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

vistalert

@Veti It's been tested from pin to pin. What you're seeing is just hot glue to keep everything stable so I can prove all of my components and then iterate forward to a more complete installation once I know how all the cables are going to be routed, and boards positioned etc.

I'm 99.99999999% sure it's not a continuity issue. I've checked multiple times for shorts. I can't help agreeing with your gut feel there's a connectivity issue, but what I think we need to progress to is:

How can we prove a signal is coming out of the BLT on its out signal. I can only quickly apply a multimeter, but I think it's a PWM signal coming back out right?

vistalert

@Veti I've check again from the connector going into io7, each pin, and traced continuity to the back of the socket on the BLTOUCH. All pins are good.

Brown/Black ground (tied togtether at BLT end)
Red -> +5v on D3

Yellow -> io7.out on D3
White -> io7.in on D3

vistalert

@Veti

Similar BLTOUCH issue with other boards/firmware
https://github.com/KevinOConnor/klipper/issues/2653#issuecomment-608998964

I see a lot of parallels with what this guy was experiencing with his BLTOUCH and not having the correctly configured pull ups. Are we 100% confident P9 has the pullup in place by default. It does appear critical for BLT 3.0 / 3.1

gshorten created this issue in KevinOConnor/klipper

closed BLTouch probe not working #2653

Veti

yes

see
https://duet3d.dozuki.com/Wiki/Connecting_a_Z_probe

M558 P9 C"^zprobe.in" H5 F100 T2000

vistalert

M558 P9 C"^zprobe.in" H5 F100 T2000

/\ Doesn't correspond to a D3 setup does it?

If P9 activates the pull up by default, why does that example show the use of ^ to activate the pull up.

That confuses me more.

Veti

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

If P9 activates the pull up by default

where does it say that p9 activates the pullup?

vistalert

@Veti not to split hairs...

I asked "Are we 100% confident P9 has the pullup in place by default."

You said yes

So for a Duet3 (my specific context), would this be correct?
M558 P9 C"^io7.in" H5 F100 T2000

Thanks

Veti

yes.

i said that is what is generated by default if you configure bltouch in the duet configurator.

vistalert

Thanks for confirming

No change in behaviour with the following in config.g
M558 P9 C"^io7.in" H5 F100 T2000

Home Z, bed continues to move when contact with probe has ocurred.

Veti

can you post your homeall.g ?

vistalert

@Veti I haven't yet got a reliable homeall.g as I haven't commissioned the BLTOUCH.

I have Home X and Home Y, which are sensorless (pending delivery of endstops)

So what I'm trying for test purposes is this:

Execute M401 - probe deploys - touch the end of the probe briefly enough to make the BLT light red. It must be released in < 650ms is my understanding, else it errors. At no time during repeated touches does the Z sensor in DWC show anything other than 0.
I use a macro to drop the bed 10mm. I execute HOME Z - with my hand on the power button, because every time I test this, the bed is going to hit the nozzle.

For what it's worth, this is the homeall.g I've built from copy / paste / learning about sensorless homing:

My objectives here, home to front left using sensorless. Then move to centre of bed and probe there for Z home. Welcome your comments recommendations, as always.

M400 					; wait til stuff stops

M574 X1 Y1 S3 			; use stall guard for endstops

M201 X2000 Y2000 		; reduce acceleration on X/Y to stop false triggers

M915 P0:1 S3 R0 F0 H400	; both motors because corexy; Sensitivity 4, don’t take action, don’t filter, 400steps/sec

G91 					; relative Positioning

G1 H2 Z5 F1200			; lower the bed


M913 X44 Y44  			; drop motor currents
G1 H1 X-500 F5000 		; move until the motor stalls - COARSE HOME

M400 					; wait til stuff stops
M913 X100 Y100  		; motor currents back to 100%
G1 H2 X30 Y0 F1200		; move away from end 
M400 					; wait til stuff stops


M913 X32 Y32  			; drop motor currents
G1 H1 Y-500 F4000 		; move until the motor stalls - COARSE HOME

M400 					; wait til stuff stops
M913 X100 Y100  		; motor currents back to 100%
G1 H2 X0 Y10 F1200		; move away from end 

M400 					; wait til stuff stops

G90 					; back to absolute positioning
M913 X100 Y100  		; motor currents back to 100%
M201 X3000 Y3000 		; accel back to original

M400 					; wait til stuff stops
G90 					; absolute positioning

G1 X250 Y250 F13000 	; Move x and Y axis over to bed center so probe is on top of bed
M558 A1 F400 			; Set single probing at faster feed rate
G30 					; Do a single probe to home our Z axis
M558 A3 F100 			; Set tripple probing at slower feed rate
G30 					; Probe again to get a more accurate position

G28 X Y

Veti

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

At no time during repeated touches does the Z sensor in DWC show anything other than 0.

the bltouch pulse is so fast that you will not see it go to 1000.

have you run the bltouch self test? its
M280 P0 S120

(edits it S120)

vistalert

I will try. But that runs on power up no?

At power on, I see the pin bounce twice then the BLT tests with solid red LED.

Veti

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

I will try. But that runs on power up no?

no the self test will retract and deploy the pin 10 times

Veti

what firmware version are you on (i hope the latest 3.1.1)

vistalert

@Veti understood

M280 P0 S120 - Don't get any activity from BLT

My firmware is:
RepRapFirmware for Duet 3 MB6HC version 3.01-RC9 running on Duet 3 MB6HC v1.01 or later

Veti

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

3.01-RC9

please update to 3.1.1 there were some versions with bltouch problems

vistalert

Sure thing

vistalert

@Veti Completed all the upgrades to 3.1.1

Confirming that the BLTOUCH 3.1 self-test does now execute after the upgrade to 3.1.1.
M401/402 deploys and retracts.

Home Z does not stop the bed raising when probe touches the bed.
Lightly touching the probe doesn't register on DWC Z sensor, the value stays at 0.

A reminder, that as the bed doesn't retract within 650ms, the BLT goes into error.
If I manually push the pin up, then issue the BLT reset command, it does reset ready for next test cycle.

So, some progress

Bear in mind I still have questionable bed.g, homez.g - almost all of my config stuff is copy /paste from elsewhere.

Not sure if Z endstop setting is needed in config,g as it is put there by the configurator, but then people say it's not needed, and others say it is.

Please advise next steps and many thanks for the patient support so far.

Veti

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

Bear in mind I still have questionable bed.g, homez.g - almost all of my config stuff is copy /paste from elsewhere.

i would suggest you create them using the configurator. this will give you clean files with bltouch support. select bltouch there and the generated files should be good.

A reminder, that as the bed doesn't retract within 650ms, the BLT goes into error.

this is not normal, try again with the clean config