Z probe Wiring

Hussain

Hello All,

I recently started work at a engineering firm and have been tasked with getting a large build volume 3D printer up and running.

The printer is a Ratrig Vcore-3 500 x 500 x 500 mm printer. It uses core XY architecture and has 3 lead screws for the z axis.

I am using a Duet 3 MB 6HC board. I have duet firmware 3.5.1.

I got the X and Y axis working along with the end stops.

I am trying to solve 2 issues.

I would like to know how to wire my inductive z probe. Also on the configuration tool what type of Z probe do I choose ?

How do I level the bed with 3 lead screws ? Is there any special G code command that I need to use.

Thank you for your time and support!

Phaedrux

Is the probe not already connected?

See here for information on connecting a probe.
https://docs.duet3d.com/User_manual/Connecting_hardware/Z_probe_connecting

If you still need assistance you'll have to share more information on the exact probe you have.

For leveling the bed with multiple lead screws see here.
https://docs.duet3d.com/en/User_manual/Connecting_hardware/Z_probe_auto_levelling

Hussain

@Phaedrux

I have the 5V super pinda probe, I cant post a link but its on the ratrig website

But I am not sure which wire would be signal, power and ground , is there a way to test it before I plug them in ?

Also what do I choose for the Z endstop in the rrf configuration tool (Image attached)

I did read through the 3 motor levelling, is that a feature inside the rrf tool as well or do I need to write the code in the config.g and bed.g files

Thank you for your time!

Phaedrux

Take a look here for the super pinda.

https://forum.duet3d.com/topic/26641/duet-2-with-pinda-or-superpinda-z-probe/4?_=1741378614348

You may be able to find some more if you search the forum.

For Z endstop, if you have no standard endstop, choose none.

For the automatic leveling that is something you would have to configure manually after you're up and running.

Hussain

@Phaedrux

I just got it working using the digital mode

M558 K0 P5 C"io2.in" H5 F120 T6000

I changed p3 to p5 and its working,

the issue I am having now is that while homing the head goes to 0,0 position on the x and y and this pushes the probe outside the bed.

Is there a way I can tell the head to move to a center location. i know its in the forums somewhere but I am digging to find it .

This is the code from my home z

; homez.g
; called to home the Z axis
;
; generated by RepRapFirmware Configuration Tool v3.5.10 on Thu Mar 06 2025 13:28:18 GMT-0500 (Eastern Standard Time)

; increase Z
G91 ; relative positioning
G1 H2 Z5 ; move Z relative to current position to avoid dragging nozzle over the bed
G90 ; absolute positioning

; home Z
var xCenter = move.compensation.probeGrid.mins[0] + (move.compensation.probeGrid.maxs[0] - move.compensation.probeGrid.mins[0]) / 2 - sensors.probes[0].offsets[0]
var yCenter = move.compensation.probeGrid.mins[1] + (move.compensation.probeGrid.maxs[1] - move.compensation.probeGrid.mins[1]) / 2 - sensors.probes[0].offsets[1]
G1 X{var.xCenter} Y{var.yCenter} F6000 ; go to bed centre
G30 ; probe the bed

the line above G30 does tell the head to go to the center so I dont know why it goes to 0,0 unless it thinks thats the center

maybe I can add offsets in the config.g file

Hussain

@Hussain

for now I have manually changed the homez.g file to look like this

; home Z
var xCenter = move.compensation.probeGrid.mins[0] + (move.compensation.probeGrid.maxs[0] - move.compensation.probeGrid.mins[0]) / 2 - sensors.probes[0].offsets[0]
var yCenter = move.compensation.probeGrid.mins[1] + (move.compensation.probeGrid.maxs[1] - move.compensation.probeGrid.mins[1]) / 2 - sensors.probes[0].offsets[1]
;G1 X{var.xCenter} Y{var.yCenter} F6000 ; go to bed centre
G1 X250 Y250 F6000
G30 ; probe the bed

and it seems to work file

I will do the same to the homeall.g file as well.

Does G28 call the homeall.g file ?

Hussain

@Phaedrux

A question I have regarding leveling the bed:

Do I need to know the position of the lead screw itself with respect to the origin.

below is a piece of code from the instructions

M671 X-15:100:215 Y-10:190:-10 S0.5 ; position of leadscrew/bed pivot point at front left, rear middle and front right

How would I be able to tell the position of the lead screws if I did not design the machine?

Phaedrux

You should confirm that your XY coordinates are correct and that the printer is moving in the correct way.

0,0 should be the front left of the bed.

-X should move left, +X should move right
-Y should move to the nozzle to the front of the bed, +Y to the back.
-Z should move the nozzle and bed closer together, +Z farther apart.

The homing moves should move towards the endstops. If the endstop is on the negative side, it's a low end endstop. If on the positive side it's high end.

Hussain

@Phaedrux

My X, Y and Z axis are moving in the correct direction.

When I home the z axis the X and Y axis move to the 0,0 position which shifts the inductive probe off the bed. I was trying to have the X and Y axis at 250 , 250 mm when Z was homing.

I have modified the homez.g and homeall.g files and it seems to working fine for now, I have not tried to print anything yet.

Regarding bed leveling:

Do I need to know the position of the lead screw ? cause I did not design the machine so its hard for me to know where the lead screw would be.

Phaedrux

Yes you would need to modify the homing files to position the probe where you want it before the G30 happens.

Not sure why the initial file using variables wasn't working correctly to get to the center. It's possible your M557 grid isn't setup correctly for your bed size.

For the lead screw positions you can estimate by moving the print head as close to the lead screw position as you can get it and then using a ruler to measure the distance from there. It doesn't need to be sub millimetre accurate to work, just close enough.

Then in your bed.g file you would manually move the probe to the nearest position it can reach close to the lead screw and probe there. The guide describes everything needed in more detail.