Glossary
What is Anti-windup?
Handling that stops the integral term of a PID from growing without limit while the output is saturated at its high or low clamp.
Without it: the valve is 100% open, the value still has not reached setpoint, and the integral keeps growing. When the value finally arrives, the output stays saturated for minutes while the accumulated integral unwinds, and the process overshoots badly.
The simplest fix is to clamp the integral term within the output range, or to freeze integration entirely while the output is saturated in the same direction as the error.
Related terms
- PID controller
- A control algorithm that computes its output from the difference between the setpoint (SP) and the measured value (PV), in three parts: proportional, integral and derivative.
- State machine
- A pattern where the process is in exactly one known state at a time and moves between states on defined conditions.