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    PID Issues 3.4 RC1

    Scheduled Pinned Locked Moved Unsolved
    Beta Firmware
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    • Phaedruxundefined
      Phaedrux Moderator @Reefwarrior
      last edited by

      @reefwarrior said in PID Issues 3.4 RC1:

      D8.78

      The dead time for the hotend seems high to me.

      Z-Bot CoreXY Build | Thingiverse Profile

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

        @phaedrux
        @dc42

        Sorry I have not uploaded a photo yet - been a bit busy- only got the printer fully assembled again this evening - weird thing now is the temperature stays about 10 to 15 degrees HOTTER than requested.

        Did a tuning with 200C and PWM of 0.8 and this was the result:

        M307 H1 R2.723 K0.545:0.322 D10.96 E1.35 S0.80 B0 V24.1

        Rgds
        Tinus

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        • Phaedruxundefined
          Phaedrux Moderator
          last edited by

          That dead time of 10 seconds seems unusually high for an E3D V6 style hotend.

          Z-Bot CoreXY Build | Thingiverse Profile

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          • Reefwarriorundefined
            Reefwarrior @Phaedrux
            last edited by

            @phaedrux That's the 'D' parameter in the line? To what do you suggest should I decrease it?

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            • Phaedruxundefined
              Phaedrux Moderator
              last edited by

              It means it's taking 10 seconds for the sensor to register a change in temp between the time heat was requested and when it's detected. For my V6 it's closer to 2 seconds. So I wonder if there is something off with assembly causing that.

              Hence the request for photos to see what is happening or if it's an unusual design etc.

              Is the hot block in direct contact with the cold end heatsink or something? Or the heater cartridge or sensor not firmly secured?

              Z-Bot CoreXY Build | Thingiverse Profile

              Reefwarriorundefined OwenDundefined 2 Replies Last reply Reply Quote 0
              • Reefwarriorundefined
                Reefwarrior @Phaedrux
                last edited by

                @phaedrux Everything is firmly secured - did double check it 🙂

                The only thing that may be a little weird is the gap between the nozzle and the heat block, may be a tad big.... but that should not be an issue, should it?

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                • Phaedruxundefined
                  Phaedrux Moderator
                  last edited by

                  Maybe? We're looking for anything non-standard, so...

                  Z-Bot CoreXY Build | Thingiverse Profile

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                  • OwenDundefined
                    OwenD @Phaedrux
                    last edited by OwenD

                    @phaedrux
                    Have you done a PID autotune with 2.4rc1 3.4rc1?
                    I'm getting D values in the 10 second range with my E3D V6 as well.
                    As you probably know I've been experiencing issues with wild temperature fluctuations with later releases.

                    Reefwarriorundefined 1 Reply Last reply Reply Quote 1
                    • Reefwarriorundefined
                      Reefwarrior @OwenD
                      last edited by

                      @owend you mean 3.4rc1?

                      OwenDundefined 1 Reply Last reply Reply Quote 0
                      • OwenDundefined
                        OwenD @Reefwarrior
                        last edited by

                        @reefwarrior Yes. My fingers are dyslexic 🙄

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                        • OwenDundefined
                          OwenD
                          last edited by

                          Not wanting to hijack this thread......
                          A search reveals that in November 2021 in V3.4.0b6 , I was getting PID results of

                          M307 H1 B0 R1.594 C358.1:217.5 D6.05 S1.00 V24.3
                          

                          With same hardware in 3.4rc1

                          M307 H1 R2.848 K0.325:0.197 D10.51 E1.35 S1.00 B0 V24.3
                          

                          Different algorithm of course, but I wouldn't have thought the dead time would change that much as a result and it may explain the over shoots I now get.

                          Reefwarriorundefined 1 Reply Last reply Reply Quote 1
                          • Reefwarriorundefined
                            Reefwarrior @OwenD
                            last edited by

                            @owend I will try a different firmware version tomorrow, however 3.4 is needed to keep my mini12864 up and running. My overshoot is typically 10 to 15 degrees at the moment...

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

                              @reefwarrior said in PID Issues 3.4 RC1:

                              @owend I will try a different firmware version tomorrow, however 3.4 is needed to keep my mini12864 up and running. My overshoot is typically 10 to 15 degrees at the moment...

                              Overshoot is typically caused by the R parameter being too high. It appears to have increased significantly from earlier. Try reducing it.

                              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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                              • Reefwarriorundefined
                                Reefwarrior
                                last edited by

                                @dc42

                                WhatsApp Image 2022-02-19 at 8.09.25 AM.jpeg WhatsApp Image 2022-02-19 at 8.09.25 AM (1).jpeg WhatsApp Image 2022-02-19 at 8.09.26 AM.jpeg

                                Reefwarriorundefined 1 Reply Last reply Reply Quote 0
                                • Reefwarriorundefined
                                  Reefwarrior @Reefwarrior
                                  last edited by

                                  Also:

                                  M307 H1 R2.0 K0.545:0.322 D10.96 E1.35 S0.80 B0 V24.1 ;V3.4RC1
                                  M307 H1 B0 R2.788 C90.8:60.3 D10.93 S0.80 V24.1 ;V3.3

                                  Reefwarriorundefined 1 Reply Last reply Reply Quote 0
                                  • Reefwarriorundefined
                                    Reefwarrior @Reefwarrior
                                    last edited by Reefwarrior

                                    My layer 1 printed perfectly. Just after beginning on layer two, temperature exceeded by 15 degrees; and cause a heater fault.

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

                                      @reefwarrior Does the part cooling fan turn on for layer two? It seems as if the firmware is anticipating a drop in temperature from the cooling and and tries to compensate.

                                      Do you have a nozzle sock to test with?

                                      Also it seems like your heatsink fan may be acting to cool the hot block as well.

                                      Z-Bot CoreXY Build | Thingiverse Profile

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                                      • Reefwarriorundefined
                                        Reefwarrior @Phaedrux
                                        last edited by Reefwarrior

                                        @phaedrux Hi. Yeah tested with a sock too. Same result. Hot end fan is isolated from heat block - there is like a round 'O' of plastic (like a divider) between the heat block and the fins.

                                        Also what is the approximate time of a PID cycle with defaults? I quite frequently have 30+ minutes. I even swapped out the board this morning. Same result!

                                        Reefwarriorundefined dc42undefined 2 Replies Last reply Reply Quote 0
                                        • Reefwarriorundefined
                                          Reefwarrior @Reefwarrior
                                          last edited by

                                          Also changed hot end fans. No difference.

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                                          • dc42undefined
                                            dc42 administrators @Reefwarrior
                                            last edited by

                                            @reefwarrior with cooling like that and no silicone sock over the heater block, you are certain to get a big temperature drop when the part cooling fan turns on. So I suggest you add a silicone sock, then re-run heater tuning for that tool. By running it for the tool (i.e. using the T parameter in the M303 command instead of the H parameter), it will tune with the fan both on and off, and help correct for the cooling effect of the fan.

                                            Heater tuning on hot ends normally finishes fairly quickly. Heater tuning on bed heaters can take a long time, especially if the bed has high thermal mass so it cools down very slowly.

                                            If the problem persists, please post a screen shot of the hot end temperature plot in DWC, from just before the first layer ends up until the heater fault.

                                            As a last resort you can increase the allowed temperature variation using the M570 command; however if you get a temperature drop exceeding 15C when the fan turns on, that is likely to cause you extrusion problems.

                                            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

                                            Exerqtorundefined 1 Reply Last reply Reply Quote 0
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