Duet3 BLTOUCH3.1 Probe deploys but doesn't trigger on Z Home

vistalert

The BLT and bed are intrinsically linked for Z probing, so don't we need to ensure bed.g and homez.g are in alignment?

What steps do you want me to take now that I have the clean files? These files are initially not suitable without editing (which as a newbie is challenging). For example, the Z was travelling way too fast. There's no support in the configurator for triple steppers.

What specific steps do you want me to take with what specific actions from the UI, or GCODE from the console?

I think we need a less generic approach, and I need to be told: do this, expect this.

We spent all day yesterday circling around my wiring, to find we should have started with the firmware version. Today you're telling me to use the configurator and without specific knowledge of the stepper setup, the bed almost shot off the top of the screws at high speed.

Veti

@vistalert said in Duet3 BLTOUCH3.1 Probe deploys but doesn't trigger on Z Home:

The BLT and bed are intrinsically linked for Z probing, so don't we need to ensure bed.g and homez.g are in alignment?

the bed.g is used for leveling the bed using independent z motors. this required a working probe.
the homez from the configurator should be correct. please post it to verify.

https://forum.duet3d.com/topic/5909/guide-for-posting-requests-for-help/11

@vistalert said in Duet3 BLTOUCH3.1 Probe deploys but doesn't trigger on Z Home:

What steps do you want me to take now that I have the clean files? These files are initially not suitable without editing (which as a newbie is challenging). For example, the Z was travelling way too fast. There's no support in the configurator for triple steppers.

i wanted to rule out any problem in your config file. if the files from the configurator with selected bltouch do not work, we can rule out a config problem.
for the 3 z motor just add the motors back to M584.
to change the speed of z change it in https://configtool.reprapfirmware.org/Motors Max. Speed (mm/s). the default is 3mm/s. is that too fast?

We spent all day yesterday circling around my wiring, to find we should have started with the firmware version. Today you're telling me to use the configurator and without specific knowledge of the stepper setup, the bed almost shot off the top of the screws at high speed.

remote debugging is hard. and you did not provide all the information specified in the guide on how to ask for help https://forum.duet3d.com/topic/5909/guide-for-posting-requests-for-help/11

so post the new config files that you generated.

I think we need a less generic approach, and I need to be told: do this, expect this.

see if the bltouch is now working. next maybe the port is bad.
so switch to a different port in the configurator and move the wiring.

but to be honest, i think the bltouch is broken.

Phaedrux

Please post your new files for 3.1.1 config.g, homing files, bed.g and a thorough description of your printer hardware and we can work from there.

vistalert

Thank you @Phaedrux - I will certainly do that. Also, I'd like to apologise to @Veti for the tone of my previous post. I was a little shaken by what happened with the bed raising, but no excuses. I didn't mean to be rude.

Phaedrux

Any time testing motor movement on a new printer it's wise to reduce motor currents in case of a crash. And always have a hand near the power switch. This is true of any printer/board/firmware.

vistalert

XYZ Steppers are all: LDO Motors 1.8degree - LDO-42STH47-2504AC
BL TOUCH 3.1

Extension cable from BLT to D3 board is two twisted pairs:
pair 1 is +5v/Gnd
second pair is in/out.

Build plate 500x500x500
Z screw offsets as per config

Thanks again

I can't upload a zip file, but here is the entire set of config files:

tpre0.g tpost0.g tfree0.g stop.g sleep.g retractprobe.g resume.g pause.g homez.g homey.g homex.g homeall.g dwc2settings.json deployprobe.g config-override.g config.g bed.g

vistalert

By the way - I just moved the connector for the BLTouch from io7 to io9 for another quick continuity test, so I could prove continuity by probing from the PCB on the BLT, to the back of the Duet3 PCB. All wires run pin to pin.

Phaedrux

It's also possible to use IO_4 or IO_5 instead of IO_7, but I'm not sure about io_9. https://duet3d.dozuki.com/Wiki/Connecting_a_Z_probe#Section_Duet_Num_3

There were some issues with the BLTouch 3.1 but I believe that was when using a tool board, but directly to the Duet 3.

Your config looks correct. If you send M98 P"config.g" do you get any error messages?

Veti

M203 X6000.00 Y6000.00 Z1000.00 E1200.00

this is why your bed is moving so fast; Z1000
you must have changed the value in the configurator, as the default there is Z180.00

also the configurator only offers IO_4, IO_5 and IO_7 for the bltouch.

vistalert

I only used io9 for continuity tests, as it's convenient to probe the board, so I could literally prove the signal gets to the PCB, not just the end of the wire

I also tried moving and doing config to io5, all same results.

I'll try the M98 and see what happens.

I've also ordered a second BLTouch in case that is the issue, I'm planning to build a second machine anyway. Hope that will enable further elimination of 3rd party issues.

I did find it odd that the self test command wouldn't work with the earlier firmware and with the latest it does.

I am sure you guys are feeling the same as I am, that there is some issue with the returning signal from the BL touch in an electrical, or fault sense.

So I can consider other options. What is a good quality alternative to the BL Touch? I have a large aluminium plate with PEI magnetic sheet, so I think there are multiple options, but want the best quality outcomes. Any recommendation are welcome.

vistalert

@Veti I'm not sure it was the speed, as the config I downloaded by default, and used in previous tests has Z180. When I tested bed movement today, and I executed....

G91
G1 H2 Z1

The bed moved more than 1mm....a lot more, so could it have been to do with steps/mm or something?

That's why you'll see deviations between the config provided by the configurator, as I pasted back in my previous stepper configs.

Veti

@vistalert said in Duet3 BLTOUCH3.1 Probe deploys but doesn't trigger on Z Home:

So I can consider other options. What is a good quality alternative to the BL Touch?

I actually prefer this over the bltouch.
https://www.thingiverse.com/thing:3303618
Its cheaper
it uses an optical endstop, same (or even better) accuracy, but it gives a constant signal.
same form factor

Veti

@vistalert said in Duet3 BLTOUCH3.1 Probe deploys but doesn't trigger on Z Home:

That's why you'll see deviations between the config provided by the configurator, as I pasted back in my previous stepper configs.

as far as i can see both have Z400 for steps/mm

vistalert

That's a very smart solution with the optical endstop and easy to comprehend

vistalert

@Phaedrux said in Duet3 BLTOUCH3.1 Probe deploys but doesn't trigger on Z Home:

M98 P"config.g"

OUTPUT - no errors just the heater warnings...

M98 P"config.g"
Warning: M307: Heater 0 appears to be over-powered. If left on at full power, its temperature is predicted to reach 365C
Warning: M307: Heater 0 appears to be over-powered. If left on at full power, its temperature is predicted to reach 318C
Warning: M307: Heater 1 appears to be over-powered. If left on at full power, its temperature is predicted to reach 937C

Phaedrux

@vistalert said in Duet3 BLTOUCH3.1 Probe deploys but doesn't trigger on Z Home:

The bed moved more than 1mm....a lot more, so could it have been to do with steps/mm or something?

If you send M92 by itself it will report the currently configured steps per mm for all axis. Are you sure 400 is correct?

Formula for calculating z steps per mm with lead screw (without gearing) is:

Z_steps_per_mm = (motor_steps_per_rev * driver_microstep) / screw_lead

Thalios

I could not get my BL touch to work at all on ports IO6 and IO7. Only when plugged on IO5 did it work.

I'd try that first, easy swap.

vistalert

@Thalios I have tried io5 yes, didn't work. Could you please share your relevant rows from config.g for anything to do with the BL Touch and endstops. Also your deploy/retract probe.

What version of the BL Touch do you have? Confirm you have a Duet3 with v3.1.1?

Thanks!

vistalert

@Phaedrux - I have a lot to learn yet, so appreciate the input. I can't state with much confidence that anything about my configs is correct yet. I'm just in the commissioning phase of "getting things to move, or blink" and hoping that nothing goes "bang!"

Once I get through the BL Touch issue, I'll feel at least in control of the basic functions, and can then learn and refine as I start to do the calibration work.

Phaedrux

Can you provide the results of M122 and M98 P"config.g"?

Are you using the Duet 3 in SBC mode?

; Endstops
M574 Z1 S2                                   ; configure Z-probe endstop for low end on Z

; Z-Probe
M950 S0 C"io5.out"                           ; create servo pin 0 for BLTouch
M558 P9 C"^io5.in" H5 F120 T6000             ; set Z probe type to bltouch and the dive height + speeds
G31 P500 X0 Y0 Z2.5                          ; set Z probe trigger value, offset and trigger height
M557 X15:215 Y15:195 S20                     ; define mesh grid

M280 P0 S10 ; deploy BLTouch
M280 P0 S90 ; retract BLTouch

Have you seen the BLTouch 3.1 manual?
https://5020dafe-17d8-4c4c-bf3b-914a8fdd5140.filesusr.com/ugd/f5a1c8_d40d077cf5c24918bd25b6524f649f11.pdf

Or seen this?
https://www.antclabs.com/logic