G-Code for ALT_MOT ?

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DennisC
Posts: 5
Joined: Wed Mar 14, 2018 1:27 pm

G-Code for ALT_MOT ?

Postby DennisC » Tue Aug 14, 2018 9:35 am

There is a mount for a sixth motor drive on the mainboard lettered with "ALT_MOT".
Is there a way to control this drive with G-Code with out editing the operating system on the board ?
I would like to use it to control a Nozzle lift mechanics.
IMG_1538.jpeg

My printer is a Raise N2plus (dual)

Jetguy
Posts: 2700
Joined: Tue Mar 22, 2016 1:40 am
Location: In a van, down by the river

Re: G-Code for ALT_MOT ?

Postby Jetguy » Tue Aug 14, 2018 11:13 am

No, you will have to modify the source code firmware and flash custom firmware. The current firmware is only assigned 2 extruders and XYZ (5 motors in total). While you can twiddle and PWM pin outputs using gcode, to drive a stepper driver you need to control Enable, Direction, and Step pins in that socket in a timing sequence compatible with standard stepper drivers and that just not really possible for any decent control using gcode alone while running stock firmware. Again, you have to set the pin state for enable and direction, and then toggle step in a timed sequence at both the rate and total count to get the distance move or speed you desire.
I really don't even want to give you this command, but here is how in gcode you tell it to set a pin state. https://github.com/MarlinFirmware/Marlin/wiki/M42
I would say do not use this, it's a bad idea on so many levels.

#1 The board is derived from RUMBA- so while Raise3D does not provide any schematics- in this case, we can look at the source where this custom board was derived and get most of the information needed. https://reprap.org/mediawiki/images/2/2 ... MATICS.png and the page in general https://reprap.org/wiki/RUMBA
#2 Next, taking and knowing that previous schematic, we then go into source firmware and somehow assign the 6th motor to an axis definition- however, I'm not sure how to best assign that 6th axis to perform this function as Raise3d is using a standard radio control style servo and thus PWM commands to do positions all set in firmware- not actually using any extra tool change gcode in Pro2. Using an axis as a stepper motor to move a distance- this is immediately quite complicated. You also either are trying to do it with gcode commands (add a script at every tool change), however, you should more integrate it into firmware tool change so when the left and right extruders are called, the firmware handles the function without further added gcode commands. I also don't know if what you want to do will break communications with the front panel LCD software (Raisetouch). https://github.com/Raise3D/Marlin-Raise3D-N-Series

In short, you are attempting to do something quite complicated. Something I have not seen anyone else do ever in this group and while talked about, nobody did it and posted about it that I can remember (I've read nearly every post, every day since this forum was started).
Heck, even Raise 3D had firmware bugs with tool selection in early Pro2 firmware, so again, they struggled to get it right and they designed the boards and the hardware. Also- Pro2 firmware is NOT published (we asked) as it's closed source.

Jetguy
Posts: 2700
Joined: Tue Mar 22, 2016 1:40 am
Location: In a van, down by the river

Re: G-Code for ALT_MOT ?

Postby Jetguy » Tue Aug 14, 2018 11:53 am

Again, based on what even casual research says:
#1 nobody I can find uses that 6th axis and a stepper to do nozzle lifting using a stepper axis
#2 everyone doing this is using RC servos and PWM to tell the servo the up and down positions including Raise3D themselves on the Pro2 series https://reprap.org/forum/read.php?263,506622
#3 Since BLTouch also uses PWM servo commands and a specific pin output on the mainboard, you might gather some information from looking there as that has been done on a Raise3D N series- but again, required custom firmware.

DennisC
Posts: 5
Joined: Wed Mar 14, 2018 1:27 pm

Re: G-Code for ALT_MOT ?

Postby DennisC » Tue Aug 14, 2018 1:43 pm

Thanks for the link Jetguy

I also use a servo to lift the nozzle.
My idear was to control the servo with an arduino, so the arduino need the information wich is the used printhead.
I just want to query the enable pin of the 6th axis.
Using simplify3D it should be easy to add a G-Code part when changing the printhead.


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