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    PID Tuning help needed

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    Tuning and tweaking
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    • deckingmanundefined
      deckingman @droftarts
      last edited by

      @droftarts Did you check the earlier posts? It transpires the OP has a 12V cartridge and a 24V system. So around 140 Watt instead of 35. Methinks, that's more likely to cause the oscillations.

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

      droftartsundefined 1 Reply Last reply Reply Quote 0
      • droftartsundefined
        droftarts administrators @deckingman
        last edited by

        @deckingman Yes, read the whole thread. @Reefwarrior said "The graphs show spikes". While I'm sure the heater can create a spike up in temperature, it probably can't create a drop as quickly! But a dodgy thermistor can, though I guess it could be a power drop across the board when the heater switches on, if the PSU isn't up to it.

        @Reefwarrior A screenshot of the temperature graph misbehaving would go some way to disambiguate the cause of the "spikes". Try wiggling the thermistor wires, see if that causes the spikes, too.

        Ian

        Bed-slinger - Mini5+ WiFi/1LC | RRP Fisher v1 - D2 WiFi | Polargraph - D2 WiFi | TronXY X5S - 6HC/Roto | CNC router - 6HC | Tractus3D T1250 - D2 Eth

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

          @droftarts I guess it depends on the definition of "spike". I read this (quote)

          Other strange thing is, there are quite a lot of oscillations with regards to the temperature being sensed. (Up to 3 to 4 degrees up and down)

          As you say, we need a picture of the graph......

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

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          • Phaedruxundefined
            Phaedrux Moderator
            last edited by

            A picture of the graph would be nice, but don't don't run that 12v heater at 24v just to make a graph for us. You're liable to melt something. Just replace the heater with a 24v version before you do anything else.

            Z-Bot CoreXY Build | Thingiverse Profile

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            • Reefwarriorundefined
              Reefwarrior
              last edited by Reefwarrior

              Hi all,

              OK so I swapped the cartridge for a 24V one. Did the PID tuning... results:

              Warning: heater behaviour was not consistent during tuning
              Auto tuning heater 1 completed after 4 idle and 25 tuning cycles in 1494 seconds. This heater needs the following M307 command:
              M307 H1 R3.064 C165.3 D10.06 S1.00 V24.3
              Send M500 to save this command in config-override.g

              Bothers me a bit with the 'warning'. Also it seems the temperature sensing thing is a PT1000 I think? It's a little silver cylinder that connects directly to the board, no daughterboard. Chinese brand.

              https://imgur.com/p5oTiy3

              there is the picture that I am referring to. Look at both the blue and the red - the curves are not smooth - it's like jagged. Even the 'MCU Temperature' seems to oscillate by about 1 degree up and down (including the decimals....)

              Also got this after PID tuning my bed:

              Warning: heater behaviour was not consistent during tuning
              Auto tuning heater 0 completed after 4 idle and 25 tuning cycles in 1536 seconds. This heater needs the following M307 command:
              M307 H0 R1.369 C277.3 D5.29 S1.00 V24.2
              Send M500 to save this command in config-override.g

              Phaedruxundefined 1 Reply Last reply Reply Quote 0
              • Phaedruxundefined
                Phaedrux Moderator @Reefwarrior
                last edited by

                @Reefwarrior said in PID Tuning help needed:

                Also it seems the temperature sensing thing is a PT1000 I think? It's a little silver cylinder that connects directly to the board, no daughterboard. Chinese brand.

                Why do you think Pt1000? It could be a plain thermistor.

                Photos?

                Yeah that graph looks a bit fuzzy which would explain the warning.

                The overall curve of the graph looks ok though, so I think the values it provides should be usable.

                Perhaps a good time to replace the temp sensor with something better quality.

                Z-Bot CoreXY Build | Thingiverse Profile

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                • Reefwarriorundefined
                  Reefwarrior @Phaedrux
                  last edited by

                  @Phaedrux Unfortunately I am not in a position to be able to do that. I'm one of 70 pilots that got retrenched when our government decided to liquidate the national airline.

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                  • Phaedruxundefined
                    Phaedrux Moderator
                    last edited by

                    I'm not sure that that means, but if you want to continue to roll with the equipment on hand, you can verify that the tuning results are accurate by setting a printing temp and seeing if the graph and reported temps are stable.

                    The fuzziness in the graph may also be a result of noise from running near other cables. You could verify that by temporarily isolating the thermistor wiring and seeing if that makes a difference.

                    Z-Bot CoreXY Build | Thingiverse Profile

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                    • Reefwarriorundefined
                      Reefwarrior @Phaedrux
                      last edited by

                      @Phaedrux hi, yeah it's a plain thermistor NTC 100k; 3950B.

                      droftartsundefined 1 Reply Last reply Reply Quote 0
                      • droftartsundefined
                        droftarts administrators @Reefwarrior
                        last edited by

                        @Reefwarrior said in PID Tuning help needed:

                        NTC 100k; 3950B

                        These are known for being pretty cheap, poor thermistors, which might explain your fuzzy readings.

                        Ian

                        Bed-slinger - Mini5+ WiFi/1LC | RRP Fisher v1 - D2 WiFi | Polargraph - D2 WiFi | TronXY X5S - 6HC/Roto | CNC router - 6HC | Tractus3D T1250 - D2 Eth

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                        • Reefwarriorundefined
                          Reefwarrior
                          last edited by

                          Ok, seems I got it fixed, somehow. Next issue is now the heatbed....

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                          • Reefwarriorundefined
                            Reefwarrior
                            last edited by

                            Ok, bed issue solved too. Seems the algorithm is too sensitive in my case.

                            How do I mark this as 'SOLVED' ?

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