I'm reviewing a coupon-check interface where the PLC briefly raises request and then clears it on a timer. Our application sometimes reads before and after the pulse, with nothing in between. Neither side has a clear acknowledgement rule. This is ordinary job messaging, separate from the cell's safety controls.
Replying to RosaChan1075
Agree who writes each signal and what acknowledged means. Retain the request and its identity until that agreed response, then test a delayed application. Include restart and cancellation in the clearing rules.
22 points