Piezo Orion + RRF 3.... Problems

chop

16.10.2020, 22:43:59 Error: Z probe readings not consistent
16.10.2020, 22:43:38 Error: Z probe readings not consistent
16.10.2020, 22:43:13 Error: Z probe readings not consistent

chop

@arhi

if i use Analog DWC says Z-Probe 492 and not 0. without contact.

how to tune?

arhi

@chop said in Piezo Orion + RRF 3.... Problems:

@arhi pls gimme a example config. I will test it

you need to run the analog output to the zprobe.in using a coax cable (I'm using balanced audio cable for e.g.)

config:

; ORION ANALOG 
M558 P1 C"!zprobe.in" R2 H6 F2400 T3600 A4 S0.03 K0 
G31 X0 Y0 Z-0.1 P250

how to use it:
homez.g

; HOME Z WITH ORION

M400

T0
G90
G0 X0Y0 F3000           ; go to center of the bed, complain if X or Y not homed
G91                     ; relative positioning
;G0 Z5   F900  H2        ; drop bed for 5mm
G90                     ; absolute positioning
G4S3                    ; wait 3sec

G31 P{sensors.probes[0].value[0] + 3}

G30                     ; Probe the bed at the current XY position. 
                        ; When the probe is triggered, set the Z coordinate 
						; to the probe trigger height.

the G31 here takes current reading from the analog input and set treshold to +3 that value

bed.g

; bed.g
; called to perform automatic bed compensation via G32

G29 S2 ; delete compensations
M561   ; clear any bed transform
G28    ; home

M400
M913 X30 Y30 Z100 ; go to first test point
M400
G4 S1
M400

G31 P{sensors.probes[0].value[0] + 3}
G29 S0

this way the issue with sh$%%^tty potentiometer on the board for setting trashold for digital output is solved.

There's still issue with mounting ppiezo but that's another bag of worms, but this is the good start so you at least have treshold set right.

notice that if you are having "premature trigger" with

G31 P{sensors.probes[0].value[0] + 3}

you can change to +5 or more, but that really means that you are picking up a lot of noise and you need a better cable or that your head is vibrating or .. it should work with +2 or +3

arhi

also note that you want probing to be "fast" as the fastes you hit the nozzle better it will react, piezo do not like to be "slowly pressure" it likes to be tapped. The problem with current firmware is that it slows down when the read value is close to treshold (and it always is as it does not change like with ir sensor). dc42 said he'll change this in one of the next versions but so far it has not happened so you need to push the speed in the m558

chop

@arhi

thanky you. but how can i adjust the trigger?

arhi

@chop said in Piezo Orion + RRF 3.... Problems:

@arhi

thanky you. but how can i adjust the trigger?

this does it:

G31 P{sensors.probes[0].value[0] + 3}

analog output from the orion ignores the pot, so don't touch the pot.
this reads the current value of the analog output from the orion ( sensors.probes[0].value[0] and sets the new treshold value to read value+3

chop

@arhi hm . changed from 1 to 25 and nothing changed

arhi

@chop what do you expect to change?

chop

@arhi the trigger value in dwc its @ 492 and with s lot of preasure it Gos over 500

arhi

@chop what you see in DWC is the read of the analog value, that will not change by any g-code, it's what the orion is sending and it changes as the orion is deformed. the G31 I gave you changes the threshold. to see the threshold value you need to send just G31

chop

@arhi ah okay. Ty! Today i will give some anti backlash nuts a shot. After install i will try your Tipps.

chop

@arhi @engikeneer

So it works! Thank you for your help. But now I have the next problem. How can I use the orion correctly? How do I set z. no matter what I do . He starts printing in the air. With rrf3 I determine z with 92z0 right? Then I create a mesh. What do I have to enter in his? I'm still new to rrf. before marlin sorry. do not quite understand all of this yet

arhi

@chop now you need to manually figure out the Z offset of the probe and put it in the config.

super important is that you heat up your bed and nozzle before you home Z with the orion
super important that you clean a nozzle before you probe (so heat up, wipe, retract, wipe is what I do, visually inspect when nozzle is sitting above center of the bed that nozzle is clean)
after you home Z, you then need to find the "offset"

this offset is normally in the range of 0 to -0.1mm depending on how sensitive your orion is and how fast you probe so it's basically the travel your bed does during a trigger delay. how to setup this offset ... ppl have different preferences, what I do is I'd leave nozzle in the center of the bed (homing position) and do

G0Z1

this should have your nozzle close to the bed but not touching it

disable soft limits

M564 S0 H0

now I put piece of paper between nozzle and bed and start reducing this value

G0Z0.5

G0Z0.3
G0Z0.2
...
G0Z-0.2
...

till I get to point that paper is being grabbed by the nozzle

this position need to be your Z0 so see how far you are from it (you know what Z value you gave it), change the sign of that value and put in the config of the probe (G31, the Z value):
e.g.:

G31 X0 Y0 Z-0.1 P250

hope this helps

btw, do this while everything is HOT and nozzle is clean. Otherwise not much point in using orion, as if you probe cold those are not real value during print.... this is why I like the durable print surfaces like printbite as if you have those soft print surfaces they can dislike the hot nozzle so then you might want to work hot but heat up the bed to your print temperature but heat up the nozzle to lower temp like 100-120C enough for it to "get bigger" but not hot enough to damage the print board if you mess something up

useful read: https://duet3d.dozuki.com/Wiki/Test_and_calibrate_the_Z_probe

arhi

one hint, since digging hot nozzle into print bed is a real solution when you do this first time I suggest you use a PCB on top of your print bed, or use glass as your print surface for the first test... so both probe over the hard surface that's temperature resistent (pcb/FR4 or glass) and start the first print on top of such surface to be sure you got the probing and configuration (offset) properly calibrated

going further, one other hint .. before you start printing, make sure that ORION Is ok and that you are not drowning in noise .. so run a test probing same point many times

chop

@arhi ty . I will try. But, how to set z0 corect? After z0 i can set offset !? Right? Once i get the offset. I have to tell the Slicer to use the mesh?

chop

@arhi said in Piezo Orion + RRF 3.... Problems:

@chop now you need to manually figure out the Z offset of the probe and put it in the config.

super important is that you heat up your bed and nozzle before you home Z with the orion

super important that you clean a nozzle before you probe (so heat up, wipe, retract, wipe is what I do, visually inspect when nozzle is sitting above center of the bed that nozzle is clean)

after you home Z, you then need to find the "offset"

this offset is normally in the range of 0 to -0.1mm depending on how sensitive your orion is and how fast you probe so it's basically the travel your bed does during a trigger delay. how to setup this offset ... ppl have different preferences, what I do is I'd leave nozzle in the center of the bed (homing position) and do

G0Z1

this should have your nozzle close to the bed but not touching it

disable soft limits

M564 S0 H0

now I put piece of paper between nozzle and bed and start reducing this value

G0Z0.5

G0Z0.3
G0Z0.2
...
G0Z-0.2
...

till I get to point that paper is being grabbed by the nozzle

this position need to be your Z0 so see how far you are from it (you know what Z value you gave it), change the sign of that value and put in the config of the probe (G31, the Z value):
e.g.:

G31 X0 Y0 Z-0.1 P250

hope this helps

btw, do this while everything is HOT and nozzle is clean. Otherwise not much point in using orion, as if you probe cold those are not real value during print.... this is why I like the durable print surfaces like printbite as if you have those soft print surfaces they can dislike the hot nozzle so then you might want to work hot but heat up the bed to your print temperature but heat up the nozzle to lower temp like 100-120C enough for it to "get bigger" but not hot enough to damage the print board if you mess something up

useful read: https://duet3d.dozuki.com/Wiki/Test_and_calibrate_the_Z_probe

Make sure the dynamic test is successful (Z probe stops when it senses the bed) before doing this.
Cancel any currently active mesh compensation with M561
Use the X and Y jog buttons to position the nozzle over the centre of the bed
Jog the nozzle down until it is just touching the bed or just gripping a sheet of paper. If the firmware doesn't let you jog it down far enough, send M564 S0 to disable axis limits.
Once you have the nozzle touching the bed, send command G92 Z0 to tell the firmware that the head is at Z=0
Jog the head up by 5 to 10mm
Send command G30 S-1. The nozzle will descend or the bed rise until the probe triggers and the Z height at which the probe stopped will be reported. If you are using a nozzle-contact Z probe, the trigger height will be slightly negative. For any other type of Z probe where the probe triggers before the nozzle contacts the bed, it will be positive.
Repeat from step 5 two or three times to make sure that the trigger height is consistent.
In Duet Web Control, go to Settings -> System Editor and edit the config.g file. Set the Z parameter in the G31 command to the trigger height that was reported. Save the file.
Open config-override.g and check that there are no G31 commands in it. If you find any, delete those lines and save the file.
To apply the new trigger height, restart the Duet by sending M999 or pressing Emergency Stop.

Thats what i do...print starts mid air

arhi

testing the repeatability - very important with piezo

G28
M401
G30 P0 X151 Y161 Z-9999
G30 P1 X151 Y161 Z-9999
G30 P2 X151 Y161 Z-9999
G30 P3 X151 Y161 Z-9999
G30 P4 X151 Y161 Z-9999
G30 P5 X151 Y161 Z-9999
G30 P6 X151 Y161 Z-9999
G30 P7 X151 Y161 Z-9999
G30 P8 X151 Y161 Z-9999
G30 P9 X151 Y161 Z-9999 S-1
M402

change X and Y values to be in the center of your bed
more details here: https://forum.duet3d.com/topic/6962/m48-measure-z-probe-repeatability-and-print-to-serial-output/4

arhi

@chop said in Piezo Orion + RRF 3.... Problems:

Thats what i do...print starts mid air

what is your G31 config line now?
what does your G31 report when you execute it?
did you run repeatability macro?

chop

@arhi alt text

arhi

@chop that is nicely repeatable, you have it working good I'd say

you need to change your G31, if you are printing in the air you need to lower the value more into negative... zo try Z-0.1 or Z-0.15 or even more Z-0.2 till you get satisfying first layer. I never seen it need more then -0.15 for ppiezo but .. if I didn't see it, it does not mean it does not exist