Precision Piezo z probes guide for duet users reference

Lakko

@moriquendi said in Precision Piezo z probes guide for duet users reference:

Which version of the Piezo20 do you have, there is a version number on the back, underneath the piezo connections pins.

I have the piezo20 v0.6

@moriquendi said in Precision Piezo z probes guide for duet users reference:

You cannot change the sensitivity using P1, the output of the module is digital, it's either on or off. The only way to adjust the sensitivity is with the potentiometer/s on the board.

Idris

Sorry Idris i badly explained myself, i meant that if i use P1 instead of P5 or P8 for example:

M558 P1 I0 R0.4 F330
G31 X0 Y0 Z-0.1 P100

Than i can use VR1 on piezo PCB to adjust the sensitivity on the fly but the threshold P100 in the G31 is useless or it is still used?

Moriquendi

To reset the v0.6 to factory settings, turn VR1 and VR2 so that the flat part of the adjuster is closets to the bottom of the PCB.

You CAN use P1 but it has no advantage over P5 or P8 and may have some disadvantages. The output of the PCB is either 0v (roughly) or 3.3v (again roughly, later boards are better at this, they go closer to 0v but for this explanation assume 0v). The duet reads these values as either 1000 or 0. Because the output is digital, the value is either 1000 or 0 but nothing else inbetween. So the threshold makes no difference except that noise or interference on the signal wire might cause a false trigger.

David might be able to give more detail about how the firmware processes P1 and P5/8 differently.

TLDR: use P8

Idris

Lakko

@moriquendi said in Precision Piezo z probes guide for duet users reference:

To reset the v0.6 to factory settings, turn VR1 and VR2 so that the flat part of the adjuster is closets to the bottom of the PCB.

Last question, clockwise or counterclockwise?

@moriquendi said in Precision Piezo z probes guide for duet users reference:

David might be able to give more detail about how the firmware processes P1 and P5/8 differently.

it isn't necessary, it was just a curiosity.

Thank you for your help Idris

Moriquendi

Either way, there are no physical stops.

Idris

papilio

@moriquendi ...

Hi Idris!

I'm afraid that I seem to be having quite a lot of trouble with the new V2.75 board which I just received from you. I'm using an under-bed setup and had gotten it to work well, and fairly easily, with the V2.02 board -- but I wore out the pots on that one. Now I'm getting an insane level of false triggering which I seem unable to tune out. Might you by chance still have any V2.02 (or equiv) lying around?

I am wondering whether my trouble may merely be caused by the long (slightly over recommended) cables from the piezos, perhaps since in the current state of the build they're still just draped across other electronics under the bed -- but again, the same was true with the earlier board and no problems were evident. Might shielded cables resolve my issue? Having trouble locating stranded ones on Amazon.

I'm still stunned every time I look at your piezo endstop board, knowing that you soldered the entire thing by hand.

Michael

Moriquendi

Hi Michael

The v2.75 version of the universal PCB has two solder jumpers on the back, closing the two jumpers will allow you to use the full tuning range of the board.

As supplies the v2.75 board has the tuning window reduced, this makes it easier to tune because you need more rotation of the pot for the same change in tuning. For most people this is a good deal because most people don't need the full tuning range but for those who do it's just a matter of putting a blob of solder on each of the jumpers.

If you're looking for flexible, shielded cable you might try a headphone lead, they're often shielded.

I don't exactly solder them all by hand, I assemble them by hand and reflow them in an oven, I've got a video of the process here

Idris

papilio

Thanks Idris ... yes I'd seen that idea in the manual, but had forgotten. I'll give it a shot!
And thanks for the tip on the cables.

papilio

Wow fascinating video Idris! Thanks so much for taking the time to show us!

2689Matt

Hi,

I have an under bed setup using 4 piezo on a universal board... until last night!

I have changed my extruder and new hotend is a mk10 from a mk8. I cannot see why this might make a difference but now my piezo setup won’t work!

Any suggestions please? Nothing else in my setup has changed... except the M92 E value for new extruder!

Now it still triggers as it did when tapping the bed, but nozzle just crashes when probing..

Many thanks,

Matt

Cubex249

Installing a Orion Piezo on a cubex. The Z probe is always at 1000 with or without piezo connected to probe header. When connected and i touch the end of the hot end the blue light flashes and Z probe goes to zero. in this configuration I get a error that the Z home signal is on before homing starts. I'm configuring this thru the RepRap configuration software. I've also have left the configuration to z probe and then used a n/c switch but it start to home but i can't stop it. the blue led flashes when I tap the hot end but it doesn't stop. The following moves x,y to 25mm z retracts (30mm?) and then I get the error. Thank You for your help. I'm about as new as one can get to this.

G90 ; Send absolute coordinates...
M83 ; ...but relative extruder moves

; Network
M550 P"Cubex" ; Set machine name
M552 S1 ; Enable network
;*** Access point is configured manually via M587
M586 P0 S1 ; Enable HTTP
M586 P1 S0 ; Disable FTP
M586 P2 S0 ; Disable Telnet

; Drives
M569 P0 S0 ; Physical drive 0 goes backwards
M569 P1 S0 ; Physical drive 1 goes backwards
M569 P2 S1 ; Physical drive 2 goes forwards
M569 P3 S1 ; Physical drive 3 goes forwards
M350 X16 Y16 Z16 E16 I1 ; Configure microstepping with interpolation
M92 X80.00 Y80.00 Z4000.00 E420.00 ; Set steps per mm
M566 X900.00 Y900.00 Z12.00 E120.00 ; Set maximum instantaneous speed changes (mm/min)
M203 X6000.00 Y6000.00 Z180.00 E1200.00 ; Set maximum speeds (mm/min)
M201 X500.00 Y500.00 Z20.00 E250.00 ; Set accelerations (mm/s^2)
M906 X800.00 Y800.00 Z800.00 E800.00 I30 ; Set motor currents (mA) and motor idle factor in per cent
M84 S30 ; Set idle timeout

; Axis Limits
M208 X25 Y10 Z0 S1 ; Set axis minima
M208 X250 Y250 Z220 S0 ; Set axis maxima

; Endstops
M574 X1 Y1 S0 ; Set active low and disabled endstops

; Z-Probe
M574 Z1 S2 ; Set endstops controlled by probe
M558 P5 R0.4 H5 F1200 T6000 ; Set Z probe type to effector and the dive height + speeds
G31 P500 X0 Y0 Z2.5 ; Set Z probe trigger value, offset and trigger height
M557 X25:25 Y25:195 S20 ; Define mesh grid

; Heaters
M140 H-1 ; Disable heated bed
M305 P1 T100000 B4138 R4700 ; Set thermistor + ADC parameters for heater 1
M143 H1 S280 ; Set temperature limit for heater 1 to 280C

; Fans
M106 P0 S1 I0 F500 H-1 ; Set fan 0 value, PWM signal inversion and frequency. Thermostatic control is turned off
M106 P1 S1 I0 F500 H-1 ; Set fan 1 value, PWM signal inversion and frequency. Thermostatic control is turned off

; Tools
M563 P0 D0 H1 ; 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

; Automatic power saving
M911 S10 R11 P"M913 X0 Y0 G91 M83 G1 Z3 E-5 F1000" ; Set voltage thresholds and actions to run on power loss

; Custom settings are not configured

; homez.g
; called to home the Z axis
;
; generated by RepRapFirmware Configuration Tool v2 on Tue May 21 2019 15:52:37 GMT-0400 (Eastern Daylight Time)
G91 ; relative positioning
G1 Z5 F6000 S2 ; lift Z relative to current position
G90 ; absolute positioning
G1 X25 Y25 F6000 ; go to first probe point
G30 ; home Z by probing the bed

; Uncomment the following lines to lift Z after probing
;G91 ; relative positioning
;G1 S2 Z5 F100 ; lift Z relative to current position
;G90 ; absolute positioning

Cubex249

@cubex249
I figured it out. I added a I1 in the M558

alil2096

Hi,

I've a problem with the Andromeda system. I've installated all, and if I try with my hand all works fine. But when I run the G29 command, at the fourth or fifth point, the piezo stops working and I get the error:

I've this error:

Error: Z probe was not triggered during probing move

This is my config.g (i've try to reduce the R parameter and increase the speed, but the situation dosen't change):

; Z-Probe
M558 P8 I1 R0.2 F1000 X0 Y0 Z0     ; digital mode, NO/NC, delay, speed, not used as axis endstop
G31 X0 Y0 Z-2.5 P100               ; X Y Z offsets. P=debounce interval (The debounce interval in ms smoothes the signal)
M557 X15:375 Y30:390 S60           ; define mesh grid

How I can fix this?

Thanks,

Andrea

Dr_Ju_Ju

If you tap the probe, with your finger, do the led lights flash on the control board and does it also show as triggered in the DWC ???

If leds flash, but no show in the DWC then your configuration is incorrect. If they don't flash, you need to check your board\wiring\probe etc.

alil2096

Sorry, but what's DWC?

The probe works, because the first points are probed correctly. At the fourth point, however, it stopped working..

Dr_Ju_Ju

DWC - Duet control web pages & sorry I should have taken in what you've written...

So I take it, that at the fourth point the probe hits the bed ??

FYI, as it looks like you are still on RRF2, if so, this was my setting for that version (which worked well)

M558 P8 I1 R0.5 H5 T24000 F250 A3 S0.08 ; Set Peizo - P probe type, I Invert, R recovery time, H dive hight, T inter-probe-point speeds, F Probing Speed, 3 Dives , S calculated difference

alil2096

I've try your code but for me dosenìt work.. the bed don't feel the probe..

Deltasquare

Hey all!

So I have been playing with the piezo probes a couple of times now. However, even after having had my hands on 4 sets of piezo probes, it just does not work.

My setup is a Duet Wifi with under-the-bed piezo sensors. They are Andromeda sensors hanging under the bed, screwed to the frame, with the central Screw propping up the bed.

The relevant Duet Code I am using is as follows:

M558 H25 T9000 A10 P3 I1 R0.4 S0.02 F500
G31 X0 Y0 Z-0.15 P100

In order to test I run following script:

G28 X

G1 Z25 F8000
G30 S-1
...the above two lines  *100

G28 X

I get a drift or roughly 0,3mm over the first 30 measurements, with increments of drift ranging from 0 to 0,018mm. After leveling out at approximately the 30-probe mark (this is by no means a hard limit) measurements jump back and forth between 0,002mm to max 0,015mm altough the larger differences are usually followed by an equally large countermovement (so if it measures 0,015 higher than the previous measurement, it is likely it is going to measure 0,015 lower the next cycle around).

I don't know what it is but with this problem I can not work with the piezo probes especially not with the arrangement I have got here.

I tried a lot and t kills me that it does not work. On top, I actually thought it was the perfect system for our business 3D printer and it not working doe not really help me at all.

I posted a similar request in the reprap forum, as I am trying to cover all my bases here and the problem persists for more than 12 months already.

Best regards
Deltasquare

droftarts

@Deltasquare said in Precision Piezo z probes guide for duet users reference:

M558 H25 T9000 A10 P3 I1 R0.4 S0.02 F500

I think this could be improved for accuracy/repeatability:
P3 - This mode is the analogue input. Usually piezos use the P8 (digital, unfiltered, faster) mode. You will probably still need to invert, which you're doing already.
H25 - this is the dive height. Unless your bed is wildly out of whack, you don't need to move the probe up this high. Try H5. Will also speed things up.
F500 - this is the probing speed. 500mm/min is FAST for probing. Most people in this thread seem to use F120. Try slow, then speed up if it still holds accuracy.

Ian

Deltasquare

Hi Ian!

Thank you for your quick reply!

ad dive height.:
I have run apprx 20 tests with 100 reps each for distinguishing the optimal probing height. I previously got the least offset when probing from 25mm height. My guess is that at 25mm is a multiplier of the full steps required to get to the bed.

ad analog vs digital.:
I had the impression that the analog was supposed to be the more accurate, is this not true?

I am implementing all your suggestions as I am writing. I will be getting back with results.

thk
dsq

Deltasquare

So I implemented the changes as suggested. There is no change.

In this attempt I have run 3 scripts twice each. The results are supporting one another in most cases.

Run1 & 2 were with the previous test script.

Run 3 & 5 were with the suggested improvements:

Improvements:

M558 H5 T9000 A10 P8 I1 R0.4 S0.02 F120	; M558 dive Height, Travel speed, probing Attempts, Probe type, Remain, dive speed F
G31 X0 Y0 Z-0.15 P100				; Set Z probe trigger value, offset and trigger height Z-0.012 / Z-0.45

Script Z5:

G28 X

G1 Z5 F3000
G30 S-1
... above two lines x100

G28 X

and out of curiosity i also run the same settings with following script, to move the sliders a little more, as it is likely to happen in my setup.

Script Z5 updown:

G28 X
G1 Z5 F3000

G30 S-1
G1 Z40 F6000
G1 Z5 F6000
... above three lines x100
G28 X

Results you can find here, mind the tabs:
https://drive.google.com/file/d/19arr1t3R8NCq5BxTw2s26OPm-Wabvvv0/view?usp=sharing