DC42 Z-probe reporting -0.56 Z height

  • As the title says following the instructions on DC42 website the probe goes from a reading of 468 to 540 (and red LED) but the reported Z height at triggering is negative not 0.5-2.0mm.
    RepRapfirmware 2.05.1 Ormerod 2. Its raining here so no excessive radiation (IR, vis or UV!)
    If I put the -0.62 value in config.g will it work otherwise what's going wrong?

  • which buildplate?

  • What's a buildplate and how would I ascertain, purchased fromThink3DPrint3D in November 2018 Invoice #4873

  • on which surface are you printing 😉

  • Glass with Klapton tape on top and black paper under the glass which is supported on aluminum plate

  • @sinnedwrong

    Does putting a sheet of paper on the bed change the trigger height ?

  • The setup is as described on DC42 website

    Glass (with or without coatings such as hairspray, PVA or Kapton tape): works as-is if placed directly on a PCB bed heater or other surface that does not reflect strongly. If there is an aluminium heat spreader or bed plate underneath the glass, then either paint the aluminium surface matt black (see below), or put a sheet of matt black paper between the glass and the aluminium. Coatings on the glass affect the trigger height slightly.


  • @sinnedwrong

    Hi Dennis,

    I don't doubt it ... but if you put a sheet of paper under the probe does it change the probe height? as it may be seeing through the tape.

  • Doing the commissioning sequence from DC42 website but with a piece of white paper under the sensor and nozzle the Z axis reads 1.38 so within the range 0.5 to 2.5mm as required. I presume that even with the black paper under the glass there is not enough reflection from the klapton tape. Suggestions as I can't find a solution to this un the website. Thanks Dennis

  • @sinnedwrong

    Well good it appears to function as intended..
    My first suggestion would be that not all Kapton tape being equal possibly source a higher grade tape or my choice would be adhesive backed plain pei sheet avoid white text or such if possible these are relatively inexpensive from places like amazon/ebay which it what I use with my dc42 ir sensor with great success.

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