Problems with BLTouch V3.1



  • @btmerz My sensor is blue when the pin is down and solid red when the pin retracts. It does blink red when the pin is up and the alarm mode is triggered.



  • So then it could be, that I have a defective sensor? When I deploy the probe with M401 it is dark (red switches off, no blue).



  • @btmerz said in Problems with BLTouch V3.1:

    So then it could be, that I have a defective sensor? When I deploy the probe with M401 it is dark (red switches off, no blue).

    do you use M501 and config-overwrite.g?



  • No,
    sorry, but what's that for?
    Doest it read the whole config at power on?
    What should be inside the config-overwrite.g file?



  • it could overwrite your settings. please post the entire config.g



  • @btmerz said in Problems with BLTouch V3.1:

    I also tested it without the Touch SW Mode - same negative result.

    So you created the two files I mentioned and entered in the correct M280 commands?

    Did you verify operation using M401 and M402?

    Frederick



  • @fcwilt yes. M401 and M402 are working as expected. Deploying and retracting the pin.



  • @delvis said in Problems with BLTouch V3.1:

    @fcwilt yes. M401 and M402 are working as expected. Deploying and retracting the pin.

    Well then it should work in all instances that rely on M401 and M402.

    Try changing the P parameter in the G31 command to 20.

    SInce M401 and M402 work we know that the wiring that controls the BLTouch is working.

    What we don't know yet is if the wiring which sends the signal to the Duet is working. If something is wrong there that could explain the problem you are seeing.

    Double check that wiring.

    Frederick



  • Check the white wire especially. I believe that is the signal wire.


  • administrators

    It sounds as though either the BLTouch isn't triggering, or there is a short circuit between the signal output and ground, or the internal pullup resistor in the Duet MCU isn't working. Suggestions:

    1. Send M558 without parameters and check that it reports probe type 9.

    2. Disconnect the white wire from BLTouch to the Duet (and the black wire at the same time if it's easiest, it doesn't matter). The Z probe reading in DWC should jump to 1000. If it does, that implies that the BLTouch isn't triggering, or that its output has a large leakage current, or there is a stray strand of wire shorting the white and black wires together.


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