Question:
What is the primary function of integral action in PID control?
Options:
A) Add damping
B) Predict error
C) Remove offset
D) Reduce gain
View Answer
Correct Answer: C) Remove offset
Detailed Explanation
The primary function of integral action is to eliminate steady-state error (offset).
Integral action works by accumulating error over time:
If a small error persists:
- The integral term continues to increase
- Controller output keeps adjusting
- Eventually, the error becomes zero
This ensures accurate long-term control.
Why It Is Necessary
In proportional-only control:
- Some steady-state error must remain
- Because output depends directly on error
Integral action removes that limitation.
Why Other Options Are Incorrect
A) Add damping → Damping is mainly provided by derivative action.
B) Predict error → That is the role of derivative action.
D) Reduce gain → Integral action does not reduce proportional gain.