Duet 2 and Precision Piezo Orion v2

SAtech

Hi, I have a custom BLV cube CoreXY machine, and have been using a Duet 2 for quite some time, and I really love it. I have been using an ir probe, and recently I decided to switch to a piezo probe since the ir probe wasn't quite as accurate as I liked. So, I designed and printed up a mounting system for it (basically just integrated the mount they designed in to my toolhead). It went together well, and testing it by tapping my finger on the probe, it triggers. The problem is this. When I try to home the bed using G30, the head comes down and presses on the bed, but the bed keeps moving up about 5mm past the head, flexing the mount, basically causing a soft crash. I have tried many combinations of probing speed (5-50mm/s) and sensitivity of the probe itself, to no avail. What am I doing wrong?

Here is my config.g:

; Configuration file for Duet WiFi (firmware version 2.03)
; executed by the firmware on start-up
;
; generated by RepRapFirmware Configuration Tool v2.1.8 on Fri Mar 13 2020 18:19:29 GMT-0600 (Mountain Daylight Time)

; General preferences
G90                                      ; send absolute coordinates...
M83                                      ; ...but relative extruder moves
M550 P"Ultibot"                          ; set printer name

M667 S1                                  ; select CoreXY mode

; Network
M552 P192.168.0.10 S1                    ; enable network and set IP address
M553 P255.255.255.0                      ; set netmask
M554 P192.168.0.1                        ; set gateway
M586 P0 S1                               ; enable HTTP
M586 P1 S0                               ; disable FTP
M586 P2 S0                               ; disable Telnet

; Drives
M569 P0 S1                               ; physical drive 0 goes backwards
M569 P1 S1                               ; physical drive 1 goes backwards
M569 P2 S0                               ; physical drive 2 goes forwards
M569 P3 S0                               ; physical drive 3 goes forwards
M569 P4 S0								 ; physical drive 4 goes forwards
M584 X0 Y1 Z2:4 E3                       ; set drive mapping
M671 X0:350 Y0:0 S3 				     ; leadscrews at left (connected to Z) and right (connected to E1) of X axis
M350 X16 Y16 Z16 E16 I1                  ; configure microstepping with interpolation
M92 X99.979 Y99.979 Z803.166 E420.076    ; set steps per mm

; Movement Settings
M566 X1000.00 Y1000.00 Z300.00 E1000.00  ; set maximum instantaneous speed changes (mm/min)
M203 X32400 Y32400 Z3000 E80000.00       ; set maximum speeds (mm/min)
M201 X6000 Y6000 Z400.00 E10000.00       ; set accelerations (mm/s^2)
M204 P3000 T6000						 ; set print and travel accelerations

M906 X1600 Y1600 Z800 E1100 I30          ; set motor currents (mA) and motor idle factor in per cent
M84 S30                                  ; Set idle timeout

; Axis Limits
M208 X-23 Y-20 Z0 S1                     ; set axis minima
M208 X330 Y340 Z440 S0                   ; set axis maxima

; Endstops
M574 X1 Y2 S1                            ; set active high endstops
M574 Z1 S2                               ; set endstops controlled by probe

; Z-Probe
M558 P5 H5 I1 R0.25 F400 T12000 A3       ; set Z probe type to piezo and the dive height + speeds
G31 P500 X0 Y0 Z0               		 ; set Z probe trigger value, offset and trigger height
M557 X10:300 Y10:300 P12                 ; define mesh grid
M376 H40								 ; set mesh transition height

; Heaters
M305 P0 T100000 B4725 C7.060000e-8 R4700 ; set thermistor + ADC parameters for heater 0
M143 H0 S120                             ; set temperature limit for heater 0 to 120C
M305 P1 T100000 B4725 C7.060000e-8 R4700 ; set thermistor + ADC parameters for heater 1
M143 H1 S280                             ; set temperature limit for heater 1 to 280C

; Fans
M106 P0 C"Layer Fan" B0.1 S0 F100 H-1    ; set fan 0 name, value, PWM signal inversion and frequency. Thermostatic control is turned off
M106 P1 C"Tool Cooling Fan" F500 H1 T45	 ; set up cooling fan on output 2
M106 P2 C"LEDs" F25000 B0 L0			 ; set up LEDs on fan output 3

; Tools
M563 P0 D0 H1 F0                         ; define tool 0
G10 P0 X0 Y0 Z0                          ; set tool 0 axis offsets
G10 P0 R0 S0                             ; set initial tool 0 active and standby temperatures to 0C

; Custom settings
;M572 D0 S0.55							 ; enable pressure advance
M207 S1.5 F10000					 	 ; set default firmware retract settings
M912 P0 S-5.2							 ; adjust MCU temp sensor

M501									 ; load settings from config_override.g
;M592 D0 A-0.00118 B0.000248			 ; define nonlinear extrusion

; Miscellaneous
T0                                       ; select first tool

And my homez.g:

; homez.g
; called to home the Z axis
;
; generated by RepRapFirmware Configuration Tool v2.1.8 on Fri Mar 13 2020 18:19:30 GMT-0600 (Mountain Daylight Time)
G10 P0 S130		 	; set to 130c for probing
G91              	; relative positioning
G1 H2 Z5 F6000   	; lift Z relative to current position
G90              	; absolute positioning
G1 X155 Y155 F6000 	; go to first probe point
M116 P0			 	; wait for temp to stabilize
;G91				; relative positioning
;G1 H1 Z-480 F4000 	; move Z to raw probe position
;G1 Z5 F600			; lower bed a bit
;G90				; absolute positioning
G30              	; home Z by probing the bed

Phaedrux

Probe dive speed may be too low. The piezo needs a short sharp shock to trigger.

Try M558 F600 and G31 P100

Might also want to reduce the Z axis motor current a bit in case of a crash.

How much flex is there in the mount for the piezo? If it's too squishy it might not trigger the piezo either.

SAtech

You got me thinking about it, and I discovered that you can use it in analog mode. Doing this, I got it to work, but yes, the frame is somewhat flexible, as it is printed out of PETG. Eventually, I am planning to print it out of heat-treated carbon fiber PLA.