The PLC sends a short inspection request that our application sometimes misses. I asked when it gets cleared and received two answers: after the timer, and after acknowledgement. Or perhaps those describe different versions; nobody has established that yet. This is the ordinary job handshake, separate from the engineered safety functions.
Have the two interface owners identify the installed versions before reconciling their descriptions. Then walk through one request, receipt, result and clearing sequence together. Include what happens when the application never sees the request, not just the normal successful path.
A timer clearing it in the trace. The acknowledgement answer came from an older interface note. Both developers agree those are different now, so that confusion is cleared up.
And what is the operator told when the request disappears? If the current answer is press again, the handover may already be teaching a retry nobody has defined.
Imran, a replacement sequence is being drafted together. Jamie, the commissioning note says request again if nothing happens. I've flagged that for withdrawal while they define the unanswered-request case.
The replacement should distinguish receipt from completed inspection, with an attempt identity and explicit ownership for clearing. Also decide how a timed-out attempt is reconciled before any repeat is permitted.
I would ask them to include the operator-facing outcome in their walkthrough, too. Two systems can agree with each other while the person waiting beside the fixture has no idea whether to call maintenance.
Jamie, yes. Especially a timeout with receipt uncertain. The visible message needs to describe that uncertainty, not imply that the housing has definitely remained uninspected.
The draft now has separate received and inspection-complete events. It also holds an uncertain request for review instead of offering an automatic repeat. The owners still need to define restart on either side.
Maintenance lead for that shift, Farah. Imran, the attempt-identity lifetime is in the restart discussion. The family name is only descriptive in the new draft.
Does the maintenance lead have an agreed reconciliation method yet, Rachel, or just their name in the box? That is the bit they will actually need when called.
Just the named responsibility so far. Method still being defined with the interface owners. Thanks Jamie, I've made that outstanding work explicit beside the role.
An offline walkthrough with an old completion arriving after a restart would help review both identity and reconciliation. Keep a missing receipt case separate; they need not have the same available evidence.
Those two cases are on the review sheet now. No commissioning sign-off from this thread; we have a much clearer set of unanswered questions than when I started.