Hotend completes autotune but errors on cold heat up

cosmic_crunch

I just upgraded my delta from an azteeg x5 mini to a Duet WiFi on 3.2.2 Stable. Running a 24v power supply. Everything works great but the hotend keeps throwing an error when I try to start a print or set the temp manually.

Heater 1 fault: temperature rising much more slowly than the expected 2.2°C/sec

I've tuned the hotend 3 times and it completes within 10 cycles without a hitch. The block, heater and thermistor are volcano clone from TriangleLabs. I set the thermistor according to their recommendations and it matches what my IR thermometer reads. I can get it to print by resetting a few times and once it gets over 100C the error doesn't trigger any more.

I tune close to the bed to account for deflection of the part cooling fans on the large volcano heater block, which has a silicone sleeve on it to minimize the interference from the 2 x 4010 radial fans that kick in from layer 2 on. I print PLA mainly so my fans are 100%.

Here are the heater models in my config.g (I have the same M307 lines in config-override.g and M501 initiated in config.g):

; Heaters
M308 S0 P"bedtemp" Y"thermistor" T100000 B4092         ; configure sensor 0 as thermistor on pin bedtemp
M950 H0 C"bedheat" T0                                  ; create bed heater output on bedheat and map it to sensor 0
M307 H0 R0.378 C464.142:464.142 D6.18 S1.00 V24.0 B0   ; set PID for bed heater 0
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 B4725 C7.06e-8 ; configure sensor 1 as thermistor on pin e0temp
M950 H1 C"e0heat" T1                                   ; create nozzle heater output on e0heat and map it to sensor 1
M307 H1 R1.869 C225.363:121.113 D6.25 S1.00 V23.9 B0   ; disable bang-bang mode for heater  and set PWM limit
M570 H1 P12											   ; time in seconds before tripping heater fault for hotend
M143 H1 S285                                           ; set temperature limit for heater 1 to 285C

Is there anything in there that doesn't look right?

cosmic_crunch

I should have mentioned that I've been printing with this machine for 3 years on smoothie with zero issues but Duet and RRF is so much better.

M307 H1
Heater 1 model: heating rate 1.869, cooling time constant 225.4/121.1, dead time 6.25, max PWM 1.00, calibration voltage 23.9, mode PID
Computed PID parameters: setpoint change: P15.3, I0.407, D66.9, load change: P15.3, I0.957, D66.9

nick9one1

Sounds similar to my issue
https://forum.duet3d.com/topic/22274/strange-message-when-pid-tuning/12

cosmic_crunch

Yes looks the same. I think the new heater model is too paranoid. Maybe a new parameter to relax the heating rate checks could help fix this? I'm down for beta testing if someone can make a fork.

Phaedrux

Did you tune with M303 T0 S200? The T0 tunes it as a tool rather than just a heater.

What does the heater graph look like during the tuning process?

cosmic_crunch

@Phaedrux Yeah I tuned it as a tool using M303 T0 S210 so that it can account for the fan in the last phase.

The heater graph looks perfectly normal during tuning, it rises to ~215 and falls to ~205 consistently.

Phaedrux

Thanks. There will be some changes coming to the tuning algorithm that should help with this error.

cosmic_crunch

Thanks Phaedrux. What's the most recent version that uses the old tuning method?

jay_s_uk

@cosmic_crunch 3.1.1