Glossary · Control theory and process control
Integral absolute error (IAE)
Also known as: IAE
German: Integral des absoluten Fehlers (IAE)
In control engineering, the integral absolute error (IAE) is a performance index calculated as the time integral of the absolute value of the control error, used to compare how well control loops or tunings track a setpoint or reject a disturbance.
- Control theory
In one sentence
IAE integrates the absolute control error over time; a lower value means the loop stays closer to its setpoint.
Example
Two tunings of a flow loop are compared after the same setpoint step: the new tuning reduces the IAE by 30 percent without increasing valve travel much.
How it applies
- Engineering: IAE weights all errors equally over time. Related indices are ISE (integral of squared error, penalizing large errors) and ITAE (time-weighted, penalizing long-lasting errors). Tuning methods often minimize one of them.
- Commissioning: IAE is only comparable for the same test: same step size, same disturbance, same time window. Record these conditions with the value.
- Documentation: If IAE serves as an Acceptance criterion in a performance specification, define the test, the integration window and the limit. Otherwise the figure can't be verified later.
IAE vs. overshoot and settling time
Overshoot and Settling time describe individual features of a step response. IAE condenses the whole response into one number, which is convenient for comparison but hides how the error arose.