How do you establish a MODBUS-RTU communication with STEP 7 (TIA Portal) for the SIMATIC S7-1200?
The SIMATIC S7-1200 enables point-to-point communication via the CPU extension with the interfaces RS422/485 and RS232. Using the MODBUS library integrated in STEP 7 (TIA Portal) you can define each communication module as a MODBUS master or slave. If you select MODBUS Master, you can communicate
- With only one slave using the CM 1241 RS232 (physical limitation).
- With up to 10 slaves one after the other using the RS422 (via CM 1241 RS422/RS485).
- With up to 32 slaves one after the other using the RS485 (via CM or CB 1241 RS485).
We will take the sample project to describe the configuration procedure in STEP 7 (TIA Portal) for communication with multiple slaves using the CM 1241 RS422/485.
you will find in the following table: