According to the driving mode, the control valve is mainly divided into two types: electric control valve and pneumatic control valve to adapt to different working conditions and process requirements. The electric control valve is generally directly driven by a quarter-stroke electric actuator through 4-20mA or 0 The analog signal of ~10V controls the opening of the valve, so as to achieve the purpose of control. The valves used in angular stroke control mainly include ball valves and butterfly valves. The electric control valve is simple to operate and does not require compressed air, but its response speed is slow, control accuracy and adjustment performance are poor, and it is limited to some workplaces that do not require high control accuracy and low operating frequency. In comparison, pneumatic control valves are widely used in process control fields in all walks of life due to their high control accuracy, fast response speed, good working stability, and wide range of applications.

As the brain of the control valve, the valve positioner plays a decisive role in the control performance and field functions of the entire control valve. Compared with the traditional electric-pneumatic conversion valve positioner, the intelligent valve positioner has a wider application and market prospects in terms of control valve control accuracy, response speed, function expansion, and improvement of valve automation control level. Therefore, the intelligent valve positioner is regarded as the development direction of the valve positioner in the future.

New intelligent valve positioner

Different intelligent valve positioners have commonalities in structure and function, but also have their own characteristics.

What 　　 has in common:

As a standard valve positioner (electric-pneumatic converter function), it can be widely used in the position control of various process control valves with pneumatic actuators;

As a process controller (with PID function), it forms an intelligent regulating valve with a valve with a pneumatic actuator. It can directly receive the real-time process value signal of the sensor, and form a relatively independent complete process control loop with the sensor to realize the closed-loop control function;

It can not only be combined with valves with linear pneumatic actuators such as angle seat valves, globe valves, diaphragm valves, etc., using external line position sensors to form a valve positioning control system; it can also be combined with valves with angular stroke pneumatic actuators such as: ball valves, Butterfly valves, and diaphragm pneumatic control valves, etc., use built-in angular travel sensors to form a valve positioning control system;

can be used not only for single-acting actuator valves, such as normally open or normally closed valves, but also for the control of valves or cylinders of double-acting actuators;

can be equipped with analog position feedback output and two binary output signals. The position feedback signal can feed back the actual position or actual process value of the valve to the PLC or controller, which is convenient for system information collection and monitoring. The binary output signal can expand the control function of the regulating valve and improve the automation degree of the system;

Good man-machine interface, easy to operate; large-screen digital liquid crystal display, real-time display of the set value and actual value and can display the valve ambient temperature; three-button menu instruction operation, easy on-site debugging and maintenance.