Manually Tuning 1000W Heater

JRCL

Hello all,

I'm trying to tune a 110V 1000W heater connected to a Duet 2 wifi via an SSR.

I started by using the M303 command to run autotune on it but it never made it past phase 4. No errors thrown, just never completed after an hour or so of run time.
I switched to manual tuning after that but even after following the manual tuning directions for R & C values, I kept getting slow heat-up errors.
I played around w R & D parameters to no avail.

Wondering if anyone has recommendations for something as slow and clunky as this element so it doesn't keep faulting and stopping the heater from continuing its machine cycle.

; Heaters
M308 S1 P"e0temp" Y"thermistor" T100000 B4725 C7.06e-8
M950 H1 C"e0heat" T1                   ; create nozzle heater output on e0heat and map it to sensor 1
M307 H1 B0 S1.00 D5                     ; disable bang-bang mode for heater  and set PWM limit
M308 S2 P"e1temp" Y"thermistor" T100000 B4725 C7.06e-8 
M950 H2 C"e1heat" T2                   ; create nozzle heater output on e0heat and map it to sensor 2
M307 H2 B0 S1 D5 			   ; set model parameters for heater 2 and use PID Mode
M143 H2 S200									; 200C limit on heater

; Tools
M563 P1 H2 F3:4			        ; tool 1 with heater 2 and fan 2
G10 P1 R0 S0				; set initial tool 1 active and standby temperature to 0

Nxt-1

@jrcl Since the new heater tuning model got implemented, tuning on large thermal mass beds has been known to take a while. As it happens I tuned my 2kW bed just last weekend and that took several hours.
So what you encountered might in fact be just normal behaviour.

JRCL

@nxt-1 Woahhhh this is great to hear. Maybe I'll give it a try this weekend, thanks for the optimism!

Phaedrux

Yes it can take a very long time for large thermal mass heaters.

dc42

@jrcl if the temperature reading is stable (no visible noise in it) then you can use the Y parameter in the M303 command to reduce the tuning hysteresis from its default value of 5 to about 2.5 or 3. That will speed up tuning somewhat. https://docs.duet3d.com/en/User_manual/Reference/Gcodes#m303-run-heater-tuning

JRCL

Thank everyone for the helpful tips to use next time. Luckily some more patience with the auto-tune did the trick and the fault no longer occurs.