Hot end: Auto tune of heater 1 failed



  • Hi, I've just finished my 3d printer build and am trying to complete a successful hot end auto tune, but I keep getting the same error.
    Im a bit of a newb at this, so im sure im doing something wrong. Hopefully somebody can help.

    Here is my gcode and settings from tonight.

    10:02:52 PMWarning: Auto tune of heater 1 failed due to bad curve fit (A=3655.1, C=227.0, D=4.6)
    9:59:24 PMAuto tune phase 3, peak temperature was 296.2
    9:59:12 PMAuto tune phase 2, heater off
    9:58:47 PMAuto tune phase 1, heater on
    9:58:41 PMM303 H1 S240
    Auto tuning heater 1 using target temperature 240.0°C and PWM 1.00 - do not leave printer unattended
    9:42:06 PMWarning: Auto tune of heater 1 failed due to bad curve fit (A=3822.9, C=222.0, D=4.3)
    9:38:43 PMAuto tune phase 3, peak temperature was 299.0
    9:38:30 PMAuto tune phase 2, heater off
    9:38:06 PMAuto tune phase 1, heater on
    9:38:00 PMM303 H1 S240
    Auto tuning heater 1 using target temperature 240.0°C and PWM 1.00 - do not leave printer unattended
    9:35:27 PMG28 X
    9:24:46 PMM106 S0.3
    9:22:27 PMM120
    G91
    G1 Z25 F6000
    M121
    9:22:18 PMM120
    G91
    G1 Z25 F6000
    M121
    9:18:01 PMM307 H1
    Heater 1 model: gain 340.0, time constant 140.0, dead time 5.5, max PWM 1.00, calibration voltage 0.0, mode PID, inverted no, frequency default
    Computed PID parameters for setpoint change: P13.4, I0.482, D51.4
    Computed PID parameters for load change: P13.4
    9:17:01 PMM303
    Heater 1 tuning failed
    9:16:20 PMWarning: Auto tune of heater 1 failed due to bad curve fit (A=3411.4, C=198.1, D=4.2)
    9:16:01 PMM303
    Heater 1 is being tuned, phase 4 of 4
    9:14:03 PMM303
    Heater 1 is being tuned, phase 4 of 4
    9:13:17 PMAuto tune phase 3, peak temperature was 294.9
    9:13:05 PMAuto tune phase 2, heater off
    9:12:42 PMAuto tune phase 1, heater on
    9:12:36 PMM303 H1 S240
    Auto tuning heater 1 using target temperature 240.0°C and PWM 1.00 - do not leave printer unattended

    Firmware Name: RepRapFirmware for Duet 2 WiFi/Ethernet
    Firmware Electronics: Duet WiFi 1.02 or later
    Firmware Version: 2.02(RTOS) (2018-12-24b1)
    WiFi Server Version: 1.22
    Web Interface Version: 1.22.6


    Im using 24V, and an E3D PT100 sensor.



  • What does your temp plot look like? Sharp spikes can indicate dodgy connection, failed sensor, or electrical noise.

    Sharp drops made mine fail.had tp replace a sensor, but it was a standard thermistor.



  • Is the heater cartridge and PT100 cartridge firmly secured in the heat block?
    Do you have a fan blowing on the heat block?


  • administrators

    The gain is way too high. Are you using a 12V heater cartridge with 24V power?



  • The temperature plot looks smooth. The only problem is that it doesn't stop heating until it reaches the maximum temp which is set to 280°

    Everything in my hot end feels secure, although come to think of it I haven't tightened it in its heated state.

    My cartridge is definitely 24V.



  • @geekness said in Hot end: Auto tune of heater 1 failed:

    My cartridge is definitely 24V.

    Confirmed by measuring resistance?

    Assuming it's an E3D: https://wiki.e3d-online.com/E3D-v6_Assembly#Heater_Cartridge



  • @phaedrux
    Hmm, no-not tested.
    I'll test it tonight when I get home. What kind of resistance should I be looking for each voltage cartridge?
    What is the resistance value I should be getting for 12V vs 24V?
    Im pretty sure its a 40W cartridge either way, but It should be easy enough to figure out



  • @geekness From the link:

    Heater inserted into block.
    If you have one, grab a multimeter and check the resistance of your heater cartridge against the table below. Expect your value to deviate a little from these, a difference of around plus or minus 5W is fine, however if yours is significantly off or you are concerned you have the wrong cartridge please get in touch.

    P\V 12v 24v
    40w (Red Leads) 3.6Ω 14.4Ω
    25w (Blue Leads) 5.76Ω 23.04Ω
    30w (Blue Leads) 4.8Ω 19.2Ω



  • @phaedrux I came home tonight and checked my heater cartridge, and yes it is a 12V cartridge.
    I swapped it out for a 12V cartridge then ran auto tune again, and voila, I now have a functioning hot end. Thanks.


  • administrators

    @geekness, I assume you mean that you swapped it for a 24V cartridge. I'm glad you got it working.



  • @dc42 haha, yes woops. Swapped it out for 24V. Thanks again


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