Maximize heater sampling rate for troubleshooting

[Yonkiman]

I just had a heater fault stop my print about 18 hours into the print. It's clearly something that fails very infrequently. I've been moving/tapping wires and couplers to try to catch the temperature jumping but haven't been able to.

I was thinking that it would be great to have a test mode where the temp for a chosen heater could be sampled as fast as possible and displayed on the temp graph. That way (hopefully) I could tap/wiggle things around, and a disconnect as short as a few ms would be captured, narrowing down what part of the wiring I need to rewire.

[dc42]

You an use M135 to adjust the temperature sampling interval, see https://duet3d.dozuki.com/Wiki/Gcode?revisionid=HEAD#Section_M135_Set_PID_sample_interval. Odd things may happen if you set it too low.

[Yonkiman]

@dc42 Thanks - that should help debug.