Disabling unused steppers

As per https://reprap.org/wiki/G-code M18 and M84 allow to disable all steppers, but is there a way to disable one particular motor without unplugging it?
Here is my use case - IDEX printer with two X steppers prints in non-ditto mode (only 1 printhead is used). X1 motor acts as X-stepper. X2 motor is not needed but is still enabled and consumes power. I'd like to disable it.


Reprap seems to think you can... M18. But are you saying that you have two E extruder motors? They don't seem to allow that.

Hm... if you were to add an inline switch to the VCC on that motor then in theory your firmware might notice that it's unresponsive and panic (but you could test that theory). Then you could use GPIO control over a relay or a solid-state relay to turn it on/off. You'd think that you could do this with firmware.

And yet, fork Marlin and DIY if you want to. It's probably related to this: disable_e_steppers()

@OutsourcedGuru Thanks for the link and suggestions.

This is for brand new IDEX printer of my own design running Repetier firmware on Ultratronics pro v1.0 board + RPI/Octoprint. It has 2 extruders, 2 X-steppers, 1 Y-stepper and 2 Z-steppers sharing the same driver. So far I installed only one hotend (the 2nd e3d arrives tomorrow) and tested the printer in single head printing mode (with 2 extruders defined). X2 motor was not used, but powered on during the entire print.
I could control stepper drivers' enable/disable pin from RPI/GPI, but I rather won't. Making the change to Repetier firmware looks like a safer option.


Don't think I've ever worked with that but here's a gcode command I've not seen before.

IDEX seems so cool in theory. Curious how hard leveling 2 independent heads are going to be. You should share your printer in the Showcase category.

@OutsourcedGuru I think you just hit the bullseye! G204 added 3 years ago by one of Repetier's users may be doing exactly what I need.

G204 P<motorId> S<0/1> - Enable/disable motor

I will double check with the developers.

@jneilliii I agree, IDEX printers are cool! In fact, the very first time I saw IDEX printing on Youtube, I knew that it will be my next printer. Considering how much they cost, I decided to design my own...
As for leveling - it is not too hard. I have one print-head in fixed position along Z axis, another can be manually adjusted with M3 screw. Z-probe is attached to fixed print-head.

Here is the answer from Repetier developer:

G204 is not for regular steppers only for motors controlled with 20x.
X2 motor gets enabled by home x and stays enabled to not loose position after that. Firmware can not know that you do not want to use that one. In v2 Firmware you could use M18 A0 to disable it until next use, but in V1 it is part of X axis so no separate way to address that motor.

I volunteered for Repetier v2 beta-testing, so will be able to try M18 soon.

1 Like

I'm not ready to share yet, since it is incomplete, but you can have a look at it here https://www.youtube.com/watch?v=Hy6spEr7aNk Sorry for TV sound in the background.


That looks very well put together. What kind of control board is that, it looks massive.

Ultratronics Pro v1.0 - https://reprapworld.com/products/electronics/ultratronics/ultratronics_pro_v1_0/

That is one big printer. The slide rails look like there's zero sag over that expanse.

Yes, the frame dimensions are 77cm x 59cm x 53cm (30.3" x 23.2" x 20.9"). Rails are 50cm long for Y and Z and 55cm for X. It definitely is bigger than I expected. :slight_smile:

1 Like