Percision peizo probing help

arhi

one other thing, RRF v3.1.1 will not do a probe at the speed configured with M558 because for analog probe RRF assume you are using IR probe and that analog value is proportional to the distance from the bed. This is why RRF will start probing at configured speed and then drop the speed when "close to bed". With ORION you have non stop value "close to bed" till it triggers so the probing is done much slower than configured in M558. @dc42 promissed to change this for 3.2 so that we can define a probe for piezo properly. Note that when you are probing with piezo too slow the value will not change enough for the probe to be recognised so you want to increase the probing speed in order to have piezo detect the colision properly. Also you want to drop jerk and acceleration of Z axis to a very low value so you do not vibrate the sensor into triggering when you start the probing move. And finally, fairly important hint, you want to wipe your hotend before you start probing so make sure you have your wipe procedure working ok.

gorf26

Thanks When i setup analog before i was not getting a good trigger variation i am assuming..
probe no hit it was 475 to 480 when hit signal went maybe up to 490 sometimes to 500 not enough for duet to see probe was hit I'm thinking,
I was a little nervous also about adjusting the pot and toughing things way off...

I don't have the probe mounted right now i just connected it to the E1stop pin and i have tried 10 or 15 g31 moves and just tapped the probe and it seems to be stopping the axis right away every time, of course every thing can change when i remount it to the effector... i am thinking that the problem is with the zprobe.in pin on the duet so if thats the case i don't think analog will work correct either.

also not sure if your homing will work i only have the deltahome.g no home x y or z files

I have increased homing speeds from 300 up to 2400 before with no change.. but now that i have a signal on the e1stop, from the looks of it, it may work..

of course now that i may have it working, and after i removed it, i just have the hotend mounted to the effector, also i spent all day yesterday doing manual bed leveling, almost hate to swap it back and start all over..

also right now my hot end is clean, i cleaned it put new tip and have no filament in.

Thanks gary

arhi

@gorf26 said in Percision peizo probing help:

Thanks When i setup analog before i was not getting a good trigger variation i am assuming..
probe no hit it was 475 to 480 when hit signal went maybe up to 490 sometimes to 500 not enough for duet to see probe was hit I'm thinking,
I was a little nervous also about adjusting the pot and toughing things way off...

The potentiometer on board does not affect analog output. Those smd trimmers are only good for up to 20 "moves" and then they go bad, and they are inprecise to begin with. Using analog output you solve that problem.

If you didn't use coax cable (for e.g. shielded microphone cable, or shielded balanced audio cable or something like that) to link analog output to the zprobe.in you had a lot of noise picked up by the wires and the noisy trigger is not nicely handled by the RRF (questionable if even possible). I for e.g. use balanced audio cable, there's a twisted pair that's additionally shielded, one of the pair wires I connect to analog output, other to ground on both sides, of course. The shiled of the cable on the duet side I connect to ground and on piezo side I do not connect anywhere. This kills the noise almost completely.

I don't have the probe mounted right now i just connected it to the E1stop pin and i have tried 10 or 15 g31 moves and just tapped the probe and it seems to be stopping the axis right away every time, of course every thing can change when i remount it to the effector... i am thinking that the problem is with the zprobe.in pin on the duet so if thats the case i don't think analog will work correct either.

Analog will work much better than digital output.

You need to make sure, of course, that the sensor is properly placed. If you put sensor outside and tap it by hand it is very different from probing as you tap it faster than it bends during probing, also it's not constrained in the head. Dunno what mount style you use but if you go with similar to what they are selling (grove style) the 4 screws that compress the orion, they should be only fingertight, if you overtighten them the probe won't work.

also not sure if your homing will work i only have the deltahome.g no home x y or z files

I don't do delta so you have to use the idea from my homing and apply to delta. The general idea is to bring the nozzle close to probing point, do not move anything for few seconds and then do

M400
G4S1
G31 P{sensors.probes[0].value[0] + 2}

M400 will wait for all moves to stop
G4S1 will wait for 1 sec for everything to stop shaking
G31... will read the current probe value and set threshold value to that value + 2

So this will dynamically set threshold just before you start probing. If you get trigger before you touch the print plate increase the +2 to something bigger (+3 or +4). If you do not trigger on touch with +2 you need to increase probing speed.

gorf26

Thanks a lot i will give it a try, i need to re design a new top screw mount for the pizeo, when mounted to the all metal effector, the bowden tube fitting is to far down to release if i need to pull the tube.

I have it drawn up just need to print it now hopefully my manual bed leveling is good, will be giving it a go this afternoon...

if it go's well i will test out your suggestions..

Thanks Gary

gorf26

@Phaedrux

You may be right i just received a reply from Idris and he said you need a pullup resistor in digital mode but not in analog..

I had trouble getting it printing again but got a good cube printed today so will be printing a new mount and get the piezo remounted and see how it go's..

just a thought do you know if the E0Stop is set to pullup, it do's seem to work on that connector...,? but I will go back to the zprobe.in with pullup and see how that goes

He also said in analog mode the pot has no effect.

Gary

gorf26

sorry to bring the piezo back up, but i had to redesign a mount for my all metal effector.
I have it mounted now and running... in digital mode..

Most of the suggestion's are to use analog, i have tried all different combinations in the firmware but no matter what i always seem to have a high signal, in the DWC it shows 478 or so when booted, and when probe is hit it only changes to around 480 485. never go's to 0.

When i do a probe move i always get the message probe triggered so no movement is started..

I have tried with pullup's on and off and also inverted on and off, the same results.

Thanks gary

nriviera

The probe doesn't need to go back to zero it just need to go to roughly the starting value. The "zero" is the value that the probe is at baseline (with some leeway for temperature fluctuation) that you set a trigger value above which it triggers. For you I'd set my trigger value to 480 and see if it works. DWC should go from grey to red when the value goes above the trigger value. If you are on analogue the Pot doesn't change the trigger value - you need to change the config files instead.

The other thing I found with them is they are very sensitive to how tight you have the screws and work best when it's on the slightly looser side (but not loose enough to cause the hotend to move). I've been mounting my piezo disc on a bit of car gasket maker which makes the discs a bit more robust to head strikes and over tightening. I can't find a picture right now unfortunately. Piezo's are a pain to get working because you have to redesign everything around them but they're great when they do.

The other thing that is worth mentioning with a delta is an under bed sensor might be better as you have a static Z (really wishing I went the Voron route right now!) which makes designing a hot end as easy as it gets.

gorf26

You are right the 478 is ok i found that if i set the g31 pXXX in config.g to somewhere between 5 to 15 higher it does work so 478 + 5 to 15, you will have to play with it but it works i did a g32 and had no miss hits probed good..

Thanks gary

peirof

Hi,

has you try to do a test of Precision Piezo

with this gcode

G30 S-1

And works?

Maybe, the height that PPO low searching the bed its not enought
and no encounter bed

gorf26

Yes have used G30 S-1, i have had it, or as it seemed working ok with G30 S-1,,
But when i try a G32 it will seem to probe ok then at one point or another it may probe good with the first hit then retract and on the second hit it messes up either hits and skids a few steps across the bed or i get the message no probe hit, it just seem to be very erratically and i can't get it working right, so for now i pulled it and went back to my old setup and i am doing a manual probing for now...
I tried different wire's all kinds of different settings in the firmware but with same results starts off looking good then at one point messes up and not always the same probe point.
Its a delta so i may just switch to the duet effector probe.. hopefully that will work better..

Thanks gary