Auto Bed compensation not correct

  • I've got a strage issue here with the auto bed configuration. The Z-Offset for the IR probe is set to 1.18 so when i do auto homing it moves the Z-axis to 1.18 and when i start the auto bed compensation the first point comes to 1.18 as well. Then for the scond point it comes to about 2.22 which is really strange because when i do it manually the IR probes light comes on when I am at 0.97.
    The really strange thing is that points 2-5 are all in about the same height but the first point is always much lower. No matter what I set for Z-Offset the difference between the first and third point is always more thant 1mm. Why is that?

  • Does no one have an idea?

  • administrators

    What sort of 3D printer is it?

  • It's an Ultimaker Original.

  • i have also noticed some inconstancy with my ir probe. I have a large format delta, using duet wifi, with a glass bed. I have tried sand blasting the backside of the glass, along with various colored paper glued to the back.
    I noticed that my probe points vary .2 to .4 mm in the same spot. and my calibration factors are all over the place every time a run a auto calibration i have also noticed that the value given on the DWC is very erratic at some heights, and almost none responsive at others. When lower the probe close to the surface, i will start getting erratic reading 180 and 300, as i bring it even closer it will go back to 0. as i step it closer, it will eventually jump to 466 at about 2mm above the bed and stay there as i continue to bring it down, it will then switch to 535 and turn the red led on and stay a that reading until it is at Z0. i have M558 set to mode 1, i get 4 led flashes when it powers up. both emitters are producing a light when viewed threw a camera and my power is 3.3v ground is 0 and the sensor voltage is also erratic when slowly bringing it close to an object.
    is this normal, or bad sensor. Its only 2 months old.

  • administrators

    Those readings of 180 to 300 indicate that you have a bad connection in your IR sensor wiring, or just possibly a cracked resistor on the sensor. You should only get readings that are very close to 0, 465 and 535.

  • Yes, my readings are correct. They re around 535 when triggering the bed to stop. Like I said, it all works correctly when I'm doing it manually. I just wonder why the auto bed compensation algorithm works and why the readings for points 2-5 are close to each other but way higher than point 1.

  • Still nothing to solve this problem?

  • administrators

    Have you tried measuring the probe trigger height at different places to make sure it is consistent? For example, measure it at the first and third points.

Log in to reply