Programmable Controllers

Transcription

1 Programmable Controllers Communication in Simatic S7 Marcin Czubala Tomasz Wróbel

2 1. Introduction As a task of our project we have chosen to configure communication between two Siemens controllers using both Profinet and Profibus-DP protocols. Industrial Ethernet connection was established by means of CP Lean module. Profibus RS485 was connected with a use of build in CPU 31x joint. Moreover we have prepared next project for control of traffic lights. 2. Profinet First we have performed rack configuration. Next step was to set proper parameters of the CP 343 modules. It was done in Hardware Configuration and than Property windows by clicking properties of ethernet interface. There the new network and proper IP address/mask were created/chaned. Picture 1. CP 343 configuration Third step was to open NetPro. In this program connection between two PLC's was created. It could be done by inserting new connection in CPU, choosing proper controller to communicate with, select TCP type connection and checked Active connection establishment.

3 Picture 2. NetPro configuration Last step was to write program. We used AG_SEND and AG_RECV blocks to transfer data. After proper configuration of hardware clicking left on ID input our connetion was listed as a one of options. Signal EN enables block and signal ACT sends the data declared on the SEND input. Picture 3. Program blocks

4 3. Profibus-DP Next task was to create Profibus communictation between the same PLC's. To do this first we created new Profibus network by clicking on DP part of CPU in HW Config. Than analogically to Profinet we set the parameters and addresses of controllers. In case of slave CPU operating mode should have been chanaged to DP Slave. Next step was to connect slave station to the Profibus DP master system in master's HW Config and coupled them in windows that automatically pop out after connecting slave to network. Picture 4. Master and slave configuration The last part was declaring in DP slave properties window area of input/output memory. There the address type (Input/Output), address, length and unit for both master and slave could be write. To communicate between controllers we used simple move function. Picture 5. Example of code for both master and slave It should be noted that for proper communication in this type of Profibus connection blocks OB82 and OB86 had to be included in program.

5 4. Control of traffic lights As a second part of our project we have prepared control of the traffic lights. We have programmed it in Ladder. We have started from defining the variables. We have created 4 outputs for control of the lamps: two for green and two for red ones. We have created following networks: Firs we have programmed initialization phase, where we have reset all lights.

6 In the next phase we have switched off the lights, so we set both red light indicators. Next we check whether the car approaches the crossroad or not. If the cars occurs and Initiator_1 is equal to one we start timer T1.

7 After time 5 seconds we begin a green phase at J1 for 10 seconds, by starting timer T2. Next we begin to change lights to red for J1 by resetting LG1 and setting LR1.

8 Next we check whether the other car approaches the crossroad or not. If the car occurs and Initiator_2 is equal to one we start timer T3. Next we switch on the green light for the other car for five seconds by starting timer T4.

9 Next we have to maintain a green phase at J2. Finally we turn green light off and turn on the red light for J2. It is important to remember that to open software we need to modify Language file inside the project. Here is the instruction: Step 1: Open project and find folder name Global

10 Step 2: In this folder find Language file Step 3: Open this file using windows notebook and replace language data 5. Conclusions Our communication worked properly. We were able to perform communication between two CPUs using two different protocols. To sum up controller communication is on daily basis of real life industry applications. To make the network reliable lot of thoughts and configurations have to be made. This project gave us small picture of what is important and difficult in even as small as two PLCs network.