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Modbus channels performance

Posted: Mon Nov 29, 2010 10:45 am
by riccardo.tribbia
I submit an email discussion about Modbus channels performance:

Configuring two Modbus channels on two PLCs instead of use a single channel with two devices?

With 2 channels:
-> Monitoring has done in parallel so scanner cicle can has half lifetime;
-> If one PLC is broken (or communication error), it doesn't delay also the other PLC

With 1 single channel and 2 modbus devices:
-> Less memory used 'cause only one process is launched.

We can try to optimize communication with channel on Read Timeout and Query Pause protocol configuration parameters (Query Pause also with 0 value, if PLC can manage high frequency sampling).
We can also group gates in blocks and define "in monitor" gates which don't need to be read always.