Walk Home ?

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    Simple script, does not work. Stepper motors chomp.
    Axidraw SE/A3, firmware 3.7.0

    Start with Axidraw at home.

    I run this python script:

    from pyaxidraw import axidraw # Import the Axidraw module


    x_step_length_mm = 124
    y_step_length_mm = 44

    ad = axidraw.AxiDraw()
    ad.options.mode = “manual”

    ad.options.manual_cmd = “walk_mmy”
    ad.options.walk_dist = y_step_length_mm
    ad.plot_run() # moves properly

    ad.options.manual_cmd = “walk_mmx”
    ad.options.walk_dist = x_step_length_mm
    ad.plot_run() # moves properly

    ad.options.manual_cmd = “walk_home”
    ad.plot_run() # Stepper motor goes nuts.

    Windell Oskay


    Testing with the current release version ( AxiDraw Command Line Interface 3.7.2; AxiDraw Software 3.7.1), I’m not currently able to reproduce the issue with this script. I downgraded to 3.7.0, and I’m still not able to reproduce it.

    Check to make sure that you have EBB firmware 2.6.2 or newer; the current version is 2.8.1.

    One subtle thing about the walk_home command is that it tries to move the carriage to the position where the motors were enabled (or, last time the resolution was set), by querying the total sum of motor steps since then. This isn’t necessarily the same as where the “software” origin is located; a temporary origin is created each time that you call ad.plot_setup, for example.

    If there has been a position-loss event — grinding motor noises etc. — then you may want to try resetting the AxiDraw (unplug power and USB) or disabling then re-enabling the motors to be sure that it’s position is reset. Otherwise, it may not know the correct direction and distance from its current position to that power-on position.


    How do I check the EBB firmware?

    Inkscape options are:
    This is AxiDraw Control version 3.7.0.
    Your AxiDraw Control software is up to date.

    Your AxiDraw has firmware version 2.8.1.
    Your firmware is up to date; no updates are available.

    Additional system information:
    3.10.4 (main, Apr 10 2022, 21:38:20) [Clang 13.0.0 (clang-1300.0.29.30)]
    Voltage readout: 7 (~ 0.51 V).
    Current setpoint: 542 (~ 0.99 A).


    Found the problem — you’re right.

    I had reset the system by just removing 9V power from the Axidraw. But I left the machine connected to the USB cable. *sigh*

    1) Before running the program, I pull the 9 volt power supply
    2) Remove the USB connection.
    3) Plug in both of these connectors.
    4) Now run the program. It works!

    Windell Oskay

    Looks like your firmware is up to date; that all looks just fine.

    Instead of physically unplugging, I do expect that either rebooting the EBB or disengaging the motors first would work just as well. (There’s no CLI command to reboot the EBB, but I can write you a very short python script to do so if that’s helpful.)


    Related question:

    In /manual/ mode, is there any way to speed up the motion?

    ad.options.mode = “manual”
    ad.options.speed_penup = 110 # nope, not for manual mode`
    ad.options.speed_penpendown = 110 # nope, not for manual mode`


    Windell Oskay

    At first glance, I agree that something looks wrong there; probably a bug. I’ll look into it and report back.

    Windell Oskay

    This too is subtle: you have ad.options.speed_penpendown there, not ad.options.speed_pendown — which does work.

    After fixing *that*, this seems to be more responsive.

    A separate question is why does it assume that the pen is down? And, that may be a bug proper. (The pen state is somewhat undefined until it is asserted, and that’s part of the problem.)

    Add this above your move commands to ensure that the pen state is well defined:

    ad.options.manual_cmd = "raise_pen"

    Yep, you caught me again! How’d I make that goof?

    Thanks from your all-too-error-prone axidraw addict!

    • This reply was modified 1 month ago by CliffStoll.
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