Control.com - Nerds in Control

Hi, I am a fresher and just joined Essar, would like to know the operation of positioner. Like 4 to 20 milli amps is converted to 3 to 15 PSI by I/P. this 3 to 15 psi is the control signal for positioner, I would like to know the exact working as I am into projects.

A positioner is a device put into a valve to ensure that it is at a correct position of opening as per the control signal. An I/P converter only sends the opening/closing request to valve but can not confirm its position.

Positioner senses the valve opening through a position feedback link connected to valve stem which is its input signal. I/P converter output is its setpoint input. The difference between these two is the error signal based on which the positioner positions the valve to correct position to reduce error to zero. Hence positioner is nothing but a pneumatic feedback controller. Controlled external supply air to positioner provides power to positioner to position a valve. Also positioner is used in a valve when valve operating signal range is different from I/P converter output range.

In recent days software configurable digital positioner are being used in valves which do not require I/P converter and has many features like advanced valve diagnostics, partial stroke testing, remote communication etc.

Dear Hemanth,

Without you knowing the concept of Postioner, who selected you in ESSAR? Pls return to your college and study once again and join... I think it would be better for you. MR

Bye.

Dear Mr.Anonymous person,

Nobody knows everything (even if it is basics)

If some body needs to go back to college, if he/she does not know a basic concept, then everybody will be sitting in college

What is really required, is only the attitude,
to learn and keep learning

Dear Mr.Anonymous person,
you are right with your question i learn detail about the positioner usally i use to only calibrate now i know the detail thankyou please do share your knowledge and problem you face during calibration i will love to read it.

The positioner is designed for controlling control valves by producing analog pneumatic signal to control the percentage of opening or closing operation for valve.

Example:
Inputs to positioner
Air supply (feeding of positioner)
Control pneumatic signal: it comes from I/P equipment

Output: pneumatic signal

Numerical example:
Air supply: 35 psi
Control signal: 3-15 psi
Output : 6-30 psi