Servo Config / Testing


 
Actually, you've got a point there... What it is showing when you hover over the graph is the OUTPUT, which is the actual damper position in this config, your blower should be running at 10% of that value it displays. (since Max=10%)... I would think it should say OUTPUT there when you hover rather than FAN, that is confusing...
 
What is confusing me now about your cook is the pit temp has gone 10F+ above the setpoint and rising steeply while the output % still remains high?... and now it is quite a bit below the setpoint and dropping yet the HM hasn't ramped to 100%? On my HM with the old default PID settings I see some overlap where the damper output is above zero when the pit temp is above the setpoint, but never to the extent I am seeing there on your graph. Are you still running the old PID default values?
 
Where do you have your pit probe placed? It seems to react rather drastically to air flow changes, it just changed 15 degrees in 1 minute....
 
RalphTrimble said:
Where do you have your pit probe placed? It seems to react rather drastically to air flow changes, it just changed 15 degrees in 1 minute....
Click to expand...

Clipped to the underside of the cooking grate which is 5" from the top of the drum.

Sorry you asked about current PID settings.....

wEPuXy9.jpg
 
It seems when the pit temp is horizontal the HM output is about 75%, which is a bit high for a steady state condition. I like to see things stable with the output between 30-50%. And perhaps the weber lid vent wide open is a bit too open for the UDS on the top vent. In general, when running damper only the top vent can be open wider, and when the fan is running all the time the top vent needs to be closed more... So in the current setup with what I am seeing I would bump your Max to 20% (in attempt to move that 75% steady state down to about 35%) and close down the top vent quite a bit.
 
Ok, looking better... Output running about 25-30%, temp a degree or two from setpoint, not perfect but getting much closer....
From here you can tweak slightly the top vent, blower Max and perhaps the PID settings a bit to smooth thing out to perfection... After you get a few cooks under your belt you should get a feeling for how things operate, how to set the vents etc, and making the final adjustments should come easier...
 
Last edited:
Much happier with how it's running now, and am reasonably confident with what to tweak and how that will affect the temp control.

Thanks so much for the help, and for the RD3, it's a little wonder!
 
No problem, glad to help....
I gained some experience tweaking the system on a UDS from half way around the planet, gotta love the internet!
Cheers...
 
Hi Ralph, not sure if you're still subscribed to this thread, but running another cook right now and am getting a bit too much fluctuation in the temperature. To me it looks like the error is increasing, meaning the P value is too high? Could I get your opinion?

http://27.33.85.127:8888
 
You must log in or register to reply here.

 

Back
Top