BEE2961Industrial

Electropneumatic

PLCConfiguration

PLC Introduction--------------------------

A Programmable Logic Controller (PLC) is a digital computer used for automation of electromechanical processes, such as control of machinery on factory assembly lines, amusement rides, or light fixtures

PLCs are used in many industries and machines where it is designed for multiple inputs and output arrangements, extended temperature ranges, immunity to electrical noise, and resistance to vibration and impact

Programs to control machine operation are typically stored in battery-backed-up or non-volatile memory

A PLC is an example of a hard real-time system since output results must be produced in response to input conditions within a limited time, otherwise unintended operation will result

In this subject, we will use PLC to control electropneumatics system that has been learned previously

What is PLC?

PLC Overview

PC (Siemens STEP 7 Software)

PLC I/O Board

PLC CPU

MPI Interface* Interface adapterbetween PC and PLC

* Processor of PLC

* Input/Output pin for PLC

PLC I/O Board

Analog I/O pin (we don’tuse this in this course)

Digital output pin

Digital input pin

Toggle switch (digital input)

PLC ground

All the hardware components will be connected via PLC I/O board in order to control them according to the ladder programming written

Each hardware components needs to be identified whether they acted as an input or output for/from PLC

All the connected I/O pins must have the same address assigned to them in ladder programming

PLC I/O Board

PLC CPU

Output port indicatorInput port indicator

CPU order number

CPU model/module

Reset switch

Status indicator

Memory slot

The CPU controls all the input and output from PLC I/O Board according to the program that has been downloaded into it

The status indicator shows the status of the CPU whether it is on RUN or STOP mode

The order number must be exactly the same as the order number selected during the hardware configuration to ensure that PC ‘recognize’ the PLC CPU

The input and output port indicator must be monitored regularly to ensure that the programmed system is working according to the ladder programming written

PLC CPU

MPI Interface

FLIPRS232 connecter from PC

Transmission rate selector

Power and active indicator

MPI Interface acts as a connector between PC and PLC CPU

The transmission rate selector must be set to the exact same value set in hardware configuration

Power indicator must be shown in order for PC and PLC CPU to interact with each other

Active indicator will be lighted whenever there’s a download or monitor activity going on in that period of time

MPI Interface

Siemens Step-7 Software is used to write ladder programming that will be transferred to PLC CPU in order to control the electropneumatics system

Before writing a ladder programming, hardware configuration must be set first as the hardware cannot be detected automatically

A misconfigured setting will results in failure or error of the electropneumatics control system

Siemens Step-7 Software

The Flowchart of PLC Configuration Process

Setup a new project

Interface setup

Hardware configuration

Download to PLC CPU

Hardware monitoring test

(optional)

Setting Up a Project--------------------------

1. Start up your PC2. Start up your PLC

◦ PLC doesn’t have a start switch, just switch on after plugging the cable to an electric socket

3. Push the CPU switch to ‘RUN’4. Wait for the status indicator LED

to stop blinking◦ Only DC5V and RUN indicator will

light on

5. Double click SIMATIC Managerin your PC

Starting Procedures

A New Project Wizard will pop-up. Click Next

STEP 7 Wizard

Select CPU: CPU313C MPI address: 2 Click Next

STEP 7 Wizard

Inspect the PLC CPU model

Select Blocks: OB1 Language for Selected Blocks: LAD Click Next

STEP 7 Wizard

OB1 is the main program,we don’t use others in

this subject

LAD for ladderprogramming

Write in a new project name Click Finish

STEP 7 Wizard

Write your projectname here

A new project has been created

SIMATIC Manager Window

Make sure the SIMATIC Managerwindow display your project name

Interface Setup--------------------------

In order to transfer hardware configuration orladderprogramming toPLC CPU, MPIInterface needs tobe setup first Usually, we willuse the defaultsetup, however wewill learn to inspect the setup Click Options Set PG/PC Interface

SIMATIC Manager

Double click PC Adapter [MPI]

SIMATIC Manager

The default setting should be:◦ Address: 3◦ Timeout: 10s◦ Transmission Rate 187.5 Kbps◦ Highest Station Address: 31

Next, click on LocalConnection tab

SIMATIC Manager

Never change this number, it will resultsin hardware error if it is changed

The default setting should be:◦ Connection to: COM1◦ Transmission Rate: 19200

Lastly, click OK

SIMATIC Manager

Ensure that the transmission rateselector on MPI interface is

selected at 19.2

Hardware Configuration

--------------------------

Double click Hardware

SIMATIC Manager

Click ‘+’ to expand the subfolder view

A HW Config will pop-up

HW Config

Rack with individual slot

Configuration settings Hardware catalog

HW ConfigExpand these columns to have a clear view of each settings

If the order number is not the same as the onewritten on your PLC CPU, change it by searchingthe correct order number from Hardware Catalog

HW Config Click Yes

A warning message will pop-upconfirming the changes ofCPU order number

The order number has been changed

HW Config

Make sure the order number is correct

Double click on ‘DI24/DO16’ row

HW Config

Double click here to change the addressfor input (I) and output (Q)

A Properties window will pop-up

HW Config

Click the Addresses tab tochange the input and

output address

The PLC address needs to be started from 0 for input and output. This is due to the I/O port numbering in PLC I/O Board

HW Config

Deselect System Default as wewant to key-in our own address

Change both the starting address to ‘0’ Click OK

HW Config

The end address will beautomatically set

To save the settings, click Save and Compile Then, to download the settings into PLC

CPU, click Download A message willpop-up confirmingthe target module.Click OK

HW Config

Another message will pop-up informing the node address selection. Click OK

HW Config

In order for the new settings to take place, all the previous activity in PLC CPU will be stop during the downloading process

A message will pop-up, click OK

HW Config

After stopping, the module needs to be restarted A message asking for a module restart will be

prompt. Click Yes

Congratulation, the PLC CPU has been downloaded with a hardware configuration settings

HW Config

Hardware Monitoring Tests

--------------------------

After the new settings have been downloaded, all PLC’s activities can now be monitored by STEP-7 Software

To test it, we needto setup the STEP-7Software in an‘online’ mode Click Station Open ONLINE

HW Config

Right click on ‘DI24/DO16’ row Then click Monitor/Modify

HW Config (ONLINE)

Notice that the window nowprompting that it is in ‘online’

mode

A new Monitor/Modify window will pop-up

HW Config (ONLINE)

These are all the input (I) addressthat we have set in

hardware configuration

The input that has been setup isdigital only. As for that, it is

in Boolean format (BOOL)

Check the Monitor checkbox

HW Config (ONLINE)

In Boolean format,‘0’ will be stated as ‘FALSE’

and ‘1’ will be stated as ‘TRUE”

During ‘running’ or ‘online’ activity,notice that the active indicator on

MPI Interface will light on

Now, test the monitoring effects by playing around with the toggle switch on PLC I/O Board

Any toggle switch that isselect to ‘ON’ position willresult in ‘TRUE’ on theMonitor/Modify window After finish, click CLOSE

HW Config (ONLINE)

The resultsmust bethe same