1 Topic by mlove01001101

  • mlove01001101
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Topic: Tuning the bed's PID controllers

How would I go about doing this?  My bed's temp is currently oscillating with an amplitude of around 5-10 degrees C.

2 Reply by grob

  • grob
  • grob
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Re: Tuning the bed's PID controllers

As solidoodle ships them, the bed is a 'bang-bang' type control: when it gets about a few degrees over the set temp, it switches off, and if it gets a few degrees below, it switches on. It saves processing time, and the resulting 5-10 degree sawtooth doesn't cause too much trouble - the thermistor temp moves much quicker than the actual bed plate, so the real surface temps will be oscillating much less than it looks!

You can enable PID for the bed (the board will happily handle it), but it requires updating the firmware to enable it. Look up 'bed pid' on this forum to find some instructions. You'll also need to read up on updating the firmware, which can be a fussy process! Be prepared...

There is a basic set of PID values to start with (these are in the adrian/lawsy community version of the firmware), but they can be tuned to suit your individual printer much the same way as the extruder PID with a different set of M codes. Look up 'reprap g code' on google to find a great list of all the instructions on the reprap wiki.

SD3. Mk2b + glass, heated enclosure, GT2 belts, direct drive y shaft, linear bearings, bowden-feed E3D v5 w/ 0.9° stepper
Smoothieboard via Octoprint on RPi

3 Reply by mlove01001101

  • mlove01001101
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Re: Tuning the bed's PID controllers

Thanks so much for the answer! That really helps.