How do you use the Modbus block "MODBUSPN" to communicate with multiple Modbus devices via one connection resource of the CPU?
Simultaneous communication with all partners is not possible if the number of Modbus/TCP communication partners exceeds the number of available communication resources. However, you can still realize communication by multiplexing the connections.
The document below describes how to use just one connection resource of the PROFINET CPU to read data from multiple communication partners via Modbus/TCP.
109479369_ModbusTCP_Communication_v10_en.pdf (2.3 MB)
The download includes the project "109479369_Modbus_TCP.zip".
Unpack the "109479369_Modbus_TCP.zip" file in a separate directory. Then you can use STEP 7 to open and edit the project.
The screens and downloads in this FAQ response were created with STEP 7 V5.5 SP4.