Bltouch blue light not on during power up but on after homing



  • Wondering if the behavior im seeing is an indication of something being wrong:

    • I power on my printer
    • Bltouch self tests
    • Bltouch sits at rest with only the RED led on
    • Z axis is homed and occurs successfully (Blue led turns on when probe deploys and then turns red when triggered)
    • BLtouch sits at rest with RED led on AND Blue led is now on

    BLtouch wiring
    2956ac09-154b-4863-945d-41252f8a1b0e-image.png

    Do I need to change a header to activate 5V_Ext for this? Looking at the Duet 3 wiring layout it lists this as 5V_EXT instead of just 5V

    I had asked another user with the same board (Duet 3 6HC) and he said his light was on at power up but since my self test and Z-homing seemed to be working fine I didnt think much of it.

    That is until I realized my heightmap was very bad.
    ea643fab-3c4d-451f-aa7c-8884cd9bca4f-image.png

    I've noticed that during probing this again differs from what I see on my Marlin machines. I'm using Marlin as my reference as this is my first dive into Duet 3 bed leveling and I have it working well on the Marlin side with BLtouch.

    Marlin

    • Solid red when moving between probing points
    • Blue when probe is deployed
    • Red when probe is triggered and it remains red until the next probing event

    Duet 3

    • Solid red when moving between probing points
    • Blue when probe is deployed
    • Red when probe is triggered but at some points it flashes red off for a split second and then turns back on until the next probe point

    This difference in probing behavior during G29 makes me think that is contributing to my poor height map paired with the weirdness I see during power up. I'm sure I have something off in my bed/config files but thinking I might need to figure the wiring out first. Open to any suggestions!

    Board: Duet 3 6HC
    Firmware: MB6HC 3.2 (2021-01-05)
    DWC 3.2.0


  • Moderator

    The difference you describe doesn't sound like a problem. It's working otherwise, isn't it?

    Post your M558 and G31 commands so we can see how you have it configured.



  • Great! Happy to hear that I might be overreacting and looking in the wrong area. It is indeed working as expected otherwise just wanted to rule out that being an issue.

    This is what produced the height level map above
    M558 P9 C"^io7.in" H5 F120 T6000

    After reading through other posts one of which I believe you commented on I changed to this

    M558 P9 C"^io7.in" H3 F60 T6000 A10 R0.75 S0.003 and this produced

    d40b61f6-f03e-409c-8d58-8c35146b4995-image.png

    Seems like an improvement with multiple probing, one thing I noticed with this new M558 is that at some points it will probe 2-3x but others a single time, how does it decide when greater accuracy is needed?

    G31 P25 X-5 Y48 Z2.67 ; set Z probe trigger value, offset and trigger height
    This is what has been used for both maps



  • @singhm29 said in Bltouch blue light not on during power up but on after homing:

    Seems like an improvement with multiple probing, one thing I noticed with this new M558 is that at some points it will probe 2-3x but others a single time, how does it decide when greater accuracy is needed?

    In M558 with an A value > 1 you should always see at least two probes.

    The process is to probe until two consecutive readings are within the range specified by S OR until the number of attempts specified by A are reached.

    If you use a S value of -1 it will average the number of readings specified by A

    Frederick


  • Moderator

    It looks like you need to relevel your bed as there is a tilt going down to the back.


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