Our FR10 read-only display pauses when detailed logging is enabled, while the separate cell controls continue normally. How can I distinguish slow reads from blocked file writes?
Measure the read and the write separately in the diagnostic app. I'd start with elapsed timings kept in memory for a short controlled comparison, so the measurement itself doesn't add another file write to every update.
That explains why the existing log can't separate them. Ask for display-update timing too, because the data might arrive promptly and then wait behind another job on the screen's thread.
Is the folder local or shared? Our diagnostic utility looked like it had lost the controller whenever the network share stalled. Different machine, same wonderfully misleading symptom. We only found it after timing the output stage.
Worth checking, though even local storage can stall. I'd avoid moving everything around until you've captured which stage accounts for the pause; otherwise you may remove the symptom without learning what delayed it.
The age display will help people interpret a pause. If they later move logging to a queue, ask what happens when that queue fills; an endless memory backlog would just postpone the problem.
Document what a stale display means for the person using it, including how they obtain current diagnostic information. Since this is separate from cell control, its frozen value should not quietly become an operator's assumed live status.