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Technical support / Re:MODBUS/Coms issue
« on: December 31, 2010, 05:26:07 PM »
I used SETPROTOCOL 1, 1 as I use MODBUS RTU but I still have the same problem, even now with a different PLC program.
This is the sequence of events:
1) MODBUS is working fine.
2) I depower and repower the PLC and MODBUS doesn't work
3) I turn DIP 4 on and MODBUS doesn't work
4) I depower and repower with DIP 4 on and MODBUS works
5) I turn DIP 4 off and MODBUS still works (this is what I had to do before step 1)
The MODBUS routine in this instance simply writes an incrementing variable to DM[100] (pauses 2s) then reads DM[100] to DM[109]. Interestingly the returned values are a mix of random numbers (DM[100] is correct) which don't match with what I see from the Trilogi online monitoring.
This is the sequence of events:
1) MODBUS is working fine.
2) I depower and repower the PLC and MODBUS doesn't work
3) I turn DIP 4 on and MODBUS doesn't work
4) I depower and repower with DIP 4 on and MODBUS works
5) I turn DIP 4 off and MODBUS still works (this is what I had to do before step 1)
The MODBUS routine in this instance simply writes an incrementing variable to DM[100] (pauses 2s) then reads DM[100] to DM[109]. Interestingly the returned values are a mix of random numbers (DM[100] is correct) which don't match with what I see from the Trilogi online monitoring.