Z-probe (BLTouch) and dual z axis help on Duet 3

ajcraig99

Yeah G31 should have the offset in X and Y which is the distance in mm from the centre of the nozzle.

Are you able to get the probe to deply when doing a G30?

dc42

@triumphantduke, your config.g extract looks ok to me apart from the zero X and Y offsets. Are you able to deploy and retract the pin using ~~M400 and M401~~ M401 and M402? What do you have in your deployprobe.g and retractprobe.g files?

triumphantduke

@ajcraig99 nothing happens when using G30, besides X-axis moving over a little.
@dc42 no movement of bltouch pin when using M400 or M401, the bltouch does run its internal self test when machine powers on.

When hitting home Z button (after successfully homing X and Y) in web interface, I see no movement besides x-axis moving over a little. I think rep rap isn't happy with how I specified the 2 z motors, since there is no Z axis movement for either Z motor.

Fixed M350 Driver 2 and Driver 3 does not support x0 micro stepping with interpolation error, PEBKAT lol.. firmware only supports designating micro steps per axis and is not to be set twice for two z axis motors.

deployprobe.g
M950 S0 C"io2.out"
M280 P0 S10

retractprobe.g
M950 S0 C"io2.out"
M280 P0 S90

thank you for any input!

triumphantduke

So... Learning experience. Fixed the z motor lack of movement. The only place to mention that there are two z motors is in the initial declaration, you can't put multiple step settings/amp settings/etc. Still working on BLtouch to work, and fixing super low temps on thermistors at room temperature, like -275C, but if i fake it and up the resistance, and get it to heat, it has not issues (false open circuit failure if i dont mod the resistance for first heat)

triumphantduke

Another learning experience for those out there configuring a duet 3, with beta firmware, when you do this M584 X0.0 Y0.1 Z0.2:0.3 E0.4:0.5 you end up controlling z motors when you try to retract/extrude lol BUT when you do:
M584 X0.0 Y0.1 Z0.2:0.3
M584 E0.4:0.5

Then retracting/extruding ends up using the right motors.

Now.... the last piece of the puzzle is the BLtouch and then setup mesh bed leveling. It does successfully self test a couple times when powered on, then led stays solid red and duet web interface shows "0" for z probe. When I try to do M401 then nothing.. if I'm using a duet 3 what governs "pin" or "servo" number in the below? (M950 S# or M280 P#) I'm running out of trouble shooting strategies..

config.g
; Z-Probe
M558 P9 C"io2.in" H5 R1 F50 T6000 A5 S0.02 B1 ; set Z probe type to bltouch and the dive height + speeds
M950 S0 C"io2.out"
G31 P500 X1 Y2 Z2.5 ; set Z probe trigger value, offset and trigger height
M557 X15:440 Y15:440 P20 ; define mesh grid

deployprobe.g
M950 S0 C"io2.out"
M280 P0 S10

retractprobe.g
M950 S0 C"io2.out"
M280 P0 S90

Pin connections...
Red 5v to 5v EXT
Yellow/orange, signal to io2.out
2 grnd wires to GRND
White, Zmin to io2.in

stereo

Maybe you need PWM on the orange cable? On https://duet3d.dozuki.com/Wiki/RepRapFirmware_3_overview have SERVO pin.. Where is he? It doesn’t work for me either. There is no instruction where to connect which cable.

triumphantduke

So new finding... Plugging in BLTouch to io2 had no success, BUT simply plugging into io8 works now?

Should I do a warranty claim @dc42? I had this same issue when with fans, some plugs on board seem to not function and changing to a different one caused the fans to work too

stereo

YES, in 8 work. thx

triumphantduke

new nuance found, to successfully save bed mesh grid (G29), you need to have a memory card hooked up to the duet 3 board. Running mesh bed compensation will not automatically understand to save to SBC if there is no mem card on duet 3, and I didn't find a way to point it in the right direction. After it runs, it will save a file to the board, cool but now you have to take the sd card out from the duet 3 and manually transfer that file from the duet 3 sd to your SBC sd card in the same directory as config.g (easier to just connect to your SBC through web and drag and drop the file.). On the plus side, it's time for my first test print! woohoo!

gtj0

This was just fixed but I don't think it's been released yet.
https://forum.duet3d.com/post/111473

stereo

@triumphantduke Does it make sense in SBC on a regular printer with 4 motors? What is it that they all rush about with it?

triumphantduke

@stereo for the low number of motors, probably no biggg deal for printing. BUT it makes a huge difference in the web/user interface speeds for only 40 dollarsish for a raspberry pi. Then you get the added benefits of taking pictures/streaming while you print, incase youre into that

triumphantduke

uploaded my config here... first print went ok! but need to get some part cooling going on for PLA

https://github.com/murtagh1/Cartisian_Duet3_RRF3

dc42

I assume you have a Duet 3 version 0.6. Pin io2.out is not PWM capable, so it cannot be used to control a BLTouch. Use io4, 5, 6, 7 or 8 instead. I am sorry I didn't spot this earlier in your config.

brendon

Thanks @triumphantduke for posting all of your work along the way. The wiring connections you mentioned and sharing your git repo for your config.g were very helpful for me in getting G29 working in only a few minutes. If you have the bltouch working on your end, could you mark the thread 'resolved' so people know that it contains an accurate solution?

triumphantduke

@brendon I'm glad it helped! Sorry, yes i should mark it as resolved. Still working on slicer settings, but hopefully will zone in on something functional!

triumphantduke

@dc42 Thank you!

dc42

I have updated the instructions on connecting Z probes to include how to connect a BLTouch to Duet 3.