Question

Dynamic and control process

in a water tank in the toiled

what is the controlled variable?

what is the disturbance variable?

what is the manipulated variable?

Answer 1

Controlled variable are those variable that need to be control in system and we measure this variable.

Disturbance is that input variable which comes in the system automatically and we can't control it , it is not in our hand.

Manipulated is that input variable which we can control in the system.

Example- if we have a tank in which water is coming and going . Here if want to control the height of tank. Height is the controlled variable for which we will install controller. Inlet flow rate is disturbance because we can not control it and it can change the value of controlled variable . Outlet flow rate can be controlled by valve so it is manipulated because if there is change in inlet flow rate and we want to height remain same so we can use valve to counter that affect so outlet flow rate is manipulated variable and we are controlling it.

So where ever we see valve means that variable can be controlled and will be manipulated.