Got my fermentation chambers and glycol chest freezer going. What am I doing wrong with my settings? The beer is going up 4 degrees then down 4 degrees. I’d like a more consistent beer temperature. That said, I’d like the digital actuators to be 100% or 0%. Nothing in between. Any assistance is appreciated.
Thanks for the reply, Bob.
My setup is a chest freezer that holds about 20 gallons of water and glycol. It’s controlled by the pid. Two submerged pumps are controlled by the other pids for each fermenter. No heater.
What are the constraints on the cool actuator?
What is the period of the cool PWM?
I think this might be a bug in the PWM calculation that I will fix this week. Currently working on it.
The gist is that it sees a short ON time in the past, followed by a long OFF time, which on average is still above the currently desired value, so it doesn’t turn on yet. The fix is to limit how far it looks back.
What will help directly is to reduce the minimum ON time set on the cool actuator.
Set the PWM period to 10 minutes, and the minimum ON time to 5s.
Why did you add a delayedOn constraint on Ferm 2 chill?
Min Off time on Glycol chill is very large
All PWMs have a very short period of 4s, which doesn’t make sense. Especially in combination with minimum ON/OFF times that are larger than the period. 4s is only used for heaters that don’t have constraints in our wizards.
Did you set this up using our glycol wizard? Perhaps erasing all blocks and starting from scratch by running the appropriate wizards again makes more sense at this point.
The constraints are only for protection in edge cases. The PWM module is smart and allowed to adapt its period if needed, within limits. If it has a period of 10 minutes, and its target has a minimum ON time of 1 minute, then it will lengthen the period to 20m if it needs to run at 5%.
But if you ask for impossible things, like a minimal 20m OFF period in a 4s PWM cycle, then it will not behave correctly.
The wizards let you assign custom names, but the fields to do so are collapsed by default in the wizard. You’ll have to expand them.