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from the PLC Communication/Running Status department...
Momentum/ 984/ Premium PLC's - how do I monitor the Modbus Plus link light status and Running status in WW InTouch?
I had a situation where the program on a PLC program was not running, but my IO status thought the communications were 'good'. I would like to know:
(1) if there is an internal register in the PLC that stores the status of the PLC program - ie: Running/Not Running.
(2) if there is an internal register in the PLC that stores the status of the PLC communications on Modbus Plus as well as ethernet.
(1) if there is an internal register in the PLC that stores the status of the PLC program - ie: Running/Not Running.
(2) if there is an internal register in the PLC that stores the status of the PLC communications on Modbus Plus as well as ethernet.
The most common method of making a "Watch Dog Timer" is to have a Modbus register continually increment and roll over controlled by the PLC program. Then the Host monitors that Modbus register to ensure it is always changing.
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