What type of control is implemented when a proportional band is set to a maximum position?

When a proportional band is set to a maximum position, it indicates that the control system is set to make continuous adjustments based on input to maintain a setpoint. This is characteristic of variable control, which allows for fine-tuning of the input to achieve the desired output, rather than simply turning the output fully on or off.

In variable control systems, the proportional band determines the range over which the control output varies in response to changes in the measured variable. In this case, a maximum proportional band means the system can continuously adjust the output, providing more precise control.

On the other hand, on/off control would involve toggling the output between fully on and fully off, which does not allow for such graduated responses. Feedback control would also typically rely on variations within a defined proportional band rather than maximizing it. Open-loop control lacks feedback to adjust the output based on the desired setpoint, differing from a system that operates within a defined variable range. Thus, the concept of a proportional band set at its maximum aligns closely with variable control methods.