AutoTune process (Power User)
Note for onboarding: This chapter is for advanced users. You can skip it during initial Brautomat setup and return later if needed. Start first with AutoTune step by step and Brew-day quick guide.
AutoTune determines suitable control parameters for your specific brewing setup. The goal is stable temperature control with minimal overshoot and undershoot during mashing.
Note: A small overshoot of about 0.5°C is normal. Depending on insulation and stored heat in the kettle, temperature may still rise slightly after heating is switched off.
The next sections explain P, I, D, and interval behavior. If you only want practical setup, you can skip directly to the step-by-step chapter.
The controller calculates required power from:
Required power = P + I + D
After valid PID values are found, SampleTime defines how often power is recalculated.
P value
The P component reacts to the current difference between actual temperature and target temperature.
Large difference -> higher power contribution
Close to target -> lower power contribution
At/above target -> P contribution approaches 0
A very high P value can cause strong overshoot and oscillation.
I value
The I component accumulates over time while heating.
If heating takes longer, I grows more
Near target, P gets smaller while I often carries the final approach
Above target, I decreases again
Too much I can cause overshoot.
D value
The D component damps rapid changes and reduces oscillation. Too much D makes control sluggish.
Interval (SampleTime)
PID math runs continuously, but output updates happen at intervals.
Too short (for example 1000 ms): more noise and twitchy control
Too long (for example 7000 ms): slow reaction
Typical useful values are 2000 ms to 3000 ms. Allowed values are 1000 to 7000 ms in 1000 ms steps.
Deep dive (Power User)
Further details about 1.60 PID behavior, Compute() sequencing, and L/R-based derivation: PID engine reference 1.60 (Power User)
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