BLT randomly deploys

CanDo415

Hi, My BLTouch wich worked fine on my DuetWifi, randomly deploys (while printing and in standby) on my Duet3 6HC
Using M401 and M402 works fine.

; Bed leveling params ----------------------------------------------------------------------------------
M950 S0 C"io7.out"                              ; create servo pin 0 for BLTouch
M558 P9 C"io7.in" H5 F120 T6000                 ; set Z probe type to bltouch and the dive height + speeds
G31 P500 X0 Y34,5 Z1.15                   		; set Z probe trigger value, offset and trigger height   
M671 X-58:406:406:-58 Y16:16:439:439 S40	    ; Z leadscrews positions								
M557 X5:325 Y30:330 S15.5                       ; Bed mesh grid

I connected both GNDs to the GND of IO7, Maybe this is triggering?
Bedleveling and so on works fine.

Any ideas?

fcwilt

@cando415

Does the wiring to the BLTouch run near other wiring, say wiring to a stepper?

It might be induced noise.

I had to re-route some wiring from a sensor because of induced noise from stepper wiring.

Frederick

Nurgelrot

@fcwilt @CanDo415 I have run into this problem with the BLtouch in a couple of builds. unfortunately it seem pretty random when its going to happen. Whenever I can I don't include the touch wires in a loom with a stepper line and try to avoid long runs of parallel wires.

CanDo415

@nurgelrot @fcwilt
The loom is about 3m long including 3 Stepperwires.
rerouting is impossible on this printer.
I try to cut the power, if not needed, of the BLT instead.

Phaedrux

Are your wires in the loom braided? It can help quite a lot with noise induction.

CanDo415

@phaedrux great idea. Forgot it totally ‍️