Glossary · Manufacturing systems
Control quality
Also known as: Control performance, Control loop performance
German: Regelgüte
In control engineering, control quality is the measure of how well a closed control loop follows its setpoint and rejects disturbances, assessed with criteria such as overshoot, settling time, steady-state error and integral error measures.
- Manufacturing systems
In one sentence
Control quality describes how well a control loop follows its setpoint and rejects disturbances, for example by overshoot and settling time.
Example
After retuning the temperature loop, overshoot drops from 4 K to 1 K and settling time from 12 to 5 minutes, which improves control quality.
How it applies
- Engineering: Controller tuning balances fast response against overshoot and robustness. Integral criteria (such as IAE or ISE) summarize control quality in one number for comparison.
- Operation: Control loop monitoring tools evaluate control quality continuously and flag loops that oscillate, run in manual or sit at their limits. Poor loops often cause quality variation and energy waste.
- Documentation: Record the tuning parameters, the test conditions and the achieved values at commissioning, so later changes can be compared. In validated processes, controller parameters can be critical process parameters under change control.
Control quality vs. product quality
Control quality describes the behavior of the control loop. Product quality depends on it, but also on materials and equipment. In German, Regelgüte refers to the loop only; translations as 'quality control' would be wrong.