Duet 3 Toolboard extruder motor not idling down?



  • I'm going to put this in the beta firmware category as we didn't notice it until after upgrading to 3.2b1. What we are seeing is our extruder motors are getting very warm to the touch when not in use when all other motors are cool. We've also noticed an audible humming coming from the extruder motors which leads us to believe they are not idling down like they should..

    This is on a Duet 3 / RPi running 3.2b1.

    Our config is as follows and we've adjusted I several times but it hasn't yet made a difference.

    M906 X1700 Y1700 Z1800 E1120 I10
    M84 S30
    

    Is there anything we can do to better diagnose this issue?
    Thanks



  • Update- I believe this is only happening after printing. I just unplugged a machine for maintenance and monitored it when I brought it back online. It’s been 20 minutes or so and the extruder motor is cool to the touch..


  • administrators

    @oozeBot said in Duet 3 Toolboard extruder motor not idling down?:

    Update- I believe this is only happening after printing. I just unplugged a machine for maintenance and monitored it when I brought it back online. It’s been 20 minutes or so and the extruder motor is cool to the touch..

    Have you run the motor that is cool to the touch since you brought it back online? if a motor has not been used since the board was powered on or reset, then the motor(s) will not have been powered up.



  • @dc42 - good to know. No, I hadn't.. I'm actually now wondering if it has to do with a separate issue where the printer is still showing active after a print is complete. I'll do some more testing..

    Also, I'll test by restarting, let it cool, move the extruder motor to activate it, and then wait and see if it heats up..



  • I’ve not had much of a chance to test this until tonight.. after a print, I logged in through SSH and rebooted the RPi. After sitting idle for about an hour, I checked and the extruder motor was at 50c and humming. Ambient was around 26c. Should this have reset the extruder motor? I currently have the idle factor set to I20.

    I’ll keep working on diagnosing exactly what is happening. I had hoped the object model would show live current readings but it appears it only shows what’s set in the config..



  • @dc42 - I left a printer on overnight in a idle state. It is still early here and the office is quiet - other than the toolboard stepper motor. I can hear it from across my workbench.

    I just checked and all other motors are silent and at room temp (28c). The toolboard stepper is 47c..

    I believe there is something wrong here. I'm more than willing to assist if you or someone else can guide me on what needs to be checked?

    My configs have changed slightly, so here is the relevant part:

    M906 X1600 Y1600 Z1600 E1120 I25		; Sets motor currents (mA) and motor idle factor (I) in percent
    M84 S300					; Sets idle timeout
    

  • administrators

    I suspect you are right and idle current reduction is not working on tool and expansion boards. I will look into it. You should be able to use M917 though. The wiki says the default is 100% but I think that's wrong for tool boards, it's either 71% or 75%.



  • @dc42 thank you. I'll look into this.

    I just ran M999 on the machine and it quieted down considerable (I can now hear all motors barely idling). The toolboard stepper is much quieter now and has already dropped to 40c. I'll monitor it a bit longer to see if it cools to room temp.


  • administrators

    After a reset, if you have never commanded any movement from the tool board motor then it should be off completely. Same with all the other motors.



  • @dc42 well M917 didn't seem to work.. unless I just don't know what I'm doing. After a job completed today, I ran M917 E0 and marked the extruder temp at around 48c. I checked it about 30 minutes later and it was at 78c!


  • administrators

    @oozeBot said in Duet 3 Toolboard extruder motor not idling down?:

    @dc42 well M917 didn't seem to work.. unless I just don't know what I'm doing. After a job completed today, I ran M917 E0 and marked the extruder temp at around 48c. I checked it about 30 minutes later and it was at 78c!

    What M917 command did you use?



  • @dc42 from the console in DWC:

    M917 E0
    

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