Strange behavior after a pause and reprint?

  • I have been playing with my Wi-Fi duet for a couple of months now. I have noticed that after a pause and cancel when trying to restart the print the extruder will start to move and extrude even though temperature may not be up yet? The extruder will continue moving in air without extruding until temperature gets to the target. This is a very repeatable behavior. One other strange thing I have noticed is that after printing and completion of a good print I have the extruder go to a park position. When I try to restart from the PC web interface and run a new G-code program the extruder will just start extruding about 100 mm in the park position and start to oscillate the extruder followed by a disconnection of the PC web interface. Trying to reconnect and run the same G code the behavior is the same with a disconnection. Any ideas? Has anyone else experienced the same?

    Thanks for the help, have a great day!

    Werner Berry
    BerryBot3D Pro

  • administrators

    Hey Werner

    I presume you have your hotend cool down during the pause (maybe switch to standby?) If so do you have commands in resume.g to heat back up and wait (M116) until the active temperature is achieved before restarting?

    Also it sounds like you may have some retract/unretract commands in there that are protected from absolute/vs relative extruder extruder moves with M83.

    Please post your pause.g and resume.g files and we can help further.



  • administrators

    You have two issues:

    1. After you cancel a print, you are not selectin a tool (T0 command) prior to heating the hot end. Workarounds include:

    a) In your slicer start gcode put T0 followed by M116 at the start

    b) Upgrade to firmware 1.17RC1, which spots when slicers try to heat a tool and wait without selecting it first, and auto-selects the tool

    2. As Tony says, you are using absolute extruder coordinates and you are missing an M83 command somewhere.

  • Hi Guys thanks for the replies! Please keep in mind it happens when a part is completed and in park position then a fresh print started. Do you think I should have an M83 at the beginning of my start?

    Thanks for the help!

    This is my start script in S3D:
    G0 X-180 Y70 Z1 F6000
    G92 E0
    G1 E60 F300
    G92 E0
    G1 E-.1
    G0 X0 Y0 Z5 F6000
    G1 F6000

    ; Pause macro file
    M83 ; relative extruder moves
    G1 E-4 F2500 ; retract 4mm
    G91 ; relative moves
    G1 Z5 F5000 ; raise nozzle 2mm
    G90 ; absolute moves
    G1 X0 Y85 F5000 ; move head out of the way of the print

    ; Resume macro file
    G1 R1 Z2 F5000 ; move to 2mm above resume point
    G1 R1 ; lower nozzle to resume point
    M83 ; relative extruder moves
    G1 E4 F2500 ; undo the retraction

  • administrators

    Please show us the first and last 20 or so lines of one of your gcode files.

    I recommend that you change the S3D configuration to generate relative extruder coordinates. Although absolute coordinates should work too.

  • administrators

    If you do use absolute extruder moves remember to add M82 at the end of your pause, resume and start gcode

  • administrators


    If you do use absolute extruder moves remember to add M82 at the end of your pause, resume and start gcode

    That's not necessary. RRF saves the relative/absolute extrusion state before running any macro file, and restores it at the end. In firmware 1.17, this state is maintained separately for each input channel.

  • administrators

    So if I set relative mode explicitly in a macro I don't have to unset it?

    Cool, learn a new thing everyday!

  • Thanks Guys! I think I have it all working great!

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