Precision Piezo Orion Kit on Duet3 mini 5+ issues

MaukaEast

Re: Precision Piezo z probes guide for duet users reference

I'm been having trouble tuning PPOrion on my Duet3 5+. I'm a Titan/3D3v6 hotend on a CoreXY printer and a moving Zaxis. I'd like to replace my current Z-min endstop with the ppOrion.

I'm running digital pp mode, as I can't get any analog sensor value other than '1000' in the Web Control

I installed and test fine manually: flicking the nozzle fires the LEDs as well as changes the sensor output from 0 to 1000. I can G30 to home Z when using my finger, but whenever I try for an actual bed probe, the sensor seems to fire on release/return movement and not initial contact. So when my bed hits the nozzle, the slow constant pressure doesn't set off the sensor and it results in crashing and pushing my nozzle. Changing probe speed in setup doesn't make any difference.

It seems most of the forum suggestions are for RRF2.xxx. (playing with M552 "I" commands (which is depreciated in RRF3) or reverse the sensor lead polarity (which are hardwired on the Orion). Similarly, I'm not sure if having a Duet3 I/O socket instead of a Duet2 dedicated port has any impact; I'm on I/O_1in for reference, but don't think I need any specific config setup commands for that.

my config.g lines:
; Z-Probe
M558 P8 R0.3 F250 T4200 C"!io1.in" H6; PP sensor in digital mode connected it io1.in
G31 Z0.05 ; set Z probe trigger value, offset and trigger height
M557 X20:280 Y20:280 S60 ; define mesh grid

Any help would be appreciated. Thanks

weed2all

@MaukaEast change the R value from 0.3 to 0.5...

MaukaEast

@weed2all Thanks for the reply. Changing the R value didn't help. Still not firing on contact and pushing hard on the nozzle for a few mm until my z-axis stalls and the belt skips.

weed2all

@MaukaEast the precision piezo orion v2 I have has a small potentiometer on it to adjust the sensitivity...have you tried adjusting it..
Adjust it and tap on the nozzle and see the impact it does...

MaukaEast

@weed2all Unfortunately, this didn't seem to work. Tried for nearly an hour to find that trigger point, but I ether just get the same (too loose to not fire upon contact) or so sensitive that any movement on z-axis would fire it prematurely. Is there a way to change the G31 behavior directly? It seems my machine has a rather abrupt direction switch at the very start of the homing, which I think if I can get rid of (or ease into better), it would allow for a more sensitive sensor.

I'm tempted to also start messing with the actual Orion mounting screws to see if I can alter the firing that way, but have gotten a few contradicting notes on that (v. snug vs. 1/4 turn loose from snug)

weed2all

@MaukaEast what mount do you use? Can you show a photo? The mount you have is made by you or is what precision piezo send with the orion?

engikeneer

@MaukaEast as @weed2all says, the piezo is very sensitive to the mount design, but also any flex in your carriage & gantry. It needs a short hard tap to trigger so and flex means the tap is less hard and so it is less reliable.

Other things to try would be to temporarily reduce you z axis accel and jerk limits to be much lower. You could also drop X Y a bit too to reduce the recovery time. I have a little macro which sets my jerk and accel for all axes which I call from config.g, and after homing to make sure I always set it back to the right value (and only have one place to set what my 'normal' machine limits are).

Finally, have you tried increasing your probing speed? You are at 250mm/min which is at the lower of the PP spec (240 to 420mm/min). Higher speed sounds scary but means you get a harder tap and so a more reliable result

MaukaEast

@engikeneer Thanks for everyone's help, including Idris, who responded to an Email with some great suggestions. I got the sensor working basically taking everyone's suggestions: 1/4 turn out mounting screws, faster probe speed (now 450), and lower jerk (accel @ 20). Then it was just a matter of fin-tuning the onboard potentiometer and being patient.