3. Execute the project engineering of the slave! The PLC user
application at the slave has the following structure:
n OB 100:
Call SFC 216 (configuration as Modbus RTU slave) with
timeout setting and Modbus address in the DB and error
evaluation.
n OB 1:
Call SFC 217 (SER_SND) for data transport from the slave
CPU to the output buffer. Call SFC 218 (SER_RECV) for the
data transport from the input buffer to the CPU. Allow an
according error evaluation for both directions.
Structure for the according PLC programs for master and slave:
VIPA System 300SDeployment PtP communication
Modbus - Example communication
HB140 | CPU-SC | 313-6CF13 | GB | 15-50 174
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