BL Touch Installation what is Servo Pin?

Phaedrux

@signpostman said in BL Touch Installation what is Servo Pin?:

Is there a use for the existing endstop on my Z axis? as a max height?

Yes, you can move it to the Zmax position and use it in cases of power loss recovery where you need to home the z axis but can't use the probe because there is still a print on the bed. You need to set the Z max travel distance exactly using the probe to determine Z0 first in order to get it to be the right height to match the print position.

SignPostMan

It seems I still have a issue with the BL Touch. it does deploy and retract, but the Z axis keep descending without stopping after BL Touch triggered, the BL Touch keeps resetting but not stopping Z Descent.

SignPostMan

@phaedrux I think I will do that

fcwilt

@signpostman said in BL Touch Installation what is Servo Pin?:

It seems I still have a issue with the BL Touch. it does deploy and retract, but the Z axis keep descending without stopping after BL Touch triggered, the BL Touch keeps resetting but not stopping Z Descent.

Please copy-and-paste, using the </> tag, your current homeall.g file and and homez.g file.

Thanks.

Frederick

SignPostMan

@fcwilt ```
; homeall.g
; called to home all axes
;
; generated by RepRapFirmware Configuration Tool v3.3.0 on Sat Aug 21 2021 12:06:10 GMT-0400 (Eastern Daylight Time)

G91 ; relative positioning
G1 H2 Z30 F6000 ; lift Z relative to current position
G1 H1 X-2305 Y-1305 F3000 ; move quickly to X and Y axis endstops and stop there (first pass)
G1 H2 X5 Y5 F6000 ; go back a few mm
G1 H1 X-2305 Y-1305 F180 ; move slowly to X and Y axis endstops once more (second pass)

G90 ; absolute positioning
G1 X250 Y650 F3000 ;move probe to centre of bed

G30 ; probe bed

; Uncomment the following lines to lift Z after probing

G91 ; relative positioning
G1 Z20 F1800 ; lift Z relative to current position
G90 ; absolute positioning

fcwilt

@signpostman

Thanks.

And you say M401 and M402 work?

That would suggest that the signal from the BLTouch is not getting to the firmware.

Things to check:

wiring
BLTouch configuration commands (M950, M558 and G31)

Frederick

SignPostMan

@fcwilt M401 and M402 work, I wonder if having long cables could be the issue? My printer is huge and the cables are 5m long

fcwilt

@signpostman said in BL Touch Installation what is Servo Pin?:

@fcwilt M401 and M402 work, I wonder if having long cables could be the issue? My printer is huge and the cables are 5m long

5m - wow - that is rather long.

Did you verify that there is continuity on the wire that takes the signal from the probe back to the board?

Frederick

Phaedrux

The white wire is responsible for the trigger signal.

SignPostMan

@fcwilt I am able to trigger the probe with M401 and M402

SignPostMan

@phaedrux The probe is retracting and then resetting over and over but not stopping the z descent

fcwilt

@signpostman said in BL Touch Installation what is Servo Pin?:

@fcwilt I am able to trigger the probe with M401 and M402

That verifies that the control signal from the board to the probe is working.

There is another wire that from the probe to the board that carries the signal that tells the firmware the probe has been triggered.

Frederick

SignPostMan

@fcwilt The white wire?

fcwilt

@signpostman said in BL Touch Installation what is Servo Pin?:

@fcwilt The white wire?

I trust @Phaedrux - if he says it's the white wire it is - assuming you have a genuine BLTouch.

Frederick

SignPostMan

@fcwilt yes BL Touch brand

SignPostMan

I have the Z Endstop still mounted to the z axis. and the BL Touch is wired but setting on the bench. If I ask the machine to Home Z, The Z axis will lower and touch, triggering the endstop, then stop moving. if I then trigger the BL Touch, the Z Axis will descend again and trigger the Z Endstop again.

Does this give any clues of the issue?

; homez.g
; called to home the Z axis
;
; generated by RepRapFirmware Configuration Tool v3.3.0 on Sat Aug 21 2021 12:06:11 GMT-0400 (Eastern Daylight Time)
G91               ; relative positioning
G1 H2 Z10 F6000   ; lift Z relative to current position
G1 H1 Z-309 F2500 ; move Z down until the endstop is triggered
G1 H2 Z5 F6000    ; go back a few mm
G1 H1 Z-20Y F180  ; move slowly to Z axis endstops once more (second pass)

;G92 Z0            ; set Z position to axis minimum (you may want to adjust this)

G30 ; probe bed

; Uncomment the following lines to lift Z after probing
G91              ; relative positioning
G1 Z20 F2500      ; lift Z relative to current position
G90              ; absolute positioning

fcwilt

@signpostman said in BL Touch Installation what is Servo Pin?:

I have the Z Endstop still mounted to the z axis. and the BL Touch is wired but setting on the bench. If I ask the machine to Home Z, The Z axis will lower and touch, triggering the endstop, then stop moving. if I then trigger the BL Touch, the Z Axis will descend again and trigger the Z Endstop again.

To be sure we are on the same page what do you mean by trigger the BL Touch?

Frederick

SignPostMan

@fcwilt Probe is extended, I touch it and it retracts. It does however extend again

fcwilt

@signpostman said in BL Touch Installation what is Servo Pin?:

@fcwilt Probe is extended, I touch it and it retracts. It does however extend again

The typical settings for the M558 parameters A and S cause the probe to take multiple readings until two consecutive readings are within the range specified by the S parameter.

M558 Documentation

Triggering it by hand like that is very unlikely to obtain two consecutive readings so it will stop trying after the number of readings specified by the A parameter and average the readings it obtained.

I don't know what your current A and S parameters are but let's say they were A=5 and S=0.05.

Touching it like you are would likely take 5 readings before it stopped trying.

Frederick

fcwilt

@signpostman

If you set the A parameter to 1 it will stop after taking just 1 reading.

Frederick