The MSP-21 series Smart Valve Positioner 4 ~ 20mA current signal issued by the receiving controller or control system to control the valve opening device. Built-in microprocessor, can accurately control the valve opening, and can perform automatic settings, PID control, the HART communications, and other powerful features, which is characterized by: 
 - When the input current signal or gas source signal is disconnected, you can automatically lock the current valve opening, to ensure the normal operation of the system. 
 - Can be obtained through the HART communication valves and locator all sorts of information. 
 - Standby gas consumption is close to zero, this will reduce the plant energy. 
 - The exterior of the product is equipped with a liquid crystal screen (LCD), so you can at the scene to confirm the status of the locator. 
 - Can be any linear, quick opening, equal percentage flow characteristics. 
 - By pressing a button on the product can be easily PID parameters can also set up 16 points to implement special traffic curve.