S
We are facing a very typical problem in our plant control system.
A digital output from the DCS is wired to as a digital input to a PLC.
When the DCS output changes from 1 to 0, this is immediately reflected in the PLC input. However when DCS input changes back from 0 to 1, PLC input is still 0 for quite a long time (which is not fixed) and suddenly becomes 1.
No timer is defined in the PLC logic. Even if the timer is defined, the LED input indication of the Input card does not become ON when DCS output changes.
How should i go about trouble shooting this issue?
A digital output from the DCS is wired to as a digital input to a PLC.
When the DCS output changes from 1 to 0, this is immediately reflected in the PLC input. However when DCS input changes back from 0 to 1, PLC input is still 0 for quite a long time (which is not fixed) and suddenly becomes 1.
No timer is defined in the PLC logic. Even if the timer is defined, the LED input indication of the Input card does not become ON when DCS output changes.
How should i go about trouble shooting this issue?