Precision Piezo z probes guide for duet users reference



  • Hi
    I have installed the Orion piezo and it works . When performing G29, the first 6 point are probed, then it will always trigger before probing at 1 specific point on the bed (left,back, point number 7)....I think this has to do with some more movement due to the cable at that point...is it possible to pause a bit in G29 before probing, to let it stabilize...couldn't find a parameter for that. When doing G30 at the problem x,y point it always probes correctly



  • BTW I have this in config.g
    M558 P5 I1 R0.9 F120 X0 Y0 Z1 T3000¨ ;Piezo
    G31 X0 Y0 Z-0.1 P100 ;piezo



  • It seem sthat M558 R0.9 (before 0.4) works
    Description of M558 is confusing
    "Z probe recovery time after triggering, default zero " I think it means before probing not after triggering. Or?



  • So R is a pause before probing. Use around 0.4 seconds, some points on the bed might false trigger if your bowden cable goes tight.



  • I have an Orion on a new build (not in service yet). I'm using this in config.g:

    ;Precision Piezo Orion
    M558 P8 I1 H5 R0.5 F150
    G31 X0 Y0 Z-0.05 P600

    Last night I finally got the Orion wired and was able to home Z with it several times... all was well. This afternoon I came back to it, and it crashed the bed (not bad, I have the speed fairly slow and was able to kill it quickly). I discovered that the blue LED (trigger) is constantly lit. What can cause this?

    Thanks!



  • I would check the calibration potentiometer. Adjust it as per the documentation. It is a good idea to make this adjustment, at the temperatures you would normally use when probing the bed. So if thats with heaters off, calibrate with heaters off and vice versa. Piezos do change sensitivity when heated or cooled, its a very sensitive instrument.



  • I am having trouble getting my new peizo to trigger using G30, it works when I run homez.g but when I run G30 it just crashes into the bed.

    Is the issue with my M558 line?

    ; homez.g
    ; called to home the Z axis
    ;
    ; generated by RepRapFirmware Configuration Tool on Sat Jul 21 2018 13:51:16 GMT+1200 (New Zealand Standard 
    Time)
    G91               ; relative positioning
    G1 Z5 F6000 S2    ; lift Z relative to current position
    G1 S1 Z-295 F1800 ; move Z down until the switch triggers
    G92 Z2.5          ; set Z position to trigger height
    
    ; Uncomment the following lines to lift Z after probing
    ;G91              ; relative positioning
    ;G1 Z5 F100 S2    ; lift Z relative to current position
    ;G90              ; absolute positioning
    

    From config.g

    ; Z-Probe
    ;M558 P0 H5 F420 T6000             ; Set Z probe type to switch and the dive height + speeds
    
    G31 X0 Y0 Z-0.1 P600               ; Set Z probe trigger value, offset and trigger height
    M557 X15:305 Y15:285 S20          ; Define mesh grid
    M558 P8 H5 I1 R0.4 F1800 X0 Y0 Z0

  • administrators

    See item #1 in the FAQ page on the Duet3d wiki.



  • I have a concept i would like to test including piezo. I have bought a set for my extruder assembly but had difficulties mounting it and i scrapped that idea and using prusas induction probe ever since. Resolution is very good and i am happy with it. That being said i have thought of a concept that i would like to validate with you clever people.
    i have large cartesian printer based on CR10S4 frame. As i have piezo "in stock" i would like to try and use it as tool offset. Mainly the idea came from thinking about e3d tool changer.
    I want to mount piezo disc on the frame beside the bed. i will know piezo Z offset from the bed which will be constant. If i can have duet and piezo cooperate so the Gcode would move my nozzle off the bed where piezo disc is located and touch it to record Z offset then go about the routine of mesh mapping with induction probe.
    This would eliminate the need to fiddle with Z offset all together, when you change the nozzle, clean a clog or do maintenance.
    Any outside pointers on this?
    alt text



  • I don't see any reason why this wouldn't work, others are working on a similar idea using the new M585 command.

    Idris



  • @moriquendi said in Precision Piezo z probes guide for duet users reference:

    I don't see any reason why this wouldn't work, others are working on a similar idea using the new M585 command.

    Idris

    Can you point me to those workings?



  • @agniusm I can't I'm afraid, he's not published it yet so it's not on a forum. No doubt when it's ready I'll be able to link to it.

    Idris



  • Maybe I missed something in my M558 setup but I can't seem to get analog to work on the Orion? Does the Orion have an analog signal? I've watched DWC while moving/probing and its either at 0 (red light) or 1000 (blue light), I don't see any numbers in between.



  • @tjb1 The Orions output is strictly digital, you will only ever see 0 or 1000 unless there is noise on the signal wire.

    Idris



  • @ajcraig99 Sir. Did you get it working?



  • What I have to do if I want to reset a piezo 20 to factory value?
    I have doubt that it is broken.
    Other questions, if I use P1 in M558 so I can change sensitivity on the fly, the P in the g31 is useless?



  • Which version of the Piezo20 do you have, there is a version number on the back, underneath the piezo connections pins.

    You cannot change the sensitivity using P1, the output of the module is digital, it's either on or off. The only way to adjust the sensitivity is with the potentiometer/s on the board.

    Idris



  • @moriquendi said in Precision Piezo z probes guide for duet users reference:

    Which version of the Piezo20 do you have, there is a version number on the back, underneath the piezo connections pins.

    I have the piezo20 v0.6

    @moriquendi said in Precision Piezo z probes guide for duet users reference:

    You cannot change the sensitivity using P1, the output of the module is digital, it's either on or off. The only way to adjust the sensitivity is with the potentiometer/s on the board.

    Idris

    Sorry Idris i badly explained myself, i meant that if i use P1 instead of P5 or P8 for example:

    M558 P1 I0 R0.4 F330
    G31 X0 Y0 Z-0.1 P100

    Than i can use VR1 on piezo PCB to adjust the sensitivity on the fly but the threshold P100 in the G31 is useless or it is still used?



  • To reset the v0.6 to factory settings, turn VR1 and VR2 so that the flat part of the adjuster is closets to the bottom of the PCB.

    You CAN use P1 but it has no advantage over P5 or P8 and may have some disadvantages. The output of the PCB is either 0v (roughly) or 3.3v (again roughly, later boards are better at this, they go closer to 0v but for this explanation assume 0v). The duet reads these values as either 1000 or 0. Because the output is digital, the value is either 1000 or 0 but nothing else inbetween. So the threshold makes no difference except that noise or interference on the signal wire might cause a false trigger.

    David might be able to give more detail about how the firmware processes P1 and P5/8 differently.

    TLDR: use P8

    Idris



  • @moriquendi said in Precision Piezo z probes guide for duet users reference:

    To reset the v0.6 to factory settings, turn VR1 and VR2 so that the flat part of the adjuster is closets to the bottom of the PCB.

    Last question, clockwise or counterclockwise?

    @moriquendi said in Precision Piezo z probes guide for duet users reference:

    David might be able to give more detail about how the firmware processes P1 and P5/8 differently.

    it isn't necessary, it was just a curiosity.

    Thank you for your help Idris


 

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