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Technical support / MODBUS RTU and PLC address
« on: February 05, 2008, 06:20:02 PM »
Hello again.
I am having some difficulty using MODBUS RTU where I have 20 remote PLCs connected to a SCADA system running DAQFactory.
All comms works OK apart from the PLC's with addresses in the A to F range. It seems that when these PLC's are addressed for reading that all the others on the line also try and respond as if they all had the same address! This doesn't happen when polling the other PLC's.
Any ideas on why this may be?
I am having some difficulty using MODBUS RTU where I have 20 remote PLCs connected to a SCADA system running DAQFactory.
All comms works OK apart from the PLC's with addresses in the A to F range. It seems that when these PLC's are addressed for reading that all the others on the line also try and respond as if they all had the same address! This doesn't happen when polling the other PLC's.
Any ideas on why this may be?