hi,

  i have s7-1200 CPU 1214c(6es7214-1AG40-0XB0) i going to communicate with temperature controller with modbus RTU with modbus module CM1241 RS485 max three module can connect may i correct .?

now i want to connect Modbus TCP/IP in same cpu if can do; how many  node can connect ?

same port i want to communicate with wincc  V 7.0 scada . is this possible

thanks

Hello,

The best source of information is the System Manual for the S7-1200. Please ready the section on Modbus.

The S7-1200 CPU will support up to 3 Communication Modules (CM). You can see on the "Device Configuration" screen there are 3 slots to the left of the CPU which means you can add up to 3 CMs.

Modbus TCP uses the PROFINET port (there is only 1 on the 1214C). If you have an Ethernet switch (such as an CSM1277 Switch)  then you only need one PROFINET port to communicate with multiple Modbus TCP devices. 

In regards to your last point I do not know, but I would assume it is possible.

There is a FAQ talking about Multiport. In Genral your CPU must be FW4.1 or higher to support Multiport

The maximum number of Modbus clients that can be connected to one S7-1500 CPU is determined by the number of MB server FB instances running in parallel on the CPU and the maximum number of free connection resources.
If the CPU with integrated PROFINET interface does not support multiple ports, each local port of the CPU can only be used once, which means that when a communication connection has been established for one local port of the CPU, then youcannotset up another connection via that port.

https://support.industry.siemens.com/cs/us/en/view/34010717

Joshua H.

Modbus TCP uses the PROFINET port (there is only 1 on the 1214C). If you have an Ethernet switch (such as an CSM1277 Switch)  then you only need one PROFINET port to communicate with multiple Modbus TCP devices. 

 Hello,

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

You can have multiple Modbus connections if you use a different port for each MB_SERVER instruction.

The CPU you are using will restrict you on the maximum number of connection and the port you need to use.

I did the test on a previous project and you can use port 502, 503 and 504 to communicate with 3 modbus client at the same time.

I hope this will help you.

Best regards,

Hugo

Hello friend,

note: wincc v7.0 will communicate with s71200 via opc only. you need to check the possibility of using opc and modbus tcp in same port.

• WinCC versions V7.2 and later
  In V7.2 onwards WinCC provides a separate channel for communication with S7-1200-/S7-1500 controllers.
  The sample application in Entry ID101908495explains how to use this communication channel.
• WinCC 7.0
  From WinCC it is possible to access tags of the S7-1200/S7-1500 via the OPC. For this, you create a PC station with an OPC server, which you access with WinCC. For this you use SIMATIC NET which is included in the WinCC Distribution.
  Information about the intercompatibility of the products is available in Entry ID64847781.