimplicitzerO - enter the figure "0" in the input field (Fig. 2.45). rules "

- select "No implicit "zero rule" required" from the option menu (Fig. 2.46) to return to the input field. Enter "0" here to proceed to the next dialog section.

lnference and Defuzzification Method SlFLOC S5

2.6 lnference and Defuzzification Me- thod

The membership functions and rules created in the previous dia- Defuuification log sections must be converted into representative numeric val- Method ues (output variables). This is done in the DFUZ block. Different inference and defuuification methods are available to perform this conversion:

- MAX-MIN inference and exact center-of-gravity defuzzification

For further explanations of these methods please refer to the basics in Section 1.3.3.

Press <RETURN> to continue.

DFUZ Weighting Factors SIFLOC S5 SlMATlC S5

2.7 DFUZ Weighting Factors

You may enter a weighting factor (between 0.0 and 1 .O) for each truth value input of a DFUZ block. This permits the rules that cor- respond to these inputs to be weighted differently or to be activated and de-activated.

Once you have entered this dialog section, a screen with the message

DFUZ weighting

and the following key set (Fig. 2.50) will appear on the screen:

Return Weighting factor Menu Continue Help

Fig. 2.50 Key set for activating DFUZ weighting

Pressing the <F1 > key displays the screen with the graphic representation of the current controller structure (see Fig. 2.49, upper part) and an input field (Fig. 2.51).

DFUZ weighting for output variable no. ( 0 = none) : 1

Fig. 2.51 Output variable input field

Selecting the The number of the first selectable output variable appears as the output default setting. You may either press <RETURN> to accept it, or variable enter a different number. The screen with a graphic representa-

DFUZ Weighting Factors SIFLOC S5

tion of the selected DFUZ block will subsequently be displayed (Fig. 2.52).

Enter "0" if you wish to skip the rest of the dialog and to continue with the next dialog section "Fuzzy data file and documentation".

STEMENS DFUZ weighting

D F U Z DB no . : 2 0 1

a B m m m a R e t u r n S p e c l f y l n g one o f t h e 5 w e l g h t l n g f a c t o r s Menu C o n t l n u e Help

Fig. 2.52 User interface with a graphic representation of the current DFUZ block

The graphic representation of the DFUZ block shows the mem- bershipfunctions, their weighting factors, the names of the RULE blocks, and the name of the current output.

DFUZ Weighting Factors SIFLOC S5 SlMATlC S5

Entering The number of displayed function keys depends on the number weighting of the current weighting factors and is equal to the number of in- factors puts. The <F1 > key permits the first weighting factor to be

edited, <F2 > is associated with the second weighting factor, etc. (Fig. 2.53). The default value of a new configuration is "1.0".

Weighting f a c t o r 0.0 ... 1 .0 f o r DFUZ input 1 : 1.00

Fig. 2.53 Weighting factor input field

The edited weighting factor is entered in the graphic image immediately after the <RETURN> key has been pressed.

Next output Press <RETURN> to proceed to the next output after you have entered the weighting factors of an output. The input field (Fig. 2.51) is re-displayed, and you may select the next number.

To the next A further input field is not displayed after all outputs have been dialog section processed. Press <RETURN> to exit the dialog section "DFUZ

weighting". The system automatically moves to the section ''Fuzzy data file management" (Section 2.8).

Funy Data File Management SIFLOC S5

2.8 Fuzzy Data File Management

This dialog section permits complete information about a fuzzy structure

- to be stored (saved) in an ASCll file,

- to be displayed on the screen,

- to be printed.

The fuzzy data file is a part of the user documentation.

Using a text editor (e.g. EDIT in MS-DOS), you may edit a FUZ file at any time (add comments, for example).

W You must not modify the format, e.g. insert control characters, otherwise the data might no longer be interpreted correctly. Moreover, any texts you add yourself are over- written by SIFLOC S5 when the FUZ file is updated!

At the beginning, the data file management screen shows the Entry message

Fuzzy data file management

and the following key set (Fig. 2.54):

I Return Save file View file Print file Menu Continue Help 1

Fig. 2.54 Data file management key set

Press one of the three function keys and you will have an input Entering a field displayed in which you may enter the required file name (Fig. file name 2.55). The ".FUZn file name extension need not be entered. Spec- lfying a different extension (e.g. ".BAKn or ".OLD1') does not have any effect. The file will always be saved under ".FUZN. Exception: An existing file (see below).

Fuzzy Data File Management SIFLOC S5 SlMATlC S5

F i l e name [up t o 8 cha rac t e r s , without '.FUZ") : IH I I

Fig. 2.55 File name input field

Saving a file

To save the current file, press <F1 >, type the file name in the input field (Fig. 2.55), and press the <RETURN> key to enter it. The following text is briefly displayed at the bottom of the screen:

Fuzzy s t r u c t u r e has been w r i t t e n t o f i l e

The following message appears if the file name already exists in the fuzzy file list:

Caution! Name e x i s t s . Overwrite? Y, N .

- If you enter 'IN" (no), the last key set (Fig. 2.55) is displayed and you can enter a new file name.

- "Y" renames the existing file. This means that the extension ".FUZ1' is changed to ".BAK". The file is then no longer kept in the FUZ file list. The new file has the extension ".FUZ" and is entered in the file list (see Fig. 2.14). The following message is briefly displayed at the bottom of the screen:

Old f i l e has been saved a s BAK f i l e and new FUZ f i l e c r e a t e d .

The operator desktop with the original key set (Fig. 2.54) is re- displayed after the file has been saved.

W ASCIl files with the extension ".FUZ1' that have been created with SIFLOC S5 must not be write-protected. Write-protected ".FUZ" files may cause a program crash when they are handled by SIFLOC SS.

Fuzzy Data File Management SlMATlC S5 SIFLOC S5

m Viewing a file

Press <F2> to display the contents of a FUZ file on the screen. Type the file name into the input field (Fig. 2.55) and press <RETURN> to enter it. The file content is output on the operator desktop. The inserted keys permit the contents to be scrolled (Fig. 2.56). Only keys that are required for the current representation are output (i.e. the keys 'Arrow up" or "PgUp", for example, will not be output at the top of the list).

R e t u r n Move display

Fig. 2.56 Keys for vertically scrolling the screen content

The report image on the screen is identical to the printed report. Please refer to "Report contents and explanations" for details.

m Printing a file

Press <F3> to output the FUZ file on a printer. As long as the printout is in progress, only the <ESC> key is shown on the screen, permitting the printout to be interrupted if required. The original key set (Fig. 2.54) is displayed once the printout has been finished.

v Operator input to the program is only possible after a wai- ting time of approximately 30 seconds has elapsed if printer output is interrupted (due to an "end of paper" condition for example)


Report contents and explanations

Report Header

Listing

The report starts with the report header. The header contains:

- File name (*.FUZ) - Date when the file is created

- Space for any text. This means that comment lines may be inserted with a text editor.

The header is followed by a list of all names and parameters. Comment lines are identified by brackets "{" at the beginning of a line. - Process-related name of the fuzzy structure (project name)

e.g. TEMPKORR

- Number of input variables, number of output variables e.g. 3 2 = 3 input variables and 2 output variables

- Names of the input variables e.g. OUTLET^

RD I FF F I L L LEVEL

- Names of the output variables e.g.: INLETI

INLET2

- MIN and MAX value of each input variable e.g. of three input variables:

- 2 . 0 0 0 0 0 0 0 0 E + 0 1 2 . 0 0 0 0 0 0 0 0 E + 0 1 (Min = -20, Max = +20)

- 1 . 0 0 0 0 0 0 0 0 E + 0 2 5 . 0 0 0 0 0 0 0 0 E + 0 0 (Min = -100, Max = +S)

- 3 . 1 0 0 0 0 0 0 0 E + 0 1 1 . 8 0 0 0 0 0 0 0 E + 0 1 (Min = -31, Max = +18)

- MIN and MAX value of each output variable as for input variables

- Number of input variable membership functions e.g. of three input variables: 5 3 2

- Number of output variable membership functions e.g. of two output variables: 7 3

Fuzzy Data File Management SlMATlC S5 SlFLOC S5

- Abscissavalues of the n samples of the 1 st membership function of the 1st input variable (n = number) e.g. of four samples:

-1.50000000~t01 (value = -15.0) 0.00000000~+00 (value = 0.0) 5.00000000~+00 (value = +5.0) 1.45000000~+01 (value = +14.5)

The abscissa values of all other membership functions of the 1 st input variable follow, before all abscissa values of the 2nd input variable, etc.

- Abscissavalues of the n samples of the 1st membershipfunc- tion of the 1 st output variable as for input variables The abscissa values of all other membership functions of the 1st output variable follow, before all abscissa values of the 2nd output variable, etc.

- Linguistic values of the 1 st input variable e.g.: VL

L

M H VH

These values are followed by the linguistic values of the other input variables.

- Linguistic values of the 1 st output variable e.g.: NB

NS z P S P B

These values are followed by the linguistic values of the other output variables.

- Weighting factors of the l st output variable e.g.: 5. oooooooo~-01 (= factor 0.5)

1.00000000~t00 (= factor 1) 8.00000000~-02 (= factor 0.08)

These values are followed by the weighting factors of the other output variables.


- Defuuification method of the n output variables (n = number) e.g. of three output variables: 2 1 3 The figure specifies the method in the option menu: 2 = MAX-MIN inference and approximate center-of-gravity defuzz. 1 = MM-MIN inference and exact center-of-gravity defuzzification 3 = MM-PROD inference and rapid center-of-gravity defuuification

- Zero rule parameter of the n output variables (n = number) e.g, of three output variables: 2 0 5 2 = 2nd parameter of the linguistic values (NK) of the 1st output variable 0 = No implicit zero rule of the 2nd output variable 5 = 5th parameter of the linguistic values (PG) of the 3rd output variable

- Number of rules e.g.: 3

- Number of input variables combined in each rule. e.g. for three rules:

5 3 5

- Rule l e.g.: I F I (i) = LW ( k ) / op. pa r .

2 2 THEN O ( i ) = LW(k)

Funy Data File Management SIFLOC S5

- Figures below "I" = input variable no. (1 = OUTLET1, 2 = RDIFF, etc.) Figures below "0" = output variable no. (1 = INLET1) Figures below "LW" = number of the linguistic value (5 = VH, 2 = L, etc.). The other rules follow (two more in our example).

- Names of the FUZ blocks e.g.: 101

102 103

- Names of the RULE blocks

- Names of the DFUZ blocks e.g. 201

202

- DB or DX data blocks, e.g.: For DX 1

- FUZ FB number, e.g. 113

- DFUZ FB number, e.g. 116

- APP FB number, e.g. 150

- RULE FB number, e.g. 151

- RULE data block number, e.g. 106

- Interface number, e.g. for COM1: 1

- File name of an SEQ file that can be edited with the STL batch compiler, and contains annotated instructions. e.g.: TEMKORAO.SEQ

Off -line Analysis SlFLOC S5 SIMATIC S5

2.9 Off-line Analysis

The off -line analysis permits the static response characteristics of the configured fuzzy structure and its response in a control loop to be investigated beforehand.

Fig. 2.57 User interface used for performing off-line analysis by simulating the response characteristics

P -

The screen with the graphic representation of inputs and outputs is displayed when you select the dialog section "off-line analysis".

Off-line analysis of t h e fuzzy s t r u c t u r e SXFLDC 55

DB no. Ru les DB no. O u t p u t s ( 0 )

R e t u r n 1 / 0 view Curve Hardcopy Menu Con t lnue Help

Off -line Analysis SlMATlC S5 SIFLOC S5

Bars on the connecting lines between the inputs/outputs and Value blocks visualize the response characteristics. The lengths of representation these bars continually change (Fig. 2.57). The small vertical line represents the origin (0). This means that a bar that stretches to the right of this line represents a positive value, while a bar to the left indicates a negative value. The related behavior of the individual rules is shown by a brown filling of changing extension.

The key set contains three keys that permit the different off-line Functions analysis functions to be activated. These keys are:

- 110 monitoring: Instantaneous value monitoring of the fuzzy structure (Section 2.9.1)

- The family-of-graph representation of the "Graph" fuzzy structure (Section 2.9.2).

Off-line Analysis: Instantaneous Value Monitoring SIFLOC S5

2.9.1 lnstantaneous Value Monitoring of the Fuzzy Structure

The "Instantaneous value monitoring" function enables you to specify input values you are interested in. SIFLOC S5 calculates the output values of these values, represents them as bars, and marks the structure rules concerned.

1/0 view

Press <F1 > in the basic off-line analysis menu (Fig. 2.57) to have an input field (Fig. 2.58) displayed. This input field refers to the 1st input value, and contains its range for information purposes. The entered numeric value must be inside this range. The value appears as a bar in the graphic image immediately after <RETURN> has been pressed to enter the specified value.

D e f a u l t v a l u e (10 .00 , . . . , 8 0 . 0 0 ) f o r I1 = 10.00

- -

Fig. 2.58 Input field for input value specification

Further In the next step, the input field for the next input value is dis- inputs played, etc., until you have entered the relevant values of all in-

puts. All values will then be updated in the graphic image, and the following key set (Fig. 2.59) is displayed:

Return Defuzz Bar/number I values I no. Decr. Incr. Menu Continue Help

Fig. 2.59 "Instantaneous value monitoring" key set

Displaying the defuzzification polygon

Press <F1 > to activate the "Defuzzification" monitoring function. This displays the following new key set (Fig. 2.60):

Defuzz

Off-line Analysis: Instantaneous SIFLOC S5

I R e t u r n Output Menu C o n t i n u e Help I

Fig. 2.60 Select output for defunification function" key set

Press <F1 > to activate an input field (Fig. 2.61). Type the number Select of the relevant output in this field, and press <RETURN> to enter output the value.

Number of relevant output variable: 1

Fig. 2.61 Input field for the number of the relevant output variable

The "defuzzification polygon" of the selected output variable is displayed (Fig. 2.62).

Off-line Analysis: lnstantaneous Value Monitoring SIFLOC S5

Fig. 2.62 User interface with the defunification polygon of the selected output variable

j j j ;,, jj :,.,: :: j:.; :,:, :.:; ;:;,;,,::: I,;; :: ; j j , ; , : $ , ;$ j j $ j j j j : j j j j : j j : j j j j j j j j j : j : j j j j j j j : j j j j j : ; : , ~ j j j i j ~ j j j : : I l j ; ~ : :~ ;~ j ; ;~ l i j I j i ~ I j~~ ; : j j iii?:.:ij.j 2;::; ~~:i$:$,i;;;jj(i:jjIjj,b'&:~~dii'$~f:$:i~~~gg~~#~~y~~m:;;~,~ !$;;;: jj,,:,; ,;; ............................. ..;. : . ,.,.,: ......., ((.(,. ..., :., ,.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . . . .

The graphic image shows this membership degrees of the parti- cipating rules, the polygon area, and the associated ouput value in numeric and bar representation. The output value has been determined by calculating the area's center of gravity (visualized by the black triangle below the polygon area).

I$i[;::;$ijjjjjjjj;jj;;jjj;jj:::j:j '. .:,:. ::::,:

);zgzpg~g::;;$g$ . . . . . . . . . . . . . . . . . . . .... .., . . , . . . . . . . . . . . . . . . . . . . . . .

Pressing < ESC> takes you back to the previous screen (see key set, Fig. 2.60). Here, you may continue by selecting another output value.

0.00

0.00

0.00

1.00

0.00 100.00

F1 0

R e t u r n Menu C o n t i n u e He lp

Off-line Analysis: Instantaneous SlFLOC S5

Pressing <RETURN> takes you back to the original instantaneous value monitoring screen (Fig.2.59).

Toggling between numeric and bar representation

When monitoring instantaneous values, toggling the display of these values between numeric and bar representation may be of interest. You can do this by pressing the <F2> key.

The screen with the instantaneous value monitoring key set forms the initial situation (Fig. 2.59). Every time you press the <F2> key, the display changes between the two representation B ~ ~ , ~ ~ ~ ~ ~ ~ types (numeric and bar representation). The bar representation is the default representation.

Representation with modified input values

In order to demonstrate the effect on output values andlor the rules involved, you may vary the values of all input variable.

The screen with the instantaneous value monitoring key set forms the initial situation (Fig. 2.59). Pressing the <F3> key dis-

you wish to use for further calculation. This value is immediately plays an input field. Enter thevalue of the 1st input (Fig. 2.58) that , values used for updating the graphic representation. Continue in the same way with all other input values. After the last input value has been processed, the previous screen with key set (Fig. 2.59) and updated graphic image will be re-displayed.

Varying an input value

The "I no." function enables you to monitor the effect on the output values andtor the rules involved, while you vary the value of a specific input variable.

The screen with the instantaneous value monitoring key set forms the initial situation (Fig. 2.59). Pressing the <F4> key dis-

you wish to vary in this field. plays an input field. Enter the number of the input variable that I no

Off-line Analysis: Instantaneous Value Monitoring SIFLOC S5 SIMATIC S5

No. of input signal to be varied: 1

Fig. 2.63 input field for the number of the varying input variable

After <RETURN> has been pressed, the following message appears briefly at the bottom of the screen:

Use arrow keys to vary input value now

Use the cursor keys to decrement (arrow left) or increment (arrow right) the value. This variation, however, is only possible inside the range that has been specified for this input.

Exiting instantaneous value monitoring

Pressing <RETURN> or <ESC> takes you back to the off-line analysis screen (Fig. 2.57).

Off-line Analysis: Family of Graphs SIFLOC S5

2.9.2 Family of Graphs of the Fuzzy Structure

The family-of-graph representation shows the static non-linear response characteristics of a fuzzy structure. Due to the two-dimensional representation you can only monitor the response characteristic between one input and one output, you can also vary a second input variable as a family parameter across the entire range. All other input variables, however, must be set to constant values.

Each family parameter value yields a non-linear curve that represents the operating-point-dependent gain of the monitored channel. The overall result consequently is a family of graphs.

Press <F2> in the basic off-line analysis menu (Fig. 2.57), and the screen of the family of graphs is displayed (Fig.2.64).

Curve

Off-line Analysis: Family of Graphs SlFLOC S5

Fig. 2.64 User interface for family-of-graph output

Procedure

SfELOC: S5 STEMENS

- Relevant input variable: Press c F1 > to display an input field, type the corresponding number in this field, and press <RE- TURN> to enter this value. Enter the lower range limit in the next field. This opens another field in which you enter the upper range limit. The background of the selected output turns yellow in the graphic representation. To represent exactly one curve of the family, enter lower range limit = upper range limit.

I N P U T S ( I ) DB no. R u l e s DB no. 0 U T P U T S ( 0 )

R e t u r n I n p u t Ou tpu t F a m l l y I I v a l u e s Num Curv Menu C o n t l n u e Help

Fwnily of graphs of the fuzzy s t w b k u r e

Off-line Analysis: Family of Graphs SlMATlC S5 SlFLOC S5

- Relevant output variable: Press <F2> to display an input field, then proceed according to the description of "input variable". The background of the selected output turns yellow in the graphic representation.

- Relevant input variable for family parameters: Press <F3> to display an input field, then proceed according to the description of "input variable". In the graphic, the selected input is represented with a red background.

- Constant values of non-varying input variables: Press <F4> to display an input field, and type the constant value of the next input value into this field. If there are any further inputs, the next field for the next input variable will be displayed when you press <RETURN> to enter the current value.

- Number of characteristic curves: Each family parameter has a characteristic curve allocated. Pressing the <F5> key opens an input field in which you may type the required number of individual curves. When you press <RETURN> to enter this value, a screen with the (still empty) field of the characteristic curves (Fig. 2.65) is displayed. The parameter field is next to the field of the characteristic curves.

Off-line Analysis: Family of Graphs SIFLOC S5 SlMATlC S5

Other input values:

Fig. 2.65 User interface for family-of-graph representation

- Curve output: A characteristic curve is output every time you press <F1 >. The numeric value of each drawn characteristic curve is displayed in the same color in the parameter field under "Family parameters". Instead of explicitly outputting each individual curve, you may display all other curves by pressing <RETURN> after you have invoked the first curve. A new key set (Fig. 2.66) is displayed once all characteristic curves have been output.

Off-line Analysis: Family of Graphs SlMATIC S5 SIFLOC S5

R e t u r n Menu C o n t i n u e H e l p

Fig. 2.66 Key set after all characteristic culves have been output

Pressing <RETURN> displays the basic "Off-line analysis" Exiting the menu (Fig. 2.57). Pressing cESC> takes you back to the fami- family of ly-of-graphs output screen (Fig. 2.64). graphs

On -line Monitoring SIFLOC S5 SlMATlC S5

2.1 0 On-line Monitoring

This dialog section, which not only deals with on-line monitoring, features two function groups:

1. Functions that permit the link parameters to be selected 2. On-line monitoring

2.1 0.1 Link Parameter Setting Functions

Skip para - In the first step, an option menu is displayed that permits the link meter setting parameters to be set (Fig. 2.67). If you do not want to set the link

parameters, you may select <F8> (or <RETURN>, as "Contin- ue" has already been selected in the default setting) to proceed to the next step (the "On-line Monitoring, Section 2.10.2).

On -line Monitoring SlMATlC S5 SlFLOC S5

Fig. 2.67 Screen with data transfer selection menu

Data transfer between PG and PLC is performed via the serial Serial COM1 interface. The default value is consequently "1" if you Interface press <RETURN> to activate the menu item "Selection of the serial interface" (Fig. 2.67). With a PG, simply press <RETURN> to acknowledge. In some cases you can also use the second interface of a PC for data transfer.

. . . . . . . ...................... . .. :.: .:.:.:.: : : : .::.::.:.

i:::$$g'~gx:;:;g$; (.? .............

. . . . . . . . . . . . . ....................... ..........: ,...:..:.:.:.:,:,:, ...?............ ............ i$&~rn~%iii i i i i i i i i i . . . . . . ........... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Press <F2> or <RETURN> to start transferring your entire fuzzy

1. Selecting the serlal lnterface

2. Transferring to the PLC

3. Saving as SEQ file

4. Activating central menu

... R e t u r n Menu s e l e c t o r b a r Acceptance D i r e c t s e l e c t i o n Help

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....... .......... ....... .... ..... ........ ::j:;:j:j:::l: ,,;:, :;;;::;,; ,;:,:,,, ;::,;:.:::,;; :.,:,,:: ; :.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . :, (. .: .:., : .: : :.:.:.:.:.: :...: :.... ................................................................ ;~iiliiiiil;i;~$$@i:::::j$,jB:rn :'.;i i: :, ;:'.:, :, ':;i ;:i'i&q;i::'i$,ufic~i$~$$(i::$;:iiii::#$j~@:jj~;;.: ;:$ . . . . . , , . : . . ; . . o . . .............................................................................. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

On -line Monitoring SIFLOC S5

application to the PLC. This transfers the APP and RULE function blocks and all DB or DX data blocks used to your target CPU. This procedure takes only a few seconds. The system enquires if you really want to transfer data (Fig. 2.67 a):

Transfer application to the PLC?

Fig. 2.67 a Data transfer input field

W The S5-155H system only permits data blocks to be loaded into the CPU that, using COM 155H, have previously been entered in the DX 1 configuration data block and have thus been enabled (cf. COM 155H Programmer Soft- ware Manual, Chapter 3.2 "Transfer Data").

Press <Y> to acknowledge or cN> to abort. Typically you will now receive the message:

Transfer successfully terminated!

This message remains displayed until you press <RETURN> for acknowledgment. The following message is displayed if, for example, a block of the same number exists in the PLC:

FUZ DB no. 11: Block exists in the PLC. Overwrite?

Each transfer must then positively be confirmed with <Y>. Ente- ring <N> displays the message:

Transfer is aborted.

The following message is displayed if, for example, the memory space proves insufficient for the transfer:

RULE FB no. 1 1 4 : Insufficient memory space in the PLC. Compress?

Transfer is resumed after the compression process has been terminated.

On -line Monitoring SIFLOC S5

Create a SEQ file and store it under a name that consists of any SEQ File six characters and the extension AO.SEQ if you need additional documentation or if you do not want to transfer your fuzzy application directly to the PLC. Press <RETURN> and enter, for example, TEMKOR in the input field which then appears (Fig. 2.67b).

Fig. 2.67 6 SEC? file name input field

Use the STL editorlbatch compiler to translate the SEQ file into an S5D file, and STEP 5 to transfer this file to the PLC at any time. You may also employ the SEQ file as an annotated source for documentation purposes.

Press <F5> now to change over to on-line monitoring.

On -line Monitoring SlFLOC S5

2.1 0.2 On-line Monitoring

Fig. 2.68 User interface for on-line monitoring

S3EK3VS

Functions of the <F1 > through <F6> keys

Select c F1 > to toggle between bar representation and numeric output.

I n p u t s ( I ) DB no. R u l e s DB no . O u t p u t s ( 0 )

~~~~~ R e t u r n Bar/number Act Defuzz Curve Menu C o n t i n u e Help

On-She, mon,d,toxing oZ t h e f u z z y s t ruc ture

Select cF2> to activatetde-activate screen updating. De-activate updating, for example, if you wish to have an extended look at a specific representation.

SIFTJQC


Select <F5> to monitor the defuzzification process of a specific output variable (see Section 2.9.1, defuuification polygon, Fig. 2.62).

Select <F6> to produce a plot of the required time-variant variables of the fuzzy structure.

W The best data updating rate possible will be 200 ms, provided that

the CPU loading tolerates it

the PG performance is adequate (e.g. PG 770) the number of data items is not too excessive

This must particularly be taken into account when curves are represented.

On-line monitoring is only in a position to gather intermediate values if the control cycle is shorter than 200 ms.

Due to the sampling theorem, these values cannot be used for representing the U signal shape! The same applies to long-term curve representation: Interpola- ting the curve between two measured values by a straight line sometimes provides incorrect representation of the & shape.

Curve representation

The screen with a table and the key set for selecting the individual table rows (Fig. 2.69) is displayed.

On -line Monitoring SlFLOC S5 SlMATlC S5

R e t u r n Curve 1 Curve 2 Curve 3 Curve 4 Menu C o n t i n u e Help

Fig. 2.69 User interface with a table of the monitored variables

Select curve Use <F1 > through <F4> to select a curve from the table. The from the table script of the current curve is light-blue, all other entries refer to

this table row. A new key set (Fig. 2.70) is displayed.

On -line Monitoring SlMATlC S5 SIFLOC S5

R e t u r n I n p u t O u t p u t G e n e r a l Delete Menu C o n t i n u e H e l p

Fig. 2.70 Key set for selecting the required variables

Use the <F1 > through <F3> function keys to define the variable Define that you wish to represent by the curve. variables

Press <F4> to delete all values of a curve. Enter the number of Delete curve the curve (1 through 4) in an open input field, and press values <RETURN> to delete the entries.

In the further dialog press <F1 > to define afuzzy input, <F2> to define a fuzzy output, or <F3> to define a general variable.

After F1 > or F2> has been pressed, the input or outputs, re- spectively, of the fuzzy structure are displayed next to the table (see Fig. 2.71). Use the arrow keys to select the required input1 output, and press <RETURN> to enter the values of this variable in the table.

The "General variable" requires additional specifications to be made. One by one, input fields will be displayed that permit further entries to be made. Pressing the <RETURN> key enters these values in the table (example: Curve 2 in Fig. 2.71).

On -line Monitoring SIFLOC S5 SlMATlC S5

-

Input v a r i a b l e s

1. OUTLETS1 . . . . . . . . .i,i.ji~:i::.::&$$g$ . . . jjjjjj j j j j j j j j : : 1 : :.I:.: : . . . . . *.: : : - 3 . F I L L LEVEL

and

Menu s e l e c t o r bar Acceptance Help

Fig. 2.71 User interface after "Curve 3" and <F1 > key "Input" have been selected

The key set shown in Fig. 2.69 is displayed after you have entered the values of the required curve. To display the curves, press <RETURN> to change the screen. The curve representation diagram and a new key set will then be displayed (Fig. 2.72).

On -line Monitoring SlMATlC S5 SIFLOC S5

Fig. 2.72 User interface with cuffe representation

SIEMEMS Carve represamkaeiofi v - 75.00 5.0

The time axis scale below the curve diagram depends on the time Time axis window, and is continuously updated according to the actual and time time. The actual (most recent) time is shown at the right edge of the diagram. This means that the curves run from the right to the left. In a time window of 1 minute, for example, the value at the left-hand chart margin is thus one minute older than the one at the right-hand margin.

100.00

60.00, 80.00

45.00, 60.00

30.00, 40.00

15.00, 20.00

0.00 0.00 14:18:18 14:18:28 14:18:38 14:18:48 14:18:58 14:19:08 14:19:18

-4 l,RDIFF -1 m rzEzq on Time window : 1-1 Time : -1

mHam Return 1 min 8 mln 2 h 24 h Meas. a x i s Hardcopy

-L----- - _ - - - - - - - -- _ .-

I I I I I

, 3.0

, 1.0

.,-l. 0

--3.0

-5.0

On -line Monitorina

Time window Use the keys <F1 > through <F4> to define the curve display time window (1 min, 8 min, 2 h, or 24 h).

Measuring The <F5> key permits the measuring axis to be displayed in axis curve representation. This measuring axis permits the values at

any points of time to be viewed in the time window.

After <F5> has been pressed, the measuring axis is displayed as a dotted vertical line at the right margin of the chart. From now on, the image is no longer updated. A new key set is displayed that permits the measuring axis to be moved (Fig. 2.73).

R e t u r n Meas. a x i s Slow F a s t Move t o marg in Hardcopy C o n t i n u e

Fig. 2.73 Key set for moving the measuring axis

Positioning While the cursor keys <"Arrow leftn> and <"Arrow right"> measuring permit almost continuous (very slow) movements of the measur- axis ing axis, the cursor keys <"Arrow up"> and <"Arrow down">

move the measuring axis in larger steps (rapidly) across the time window. The <Home> key (corresponds to the <7> key in the numeric keypad) positions the measuring axis at the right-hand margin; pressing <End> (corresponds to the <l > key in the numeric keypad) takes it to the left-hand margin. "Left-hand margin" may also stand for the end of the curve if the curve has not yet reached the left-hand margin of the time window. The corresponding values of each measuring axis position are displayed in the output fields of the individual variables.

Removing Press <RETURN> or <ESC> to remove the measuring axis and measuring to resume curve representation. Time was continued while the axis measuring axis was displayed. This means that, once the mea-

suring axis has been removed, curve representation immediately resumes from the current time and updating is continued.


To terminate on line monitoring, press <ESC> to return, then Terminate press cF10> to activate the "Central function menu", and select another dialog section or "End of program".

Exiting SlFLOC S5 SlMATlC S5

2.1 1 Exiting SIFLOC S5

Terminating You need the screen with the "Central function menu" to exit SI- FLOC SS. Activate the 10th menu line or press <F1 0> to display the screen (Fig. 2.74) with the end-of-program menu.

End+of-ptagram menu S ~ ~ ~ C S5

and o r ... Return Menu s e l e c t o r b a r Acceptance Dl rec t selection Help

2. Yes, after data has been save

3. Yes, immediately

Fig. 2.74 User interface with the "End-of-program menu"

Selecting "No, return" or pressing <F1 > takes you back to the "Central function menu", from where you may activate other dialog sections.

Exiting SlMATlC S5 SIFLOC S5

When you select "Yes, after data has been saved" or press <F2>, the system will prompt you to enter afile name. Before SI- FLOC S5 is terminated, the data will be copied to the file specified. The system then returns to the operating system level.

Selecting "Yes, immediately" or <F3> immediately takes you back to the operating system level.

Exiting SIFLOC S5

Ovenliew SlMATlC S5 Design of Funy Controllers

3 Design and Implementation of Fuuy Controllers

3.1 Overview

The verbally formulated process expertise of an experienced o g Design steps erator forms the basis of the fuzzy controller design. The configuring engineer takes this know-how and processes it according to the requirements (Fig. 3.1). Additional iterative design steps are used in which the fuzzy controller is monitored, corrected, modified, and optimized during off line analysis or in the running process.

Operator 0 Verbally formulated process expertise

D

"If pressure P1

Configuring

Fig. 3.1 Block diagram of the funy controller design activities

is very high AND . . . THEN

l open valve 8 a bit"

Monitoring the fuzzy controller

Designing the f u u y controller

v

COROS PG/PC-AT

Fuzzy with SIFLOC S5 block structure A

/ ,

\ \

l I //

\ / /

Process data \ /

s5-135U / Process data \ , S5-155U ,/

Overview Design of Fuzzy Controllers SlMATlC S5

Configuration The following configuration steps are required for a systematic steps design of a fuzzy controller:

Analyzing the control engineering task

Assessment criteria for employing a fuzzy controller

Analyzing the previous control response

Defining the process variables

Setting up the rule basis

Configuration with SIFLOC S5

Off line analysis with SIFLOC S5

Loading and commissioning a fuzzy controller

Correcting and optimizing a fuzzy controller

Preparations SlMATlC S5 Design of Fuzzy Controllers

3.2 Preparation

3.2.1 Analyzing the Control Engineering Task

Complete automation of technical processes, improving the Application- control quality, increasing productivity and product quality, and related reducing energy costs are the major goals of fuzzy control. analysis Certain classes of control engineering tasks permit these goals to be attained by fuzzy controllers. These tasks include, for example:

- Continuous control tasks that require partial manual operation.

- Time-variant or non-linear control loops and automation structures that cannot completely be automated, as a mathematical model of the control system either does not exist or requires too much expenditure.

- Control loops and automation structures, where manual intervention has a negative effect on the product quality (e.g. waste as a result of "poor" manual operation).

- Multi-variable control that cannot be mastered by a single plant operator.

- Complicated startup or shutdown processes of a control engineering subsystem (e.g. chemical reactor) that could only be performed in manual operation.

3.2.2 Assessment Criteria for Employing a Fuzzy Controller

A successful and optimized utilization of a fuzzy controller Optimized requires the process-engineering task to be assessed accord- utilization ing to the following criteria during the design phase:

- Have the possible solutions with conventional optimization procedures (such as setpoint control or parameter adaptation) been exhausted?

- Is the expertise from experienced plant operators sufficient to derive the rule basis of a fuzzy controller from it?

Preparation Design of Fuzzy Controllers SlMATlC S5

- Cost-benefit ratio: The benefit side is given by the expected monetary advantages that result from the implemented automation goals. The costs are chiefly caused by the engineering expenditure (which can be two to three man-months for complex fuzzy controllers).

3.2.3 Analyzing the Previous Control Response

Logs of The following points make it important to analyze and log the manual previous control response intervention - An inventory of the previous situation (manual operation

methods, control quality) permit comparative assessment of the results obtained by fuzzy control.

- The log of the manual interventions of plant operators permits the plausibility of the operator's statements, that will be employed in the fuzzy controller's set of rules, to be verified.

- The corresponding logs may be used for completing the rule basis if the expertise of the plant operator cannot be converted into the required IF-THEN rules.

Definition and Preparation SIMATIC S5 Design of Fuzzy Controllers

3.3 Definition and Preparation

3.3.1 Defining the Process Variables

A fuzzy controller is a multi-dimensional, non-linear function Input and out- generator controller with up to 20 inputs and outputs. Implement- put variables ing a fuzzy controller into the AS structure requires the input and output variables (process variables) to be defined. Integrating a fuzzy controller into the AS structure can be done either directly or with additional function blocks. This depends on whether the process variables already exist in the AS structure or must newly be defined.

Direct integration in the AS structure is possible if input and out- Direct inte- put variables already exist in the automation system (AS). The gration in the plant operator sees these process variables as digital values and AS structure as curves or bar diagrams on the process monitor. Converting manual interventions of a plant operator into the equivalent fuzzy rules is an example of designing a fuzzy controller with existing input and output variables. In this case, approximately two to three inputs and one output are sufficient for the fuzzy controller. If necessary, the input variables must be converted into numeric values.

New definition of process variables

Non-existent input variables must be provided to the AS struc- Additional ture via computer links or additional sensors and analog input input variables modules. Examples are:

- Laboratory analysis values of raw materials

- Energy consumption values of the company and the plant. These values may be available in host computers.

- Environmental influence, such as the effect of the weather on an outdoor reactor.

Definition and Preparation Design of Funy Controllers SlMATlC S5

3.3.2 Setting up the Rule Basis

Empirical The rule basis (totality of the fuzzy rules) forms the core of the process fuzzy controller. The rule basis represents the fuzzily formulated expertise empirical process expertise of an experienced plant operator.

The individual fuzzy rule is an IF-THEN rule of the form (see Chapter 1):

IF-THEN rule IF <condition> THEN <consequence>

The IF part may contain a combination of up to 70 conditions (see Chapter 2).

A typical IF-THEN rule may be of the following form:

IF temperature T1 high AND pressure P4 low OR gradient of T5 medium THEN coolant valve open wide

RULE block The parentheses within a fuzzy rule permit a shortened and clear representation of the operations that are performed by the RULE block when it executes the fuzzy rules.

Operating Acquiring as many operating points as possible (combination of point, implicit different input variables) that, in manual operation, are taken into zero rule account by the plant operator is the goal of setting up the rule ba-

sis. Operating points that cannot occur in manual operation or that can linguistically not be described, are covered by the "implicit zero rule" (see Chapter 2).

Configuration and Optimization SlMATlC S5 Design of Fuzzy Controllers

3.4 From Configuration to Optimization

3.4.1 Configuration with SIFLOC S5

The SIFLOC S5 configuration tool permits a largely system-in- Configuration dependent configuration of fuzzy controllers on a graphic user dialog interface. The configuration dialog using SIFLOC S5 is completely described in Chapter 3. It includes the following major functions:

- Definition of the fuzzy structure

- Defining the membership functions

- Setting up the rule basis

- Inference and defuzzification method

- DFUZ weighting factors

- Fuzzy data file and documentation

Configuring with SIFLOC S5 edits process expertise and the Editingpro- control strategy of a fuzzy controller (inputloutput definition). cess expertise "Active" SIFLOC S5 functions are not yet involved in this process.

3.4.2 Off-line Analysis with SIFLOC S5

The SIFLOC S5 off line analysis procedure permits the perform- Simulation, ance of a configured fuzzy controller to be simulated (see Section dynamic 2.9). The functions "I10 monitoring" (monitoring the input and response output variables) and "Family of graphs" are used for this purpose. These functions are used for converting the fuzzy rules into numeric values, thus permitting a step-by-step verification of the behavior of the input and output variables. Any detected errors or deviations from the expected values may be corrected by modifying the membership functions or the rule basis in the configuration dialog.

W A thorough off-line analysis accelerates commissioning of the fuzzy controller.

Configuration and Optimization Desian of F u n Controllers

3.4.3 Loading and Commissioning a Fuzzy Controller

Once the preceding configuration steps have been terminated, the fuzzy controller can be loaded into the CPU of the AS system (see Section 2.10.1).

Operatorinput Use STEP 5 now to perform the input steps required for steps commissioning:

- lnterconnecting the input variables with the FUZ blocks.

- lnterconnecting the output variables of the DFUZ blocks with the prepared AS structure.

On line loading and interconnecting of a fuzzy controller while production is running may produce significant variations of the output variable that occur a short time after the fuzzy controller has been activated. Consequently , this may disturb the production sequence. In accordance with the plant configuration, the startup strategy must be structured such that the impact of the fuzzy controller on the process is as gentle as possible.

W For safety reasons, commissioning the fuzzy controller is split into two phases: In the first phase, the outputs of the DFUZ blocks are m interconnected with the existing AS structure. The reactions of the activated fuzzy controller are logged during this process (e.g. via the SIFLOC S5 curve function). In the second phase, you may intercon- nect the outputs of the DFUZ block with the AS structure if the control actions of the fuzzy controller were plausible during the first phase.

On -line SIFLOC S5 is used for on line monitoring of the executing fuzzy Monitoring controller. You may choose between a bar representation and a

curve representation. A maximum of any four process values are read from the AS system.

Configuration and Optimization SlMATlC S5 Design of Funy Controllers

3.4.4 Correcting and Optimizing a Fuzzy Controller

The SIFLOC S5 configuration tool must always be used for Using correcting and optimizing a fuzzy controller that does not show SlFLOC S5 the required response after commissioning. This includes formodifi- modifications of the membership functions, weighting rules, and cations supplementing the rule basis.

SlMATlC S5 Hardware Requirements Hardware and Software

4 Hardware Requirements and Software Installation

4.1 Hardware Requirements

PG or IBM-compatible AT:

- PG 770 or PG 750 or PG 730 C or PG 730 SX or PG 710-Plus or CP 581 with external EGA color monitor, or PC with color monitor and graphics card with EGA mode,

- MS-DOS from version 3.3 onwards,

- SIFLOC S5 diskette,

- DR 210-N or DR 21 1 -N or DR 230-N or DR 231 -N printer with standard IBM character set and IBM Proprinter emulati- on.

SlMATlC S5 Programmable Controller:

- CPU 928 (from 6ES5 928-3UA12 onwards) or CPU 9288 in S5-135U or S5-155U.

- CPU945inS5-115U - CPU 9461947 or CPU 948 in S5-155U

- CPU 946Rl947R in SS- 155H

Cable between PG and programmable controller:

6ES5 734-2BD20 for example

Installing and Invoking SlFLOC Hardware and Software

4.2 How can SIFLOC S5 be installed and invoked?

There are three different possibilities:

a) Install SIFLOC S5 in a directory C:\SIFLOC> on the hard disk C:. Enter SIFLOCS5 <RETURN> there to call up the program, or b) Use MS-DOS commands to copy the SIFLOC directory from the diskette to any directory on any drive. Enter SIFLOC S5 <RETURN> there to call up the program, or c) Enter DR: \SIFLOC> SIFLOCS5 <RETURN> to start SIFLOC on the diskette in drive DR (A, B, ...).

Procedure for installation a):

- Insert the SIFLOC S5 diskette into DR (A,B..),

- Enter DR:\>INSTALL <RETURN> to invoke the installation program (this copies a directory C:\SIFLOC with the files SIFLOCS5.EXE, SIFLOC.OVR, SIFLOC.BLD, README, TOOL.BOX, ERROR-DAT and the help text files HILFExx.TXT onto the hard disk C:).

- This procedure remains the same if the C:\SIFLOC directory already exists (from a previous installation).

- The program must then directly be invoked from C:\SIFLOC> : SIFLOCSS <RETURN> .

Limitations

W Note the restrictions in the utilization of CPUs with two interfaces (such as 928B) that are described in the CPU Manual. Simultaneous utilization of "Force Variables" in STEP 5 and "On line monitoring" in SIFLOC SS, for example, is not permitted.

lndex

lndex

A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ANDing 1 - 11

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Animationtext 2 - 9

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Automation .. .. . . . . . . . . . . . . . . . 3 - 3

B

Bannerline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 -17

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Brackets 2 - 47

C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cable .. 4 - 1

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Center of gravity of the area 2 - 72

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Center-of-gravity defuzzification 2 - 57

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Central function menu 2 - 19

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Characteristic curve 2 - 78

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Closed-loop control circuits 1 - 1

COMA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 8 1

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Configuration steps 3 - 2

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Control response 3 . 4

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Controller 1 - 1

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Crisp sets .... 1 - 4

D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Data file 2 . 61

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Defining the range 2 . 30

Index

. ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Defuzzification .... 1 14

. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Degree of membership 1 5

. DFUZ block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 17

DFUZ weighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . 58

. Dialog section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 15

. Dialog step . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 15

Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . 61

Family of graphs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . 75

Family parameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . 77

Field of characteristic curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . 77

File . printing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . 63 -README . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 2 0

. . report explanations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 63 -saving . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 62 -viewing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 63

File list . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 21 FUZblock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 15

Fuuification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 10

Fuzzy controller, applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 1

Fuuy controller . . assessment criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3 . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . components 1 7

. correcting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . 3 . 9

. design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... .. . . . . . . . . . . . . . . . 3 . 1

. integrating in the AS structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 . 5

. interconnecting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 . 8

. loading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 . 8

. monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 . 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . optimizing 3 9

. Fuuylogic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 3

Index

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fuzzy sets 1 . 4 Fuzzy structure . creating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . 12 . defining . . . . . . . . . . . . . . . . . . . .. .. . . . . . . . . . . . . . . . . , , , , , . , . , . , , . 2 . 1 1 . modifying . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . 21

Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 . 1

IF-THEN rule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . 11. 2 . 45. 3 . 6 lnference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12 Inference and defuuification method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . 57 lnput

. . deleting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 25

. . editing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 23

Input field . . . . . . . . . . . . . . . . . . . .. ........................ , , . . . , . 2 . 20 lnputnames . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 -14 Input variable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . 2 . defining . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 . 5

Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2 Instantaneous value monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . 70 Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 2

Key input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . 18

Index

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Output names 2 . 16 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Output variable 1 . 2

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . defining 3 - 5

Parentheses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 1 1

Printer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 1

Processexpertise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Process variable 1 - 5, 3 - 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Productinference 1 - 13

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Programmable controller 4 - 1

Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 2 6

Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 5 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Response characteristics 2 . 68

Rule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . deleting 2 - 51

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . editing 2 - 51 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . printing 2 - 51 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rule basis 1 - 12, 2 - 42. 3 - 6

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rule line 2 - 46 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rule report ... 2 . 51

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . S5D file 2 - 83 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Samples 2 - 36

............................................... Selecting a variable 2 - 28 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SEQ file 2 - 83

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Set theory 1 - 4

Index

T

Time window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . 89

Truth value . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . 5. 2. 26

Weighting factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . 58

Work area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . 17

. . Zero rule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 53. 3 6

siemens · 2015. 1. 21. · inference and defuzzification method ..... 2 . 57 dfuz weighting...

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