What does a reverse acting positioner do as the control signal increases?

A reverse acting positioner is designed to operate in a manner where an increase in the control signal results in a decrease in the valve opening, leading to the closing of the control valve. This is particularly useful in processes where increased pressure or flow must be reduced to maintain system stability or to prevent overflows and other safety concerns.

In this context, as the control signal increases, the reverse acting positioner manipulates the valve mechanism so that it closes the control valve. This action helps regulate processes that require a specific balance and ensures that system dynamics are maintained correctly.

Understanding how a reverse acting positioner functions is crucial for instrument technicians, as it directly influences how control systems operate in response to varying signals. This knowledge allows technicians to troubleshoot, calibrate, and optimize control systems effectively.