Automation:

AUTOMATION:

Automation is the use of control systems such as computers to control industrial machinery and processes, replacing human operators. In the scope of industrialization, it is a step beyond mechanization. Whereas mechanization provided human operators with machinery to assist them with the physical requirements of work, automation greatly reduces the need for human sensory and mental requirements as well.

ADVANTAGES OF AUTOMATION:

The purpose of automation has shifted from increasing productivity and reducing costs, to broader issues, such as increasing quality and flexibility in the manufacturing process.

Automation is now often applied primarily to increase quality in the manufacturing process, where automation can increase quality substantially.

For example, automobile and truck pistons used to be installed into engines manually. This is rapidly being transitioned to automated machine installation, because the error rate for manual installment was around 1-1.5%, but has been reduced to 0.00001% with automation.

Hazardous operations, such as oil refining, the manufacturing of industrial chemicals, and all forms of metal working, were always early contenders for automation.

Application of AutomationPower generation

TRANSMISSION AND DISTRIBUTION:

Oil and gas industries

Process industries

Building automation

HISTORY OF AUTOMATION

MANUAL CONTROL

HARDWIRED CONTROL:Prior to PLCs, many of these control tasks were solved with contactor or relay controls. This is often referred to as hard-wired control. Circuit diagrams had to be designed, electrical components specified and installed, and wiring lists created. Electricians would then wire the components necessary to perform a specific task. If an error was made the wires had to be reconnected correctly. A change in function or system expansion required extensive component changes and rewiring.

DRAWBACKS:

Bulky and complex wiring.

Difficult to change the logic.

Unreliable.

RELAY :

RELAY LOGIC AND GATE:

ELECTRONICS CONTROL

Logic gates and Electronic Circuits are used

Ease of programming

Ease of maintenance

Drawbacks:

Difficult to Troubleshoot while Change the Logic of the Process

Difficult to expand

Not suitable for industrial conditions

PROGRAMMABLE LOGICAL CONTORLWhat is a Programmable Logic Controller PLC?

PLC is a device, which is used to control a machine or process as per the human control sequence. A PLC monitors inputs, makes decisions based on its program, and controls outputs to automate a process or machine.

Advantages Smaller physical size than hard-wire solutions

Easier and faster to make changes

PLCs have integrated diagnostics and override functions

Diagnostics are centrally available

Applications can be immediately documented

Applications can be duplicated faster and less expensively

PROCESSOR MEMORY ORGANIZATION

The memory of a PLC is organized by types.

The memory space can be divided into two broad categories:

Program and Data Memory:

Advanced ladder logic functins allow controllers to perform calculatins, make decisions and do other complex tasks. Timers and counters are examples of ladder logic functions. They are more comples than basic inputs contacts and output coils and relay heavily upon data stored in the memory of the PLC.

PROGRAM FILES:

The user program will account for most of the memory of a PLC system.

Program files contain the logic controlling machine operation.

This logic consistes of instructions that are programmed in a ladder logic format.

DATA FILES:

The data file protion of memory stores input and output status, processor status, the status of various bits and numerical data.

INPUT TABLE FILE OPERATION:

Processor continually reads current input status and updates input image table file.

OUTPUT TABLE FILE OPERATION:

Processor continually activates or deactivates ouput status according to output image table file status

PROGRAM SCAN:

During each operating cycle, the processor reads all inputs, takes these values, and energizes or de-energizes the outputs according to the user program. This process is known as a scan. Because the inputs can change at any time, the PLC must carry on this process continuously.

1. I/O scan records status data of input devices. Energizes output devices that have their associated status bits set to ON (1)

2. Program scan instruction are executed sequentially.

SCAN PROCESS:

The scan time indicates how fast the controller can react to changes in inputs. Scan times vary with computer model and program content, and length. If a controller has to react to an input signal that changes states twice during the scan time, it is possible that the PLC will never be able to detect this change.

When the inputs is closed, the input module senses a voltage and an ON condition (1) is entered into the input table bit 0012.

During the program scan the processor sets instructins 0012 and 506 to ON(1).

The processor turns light output 506 ON during the next I/O scan.

KEYENCE

ADDRESS:

INPUTS:

0000to0015

0100to0115

0200to0215

0300to0315

0400to0415

OUTPUTS:

0500 to0515

0600to0615

0700to0715

0800to0815

0900to0915

INTERNAL MEMORY BIT:

1000to1015

Upto

1900to1915

TIMERS:

TMR space #(0.1sec)

TMH space #(0.01sec)

TMS space #(0.001sec)

COUNTERS:

Up counter: C space #space

Up/Dwn counter: Cspace#

PROCEDURE FOR PROGRAMMING:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 1601. Edit command/Lable

02. Edit line command

03. Show/Hide command

04. Jump to specified line/step

05. Find

06. Replace operand

07. Usage information

08. Edit list

09. compail

010. Show compilation error

011. Transfer to PLC

012. Read from PLC

013. Plc monitor

014. Simulator

015. Display mode

016. Description of operation

1 2 3 4 5 6 7 8 9 10

01. N.O. contact OR input

02. NC contact OR input

03. NO contact input

04. NC contact input

05. Output coil

06. NC output coil

07. Input vertical connection line

08. Delete vertical connection line

09. Input Horizantal connection line

010. Delete Horizantal connection line

BASIC PROGRAMMES:

--| |--

NORMALY OPEN CONTACT

--| / |--

NORMALY CLOSED CONTACT

--( )--

COIL

EX: 1

When the switch (SW) is ON, the LOAD should ON (Rung 0001)When the switch (SW) is OFF, the LOAD should ON (Rung 0002

Note:The all programming sequence should complete with END AND ENDH.

LADDER LOGICS FOR DIGITAL GATES:

OR :

I1I2L

000

011

101

111

AND:

I1I2L

000

010

100

111

NOR:

I1I2L

001

010

100

110

NAND:

I1I2L

001

011

101

110

EX-OR:

EX-NOR:I1I2L

001

011

101

110

I1I2L

001

011

101

110

SWITCH CONTACTS:

EX 1:SW1= 0000, SW2= 0001,LD1 = 500,LD2 = 501

SW1SW2LD1LD2

1010

1101

EX 2:

SW1SW2SW3LD1LD2LD3

011100

100010

111001