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    H1 giving erratic reads while printing.

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    Tuning and tweaking
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    • dc42undefined
      dc42 administrators
      last edited by dc42

      Looks like you changed from using heater 1 output to heater 2. Did you run auto tuning on heater 2, with a target temperature around 200C or a little higher?

      What type of hot end do you have, and what are your M307 parameters for heater 2? Send M307 H2 to report them.

      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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      • pao_wikhanundefined
        pao_wikhan
        last edited by

        @dc42 said in H1 giving erratic reads while printing.:

        M307 H2

        tuned to 260, should i tune to a little lower value?

        M307 H2
        Heater 2 model: gain 347.5, time constant 196.2, dead time 6.2, max PWM 0.50, calibration voltage 24.1, mode PID, inverted no, frequency default
        Computed PID parameters for setpoint change: P16.2, I0.462, D70.5
        Computed PID parameters for load change: P16.

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        • dc42undefined
          dc42 administrators
          last edited by

          260C should be Ok for tuning. But why have you set a PWM limit of 0.5?

          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

          pao_wikhanundefined 1 Reply Last reply Reply Quote 0
          • pao_wikhanundefined
            pao_wikhan @dc42
            last edited by

            @dc42
            it gives the overpowered error during tuning.
            im using a 24V 50W heater

            deckingmanundefined 1 Reply Last reply Reply Quote 0
            • deckingmanundefined
              deckingman @pao_wikhan
              last edited by

              @pao_wikhan said in H1 giving erratic reads while printing.:

              @dc42
              it gives the overpowered error during tuning.
              im using a 24V 50W heater

              Ahhh. That's most likely the root cause of the problem. I once tried to "tame" an overpowered heater and never did have much success in reducing the oscillations. The solution for me was to use a more appropriately sized heater cartridge.

              Ian
              https://somei3deas.wordpress.com/
              https://www.youtube.com/@deckingman

              pao_wikhanundefined 1 Reply Last reply Reply Quote 0
              • pao_wikhanundefined
                pao_wikhan @deckingman
                last edited by

                @deckingman

                i think my issue is more than that..while printing it gives out erratic values from 210 down to 160-140, stopping the print

                deckingmanundefined 1 Reply Last reply Reply Quote 0
                • deckingmanundefined
                  deckingman @pao_wikhan
                  last edited by

                  @pao_wikhan said in H1 giving erratic reads while printing.:

                  @deckingman

                  i think my issue is more than that..while printing it gives out erratic values from 210 down to 160-140, stopping the print

                  I'd say, looking at the graph you posted, that you have two issues. The general +/- 2 to5 deg or so oscillation is likely just the heater being too powerful. The rapid drops in temperature can't be "real". That is to say, the temperature can't really drop by 50 degrees in such short a time unless you actually remove the hot end and drop it into dry ice or some such ☺ So that must be a wiring issue or electrical noise.

                  Ian
                  https://somei3deas.wordpress.com/
                  https://www.youtube.com/@deckingman

                  pao_wikhanundefined 1 Reply Last reply Reply Quote 1
                  • pao_wikhanundefined
                    pao_wikhan
                    last edited by

                    thats the thing. it was working for the past few month, didnt touch anything print print print. now this giving me that erratic motion is weird. so i replaced the sensor same output, and did the stuff recommended here.
                    just finished rewiring really, so im testing.

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                    • pao_wikhanundefined
                      pao_wikhan @deckingman
                      last edited by

                      @deckingman
                      rewiring is the same..oscillations..will try using e3d generic 24v 30W heater..then tune to max P1

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                      • pao_wikhanundefined
                        pao_wikhan
                        last edited by pao_wikhan

                        Thanks @dc42 @deckingman @T3P3Tony
                        i fixed it, seems like the thermistor is getting pulled and something was shorting the 5v rail. still using the new cartridge and ntc sensor (the pt100 was giving 2000degrees, but rtc1 is working when i place a 100ohm resistor) will troubleshoot that in a new chapter.
                        oh and a new psu too, seems like the psu was heavily grounded.
                        0_1550296538601_70f39bd6-45d9-49be-852d-d05853d37330-image.png

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                        • DocTruckerundefined
                          DocTrucker
                          last edited by

                          What's the logic behind having a 0.5 duty limit?

                          As I understand it this is only really useful if the heater responds too quick for the Duet to control it. If the mosfets fail on the 0.5 setting won't happen anyway and the heaters will be locked on 100%. If the thermistor drops out of its hole and gives a false low won't the heater fault detection pick this up quickly?

                          I did however have it on my mind an age ago to go seriously overpowered and fuse it so if it went 100% it would pop a fuse. Still want to try that. May need a little coil in the circuit to tame the spikes a little, with a corresponding flywheel diode.

                          Running 3 P3Steel with Duet 2. Duet 3 on the shelf looking for a suitable machine. One first generation Duet in a Logo/Turtle style robot!

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                          • pao_wikhanundefined
                            pao_wikhan
                            last edited by

                            okay its happening again. now im not sure if my duet is broken

                            0_1550300896097_e394e059-0950-4b2d-9984-818623b2748e-image.png

                            dc42undefined 1 Reply Last reply Reply Quote 0
                            • dc42undefined
                              dc42 administrators @pao_wikhan
                              last edited by

                              @pao_wikhan said in H1 giving erratic reads while printing.:

                              okay its happening again. now im not sure if my duet is broken

                              0_1550300896097_e394e059-0950-4b2d-9984-818623b2748e-image.png

                              Are you using the thermistor or the PT100 now?

                              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

                              pao_wikhanundefined 1 Reply Last reply Reply Quote 0
                              • pao_wikhanundefined
                                pao_wikhan @dc42
                                last edited by

                                @dc42
                                new thermistor, on that pic..
                                i replaced it with the one included in e3d v6, seems stable so far. but i didnt connect it to the daughter board as its not giving any values.

                                dc42undefined 1 Reply Last reply Reply Quote 0
                                • pao_wikhanundefined
                                  pao_wikhan
                                  last edited by

                                  if it happens again, i think the heatblock screw holding the sensor is not gripping correctly, but that is a long shot. (my theory that is.)

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                                  • DocTruckerundefined
                                    DocTrucker
                                    last edited by DocTrucker

                                    If you over tightened that it may edge towards occasional shorts. Too loose wouldn't cause spikes like that. That's got to be an electrical or control board issue. I doubt there are real situations survivable for the temp sensor where it could loose heat that quick - even if yanked out of the heater block.

                                    Running 3 P3Steel with Duet 2. Duet 3 on the shelf looking for a suitable machine. One first generation Duet in a Logo/Turtle style robot!

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                                    • dc42undefined
                                      dc42 administrators @pao_wikhan
                                      last edited by

                                      @pao_wikhan said in H1 giving erratic reads while printing.:

                                      @dc42
                                      new thermistor, on that pic..
                                      i replaced it with the one included in e3d v6, seems stable so far. but i didnt connect it to the daughter board as its not giving any values.

                                      If it's a thermistor (not a PT100) then negative-going spikes like that suggest a bad connection, or just possibly static discharge from the hot end metalwork to the thermistor wire. But I think they are too frequent to be static discharge.

                                      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

                                      pao_wikhanundefined 1 Reply Last reply Reply Quote 0
                                      • pao_wikhanundefined
                                        pao_wikhan @dc42
                                        last edited by pao_wikhan

                                        @dc42

                                        well 4hrs into printing, i think the e3d sensor (blue wire) did the trick. odd though cause when i measure the resistance its like 70k-100kohm and not the pt100 value of below 100ohms. its now cleaner than ever. i also replaced the cartridge and moved back to a newer 24V 50W ceramic type with 100% pwm.

                                        0_1550324881791_3a541f4a-825f-41d5-b333-4067f20761bd-image.png

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