Master-Slave Communication with Modbus RTU for S7-300 and ET 200S Systems
The application demonstrates
- the configuration of the CP 341 as Modbus RTU master.
- the configuration of the ET 200S 1SI module as Modbus RTU slave.
- the technical program implementation of a Modbus RTU master and slave program in the S7-300 CPU in STEP 7 V5.5 and STEP 7 (TIA Portal).
The example is designed such that the RTU master program as well as the RTU slave programs are realized together in one S7-300 CPU. The Modbus RTU master communication module is the CP 341, the Modbus RTU slaves are realized with the 1SI communication modules of the ET 200S. Via the ET 200 S front module, these Modbus RTU slaves are in turn connected to the S7-300 CPU via PROFINET.
The following image shows the hardware structure of the example:
The advantage of this example is that both of the realized program parts, the Modbus master and the Modbus slave, are separable. The quantity structures (number of Modbus RTU slaves, data volume, etc) are also easily adjustable for your own applications.
Current version 2.0 for STEP 7 Professional V14 (TIA Portal)
Documentation (2,0 MB)
Project for STEP 7 Professional V14 (TIA Portal) (507,3 KB)
Older version for 1.1 for STEP 7 V5.5 SP4 and STEP 7 Professional V12 (TIA Portal)
Documentation (1,5 MB)
Project for STEP 7 V5.5 SP4 (935,4 KB)
Project for STEP 7 Professional V12 (TIA Portal) (1,5 MB)
Update to TIA Portal V14