1.2 VARIABLES

1.2.1 Control variable: Process variable that is measured and / or controlled by a control system. It’s called “control” the action of measuring the system’s controlled variable’s value and act on the system’s manipulated variable to fix or limit the measured value’s deviation from the wanted one.

1.2.2 Controlled or measured variable: It is the variable that we are going to control directly, on which a constant inspection will be made. We can also define it as the measured and controlled quantity or condition. The manipulated variable is the quantity or condition varied by a controller in such a way the controlled variable’s value is affected. Normally, it is a system exit.

1.2.3 Uncontrolled variable: It is modified in order to affect the controlled variable directly.

Uncontrolled variables change the result of a made action’s curse. They create the conditions and some of the restrictions a problem might be solved with. A variable can be controlled or uncontrolled, depending on the person.

It is important to define the values of every uncontrolled variable for a problem formulation.