Warning: Heater appears to be over-powered



  • I run M303 H1 S240 and M303 H0 S90 to PID Tuning the e3d Titan aero and the heated bed. On the online configuration I had put bed heater as bang-bang and max temps 280 and 120 respectively. The Vin sensor gives when idle 12.2V. When the bed is heated the Vin drops to 11.5V.
    I received the following warnings:

    9:49:11 PMWarning: Heater 1 appears to be over-powered. If left on at full power, its temperature is predicted to reach 802C.
    Auto tune heater 1 completed in 334 sec
    Use M307 H1 to see the result, or M500 to save the result in config-override.g
    9:50:45 PMM307 H1
    Heater 1 model: gain 777.8, time constant 250.8, dead time 6.3, max PWM 1.00, calibration voltage 12.0, mode PID, inverted no, frequency default
    Computed PID parameters for setpoint change: P9.2, I0.231, D40.3
    Computed PID parameters for load change: P9.2,
    9:45:21 PMAuto tune phase 3, peak temperature was 252.3
    9:45:13 PMAuto tune phase 2, heater off
    9:45:06 PMConnection established!
    9:45:04 PMDisconnected.
    9:43:44 PMAuto tune phase 1, heater on
    9:43:37 PMM303 H1 S240
    Auto tuning heater 1 using target temperature 240.0°C and PWM 1.00 - do not leave printer unattended

    10:01:26 PMM307 H0
    Heater 0 model: gain 172.6, time constant 394.7, dead time 1.5, max PWM 1.00, calibration voltage 11.5, mode PID, inverted no, frequency default
    Computed PID parameters for setpoint change: P275.6, I11.401, D285.8
    Computed PID parameters for load change: P
    10:01:07 PMWarning: Heater 0 appears to be over-powered. If left on at full power, its temperature is predicted to reach 197C.
    Auto tune heater 0 completed in 576 sec
    Use M307 H0 to see the result, or M500 to save the result in config-override.g
    9:55:06 PMAuto tune phase 3, peak temperature was 90.4
    9:54:58 PMAuto tune phase 2, heater off
    9:51:36 PMAuto tune phase 1, heater on
    9:51:31 PMM303 H0 S90
    Auto tuning heater 0 using target temperature 90.0°C and PWM 1.00 - do not leave printer unattended

    I saved with M500 after adding in the config M501.
    Is it something to worry about with these warnings for over-power ?



  • The warning is there to give you an idea of what kind of temps could potentially be reached in a thermal runaway situation. It's up to you to decide if you're mitigating those risks adequately. Thermal cut-off fuses are a popular choice which cut power after a certain temperature is reached.

    Bang-bang mode is not recommended anymore. It often causes temp fluctuations and flexing of the heat bed. Far better results can be obtained by using PID for both bed and hotend.



  • @phaedrux Thanks a lot for your help. In order to switch the bed to pid mode do I have to upload again the firmware from the configurator?



  • @gbiski The change to use PID can be done by editing the config.g file. This is how all configuration changes are done with RepRapFirmware. You can reach it through the web interface. Under settings, system editor.

    Here's some documentation that might help you out.

    https://duet3d.dozuki.com/Wiki/Duet_Web_Control_Manual

    https://duet3d.dozuki.com/Wiki/GCode#Section_M301_Set_PID_parameters

    https://duet3d.dozuki.com/Wiki/GCode#Section_M307_Set_or_report_heating_process_parameters

    https://duet3d.dozuki.com/Wiki/Tuning_the_heater_temperature_control

    https://duet3d.dozuki.com/Wiki/Choosing_a_bed_heater

    If you haven't made any other changes you can redo the web configurator to get new config files to replace the ones you have now.



  • @phaedrux ah because I understood that after tuned with M303 and saved with M500 if you have M501 at the end of the config then automatically it switches from bang-bang to pid.



  • Can you post your config.g and config-override.g files so we can verify what your heater is set to?

    If there is an M307 with a B1 in it, that would be bang-bang. B0 would be PID.



  • @phaedrux Config:

    ; Configuration file for Duet WiFi (firmware version 1.21)
    ; executed by the firmware on start-up
    ;
    ; generated by RepRapFirmware Configuration Tool v2 on Thu Nov 29 2018 21:51:30 GMT+0200 (EET)

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

    ; Network
    M550 P"Dark Printer" ; Set machine name
    M551 P"3369: ; Set password
    M552 S1 ; Enable network
    M586 P0 S1 ; Enable HTTP
    M586 P1 S0 ; Disable FTP
    M586 P2 S0 ; Disable Telnet

    ; Drives
    M569 P0 S1 ; Drive 0 goes forwards
    M569 P1 S0 ; Drive 1 goes backwards
    M569 P2 S0 ; Drive 2 goes backwards
    M569 P3 S0 ; Drive 3 goes backwards
    M350 X16 Y16 Z16 E16 I1 ; Configure microstepping with interpolation
    M92 X160.00 Y160.00 Z800.00 E837.00 ; Set steps per mm
    M566 X900.00 Y900.00 Z12.00 E120.00 ; Set maximum instantaneous speed changes (mm/min)
    M203 X18000.00 Y18000.00 Z600.00 E1500.00 ; Set maximum speeds (mm/min)
    M201 X1000.00 Y1000.00 Z50.00 E5000.00 ; Set accelerations (mm/s^2)
    M906 X1150.00 Y1150.00 Z1250.00 E1150.00 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 X165 Y165 Z200 S0 ; Set axis maxima

    ; Endstops
    M574 X1 Y2 Z1 S1 ; Set active high endstops

    ; Z-Probe
    M558 P1 H5 F120 T6000 ; Set Z probe type to unmodulated and the dive height + speeds
    G31 P500 X20 Y35 Z1.638 ; Set Z probe trigger value, offset and trigger height
    M557 X35:165 Y35:165 S40 ; Define mesh grid

    ; Heaters
    M305 P0 T100000 B3950 R4700 ; Set thermistor + ADC parameters for heater 0
    M143 H0 S120 ; Set temperature limit for heater 0 to 120C
    M305 P1 T100000 B4388 C7.060000e-8 R4700 ; Set thermistor + ADC parameters for heater 1
    M143 H1 S280 ; Set temperature limit for heater 1 to 280C

    ; Fans
    M106 P0 S0 I0 F500 H-1 ; Set fan 0 value, PWM signal inversion and frequency. Thermostatic control is turned off
    M106 P1 S1 I0 F500 H1 T45 ; Set fan 1 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 power saving
    M911 S10 R11 P"M911 S10 R11 P”M913 X0 Y0 G91 M83 G1 Z3 E-5 F1000" ; Set voltage thresholds and actions to run on power loss

    ; Custom settings are not configured

    ; Miscellaneous
    T0 ; Select first tool
    M501

    and the config-override:

    ; This is a system-generated file - do not edit
    ; Heater model parameters
    M307 H0 A172.6 C394.7 D1.5 S1.00 V11.5 B0
    M307 H1 A777.8 C250.8 D6.3 S1.00 V12.0 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



  • You're good to go. 👍



  • @phaedrux Thank you !!! ☺


 

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