Last wish for a duet 0.8.5 Bug fix…

  • So I know that us, poor mortals with the older duets, are not going to get any updated firmware any more. I don't know what to say, it's a little bit frustrating.. I bought my Duet just before the DuetWifi was even announced. So it's been less than two years ? I will surely upgrade, but finances dictate other priorities at the moment.

    Anyway, I had this problem for a while now, I posted on the reprap forum about it but never managed to fix it. Seems that David finally discovered the bug and implemented a fix for it, but the 0.8.5 is not supported any more in that release! It's about the "jerky curves when pressure advance is used and the slicer doesn't command a uniform extrusion rate" fix in the version 1.21RC1. I had this issue for a long time and because I am a S3D user, my duet was always printing small curves and circles like it was grinding on a course stone. So bad that some of my prints were coming out with really ugly surface finish and roughness on those curved surfaces. Using another slicer somehow fixed the issue, but having paid for a S3D license I would rather get it fixed in the firmware.

    So, as a "last wish", would it be possible to implement this fix in the 0.8.5 firmware as well? I am really curious if that will fix the issue that plagued me in the last to years.

    By the way, on my duet, last working firmware is 1.20 RC1, everything above that and my end-stops are not triggering any more. Is there a known issue or my config needs to be updated? Haven't found anything in the release notes regarding that..

    Thanks in advance!


  • administrators

    Actually, release 1.21RC1 is available for the older Duets.

    What type of endstop switches do you have, and how do you have them set up in config.g?

  • Hi David,

    I tried with 1.21RC1 as well, but the printer started acting strange. When homing, it drove the axis in the wrong directions (or it was the Pause script automatically loaded?) and endstops were also not triggered.
    I have optical end-stops.

    Please ignore the comments, they don't reflect the settings…
    This is my movement section:

    M584 X5 Y6 E3:4:0:1:7:8
    M569 P0 S1                          ; Drive 0 goes forwards (change to S0 to reverse it)
    M569 P1 S1                          ; Drive 1 goes forwards
    M569 P2 S0                          ; Drive Z goes backwards
    M569 P3 S0                          ; Drive 3 goes forwards
    M569 P4 S1                          ; Drive 4 goes forwards
    M569 P5 S0
    M569 P6 S0
    M574 X2 Y1 Z0 S2
    M574 E S1					; set endstop configuration (X and Y endstops only, at low end, active high)
    M906 X700 Y900 Z900 E1400 I50           ; Set motor currents (mA)
    M201 X1600 Y1600 Z15 E20000            ; Accelerations (mm/s^2)
    M203 X20000 Y20000 Z450 E15000       ; Maximum speeds (mm/min)
    M566 X1800 Y1800 Z30 E1800              ; Minimum speeds mm/minute
    M208 X330 Y285 Z340					; set axis maxima (adjust to suit your machine)
    M208 X0 Y0 Z0 S1					; set axis minimum (adjust to make X=0 and Y=0 the edge of the bed)
    M92 X80.5 Y80.5 Z1605					; Set axis steps/mm
    M92 E146:146                     	; Set extruder steps per mm
    G21                                 ; Work in millimetres
    G90                                 ; Send absolute coordinates...

    Z-Probe Section:

    M558 P4 X0 Y0 Z1 H0.7 F100 T5000	; Smart IR Z probe, used for homing Z axis, dive height 3mm, probe speed 200mm/min, travel speed 5000mm/min
    ;G31 X18 Y-35 Z3.95 P500           ; Set the probe height and threshold (put your own values here) - 0,3 nozzle
    ;G31 X18 Y-35 Z5.15 P500	; 0,6 nozzle
    ;G31 X18 Y-35 Z4 P500		;0,2 nozzle
    G31 X18 Y-35 Z3.90 P500		;0,3 nozzle
    M557 X18:330 Y0:285 S50

    I have read all the release notes and what to pay attention to, but maybe I forgot or not understood some of it..


  • So… sorry for pushing this, but is there something I can do to fix the end-stop issue and run on the latest 1.21RC1?

  • administrators

    Please test your endstop switches as described at, also there are some troubleshooting tips for optical endstops on that page.

  • Thank you for replying, David. I checked everything I could check, wiring is fine, leds are working as they should.
    The thing is, 1.20RC1 is working, I am flashing 1.20RC3 or RC4 and suddenly they don't any more. Checking with M119, they don't get triggered when interrupting the opto-barriers. I flash back to 1.20RC1 and everything is back to normal.

    I noticed something. I am using M574 E S1 and M558 P4 in my config. Should I use M558 P6 instead and get rid of M574 E ?


  • administrators

    How are you interrupting the opto switches? It may be that the material you are using to block the slot is not sufficiently opaque.

  • The printer was build by me from the ground up. 2mm thick stainless sheet is opaque enough. Leds are turning off completely. Why should anything change on the hardware and electrical side by burning another firmware?

  • administrators

    Some firmware versions have the internal pull-up resistors enabled on the endstop inputs , others don't. Neither setting is ideal for all endstop types.

    The problem with optical endstop in particular is that they sometimes leak current even when they are supposed to be triggered, either because the slot isn't being fully blocked by opaque material or because the phototransistor leaks. Most optical endstops include on-board pull-up resistors that will counter the leakage. Perhaps your endstops don't. Can you post a schematic of them, or at least a photo?

  • These are the endstops that I use:

    I will measure the voltage on the endstop input pins when I get back home later in the evening and will post the results.

  • administrators

    Please post a schematic of the endstop. If there isn't one, post photos of the other side (and buy open source endstops next time).

  • Well, it's the first time I hear that there are open source (and closed source) endstops.
    Anyway, here is the other side of the endstop:

    It's the standard optical endstop found from hundreds of sellers on ebay.

    I measured the voltage on the input signal:

    no interruption: 0.99 Volt
    endstop interrupted : 3.26 V
    Voltage on the V-in pin : 3.27 Volt

    So it gets the whole Vin voltage on the pin. I am looking again at my M574 X2 Y1 Z0 S2. S2 is now used for the Z probe to home axis, which is not my case. Should I use S1?

    Later edit: I changed my M574 to S1 and M558 P4 changed to P6 and got everything working fine now. I guess I just had to RTFM better..

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