Z probe homes, but won't run mesh bed compensation

flyscha

Hi All!

I'm looking for some guidance please! I'm having an issue with my new build that's using a Duet 3 6HC and a Superpinda Z probe on 3.4.6 firmware. I'd also like to mention my previous build works great with the Duet 2 Wifi & Superpinda on 2.04 firmware. I've tried what seems to be endless combinations between Endstops, Z-Probe, homez, and homeall settings on the 6HC, but at best I can only get the Z to home. I've tried to copy settings from the Duet 2 Wifi for this situation, but there seems to be quite a bit different between older and newer firmwares.

When using the config below with the Z endstop line commented out, the Z will not home. I then get the following error:
G28
Error: Failed to enable endstops

When I comment the Z endstop line back in, everything homes just fine. But then when I try to run mesh compensation, nothing happens and I get the following error:
G29
Error: G29: Z probe 0 not found

Here is what I have currently:

config.g:
; Drives
M569 P0.1 S0 ; X Motor Left goes forward
M569 P0.3 S0 ; Y Motor goes reverse
M569 P0.4 S1 ; Z Motor Left goes forward
M569 P0.0 S1 ; Extruder Motor goes forward
M569 P0.2 S0 ; X Motor Right goes forward
M569 P0.5 S1 ; Z Motor Right goes forward
M584 X0.1:0.2 Y0.3 Z0.4:0.5 E0.0 ; set drive mapping
M350 X16:16 Y16 Z16:16 E16 I1 ; configure microstepping with interpolation
M92 X200.00:200.00 Y200.00 Z400.00:400.00 E420.00 ; set steps per mm
M566 X900.00:900.00 Y900.00 Z130.00:130.00 E450.00 ; Set maximum instantaneous speed changes (mm/min)was 900,900,30,3000
M203 X10000:10000 Y10000 Z2000:2000 E3000 ; Set maximum speeds (mm/min)E was 5000
M201 X5000:5000 Y5000 Z500:500 E250.00 ; Set accelerations (mm/s^2)was 600,600,250,250
M906 X1200:1200 Y1200 Z1000:1000 E650 I0 ; Set motor currents (mA) and motor idle factor in percent
M84 S200 ; Set idle timeout

; Axis Limits
M208 X0 Y0 Z0 S1 ; set axis minima
M208 X250 Y265 Z240 S0 ; set axis maxima

; Endstops
M574 X2 S1 P"io7.in" ; configure switch-type (e.g. microswitch) endstop for high end on X via pin io7.in
M574 Y2 S1 P"io8.in" ; configure switch-type (e.g. microswitch) endstop for high end on Y via pin io8.in
;M574 Z1 P"io3.in" ; low end Z-probe triggered via signal wire on pin io3.in

; Z-Probe
M558 P5 C"io3.in" H0.50 F600:120 T20000 R0.80 A2 ; Set Z probe type to effector, the axes for which it is used and the dive height + speeds
G31 P1000 X0 Y0 Z0 ; Set Z probe trigger value, offset and trigger height (more negative is further from the bed).
M557 X0.00:246 Y0.00:204.0 S82.00:68.00 ; Define mesh grid

homez.g
G91 ; relative positioning
G1 H2 Z5 F6000 ; lift Z relative to current position
G1 H1 Z-245 F1800 ; move Z down until the endstop is triggered
G1 H2 Z5 F1000 ; go back up a few mm
G1 H1 Z-10 F250 ; move slowly to Y axis endstop once more (second pass)
G92 Z0 ; set Z position to axis minimum (you may want to adjust this)

homeall.g
G91 ; relative positioning
G1 H2 Z5 F6000 ; lift Z relative to current position
G1 H1 X255 Y215 F3000 ; move quickly to X and Y axis endstops and stop there (first pass)
G1 H2 X-5 Y-5 F6000 ; go back a few mm
G1 H1 X255 Y215 F360 ; move slowly to X and Y axis endstops once more (second pass)
G1 H2 X-6.5 Y-14 F1800; move X/Y to attack position before Z homes
G1 H1 Z-245 F1800 ; move Z down stopping at the endstop
G1 H2 Z5 F1000 ; go back up a few mm
G1 H1 Z-10 F250 ; move slowly to Y axis endstop once more (second pass)
G92 X0 Y0 Z10 ; set Z position to axis minimum (you may want to adjust this)

Any help or direction would be much appreciated!

Thanks!

fcwilt

@flyscha

Well you cannot have a Z endstop on io3.in AND a Z probe on io3.in.

You can have a Z endstop on one input AND a Z probe on another input.

Your homeZ.g file is trying to home Z using the Z endstop. With no Z endstop configured (no M574) you will get that error about failing to enable endstops. The firmware is trying to enable the Z endstop but it's not configured.

When you configure the Z endstop with the M574 then you get the error about Z probe not found since you are trying to use the same input, io3.in.

When you have a working Z endstop you can home Z first and then move it to a safe position, say Z=10, and then home X and Y without any code moving Z.

I'm guessing you used the configuration tool? It generates code like in your homeALL.g

When you have the Z endstop unless you are trying to save every last second when homing all it's simpler to code your homeX.g, homeY.g and homeZ.g files and have homeALL.g just do the following:

M98 P"homeZ.g" 
M98 P"homeX.g"
M98 P"homeY.g"

Frederick

flyscha

@fcwilt

Thanks so much for the quick reply! I really appreciate all the feedback.

It makes perfect sense as to what you're saying about not being able to have io3.in assigned as the endstop AND a Z probe. That being said, I'm confused as to what to do since my goal is to use the Superpinda to act as both the Z endstop and the Z probe.

I have 2 other machines, one uses a Precision Piezo and the other uses a Superpinda. Both of them utilize those Z probes as what I consider to be endstops without issue, but they're on the older Duet 2 Wifi boards on 2.04 firmware.

Here's how the other machine with Duet 2 Wifi/Superpinda/2.04 firmware is set up (which works perfectly):

; Endstops
M574 X1 Y1 S0 ; Set active low and disabled endstops
M574 Z1 S2 ; Set endstops controlled by probe

; Z-Probe
M558 P5 I0 H1 F300 T6000 ; Set Z probe type to effector, the axes for which it is used and the dive height + speeds
G31 P500 X0 Y0 Z2.225 ; Set Z probe trigger value, offset and trigger height (more negative is further from the bed).
M557 X9.00:252.5 Y035.00:244.0 S81.166667:69.666667 ; Define mesh grid

Do you have any idea what I could do to achieve this function on the 6HC board?

Thanks so much!

fcwilt

@flyscha

From the docs on M574:

Snnn 1 = switch-type (eg microswitch) endstop input, 2 = Z probe (when used to home an axis other than Z), 3 = single motor load detection, 4 = multiple motor load detection (see Notes).

The configurator loves to toss that M574 Zn S2 line it but it rarely applies.

You can get by with just a Z probe to home Z.

You home X and Y "normally" using G1 H1 moves and then you finish by using an absolute G1 command followed by a G30 command to set the Z=0 Datum.

I don't like that setup because you are moving X and Y without really knowing the Z position. Which is why all of my printers have a Z endstop and a Z probe. Adding a Z endstop involves a micro-switch or an optical sensor and a few feet of wire plus a spare input on your controller. Assuming you have the input you are talking a couple of dollars in parts.

Frederick

flyscha

@fcwilt

Again, thank you so much for the input! As a last resort I'll toy with the G1& H1 moves in the homing files if the below can't be figured out.

I have extra optical endstops and open i/o ports on the board, so having both types would not be a problem, hardware-wise!

I have considered looking into being able to home both of my Z motors individually (it's a cartesian build) to make sure they stay equal, side to side. I guess my brain just isn't wrapping around how the Z-probe and the Z endstops would work together and allow each of their functions to happen individually without them interfering with each other. Unless of course it was a BLtouch type Z probe with a retractable pin.

Any insight on that would be great!

Much appreciated!

droftarts

@flyscha to use a probe rather than endstop for Z homing, comment out the M574 for the Z endstop, and change your homeall.g and homez.g to use G30, rather than G1 Z… H2 moves. See my post here for example : https://forum.duet3d.com/post/326438

Ian

fcwilt

@flyscha

When you have both a Z endstop and a Z probe the each do different jobs.

The Z endstop takes care of homing Z.

The Z probe takes care of setting the Z=0 Datum and probing the bed as needed for using the Mesh Bed Compensation feature and/or the Auto Bed Leveling feature.

That's basically it.

Then what you need to know is when do you need to set the Z=0 Datum.

You need to do that:

before creating the heightmap needed for using the Mesh Bed Compensation feature.
before loading the heightmap to actually use the Mesh Bed Compensation feature.
after leveling the bed if you use the Auto Bed Leveling feature (which needs multiple Z steppers).
before starting a print if you don't use the Mesh Bed Compensation feature.

I can explain in greater detail or post examples of the macros you would need to do some or all of the above.

Frederick

droftarts

@flyscha There's no problem using the Z probe for Z homing; most people do this. If you have a Z probe and a Z endstop (and yes, they should be on different io pins, they can't share), use the Z endstop for something the Z probe can't do, ie home at the max end of Z. Why? Disaster recovery. See this very similar discussion (between @fcwilt and I): https://forum.duet3d.com/post/327874

I have considered looking into being able to home both of my Z motors individually (it's a cartesian build) to make sure they stay equal, side to side. I guess my brain just isn't wrapping around how the Z-probe and the Z endstops would work together and allow each of their functions to happen individually without them interfering with each other. Unless of course it was a BLtouch type Z probe with a retractable pin.

I do this. Basically, you just use the Z probe; they don't really work together. There's a whole wiki page on it, too: https://docs.duet3d.com/en/User_manual/Connecting_hardware/Z_probe_auto_levelling
You can also do it with multiple endstops, see the end of the page.

Ian

flyscha

@fcwilt @droftarts

Thanks so much to the both of you for all of your input, directions, and suggestions! After stuffing myself with turkey today, I was able to get the Z probe set up for Z homing, at least as a temporary solution. My Z motors are falling out of alignment with each other just from constant Duet restarts after config file changes, so I’ll be getting individual Z endstops set up ASAP.

Thanks again!