Modbus channels performance
Posted: Mon Nov 29, 2010 10:45 am
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.
Riccardo
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.
Riccardo