Control valve according to the drive mode is divided into two kinds of electric control valve and pneumatic control valve to adapt to different conditions and process requirements, electric control valve, the general by the angular travel electric actuator direct drive valve through 4 ~ 20mA or 0 ~ 10V analog signal control valve opening, so as to achieve the purpose of control. Angle control valve used in the main ball valve, butterfly valve. The electric control valve is simple, without compressed air, but the response speed is slow, poor control accuracy and poor regulation, is limited to use in some of the less demanding control accuracy, lower operating frequency of the workplace. In contrast, pneumatic control valve with high control accuracy, fast response, good job stability, suitable for a wide range of applications, is widely used in various fields of process control. As the brain of the regulating valve, the valve positioner plays a decisive role in controlling the overall control valve and field functions. Compared with the traditional electro-pneumatic valve positioner, intelligent valve positioner has more extensive applications and market prospects in the control valve control accuracy, response speed, function expansion, and improve the level of automatic control of the valve. Therefore, intelligent valve positioner is regarded as the future development of valve positioner. The new smart valve positioner Different smart valve positioner both structural and functional commonality, but also have their own characteristics. Common: â– As a standard valve positioner (electro-pneumatic converter function), it can be widely used in the position control of various process control valves with pneumatic actuators. â– As a process controller (PID function) With pneumatic actuator valve composed of intelligent control valve. Can receive the real-time process value signal of the sensor directly, form a relative independent complete process control loop together with the sensor, realize the closed-loop control function; â– Can combine the valve of straight stroke pneumatic actuator such as: Angle seat valve, stop valve, diaphragm Valves, etc., the use of external position sensors form a valve position control system; can also be combined with the angular stroke pneumatic actuator valves such as: ball valves, butterfly valves, and diaphragm-type pneumatic control valve, the built-in angular position sensor valve positioning control system ; â– can be used for single-acting actuator valves, such as normally open or normally closed valves, but also for double-acting actuator valve or cylinder control; â– with analog position feedback output and two binary output signals. Position feedback signal can be the actual position of the valve or the actual process value feedback to the PLC or controller for easy system information acquisition and monitoring, binary output signal can be extended control valve control functions and improve system automation; â– good man-machine interface , Easy to operate; large-screen digital LCD display real-time display setpoint and actual value and can display the valve ambient temperature; three-button menu instructions operation, easy on-site commissioning and maintenance.
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