# What is the difference between Valve positioner and Position transmitter?

**URL:** <https://forumautomation.com/t/what-is-the-difference-between-valve-positioner-and-position-transmitter/643>\
**Category:** Valves\
**Created:** [December 4, 2015, 2:14am UTC](https://forumautomation.com/t/what-is-the-difference-between-valve-positioner-and-position-transmitter/643 "2015-12-04T02:14:21Z")\
**Posts on this page:** 1\
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**Author:** ![denizen](https://forumautomation.com/letter_avatar_proxy/v4/letter/d/848f3c/32.png) [@denizen](https://forumautomation.com/u/denizen)\
**Post date:** [December 4, 2015, 2:14am UTC](https://forumautomation.com/t/what-is-the-difference-between-valve-positioner-and-position-transmitter/643/1 "2015-12-04T02:14:21Z")

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**Valve Positioner**

Valve positioner is responsible for actual accurate positioning of the valve based on PID loop output of 4-20mA DC/0-10 V DC from standalone PID controller or PLC/DCS/BMS loop. It can be electric valve positioner (also called motor positioner) for electric motor actuated control valves or an electropneumatic valve positioner for pneumatic actuated control valves - both accept direct control signal of 4-20 mA or 0 to 10 V DC. This can be a pneumatic valve positioner for a for pneumatic actuated control valve and it would need an extra hardware of current to pneumatic converter (also called I to P converter).

A positioner receives a 0-100% (4-20 mA 24 Vdc) signal from a controller or control system and by measuring the position of the shaft of a valve will add feedback additional force to make the valve go to the chosen position

**Position Transmitter**

Position transmitter is the feedback device which gives the valve opening in percentage. This is generally a potentiometer which gives 0 to 1000 ohms or so and at times it is 4-20 mA or 0 to 10 V DC if resistance to current/voltage converter is also integrated.

In simple terms the position transmitter measures the span of travel of any moving object and transmits a 0-100% (4-20 mA 24 Vdc) signal. The position transmitter can be on the shaft of a valve or on the louvers or a cooler, it will transmit the measured distance of movement.