SOLUTION

The on-off controller is a discontinuous system.

Detailed Explanation

The controllers are basically classified as discontinuous controllers and continuous controllers.

The discontinuous mode controllers are further classified as ON-OFF controllers and multiposition controllers.

Two Position Mode(ON-OFF Controller)

• The two-position controller is also known as the ON-OFF controller.
• This type of controller is simple and inexpensive and are generally employed for home heating system, domestic water heaters, and industrial control system.
• For example, if the controlled process variable is room temperature, the switch would turn ‘ON’ the air cooler when the temperature is high and turn it “OFF° when the desired comfort level is reached.
• Thus, an ON-OFF controller operates on the manipulated variable only, when the temperature crosses the setpoint. The output has only two states, completely ON or completely OFF.
• The one stage is used when the temperature is above the desired value (setpoint) and the other state is used when the. temperature is below the set point.
• The on-off controller is discontinuous at the point when the system changes its state from on to off