Boiling Sous-Vide Eggs Using Clojure's Transducers

Re:Boiling Sous-Vide Eggs Using Clojure's Transducers by dbcooper on Monday October 06, 2014 @11:05AM (#8416237)

For temperature control, you probably want to use a PI controller with Anti-windup. This will compensate for the limits on actuator (heating element) output, and prevent large overshoots from "windup" of the Integral element.

http://jagger.berkeley.edu/~pack/me132/Section15.pdf

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Re:Boiling Sous-Vide Eggs Using Clojure's Transducers by pi-rat on Monday October 06, 2014 @11:20AM (#8416327)

Very good tip, thanks! I'll consider that for my proper setup, I've had some problems finding proper calibration values for some water containers and heaters because of the lag in the system.

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Re:Boiling Sous-Vide Eggs Using Clojure's Transducers by someengineer on Monday October 06, 2014 @11:48AM (#8416469)

To elaborate on why you can typically avoid derivative control for thermodynamic processes:

There's no natural resonance in the system caused by energy-storing elements. For instance, if you drop a cold egg into a pot of water at exactly 80 C, it won't overshoot and go up to 85 C before settling to 80 C. Mechanical systems on the other hand often have "spring-like" behavior that causes them to resonate at certain frequencies.

If you want to get hardcore with the control design then you could look into fuzzy logic controllers. It's common in high-end appliances: http://en.wikipedia.org/wiki/Fuzzy_control_system

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