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    PNP NO inductive sensor

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    • vhowardundefined
      vhoward
      last edited by

      In the Duetwifi Wiki, it says to use a combination of resistors to get the voltage output of the signal wire to 3 volts when triggered. I have a sensor that I was using with my ramps board just fine with 4.88 volts at the signal wire when triggered. I could only find 22k and 33k resistors locally and that combination brings it down from 12v to 4.88v. Is 4.88 really going to be too much for the Duetwifi? Could I just add another resistor to the signal wire to reduce an additional 1.8 v?

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      • dc42undefined
        dc42 administrators
        last edited by

        4.88V is unlikely to harm the Duet, but we can't promise it because it relies on the ESD protection diodes in the processor working properly.

        If you connect another 22K resistor in parallel with the existing 22K resistor, that should bring it down to 3V.

        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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        • vhowardundefined
          vhoward
          last edited by

          Thanks.

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          • DjDemonDundefined
            DjDemonD
            last edited by

            Make sure you measure the signal voltage under load, so attach an led, or bulb or something sometimes the sensors give odd readings when measured without any load on them.

            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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            • vhowardundefined
              vhoward
              last edited by

              There is already a 22K and a 33K resistor in there. I think those count as loads.

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              • DjDemonDundefined
                DjDemonD
                last edited by

                Fair enough.

                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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                • vhowardundefined
                  vhoward
                  last edited by

                  Adding the second 22K resistor in parallel with the first brought the voltage at the signal wire down to 2.97 volts. The probe is working fine.

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