Pen came up on its own while drawing

[Windell Oskay]

The “Toggle” command is provided specifically for this purpose. It toggles the pen between up and down, and does not require a file name. This is the equivalent of the toggle option in the Setup tab of AxiDraw Control within Inkscape.

https://axidraw.com/doc/cli_api/#toggle

• This reply was modified 5 years, 1 month ago by Windell Oskay.

[Windell Oskay]

Separately: Axidraw -M pen_up is not a valid command for the AxiDraw CLI.

I *think* that what you are looking for is:
axicli -m manual -M raise_pen, which will raise the pen and does not require an input file name.

If you use axicli -M raise_pen (or axicli -M pen_up), it will require a document, and plot that document, rather than raising pen. The -M specifies which manual_cmd to run, but since you have not specified any mode other than the default mode (plot), the AxiDraw will run in plot mode and ignore the value of the -M switch.

[vincentP]

Thanks again.

“Toggle” is further down the page than “pen_up”
I stopped reading at “pen_up”

🤡

[Windell Oskay]

No worries; don’t hesitate to ask if something doesn’t work as expected. Sometimes it’s a bug that we don’t know about. :)

[vincentP]

Well, I’m back.

The servo has apparently quit completely.

Is there a way to test this?

“Axicli -m toggle” no longer moves the pen (it did for a while).

I might get a prompt back immediately as if it had worked, or I might get a “failed to connect to axidraw” message after a bit of a wait.

I had one sketchy usb cable, but replacing it (with several different cables) has not gotten the servo to move.

So, it does not respond to “axicli -m toggle” and it does not respond when attempting a plot, that is, the pen holder runs around the paper as expected when plotting but the pen does not move up or down where I would expect it to.

Dead servo? Is there way to test other than “toggle” ?

And separately: the toggle command solves my issue with adjusting the pen, but earlier attempts to get axidraw extensions installed in inkscape on raspian suggest that this may be difficult, if not impossible.

Commands to update and install inkscape thinks an old inkscape is current, and my attempts to install from a personal repository suggest that raspian won’t recognize the commands to do that.

The command line interface seems to meet all my needs so far, but someone else down to line might get frustrated by this.

[Windell Oskay]

It sounds like you have multiple unrelated issues going on here– from USB cables to difficulty installing Inkscape. I would highly recommend that you try to solve one at a time. This can get frustrating quickly otherwise.

If you are getting messages that say “failed to connect to axidraw”, then something is wrong. That could be a USB cable, trying to connect to the AxiDraw too soon after starting up the Raspberry Pi (I suggest to give it a solid 15 second waiting period after booting for it to recognize USB devices), or something entirely different. If you aren’t sure whether an issue is due to the RPi or the AxiDraw, you might try connecting to your computer instead.

There are any number of different commands that can test whether the servo is moving — these include (yes) toggle, but you can also use the manual lift and lower commands, direct commands from the interactive python API, direct EBB commands, the setup tab in Inkscape, and plotting files.

If the servo motor is not raising and lowering but X and Y motion are working correctly, then the servo could be dead, but that can also result from having the pen-up and pen-down heights set the same or having the servo motor disconnected.

I’m not sure what the toggle issue has to do with installing Inkscape.

I have not had difficultly installing Inkscape on Raspberry Pi, but I definitely recommend against doing it– it’s a small computer with relatively few resources (speed and memory). If there is any way to do what you need to on the R Pi _without_ using Inkscape, I highly recommend that you do so.

[vincentP]

The obvious approach, connecting the axidraw back to my laptop, did not occur to me. I’ll try that tomorrow.

Pretty sure the “failed to connect” issue was a bad usb cable (a working cable that died while I was using it).

If pen up and pen down were somehow set the same, would “toggle” show movement?

[Windell Oskay]

If pen up and pen down are the same level, toggling between them will show no movement.

[vincentP]

Connected axidraw to laptop running inkscape.

Everything works except pen up / pen down.

This looks like bad servo.

[Windell Oskay]

I’m sorry to hear that — it looks like you’ve followed up separately about a replacement.

[vincentP]

Replaced the pen lift servo.
Working properly again.

Thanks for the quick turnaround on that.

[vincentP]

Dead servo again.

So I have maybe twenty hours total run time on the Axidraw before the servo died.

To be clear, that’s twenty hours of servo run time.

Maybe ten hours of a single continuous plot.

Is it possible that the belt is building up static charge when running continuously?

I ask because it has quit twice when I touched the usb cable after the plotter had been running for many hours.

(Touched, not wiggled.)

Is twenty hours of run time anywhere near the life cycle for these servos?

If not I’ve got something else going on.

I’m inclined to try grounding the Axidraw to the Raspberry Pi to see if that makes any improvement.

[Windell Oskay]

Yikes. That is not a very good lifetime. In most cases, with regular plotting duty cycles, servos last from months to years. However, some individual units do fail sooner. The most important considerations, as I already mentioned, are the conditions. Heavy duty cycle (constant up/down motion) can lead to heating, and that can lead to overheating under certain other conditions.

(I don’t have a date on it yet, but we *are* looking into servo alternatives for the future– hopefully we can end this once and for all.)

The AxiDraw should be connected to your computer through USB, which provides the grounding. If your computer is plugged in with an ungrounded two-pin prong, that is a potential concern. I have not heard of any specific issues with the belt building up a charge.

Lenore will follow up with you separately about the servo replacements.

[vincentP]

Thanks

I’ll confess to very busy duty cycle, but my studio is not warm at present.

I now have spare parts with which to make a ventilated servo case if you think that would help :-)

The raspberryPi has a touch screen, so both the pi and the touch screen are powered off usb ports built into a power strip. The Axidraw is powered by a two prong wall wart plugged into the same strip. The wall wart is not polarized.

The pi is also connected to an ethernet hub, which is on a different power strip. I can print with the ethernet disconnected if necessary.

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