Derivative controller

1. What is a derivative controller?
2. When would you use a derivative controller?
3. Where is derivative control used?
4. What is the advantage of derivative controller?

What is a derivative controller?

Derivative control monitors the rate of change of the process variable and makes changes to the controller output to accommodate unusual changes.

When would you use a derivative controller?

We recommend using derivative only if the derivative function contains a built-in filter to remove high frequency noise. Most DCSs and PLCs have this function but some do not or there is a switch to activate the derivative filter.

Where is derivative control used?

The derivative control mode gives a controller additional control action when the error changes consistently. It also makes the loop more stable (up to a point) which allows using a higher controller gain and a faster integral (shorter integral time or higher integral gain).

What is the advantage of derivative controller?

The major advantage of derivative controller is that it improves the transient response of the system.