On an inherited fixture I found two teams both clearing the same ordinary job flag. Each thought they were cleaning up after the other. Have them walk one exchange together before deciding the pulse is the only defect.

Also record whether acknowledgement means received or finished. Those cannot share an unexplained tick on the screen.

Holding the request until acknowledgement might answer the missed observation, but it introduces a retained state to reconcile at restart. I would not call the change complete with only the normal exchange documented.

Agreed. Include initial connection, either side restarting, timeout and an acknowledgement that remains present. I was describing the table, not approving a specific implementation.

The walkthrough found both problems. The PLC pulses the request. Application acknowledgement means received, but our display labels it done. The controls owners are rewriting the ordinary exchange with separate receipt and result states.

Who will maintain that table after somebody adds another inspection variant? Put it with the revision-controlled application handover.

Controls lead owns the shared table; both teams review changes. The misleading done label is corrected in the test application. We haven't changed the cell exchange yet.

Does the draft stop a stale acknowledgement being accepted as receipt of the next request?

That belongs in the test set with the delayed receiver. A longer visible request is not enough if old response state can satisfy the next exchange. Show which current request a response belongs to under the agreed contract.

Both teams approved the revised contract. In the offline test, delaying the receiver no longer loses the held request. Replaying the previous acknowledgement cannot complete the next exchange; a restart leaves an unfinished exchange for reconciliation. We also checked each normal clear transition against the table.

Useful evidence for the application contract. Keep those offline results distinct from site commissioning, especially with the separately engineered safety system outside this test.

Yes. The ownership dispute and offline defect are closed. Cell deployment is a separate reviewed job, with these test cases in its handover. Thanks Anika, the joint walkthrough found a second issue we would have missed by only stretching the pulse.