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    Precision Piezo z probes guide for duet users reference

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    • Cinproundefined
      Cinpro
      last edited by

      I have it set like in your example, except for the Z1. I don't plan to use it to home since my hot-end parks off to the side and doesn't touch the bed. Just to clarify, you are using the E0 endstop for all the wires, and not the Z-probe socket on the board beside the Panel Due socket?

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      • DjDemonDundefined
        DjDemonD
        last edited by

        Hi guys sorry for the slow response. Using the z probe connector is no issue. If the DWC or paneldue shows 1000 when the probe is open/untriggered, then just change the M558 I parameter from I1 to I0 or vice versa.

        What version of piezo device are you using? If correctly set up (red light on until triggered) a V2 universal kit board will output an active low signal (also called NC or inverted 3.3v open and nearer to 0v triggered). This offers failsafe operation in that a wire break between piezo pcb and the duet controller will show as triggered and therefore avoid a head crash. Upcoming versions of the piezo PCB (anything with V2) will work this way. Use I1.

        Currently, Piezo20 PCBs (which are v1) and the original V1.x universal kit PCBs operate with the blue LED off when open, it comes on momentarily when triggered, these devices, are active high (NO or 0v open and 3.3v triggered). Use I0. No failsafe, so when commisioning, use low motor current to avoid head crash issues.

        You can set up a v1 universal PCB inverted by moving VR2 until its just past the point where the blue LED comes ON and leaving it there, use I1 in this mode. But please DO NOT set up a Piezo20 PCB (the small one with one piezo connector) in this mode as it might burn out the blue LED (although this is less likely with 3.3v than with 5v.

        The piezo20 PCB piezo connector is wrongly labelled, so ignore the + and -, however this sometimes has to be the case as not every piezo disc is correctly polarised. The only reliable test (without a scope) is to push up on the nozzle (or down on the bed for underbed) not tap, and see if it triggers when you push. Then release the pressure, see if it triggers when you release. If it triggers on push it's correct, if it triggers on release its the wrong polarity, just turn the piezo disc plug to the piezo PCB the other way, retune and try again. If it helps when I build the ready-to-run units using genuine Murata 7bb piezos the black lead from the piezo goes to the upper pin (nearest the outside of the PCB), most of the time, but occasionally I find an inverted piezo disc.

        Simon. Precision Piezo Z-Probe Technology
        www.precisionpiezo.co.uk
        PT1000 cartridge sensors NOW IN, just attach to your Duet board directly!

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        • rmrigginundefined
          rmriggin
          last edited by

          I have an odd issue in that if I have anything connected to the VIN pin on any endstop or the probe connector the duet becomes unresponsive until I unplug the VIN wire regardless of using the VIN pin on the z endstop connection or the z probe connection. Any ideas?

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          • S1lencerundefined
            S1lencer
            last edited by

            Sounds to me like you have the polarity on youre piezo board not in the right order,
            please check if you got the signal and graund the right way around.

            mfg
            Kai

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            • DjDemonDundefined
              DjDemonD
              last edited by

              Double check wiring. On current generation piezo pcbs the wires at the Piezo PCB:
              Vin - Red - positive (3-5v)
              SIG (also labelled TRG) - green
              GND - Black - negative - 0v

              At the Duet (four pin plug) it goes
              VIN RED
              BLANK
              GND BLACK
              SIG/TRG

              With the red Vin towards the sd card slot end of the duet board.

              Please be aware standard endstop cables have GND and SIG the other way around. I swap them over when shipping (it's very tedious). We also leave the controller board end unwired to ensure that full attention is given to putting the wires in the right pins as every controller is different.

              We are bringing a new generation of boards out this year which have the wiring as per the standard endstop cable, much less work, but will cause confusion for upgraders who will need to reconfigure their cable.

              Simon. Precision Piezo Z-Probe Technology
              www.precisionpiezo.co.uk
              PT1000 cartridge sensors NOW IN, just attach to your Duet board directly!

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              • rmrigginundefined
                rmriggin
                last edited by

                seems to be an issue unique to my duet board because when testing with another sensor (dc42 ir sensor) the same issue occurs. Also tested with an inductive sensor and the same problem. If I use the 3.3v VIN on any endstop pin or the z probe pin on the duet I end up with the board dying (for lack of a better explanation) until I unplug the wire from whatever 3.3 VIN port its connected to.

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                • dc42undefined
                  dc42 administrators
                  last edited by

                  It sounds to me that you have a short in the cable or the sensor between the +3.3V and ground pins.

                  Duet WiFi hardware designer and firmware engineer
                  Please do not ask me for Duet support via PM or email, use the forum
                  http://www.escher3d.com, https://miscsolutions.wordpress.com

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                  • DjDemonDundefined
                    DjDemonD
                    last edited by

                    Can you measure the resistance between 3.3v and GND on your duet board (is there a nominal value? I'd measure mine but I'm away from home). If its happening with ir sensor and piezo sensor it's not likely to be the sensors that are both shorted.

                    Simon. Precision Piezo Z-Probe Technology
                    www.precisionpiezo.co.uk
                    PT1000 cartridge sensors NOW IN, just attach to your Duet board directly!

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                    • tekkydaveundefined
                      tekkydave
                      last edited by

                      On my Duet WiFi I get about 5.2K between 3.3v and Gnd at the Probe Connector. Hope that helps.

                      BTW that's with the probe unplugged. Its about 3.9K with a Piezo20 plugged in.

                      ~ tekkydave ~
                      D-Bot: 300x300mm | Duet WiFi + Duex2 | 3 independent z motors | X,Y & Z linear rails | E3D Titan Aero + V6 | Precision Piezo z-probe
                      FreeCAD, PrusaSlicer

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                      • rmrigginundefined
                        rmriggin
                        last edited by

                        @DjDemonD:

                        Can you measure the resistance between 3.3v and GND on your duet board (is there a nominal value? I'd measure mine but I'm away from home). If its happening with ir sensor and piezo sensor it's not likely to be the sensors that are both shorted.

                        I get a steady 3.3v when checked with my meter on all of the 3.3v pins. I get no resistance reading between ground and the 3.3v pins however.

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                        • DjDemonDundefined
                          DjDemonD
                          last edited by

                          I still haven't measured mine yet. Life is just too busy right now. However if you get nothing and tekkydave gets resistance then either you are not each measuring in the same way, or with the same power conditions, or same things attached, or something is amiss with one (or both boards).

                          You might consider powering the piezo pcb from a 3.3v source independently (or using a usb charger - I think the Z_probe IN pin is 5v tolerant). And just attach the TRG from piezo pcb to z_probe_in on Duet.

                          Please wait before using a USB charger 5v, for David/Duet3D to confirm if the z_probe_in is 5v tolerant. If not you could use a usb charger but run the TRG through a 3.3v regulator and then to the Z_probe_in, or a suitable resistor.

                          Simon. Precision Piezo Z-Probe Technology
                          www.precisionpiezo.co.uk
                          PT1000 cartridge sensors NOW IN, just attach to your Duet board directly!

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                          • DjDemonDundefined
                            DjDemonD
                            last edited by

                            We got in 3ders!

                            https://www.3ders.org/articles/20180206-fdm-3d-printer-bed-leveling-with-cheap-piezoelectric-elements.html

                            Simon. Precision Piezo Z-Probe Technology
                            www.precisionpiezo.co.uk
                            PT1000 cartridge sensors NOW IN, just attach to your Duet board directly!

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                            • Lakkoundefined
                              Lakko
                              last edited by

                              So if i understand, if i have

                              M558 P5 I0 R0.4 F330
                              G31 X0 Y0 Z-0.1 P100

                              and i have always to do -0.15 babystep i have to change config.g into:

                              M558 P5 I0 R0.4 F330
                              G31 X0 Y0 Z0.05 P100

                              right?

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                              • whosrdaddyundefined
                                whosrdaddy
                                last edited by

                                yes that is correct.
                                If you have a recent firmware, you can use P8 instead of P5 (unfiltered vs filtered input)

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                                • Lakkoundefined
                                  Lakko
                                  last edited by

                                  @whosrdaddy:

                                  yes that is correct.
                                  If you have a recent firmware, you can use P8 instead of P5 (unfiltered vs filtered input)

                                  is this also valid for piezo20? firmware 1.20

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                                  • whosrdaddyundefined
                                    whosrdaddy
                                    last edited by

                                    Yes, and your firmware supports this mode 😉

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                                    • LumberjackEngineeringundefined
                                      LumberjackEngineering
                                      last edited by

                                      Silly question, but why is the red power LED so incredibly bright? I'm running a Duet, so Vin is 3.3V. It's nearly impossible to see the blue trigger LED without covering the always-on power LED!

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                                      • DjDemonDundefined
                                        DjDemonD
                                        last edited by

                                        Well look into that it might be a batch of leds of different output to spec.

                                        Simon. Precision Piezo Z-Probe Technology
                                        www.precisionpiezo.co.uk
                                        PT1000 cartridge sensors NOW IN, just attach to your Duet board directly!

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                                        • Lakkoundefined
                                          Lakko
                                          last edited by

                                          @Lakko:

                                          So if i understand, if i have

                                          M558 P5 I0 R0.4 F330
                                          G31 X0 Y0 Z-0.1 P100

                                          and i have always to do -0.15 babystep i have to change config.g into:

                                          M558 P5 I0 R0.4 F330
                                          G31 X0 Y0 Z0.05 P100

                                          right?

                                          i noticed in my config.g file in the epilogue section a [c]M208 S1 Z-0.2 ;set minimum Z[/c]
                                          this can afflict the z height?
                                          so removing the M208 I can go back and insert again this?

                                          M558 P5 I0 R0.4 F330
                                          G31 X0 Y0 Z-0.1 P100

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                                          • DjDemonDundefined
                                            DjDemonD
                                            last edited by

                                            No I just recommend setting z min to just below the bed so you can probe points that are below the nozzle when it thinks it's at z=0.

                                            But you are right to change your G31 as you state in the first example to 0.05mm.

                                            Simon. Precision Piezo Z-Probe Technology
                                            www.precisionpiezo.co.uk
                                            PT1000 cartridge sensors NOW IN, just attach to your Duet board directly!

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