Application example: LOGO! CIM - Modbus RTU communication with SINAMICS V20

This entry focuses on controlling SINAMICS V20 drives with the integrated web server of the LOGO! Basic Module (BM).

The SINAMICS drives are connected via RS485 with the serial multiplex interface of the LOGO! CIM (Communication Interface Module). Communication over the Modbus RTU protocol is sequential. Here, the CIM is the master and the SINAMICS V20 drives are the slaves with differing Modbus addresses.

Data exchanged are cached in the CIM and passed to the LOGO! BM via S7 communication. Here, the CIM is the client and the LOGO! BM is the server.

Each drive can be controlled via the web server of the LOGO! BM by access through a browser on a connected PG/PC.

The SINAMICS V20 drive is controlled with a control word while the motor frequency is a setpoint value. The drive sends a status word and the actual frequency as feedback.