What type of control can be used for on/off functions?

Proportional-only control is specifically designed for on/off functions, making it suitable for simple applications where a system needs to operate in a binary manner—either fully on or fully off. This type of control is effective for systems that do not require fine adjustments or continuous modulation, which is why it’s commonly used for heating elements, pumps, and similar devices.

In this control method, the output responds proportionally to the error between a setpoint and the process variable; however, in practice, when the error exceeds a certain threshold, the output switches on, and when the error falls below that threshold, the output switches off. This binary nature of operation aligns perfectly with the definition of on/off control, making it a straightforward and efficient solution for such applications.

In contrast, the other control types mentioned, such as PID or proportional control, are designed for more complex control scenarios that require continuous output adjustments to maintain a desired state rather than simply an on or off position. Cascade control, on the other hand, involves multiple control loops and is used to enhance the response time and accuracy of a control system, but it is not suited for basic on/off applications.