The next BL-Touch problem... :(

Chriss

Hi *,

I got my IDEX printer back to my desk from a longer rest period in the basement. So cleaned it a bit, updated the duet 5+ and the two toolboards (1.0) to 3.4b6 and did some homing. All homes went well, only Z (bl-touch) makes me some trouble,

The head drives down, till it hits the buildplate. The printer stops the steppers and the BL-Touch starts flashing red. But the pin does not retract. The head drives than back to the parking position and the BL-Touch keeps blinking and the pin stays extracted.

The retractprobe and deployprobe contains the needed things.

The relevant part of the config.g:

M950 S0 C"121.io0.out"
M558 P9 C"121.io0.in" H5 F120 T3000
;A5 S0.003 B0 R0
                             ; create servo pin 0 for BLTouch
;M280 P0 S10 ; send control signal to BLTouch through servo/gpio 0

G31 P500 X43.3 Y-41.7 Z3.95                        ; set Z probe offset

I checked the wireing, I exchanged the BL-Touch already. I went trough "https://duet3d.dozuki.com/Wiki/Connecting_a_Z_probe#Section_BLTouch" several times not and I do not find my mistake.

Any ideas?

Cheers, Chriss

Phaedrux

There is a limitation with probes connected to expansion boards and z motors connected to the main board, but I'm not sure it would manifest in this way.

https://duet3d.dozuki.com/Wiki/Duet_3_firmware_configuration_limitations#Section_Temporary_limitations

Can you put the Bltouch into test mode so that it deploys and retracts the pin a few times? Does that work correctly?

Can you post your homing files?

Did homing work correctly before? What firmware version was that?

Chriss

@phaedrux said in The next BL-Touch problem... :

There is a limitation with probes connected to expansion boards and z motors connected to the main board, but I'm not sure it would manifest in this way.

My voron 2.4 has a toolboard with a z-probe attached to the toolboard which works without any problems. (Same firmware version).

Can you put the Bltouch into test mode so that it deploys and retracts the pin a few times? Does that work correctly?

Yes, the probe(s) work correctly. I tested one of the two in a other printer. It worked there as expected.

Can you post your homing files?
All homing files or will the homez.g be enough? (I removed "run2" for now)

; homez.g
; called to home the Z axis
;
; M300 S500 P500		; Beep
; generated by RepRapFirmware Configuration Tool v3.1.1 on Thu Jun 04 2020 17:41:46 GMT+0200 (Central European Summer Time)



; Home X if not yet homed
if !move.axes[0].homed
   M98 P"/sys/homex.g"

; Home Y if not yet homed
if !move.axes[1].homed
   M98 P"/sys/homey.g"
   
; Home Z if not yet homed   
if !move.axes[3].homed
   M98 P"/sys/homeu.g"






G90					; Absolute Positioning
G1 Y155 F6000		; Drive the bed to the center 

M561				; Unload the hightmap

G91					; relative positioning
G1 U-5 F6000
G90					; Absolute positioning
G1 U400 F6000		; Move U out of the way
G1 X150 F6000		; go to first probe point
M400
G91					; relative positioning


G1 H2 Z10 F6000		; lift Z relative to current position

;M280 P0 S10  ; deploy BLTouch
;M401
;M280 P0 S90  ; retract probe
;M401

; Run 1
;M558 F250			; set the down speed
G30					; home Z by probing the bed

;Run 2
;M558 F60			; set the down speed
;G30 
;M558 F350			; Change the speed back
 
; Park the tool
G90					; Absolute positioning
G1 H2 X-50 F6000	; park the X carriage at -50mm

Did homing work correctly before? What firmware version was that?

It worked correct in the past, I'm not 100% sure about the previous version, it should have been 3.3 b1, but without guarantee.

Cheers, Chriss

Chriss

@Phaedrux

I have the feeling that there is a problem with the CAN bus. I saw some communication issues when I played a bit with the printer in the last days but I was never able to trace it down. I'm no able to reproduce it. I guess is caused by a broken wire or a short to ground somewhere.

Is there a way to trace the data flow between the Mini and the Toolboard? To see when exactly the problem occurs?

Cheers, Chriss

dc42

@chriss do the M401 and M402 commands work correctly?

The M122 reports for the tool board and the main board after the printer has been printing for some time may give useful information about the integrity of CAN bus communication.

Chriss

@dc42 Yes, M401 M402 work correctly. The control of the Fans, heater etc work fine.

It is more like a race condition.... I move the left printhead and I see a "jump" on the temp graph from the left or from the right hotend. But not constantly at the same point of the extrusion and not always.

The update to 3.4b6 did work at the end... It is a kind of a hen egg problem. I can not print for a failing BL-Touch... I may need some test code to move the tool around for some time and observe the error rate with M122 than....

That is my Printer No 4 out of 6 and the only one which have nearly every problem you can image.

Cheers, Chriss