big 6.5 lb. extruder heater fault - heater rising too slowly

[solarsamuel]

Hello, I'm getting a heater rising too slowly heater fault after about 15 seconds of trying to heat up my pellet extruder (barrel + screw weight is 6.5 lbs.) I have a few guesses on how to solve this, but I'm not 100% sure. I'm currently having the problem on a 6HC V1.02 at 48VDC, firmware 3.4.6. Output0 goes to a voltage divider and solid state relay which turns the 120VAC to the two 500 watt band heaters on/off. The thermistors are standard 100kohm and are threaded in with good contact in the barrel. This setup worked in April 2022 (firmware attached) on a 6HC V1.01 at 24VDC, Output0 (no voltage divider since it output 24VDC). I tried copying the PID parameters, but it gets the heater fault with the old parameters.

The good news is it does heat (I reset the fault a bunch of times and can get it hot). The bad news is I get the fault, which is understandable since it has such a large mass. The question is, how do I tune it? Maybe it's a GCODE thing?

I also tried the manual tuning parameter method via this link: https://docs.duet3d.com/User_manual/Connecting_hardware/Heaters_tuning

For R - temperature rose 10C in 15 seconds
For C - temperature cooled from 130C to 110C in 640 seconds (no fans)
For D - the deadtime is about 23 seconds from room temperature until the temperature really starts to rise - note the heater alarm goes off at around 15 seconds, but this is a decent approximation

Is there a way to further delay the heater fault in time? I tried the line below but still get the error after about 15 seconds

M570 H0 P30 T15 ;

This is like like trying to get a 747 to take off vs. a piper cub. Lots of mass compared to a typical extruder.

DEC 6 2023 config file 6HC V1.02 48VDC.txt APRIL_25_2022_CONFIG_WITH PANEL DUE 6HC V1.01 24VDC.txt

[deckingman]

@solarsamuel said in big 6.5 lb. extruder heater fault - heater rising too slowly:

.....................Is there a way to further delay the heater fault in time? I tried the line below but still get the error after about 15 seconds

M570 H0 P30 T15 ;......................

That should have worked - or at least it should have needed to be in fault condition for 30 seconds before a fault mode was triggered using P30. Is H0 the correct heater number according to your config.g ? Usually and by default, H0 would be the bed heater rather than the hot end heater.

Edit. I just spotted your image which clearly shows the fault is on heater 1 not heater 0. So try M570 H1 P30 T15.

[solarsamuel]

@deckingman you are a legend. Yes, that was it. Switched H0 to H1 and it's working now. Thank you