Setting up chamber heater fault



  • I know im missing something simple here, but a lot of searching with no success.
    i have a heater running on H7, and ut works, but i get the heater fault
    'temperature is rising much faster than the 1.7c expected'
    i dont know where its gettign that form, as its in bang bang mode.

    anyone able to point me inthe right direction?

    heres my config file,

    ; Configuration file for Duet WiF (firmware version 1.21)
    ; executed by the firmware on start-up
    ;
    ; generated by RepRapFirmware Configuration Tool on Thu Sep 20 2018 19:25:44 GMT+1200 (New Zealand Standard Time)

    ; General preferences
    G90 ; Send absolute coordinates...
    M83 ; ...but relative extruder moves

    ; Network
    M550 PCubePro3D ; Set machine name
    M552 S1 ; Enable network
    M587 S" " P"" ; Configure access point. You can delete this line once connected
    M586 P0 S1 ; Enable HTTP
    M586 P1 S0 ; Disable FTP
    M586 P2 S0 ; Disable Telnet

    ; Drives
    M569 P0 S1 ; Drive 0 goes forwards X AXIS
    M569 P1 S1 ; Drive 1 goes forwards UNUSED
    M569 P2 S0 ; Drive 2 goes BACK Z DRIVE REVERSED
    M569 P3 S0 ; Drive 3 goes BACK E1
    M569 P4 S0 ; Drive 4 goes BACK E2
    M569 P5 S0 ; Drive 5 goes BACK E3
    M569 P8 S0 ; Drive 8 goes BACK Y AXIS 1
    M569 P9 S1 ; Drive 9 goes FWD Y AXIS 2

    M584 X0 Y8:9 Z2 E3:4:5 ;Driver 0 controls the X motor, Y8 & 9 e motors 3& 4 &5

    M350 X16 Y16 Z16 E16:16:16 I1 ; Configure microstepping with interpolation
    M92 X87.5 Y87.5 Z1066.75 E87.5:87.5:87.5 ; Set steps per mm
    M566 X500 Y500 Z12 E120:120:120 ; Set maximum instantaneous speed changes (mm/min)
    M203 X12000 Y12000 Z600 E1200:1200:1200 ; Set maximum speeds (mm/min)
    M201 X500 Y400 Z250 E250:250:250 ; Set accelerations (mm/s^2)
    M906 X1500 Y1500 Z1500 E1500:1500:1500 I30 ; Set motor currents (mA) and motor idle factor in per cent
    M84 S30 ; Set idle timeout

    ; Axis Limits
    M208 X0 Y0 Z0 S1 ; Set axis minima
    M208 X285 Y295 Z180 S0 ; Set axis maxima

    ; Endstops
    M574 X1 Y2 S0 ; X home to min. Y home to max, Set Normally open limit switches
    M574 Z1 S2 ;Define Z to use Probe. Home to Min

    ; Z-Probe

    M307 H5 A-1 C-1 D-1 ; Disable the 5th Heater to free up PWM channel 3 on the Duex board.

    M558 P9 H5 F100 T2000 ; Set Z probe type to bltouch and the dive height + speeds M558 P5 H5 F500 T4000 X0 Y0 Z1 ; Set Z probe type/mode 5. H=Dive Height. F=Speed the bed moves M558 P9 H5 F100 T2000 ; Set Z probe type to bltouch and the dive height + speeds

    G31 P25 X90 Y60 Z2.50 ; Z probe trigger value, offset in relation to nozzle. And trigger height adjustment higher value bigger gap

    M557 X100:200 Y15:195 S42.5 ; Define mesh grid - X start pos, end pos, Y start pos, end pos, grid spacing BL TOUCH

    ; Heaters
    M141 H7 ; Assign chamber heater to heater 7 CHAMBER

    ;M307 H0 B0 S1.0 ; Enable bang-bang mode for the bed heater and set PWM limit DISABLED

    ; M305 P4 T159230 B3142 C-3.979714e-7 R4700 ; Set thermistor + ADC parameters for heater 0 BED DISABLED
    ;M143 H0 S120 ; Set temperature limit for heater 0 to 120C

    M301 H1 S0.50 ; Set heater 1 PWM limit to 50%
    M305 P1 T159230 B3142 C-3.979714e-7 R4700 ; Set thermistor + ADC parameters for heater 1 EXTRUDER 1
    M143 H1 S280 ; Set temperature limit for heater 1 to 280C
    M301 H2 S0.50 ; Set heater 2 PWM limit to 50%
    M305 P2 T159230 B3142 C-3.979714e-7 R4700 ; Set thermistor + ADC parameters for heater 2 EXTRUDER 2
    M143 H2 S280 ; Set temperature limit for heater 2 to 280C
    ;M301 H3 S0.50 ; Set heater 3 PWM limit to 50%
    ;M305 P3 T159230 B3142 C-3.979714e-7 R4700 ; Set thermistor + ADC parameters for heater 3 EXTRUDER 3
    ;M143 H3 S280 ; Set temperature limit for heater 3 to 280C

    M305 P7 T100000 B4725 C7.060000e-8 R4700 ; Set thermistor + ADC parameters for heater 7 CHAMBER
    M301 H7 B1 S1.0 ; b0 =use pid control; b1= bang bang for the chamber heater, s1.0= max power 1.0
    M143 H7 S80 ; Set temperature limit for heater 7 to 80C

    M140 H-1 ;disable bed in system added jp

    ; Fans
    ;M106 P0 S1 I0 F500 H-1 ; Set fan 0 value, PWM signal inversion and frequency. Thermostatic control is turned off
    ;M106 P1 S1 I0 F500 H-1 ; Set fan 1 value, PWM signal inversion and frequency. Thermostatic control is turned off
    ;M106 P2 S1 I0 F500 H1:2:3:7 T30 ; Set fan 2 value, PWM signal inversion and frequency. Thermostatic control is turned on
    M106 P4 S1 I0 F500 H-1 ; Set fan 4 value, LAYER FAN PWM signal inversion and frequency. Thermostatic control is turned off
    M106 P5 S1 I0 F500 H1:2:3 T30 ; Set fan 5 value, HOT END PWM signal inversion and frequency. Thermostatic control is turned on
    M106 P6 S100 I0 F500 H1:2:3:7 T30 ; Set fan 6 value, CPU BOARD FAN PWM signal inversion and frequency. Thermostatic control is turned on
    M106 P7 S100 I0 F500 H1:2:3:7 T30 ; Set fan 7 value, LIGHTS PWM signal inversion and frequency. Thermostatic control is turned on

    ; Tools
    M563 P0 D0 H1 F4 ; Define tool 0 tool uses extruder drive 0 and heater 1. Fan 4 is mapped to fan 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
    M563 P1 D1 H2 F4 ; Define tool 1
    G10 P1 X40 Y0 Z0 ; Set tool 1 axis offsets
    G10 P1 R0 S0 ; Set initial tool 1 active and standby temperatures to 0C
    ;M563 P2 D2 H3 F4 ; Define tool 2
    ;G10 P2 X80 Y0 Z0 ; Set tool 2 axis offsets
    ;G10 P2 R0 S0 ; Set initial tool 2 active and standby temperatures to 0C

    ; Automatic saving after power loss is not enabled

    ; Custom settings are not configured


  • administrators

    Tune your heaters to determine the correct M307 model parameters, and get rid of the M301 commands. https://duet3d.dozuki.com/Wiki/Tuning_the_heater_temperature_control



  • thanks for the quick reply-
    im still missing something- yes i have read the link you sent a couple of times- im just not sure how that applies to a chamber.

    the way understand it the only lines that relate to the chamber are

    M141 H7 ; Assign chamber heater to heater 7 CHAMBER
    M301 H7 B1 S1.0 ; b0 =use pid control; b1= bang bang for the chamber heater, s1.0= max power 1.0
    M143 H7 S80 ; Set temperature limit for heater 7 to 80C

    my understanding is the m307 related to PID tuning, which does not seem relevant for a chamber heater?

    cheers

    Jason


  • administrators

    From that page:

    Each heating controller performs temperature monitoring to try to detect fault conditions such as a heater of thermistor falling out of an extruder heating block. The temperature monitor relies on the model parameters to decide what is reasonable behaviour. Therefore, even if you decide to use legacy PID parameters, you should still define an approximate model of the heater to provide good heater monitoring without false alarms.



  • Thanks- ok starting to see now.
    so how do i define PID paremeters for a heated Chamber?
    firstly its on bang, bang mode,

    and if i try to PID tune it, it fails- see below

    7:21:51 PMWarning: Auto tune of heater 7 failed due to bad curve fit (G=9.9, tc=8.8, td=0.6)
    7:21:42 PMAuto tune phase 3, peak temperature was 45.1
    7:21:35 PMAuto tune phase 2, heater off
    7:21:17 PMAuto tune phase 1, heater on
    7:21:11 PMM303 H7 P1 S45
    Auto tuning heater 7 using target temperature 45.0°C and PWM 1.00 - do not leave printer unattended


  • administrators

    From your auto tune results it looks like you have the thermistor placed very close to the heater, because tc and td are so low. I don't think that will give you good results. However, the auto tune failed because the measured gain of 9.9 is just below the minimum allowed value, which is 10. So you could try these M307 parameters:

    M307 A10 C8.8 D0.6



  • Thanks so much- that cracked it, I don’t fully understand how the pid parameters work, so was well out of my depth.
    Yes the sensor is above the heater outlet, it’s a modified cubepro from 3d systems, and that’s how they designed it in their wisdom (there’s of plenty of other strange desisions in the design too- lots of well machined hardware with no smart thinking in the design.

    Again thanks for your help


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