Answer / someone

No...valve can only be used as on/off purpose..not for control without positioner.

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.

Answer / jagan kumar

Positioner is used to give the feedback about the position of control value. ie: how much valve has been opened eg: 74%. Obiviously control value work with out positioner

Answer / jagan kumar

Positioner in control value is used to provide feedback about the position of the value. ie: How much value is opened eg: 74%. control value can be operated without the positioner.

In control valve proximity inductive sensor is taken as digital feedback for full open and full close.Normally its volts 24v when the sensor acts the feed back voltage 14v so that our relay not indicating in plc panel . kindly give the solution.

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