Hotend Temp. drifting



  • Hi,

    last night i start a new Print which should be finished this morning
    I was surprised as i looked in my Printer This Morning and my print was stopped after 6 layers.
    A look to The web frontend says that there was a temp. drift bigger than 15 degrees and the print was stopped.
    I restarted the Printer and heating up my Hotend which looks fine.
    So i started the Print again and after one hour the printer stopps and the same error occurs again
    now i have seen That the Temp. chart was a sinus Wave, so I have checked the wire but without finding a error.
    In the next step i Have changed the old heating cardrige with a new one.
    Now i have started the PID Tuning saved the result and restarted the Printer, now i have only heated up the hotend and the same sinus wave was to see ( the drifting is 5-6 degrees) in the next stepp i changed the thermistor and waited to cool down the hotend to room Temp.
    Now i Tried again the Pit Tuning and heat up the hotend ... same error the Temp. is drifting (see Video)

    The only thing i Have changed is to update from 2.04 to 2.05 can it bee that there is the Problem?

    Video

    my config.g

    
    M906 X1000.00 Y1000.00 Z1680.00 E450.00 I30 ; Set motor currents (mA) and motor idle factor in per cent
    M84 S0                                      ; Set idle timeout
    
    ; Axis Limits
    M208 X-1 Y0 Z-3 S1                          ; Set axis minima
    M208 X-5:205 Y0:200 ; Der X-Wagen bewegt sich von -5 bis 205, das Y-Bett von 0 bis 200
    M208 X400 Y370 Z450 S0                      ; Set axis maxima
    
    ; Endstops
    M574 X1 Y1 S1                               ; Set active high endstops
    
    ; Z-Probe
    M574 Z1 S2                                  ; Set endstops controlled by probe
    M558 P8 R0.4 H5 F450 T6000 I1                 ; Set Z probe type to effector and the dive height + speeds
    G31 P500 X0 Y0 Z-0.1                        ; Set Z probe trigger value, offset and trigger height
    M557 X15:390 Y15:370 S50                    ; Define mesh grid
    
    ; Heaters
    M307 H0 B0 S1.00                            ; Disable bang-bang mode for the bed heater and set PWM limit
    M305 P0 T100000 B4138 R4700                 ; Set thermistor + ADC parameters for heater 0
    M143 H0 S120                                ; Set temperature limit for heater 0 to 120C
    M305 P1 T100000 B4725 C7.06e-8 R4700                 ; Set thermistor + ADC parameters for heater 1 
    M143 H1 S290                                ; Set temperature limit for heater 1 to 280C
    
    ; Fans
    M106 P0 S0 I0 F25500 H-1 C"Kühlung"                    ; Set fan 0 value, PWM signal inversion and frequency. Thermostatic control is turned on
    M106 P1 S1 I0 F75 H1 T45 C"hotend"                  ; Set fan 1 value, PWM signal inversion and frequency. Thermostatic control is turned on
    M106 P2 S0.5 I0 F250 H-11 T35 C"LED"             ; LED Set fan 2 value, PWM signal inversion and frequency. Thermostatic control is turned on
    
    ; Tools
    M563 P0 D0 H1                               ; Define tool 0
    G10 P0 X0 Y0 Z0                             ; Set tool 0 axis offsets
    G10 P0 R0 S0                                ; Set initial tool 0 active and standby temperatures to 0C
    
    ; Automatic saving after power loss is not enabled
    
    ; Custom settings are not configured
    
    ; Miscellaneous
    
    M501                                        ; Load saved parameters from non-volatile memory
    

    and my config-override

    ; config-override.g file generated in response to M500 at 2019-12-18 12:22
    ; This is a system-generated file - do not edit
    ; Heater model parameters
    M307 H0 A176.5 C1594.8 D0.5 S1.00 V24.3 B0
    M307 H1 A294.2 C172.9 D2.5 S1.00 V24.3 B0
    M307 H2 A340.0 C140.0 D5.5 S1.00 V0.0 B0
    M307 H3 A340.0 C140.0 D5.5 S1.00 V0.0 B0
    M307 H4 A340.0 C140.0 D5.5 S1.00 V0.0 B0
    M307 H5 A340.0 C140.0 D5.5 S1.00 V0.0 B0
    M307 H6 A340.0 C140.0 D5.5 S1.00 V0.0 B0
    M307 H7 A340.0 C140.0 D5.5 S1.00 V0.0 B0
    G10 L2 P1 X0.00 Y0.00 Z0.00
    G10 L2 P2 X0.00 Y0.00 Z0.00
    G10 L2 P3 X0.00 Y0.00 Z0.00
    G10 L2 P4 X0.00 Y0.00 Z0.00
    G10 L2 P5 X0.00 Y0.00 Z0.00
    G10 L2 P6 X0.00 Y0.00 Z0.00
    G10 L2 P7 X0.00 Y0.00 Z0.00
    G10 L2 P8 X0.00 Y0.00 Z0.00
    G10 L2 P9 X0.00 Y0.00 Z0.00
    
    

  • Moderator

    What command did you send to tune the PID? Did you set the target temperature as 140C? Generally, if the temperature shows regular oscillations, the dead time (D parameter) should be increased. Yours appears low at 0.5.

    As far as I am aware, there were no changes between 2.04 and 2.05 with regards PID and heaters. Did it produce the same sine wave in 2.04, but never trigger an error? Can you revert to 2.04 and see if it replicates or fixes the problem?

    There is a section in the documentation about setting the heater PID manually: https://duet3d.dozuki.com/Wiki/Tuning_the_heater_temperature_control#Section_Setting_the_model_parameters_manually

    Ian


  • Moderator

    Do you have a silicone sock on the block? They can help a lot.
    Is the part cooling fan blowing on the block at all?
    Is that section of the model you're printing causing some blow back from the fan? Such as large flat sections of solid infill?
    Did you have the part cooling fan on during PID tuning?

    Can you post the results of an M122 diagnostic report so we can see the PSU min and max voltages.

    I suggest that you redo the PID tuning with the part cooling fan running at the same speeds you'd normally have during a print. If you have time to do some testing, compare the results between 2.04 and 2.05. They should be practically identical.

    If the results don't improve you can try this: The D parameter of your saved M307 in config-override.g is the dead time. And 0.5 seems low to me and could explain the oscillations at idle. You could try increasing it to 1 or 2.



  • Hello,

    Thanks for your answers! I think i have found the solution i have delete the config override and made a new PID-Tuning since then the temperature is stable and the printer prints now over a hour and the temperatur drift is now by max 0.2 degree.
    So somthing was wrong with the config override ?!?

    Regards
    Andy


  • Moderator

    @SIam said in Hotend Temp. drifting:

    So somthing was wrong with the config override ?!?

    Post the results of the new PID tuning to compare to your previous results. Likely the D value is now higher.



  • Yes the D value is higher but how can it be ?

    here is the new config override:

    ; config-override.g file generated in response to M500
    ; This is a system-generated file - do not edit
    ; Heater model parameters
    M307 H0 A90.0 C700.0 D10.0 S1.00 V0.0 B0
    M307 H1 A336.4 C158.4 D5.9 S1.00 V24.3 B0
    M307 H2 A340.0 C140.0 D5.5 S1.00 V0.0 B0
    M307 H3 A340.0 C140.0 D5.5 S1.00 V0.0 B0
    M307 H4 A340.0 C140.0 D5.5 S1.00 V0.0 B0
    M307 H5 A340.0 C140.0 D5.5 S1.00 V0.0 B0
    M307 H6 A340.0 C140.0 D5.5 S1.00 V0.0 B0
    M307 H7 A340.0 C140.0 D5.5 S1.00 V0.0 B0
    G10 L2 P1 X0.00 Y0.00 Z0.00
    G10 L2 P2 X0.00 Y0.00 Z0.00
    G10 L2 P3 X0.00 Y0.00 Z0.00
    G10 L2 P4 X0.00 Y0.00 Z0.00
    G10 L2 P5 X0.00 Y0.00 Z0.00
    G10 L2 P6 X0.00 Y0.00 Z0.00
    G10 L2 P7 X0.00 Y0.00 Z0.00
    G10 L2 P8 X0.00 Y0.00 Z0.00
    G10 L2 P9 X0.00 Y0.00 Z0.00
    
    

  • administrators

    The D value is the one that is hardest to measure. It's on my list to try to find a better algorithm to measure it.



  • ah ok !

    In the meantime, my printing was also successfully completed so my printer has probably been a bit bitchy 😊


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