Modbus TCP communication example for Siemens 1200/1500 series PLC

In modern industrial production, it is often the case that the host computer needs to communicate with the third-party slave computer, such as third-party instruments, inverters, temperature modules, pressure transmitters, etc. In this case, ModbusRTU and ModbusTCP/IP protocols are required. If your third-party device supports the ModbusTCP/IP protocol, network communication can be used.

Today we will introduce the TCP communication of Siemens 1200 and 1500 using the TIA Portal platform. After reading this case, you can draw inferences from it and apply it to actual projects. This case is for reference only.

We need to meet the following software and hardware requirements when doing this project case:

1.) A Siemens 1200 series PLC (in this case, it is 1215DCDCDC. The controller does not have to be the same as the one in this case, as long as it supports the modbusTCP protocol);

2.) A Siemens 1500 series PLC (in this case, it is 1513, the controller does not have to be the same as this case, as long as it supports the modbusTCP protocol);

3.) A computer with TIA Portal V16 software installed;

4.) Two communication network cables and one DC24V/10A switching power supply.

After the above conditions are met, we open the TIA Portal and start configuration. Here we first configure a server (1513PLC) and create a server communication data DB block:

How to build:

Add a data block named "TCON_IP_V4" in "Program Block". There is no need to cancel "Access Optimization Block". Add communication data with the data name "TCON" and data type "TCON_IP_V4" in the static variable "Static".

Open the "TCON" data to set the parameters, set "Interfaceld" (communication hardware port) to "64", set ID to "8", set "Connection Type" (communication protocol) to 16#0B, the default is TCP communication protocol, "ActiveEstblished" (establish connection), "1" is active connection (client), "0" is passive connection (server), continue to open "RemoteAddress" and find the "ADDR" array to set the communication IP address (generally not set by default as a server), and finally set the "LocalPort" server port number to "502".

We call the TCP communication instruction block "MB_SERVER" and drag it to the program terminal to set parameters:

After writing the server program, we configure a client PLC (i.e. 1215PLC). After configuration, we also need to add a communication data DB block, which is slightly different from the server parameters, as shown in the following figure:

The data block parameters of client and server "TCON_IP_V4" differ in the following parameters:

1.) Active Established (Established connection), "1" for active connection (client), "0" for passive connection (server). This is a client, so fill in "1"

2.) Open "RemoteAddress" and find the "ADDR" array to set the communication IP address (here is the client, you need to fill in the server IP address, that is, Siemens 1513PLC);

3.} Remote Addrese here needs to fill in the server port number (502);

4.) LocalPort" server port number is "0".

After the communication parameters are set, add a TCP communication instruction "MB——CLAYend" as shown below:

Writing data from the client to the server

We add a program to read the server:

Read server data from client (server writes data to client)

Read requirements:

The five data of MW20-MW28 on the server side (Siemens 1513) are stored in MW50-MW58 on the client side (Siemens 1215). It can also be said that the server writes to the client side.

The controller online monitoring is as follows:

Condition Monitoring:

1200/1500 data transfer

The above is a brief introduction to the data transmission between 1200 and 1500 PLCs through the Modbus TCP communication protocol. I hope it can provide a reference and help for friends who want to learn Siemens PLC communication. There are inevitably some imperfections or even errors in the article. I hope the experts will criticize and correct me.