BLTouch bouncing between probe points



  • During mesh compensation, the head goes down until it trips the sensor and starts raising the head but before it gets high enough to clear, the BLTouch is releasing the pin causing it to bounce off the bed until Z finishes raising. Is there any way to keep the pin raised for a bit longer to allow the Z to raise?


  • administrators

    Yes, upgrade to firmware 1.21RC3 (read the upgrade notes!) and use probe type 9 in the M558 command.



  • I've upgraded and still notice this issue. Probe hits the bed and retracts as normal, then is released for next probe before Z finishes raising. Also have the had the probe drop a few times in the middle of a print. I will test moving the cable outside of the chain to see if it still drops in the middle of a print.



  • If it's dropping in the middle of a print, consider the following two possibilities:

    1. The +5VDC power wire isn't stable (there's a break in the wire, a bad connector, etc.)

    2. The BLtouch "core" needs to be adjusted. (google for "bltouch core adjustment")



  • @garyd9:

    If it's dropping in the middle of a print, consider the following two possibilities:

    1. The +5VDC power wire isn't stable (there's a break in the wire, a bad connector, etc.)

    2. The BLtouch "core" needs to be adjusted. (google for "bltouch core adjustment")

    I'm not seeing anything for adjusting the core other than "Adjust the solenoid core to the factory settings.", I guess I can just try either direction to see if it helps.



  • Copied from from https://www.indiegogo.com/projects/bltouch-auto-bed-leveling-sensor-for-3d-printers#/:

    Magnetic force is weak between push-pin and solenoid.

    1. Adjust magnetic-control (turn clockwise of counterclockwise) core little by little (Max 0.6 +/- 0.3mm) with allen key.

    It doesn't state which direction, or even the thread spacing (so you just have to turn it a bit in some direction to see what happens.) I'd try one direction for a 1/2 turn (and write down the direction you turned.) Try it and if the problem is worse, undo the turn you made and turn it 1/2 way the other direction.



  • I've adjusted that and can't really tell if it's working or not. It didn't drop yesterday but it went into alarm shortly after starting the print. I'm going to try adding another ribbon cable for the BLTouch tonight and see if that works. Maybe the one from TriangleLabs isn't a great copy? I'm hesitant to spend $40-50 for an "authentic" one that may have the same issue.


 

Looks like your connection to Duet3D was lost, please wait while we try to reconnect.