What is the difference between positioner and actuator

The reasons for use of the valve positioner are summarized below:. A pneumatic signal usually psig is supplied to the positioner. The positioner translates this to a required valve position and supplies the valve actuator with the required air pressure to move the valve to the correct position. Note that the positioners used to articulate the principle of valve positioners here are pneumatic. This positioner performs the same function as the pneumatic type, but uses electrical current usually mA instead of air as the input signal.

The digital products cover three categories namely:. Here, an all-digital control signal replaces the analog control signal. Additionally, two-way digital communication is possible over the same wires. Fieldbus technologies benefit the end user by enabling improved control architecture, product capability and reduced wiring. The diagram above is for a linear sliding stem control valve without a positioner. Preventative maintenance is as important for industrial process systems as it is for any other….

Facebook LinkedIn. The Function of a Valve Positioner Valve positioners are devices used to put a valve in the correct position by increasing or decreasing the air load pressure on the actuator. Types of Valve Positioners There are four basic types of valve positioners: pneumatic, electronic, electro-pneumatic, and digital; these differ based on whether the positioner uses air or electricity to move the actuator.

Pneumatic devices, like the Fisher Pneumatic Positioner , send and receive pneumatic signals. They are intrinsically safe and can provide a large amount of force to close a valve. Single-acting or three-way pneumatic positioners send air to and exhaust air from only one side of a single-acting valve actuator that is opposed by a range spring. Double-acting or four-way pneumatic positioners send and exhaust air from both sides of the actuator.

Electric valve positioners send and receive electrical signals. There are three electric actuation types: single-phase and three-phase alternating current AC , and direct current DC voltage. Electro-pneumatic valve positioners, like the Fisher I , convert current control signals to equivalent pneumatic signals. They use a mixture of electricity and air. And most valve indicators offer local visualization, so you can see if the valve is closed or open. You also have many ways to collect the data sent from the valve indicators, from analog to digital communication.

For a long time, DeviceNet held the top spot, offering simple structure and communication for this type of signal. Today, the boom of wireless communication has helped a lot in monitoring valves. You can find vendors offering valve indicators with wireless communication built-in.

They also offer quick update times and reduce human errors, making them much more beneficial. Plus, they eliminate the need for messy restrictive cables. Of course, you can use a cable solution if it suits you better, but you should probably check the other solutions first.

Best of all, some smart valve indicators will monitor the valve strokes and provide you with advanced diagnostics. Buy industrial valves in our online shop. To know more about control valves, you can get in touch with our engineers! Control valve positioner types: how they work and when to use which one. Visaya May 31, What is a control valve positioner? Control valve positioner types Control valve positioners come in different types. Electro-pneumatic control valve positioner The working principle of the electro-pneumatic control valve positioner resembles that of the pneumatic control valve positioner.

Smart control valve positioner Smart valve positioners bring a lot of benefits to the end user. Buy industrial valves in our online shop To know more about control valves, you can get in touch with our engineers!