Device for limiting control pressure intensity, process control apparatus and valve positioner

The utility model provides a device for limiting control pressure intensity provided for an actuator of a valve coupled to a valve positioner, a process control apparatus used for limiting the output pressure intensity of the valve positioner, and a valve positioner. The valve positioner is coupled to the process control apparatus which includes a valve and an actuator and is configured to receive control signals from a process control system and control pressure intensity provided for the actuator according to the control signals; the valve positioner comprises a pneumatic stage which is configured to receive driving signals and control the output pressure intensity of the valve positioner according to the driving signals; the valve positioner further comprises an overvoltage protection control circuit; the overvoltage protection control circuit is used for obtaining measurement values from a pressure intensity sensor which is coupled to the valve positioner in a communication manner, detecting abnormal pressure intensity based on the pressure intensity measurement values, responding to the detected abnormal pressure intensity, and controlling the driving signals to limit the output pressure intensity of the valve positioner, wherein the output pressure intensity provides control pressure intensity for the actuator.