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    PID Issues 3.4 RC1

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

      Can you describe your hotend and bed setup?
      What's the fan setup like? How big is the bed? Where is the thermistor mounted?
      It's basically saying the tuned results don't meet expectations.

      Z-Bot CoreXY Build | Thingiverse Profile

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      • Reefwarriorundefined
        Reefwarrior @Phaedrux
        last edited by

        @phaedrux Morning. My setup is an Ender3 converted to a switchwire setup.

        For reference the link is:

        https://github.com/VoronDesign/VoronUsers/tree/master/printer_mods/Gizzle/ender-3_(pro)_switchwire

        Whole setup is 24V and heater cartridge is 40W. Thermistor for both bed and hotend is 100k (NTC 3950) type. Bed has an AC silicon heater mat (with the thermistor being integrated in the middle of the bed, and controlled by AC relay from the duet board's 'BED' connectors); accompanied by the original Creality 3D glass bed (approx 235 x 235 x I think about 4mm). The hotend is a E3D V6-like type; with thermistor in the heat block (it looks like a round cylinder of prob 15 to 20mm in length).

        Current parameters for the 'hot section' in the configuration file is:

        ; Heaters
        M308 S0 P"bedtemp" Y"thermistor" T100000 B3950 ; configure sensor 0 as thermistor on pin bedtemp
        M950 H0 C"bedheat" T0 Q10                          ; create bed heater output on bedheat and map it to sensor 0
        M307 H0 R1.476 K0.523:0.000 D5.70 E1.35 S0.90 B0 P0.8
        M140 H0                                        ; map heated bed to heater 0
        M143 H0 S120                                   ; set temperature limit for heater 0 to 120C
        M308 S1 P"e0temp" Y"thermistor" T100000 B3950  ; configure sensor 1 as thermistor on pin e0temp
        M950 H1 C"e0heat" T1 Q10                          ; create nozzle heater output on e0heat and map it to sensor 1
        M307 H1 R3.135 K0.382:0.302 D8.78 E1.35 S0.80 B0 V24.1
        M143 H1 S280                                   ; set temperature limit for heater 1 to 280C
        

        The parameters used in both M307 commands were the ones that was given after the PID tuning; and are stable enough to provide a constant temperature for both bed and hotend, but PID tuning still resulted in the odd behaviour.

        Hope my description provides a bit more clarity?

        Rgds
        Tinus

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        • Phaedruxundefined Phaedrux moved this topic from Tuning and tweaking
        • Reefwarriorundefined
          Reefwarrior @Reefwarrior
          last edited by

          So for what it's worth; I upgraded firmware to RC1; still experiencing the same issue when trying to do a PID tuning.

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          • dc42undefined
            dc42 administrators
            last edited by

            @reefwarrior the message about inconsistent behaviour is just a warning. It's not uncommon when tuning a bed header in which the thermistor is in better contact with the heating element than it is with the bed plate. It is much less common when tuning a hot end. Can you provide a photo of the hot end?

            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 @dc42
              last edited by

              @dc42 Hi; I will provide a photo shortly. I have in the meantime exchanged everything except for the control board - new heater cartridge, new thermistor - and same result. I have changed output of the hotend cooling fan to only 50% of the PWM; and even the part cooler fan I have defined to have a maximum of 70% PWM - still the same issue. Other thing is it takes like 30 to 40 minutes for a single PID session (only to have the warning) --- is that normal?

              For what it is worth, here is the printer in action: https://www.reddit.com/r/voroncorexy/comments/snin2s/ender3_converted_to_voron_switchwire_serial

              It doesn't have an issue with a short print, however, I have tried a 3 hour print yesterday, just to have it failed basically because the 'rise in temperature' was slower than that which is expected - I forgot the exact wording of the error.

              I will provide a photo soon of the hotend itself.

              Rgds
              Tinus

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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

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                • 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

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                        • 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.

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                                    • 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

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                                          • 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

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