Modbus/TCP-Communication S7-1200/S7-1500

Hello SIOS-Forum-Community,

the SIMATIC S7-1200/ S7-1500 supports the communication with Modbus/TCP.

The following application example is available for this:

The application example describes the communication between a S7-1500 and a S7-1200. Both controllers are parameterized as client and as server.

How do you program and parameterize Modbus/TCP communication between S7-1500 CPUs and S7-1200 CPUs?

The Modbus/TCP server uses port 502 by default. Which ports you can use and how many clients a server can serve is described in the following article:

Which ports are released for Modbus/TCP communication and how many Modbus clients can communicate with a SIMATIC S7 PN-CPU as Modbus server?

In the manuals you will find more information about the Modbus/TCP communication:

SIMATIC S7 S7-1200 Programmable controller Overview of Modbus RTU and Modbus TCP communication

SIMATIC S7-1500, ET 200MP, ET 200SP, ET 200AL, ET 200pro Communication / Set up communication via Modbus TCP

Hint:

Modbus/TCP can be done via the local interface of the CPU or with an Ethernet CM/CP. The CM/CP must support the open communication with TCP/IP. No additional license is required for Modbus/TCP communication.

This applies to the SIMATIC S7-1200, ET 200SP CPU and S7-1500.

The procedure described in this article refers to the time of writing this article (status: November 2021).

With kind regards

SIMATIC International Technical Support Hub