Heatermeter and BGE mini
- Thread starter NickH82
- Start date
Hi Nick - hartelijk welkom! I've not tried a BGE mini but have tried a Weber Go Anwhere as a big downscale from my 18" smoker. It controlled it fine using a jury rigged air feed. The HeaterMeter allows you to set the maximum fan speed so a stock/standard fan would be fine.
Could you share your settings for the wga?
Tried this weekend with the mini but didn't really succeed.
I put the max fan on 25%, P=1, I=0, D=0
The bge went to 150C initially with setpoint at 105C and didn't manage to drop temperature for the next 3 hours (fan speed 0).
Perhaps I should decrease the max fan next time. Looks like it's almost impossible to recover from an overshoot...
Tried this weekend with the mini but didn't really succeed.
I put the max fan on 25%, P=1, I=0, D=0
The bge went to 150C initially with setpoint at 105C and didn't manage to drop temperature for the next 3 hours (fan speed 0).
Perhaps I should decrease the max fan next time. Looks like it's almost impossible to recover from an overshoot...
Andy Snider
TVWBB Fan
Your I & D = 0 is also affecting overshoot. They are the 'predict the future' terms of the PID. Even with P=1, you're adding air until you reach setpoint, which is too late to NOT overshoot. You need some D to calculate the rate of temp climb, and reduce the input accordingly. I keeps a running average & keeps the P & D from oscillating (which in a kamado, results in overshoot as well).
I'd set them back to stock & try again.
You also need to make sure that the natural draft (aka, leaks) aren't too much for your setpoint. A PID control can only work if the system CAN be controlled...the longer it runs, the better it will get at controlling that system (Unless your I & D are 0, then you basically have an on/off control
)
I'd set them back to stock & try again.
You also need to make sure that the natural draft (aka, leaks) aren't too much for your setpoint. A PID control can only work if the system CAN be controlled...the longer it runs, the better it will get at controlling that system (Unless your I & D are 0, then you basically have an on/off control
)Thanks makes sense. I was just trying to tune the PID parameters however using the manual tuning technique:
https://github.com/CapnBry/HeaterMeter/wiki/PID-Tuning
Guess I will need to make P even smaller than 1, starting at 0.1 perhaps?
https://github.com/CapnBry/HeaterMeter/wiki/PID-Tuning
Guess I will need to make P even smaller than 1, starting at 0.1 perhaps?
Andy Snider
TVWBB Fan
Read the 'Before getting started' section of the link you posted. You're getting too much air 'naturally' (not fan-pushed) to control the grill at the temp you want to run at. A piece of duct tape or a ball of aluminum foil will fix your $200+ electronic control system
The stock fan is big enough for a large BGE, it's likely too big for a mini. Put the HM away. set the BGE mini up to run at 105C. I bet the bottom vent setting has a smaller open area than the square outlet from the fan, so if the fan is on there, you get more air than you need for 105C, even with the fan not spinning. This means the HM CANNOT control the pit. You need to make the fan outlet even smaller, so that you NEED a bit of fan to run at 105C. THEN the fan speed can dictate what temp the pit runs at & the PID can smooth the response of the pit.
PID will smooth control response, it won't fix an out-of-control system. Read the 'Experimental Tuning' section from the link. You're going the wrong way with P & you have I & D shut off - the PID isn't really doing much. I think I confused you with my 1st paragraph, my explanation was poor & too simple. The PID settings are a minor problem compared to what I suggested in the 2nd. Get your airflow sorted & go back to stock PID settings, you can tweak once you get it close.
The stock fan is big enough for a large BGE, it's likely too big for a mini. Put the HM away. set the BGE mini up to run at 105C. I bet the bottom vent setting has a smaller open area than the square outlet from the fan, so if the fan is on there, you get more air than you need for 105C, even with the fan not spinning. This means the HM CANNOT control the pit. You need to make the fan outlet even smaller, so that you NEED a bit of fan to run at 105C. THEN the fan speed can dictate what temp the pit runs at & the PID can smooth the response of the pit.
PID will smooth control response, it won't fix an out-of-control system. Read the 'Experimental Tuning' section from the link. You're going the wrong way with P & you have I & D shut off - the PID isn't really doing much. I think I confused you with my 1st paragraph, my explanation was poor & too simple. The PID settings are a minor problem compared to what I suggested in the 2nd. Get your airflow sorted & go back to stock PID settings, you can tweak once you get it close.
RalphTrimble
TVWBB Diamond Member
You said "+ servo", do you have a servo damper?
Yes I'm using the offset rotary damper designed by Tom Kole. Actually I made two, one for my primo and one for the bge mini with a smaller outlet. If the pid output is at zero, the air flow is almost completely shut.
In my test I indeed found the fire to be out when I opened the bbq...
In my test I indeed found the fire to be out when I opened the bbq...
Nick, start with the PID parameters that I listed in the thread. With the mini you can probably just change the limits on the fan if you want to continue with servo and fan mode, or just use servo only mode. You'll have to tweak the PID values for servo only though because I don't operate in that mode and haven't tried optimizing the parameters for it.
Definitely, make sure you don't have leaks though or else you'll have a hard time getting things to be stable with a kamado.
Definitely, make sure you don't have leaks though or else you'll have a hard time getting things to be stable with a kamado.
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Thanks Tom, you mean these?
Large BGE
B: 0
P: 3
I: 0.008
D: 5
min fan: 10%
max fan: 100%
both fan and servo on
Actually I just realised/found out that the PID parameters are different if you run in celsius mode (which I do). That might explain the "bad" results I had in the past with the standard settings. Will run in fahrenheit mode next time with the standard parameters...
Large BGE
B: 0
P: 3
I: 0.008
D: 5
min fan: 10%
max fan: 100%
both fan and servo on
Actually I just realised/found out that the PID parameters are different if you run in celsius mode (which I do). That might explain the "bad" results I had in the past with the standard settings. Will run in fahrenheit mode next time with the standard parameters...
Bryan Mayland
TVWBB Hall of Fame
You can scale the parameters by just multiplying them by 9/5 or 5/9 depending on which way you're converting. So the defaults converted to Celcius would be:
B: 0
P: 2.22
I: 0.11
D: 2.78
B: 0
P: 2.22
I: 0.11
D: 2.78