Finally had some time again to do some BBQ'ing, did a small piece of brisket today. Here's how it went:

So, I started the heatermeter as soon as the coals were lit, and it got up to the set temp pretty nicely. When it was up to temp, I put in the ~1kg of brisket along with about 1m5 litres of boling water in the heat deflector pan. It took almost half an hour to get back up to temp. Then it started dying slowly to the point where heatermeter thought the lid was open (around 14:15 in the pic) and I had to manually put the fan to the max to keep it from dying completely. Then I started adjusting the fan parameters. Still it would be either below or above the setpoint, so I started adjusting the PID parameters.
These were what I started the cook with:
P=1.25, I=0.00175, D=3
FAN on above 10%, min 10% max 40%
And I already had adjusted the FAN to Max 100%. Following the "experimental tuning" instructions here: https://github.com/CapnBry/HeaterMeter/wiki/PID-Tuning I calculated that the P value for me should be 20 (100/5, as if my kamander's temp goes 5C below setpoint, the fire is dying, so I want it to be "all in" at that point). I also increased the I to 0.00575, but felt that it was a bit too "nervous", constantly adjusting quite drastically on all values, so I put it to 0.00375 which seemed to help a bit. The temp didn't seem to lower to the setpoint, with the output always rising a bit too high bit too fast for it to be able to settle, so I increased the D to 10. The instructions say that "it's proportional to P", but not exactly how, I mean should it be exactly the same as the P or proportional how?
Anyway, at this point my brisket's temp was at 90C so I took it out. I think my PID adjustments moved to the right direction, but I am not sure if they are perfect yet. Besides the D value, I am wondering about what I can see from the "debug window"; the I value seemed to remain around 29% pretty constantly, so does that mean that it is OK, or where should it be?
The brisket is still resting, I will have a taste a bit later.


So, I started the heatermeter as soon as the coals were lit, and it got up to the set temp pretty nicely. When it was up to temp, I put in the ~1kg of brisket along with about 1m5 litres of boling water in the heat deflector pan. It took almost half an hour to get back up to temp. Then it started dying slowly to the point where heatermeter thought the lid was open (around 14:15 in the pic) and I had to manually put the fan to the max to keep it from dying completely. Then I started adjusting the fan parameters. Still it would be either below or above the setpoint, so I started adjusting the PID parameters.
These were what I started the cook with:
P=1.25, I=0.00175, D=3
FAN on above 10%, min 10% max 40%
And I already had adjusted the FAN to Max 100%. Following the "experimental tuning" instructions here: https://github.com/CapnBry/HeaterMeter/wiki/PID-Tuning I calculated that the P value for me should be 20 (100/5, as if my kamander's temp goes 5C below setpoint, the fire is dying, so I want it to be "all in" at that point). I also increased the I to 0.00575, but felt that it was a bit too "nervous", constantly adjusting quite drastically on all values, so I put it to 0.00375 which seemed to help a bit. The temp didn't seem to lower to the setpoint, with the output always rising a bit too high bit too fast for it to be able to settle, so I increased the D to 10. The instructions say that "it's proportional to P", but not exactly how, I mean should it be exactly the same as the P or proportional how?
Anyway, at this point my brisket's temp was at 90C so I took it out. I think my PID adjustments moved to the right direction, but I am not sure if they are perfect yet. Besides the D value, I am wondering about what I can see from the "debug window"; the I value seemed to remain around 29% pretty constantly, so does that mean that it is OK, or where should it be?
The brisket is still resting, I will have a taste a bit later.

