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what is the basic working principle of I/P and Positioner in 
any control valve.
 Question Submitted By :: Instrumentation
I also faced this Question!!     Answer Posted By  
# 1
I/P is basiclly working on the flapper and nozzle
principle.And the positioner is working on the Forced
balance principle.
Is This Answer Correct ?    96 Yes 7 No
# 2
I/P Converter , converts 4-20 mA signal from controller
to .2 to 1.0 Kg/cm2 pneumatic signal.

Positioner consist of air supply port , signal input port,
out put port.When positioner get in put signal ,it compare
with stem position and output is generated and signal
boosted sufficiently to operate the valve . It uses force
balance system.
Is This Answer Correct ?    46 Yes 9 No
Ashok Polampalli
# 3
It works on force balance principle. A coil is suspended
in a magnetic field on a flexible mount. At the lower end
of the coil is a flapper valve that operates against a
precision ground nozzle to create a backpressure on the
servo diaphragm of a booster relay. The input current flows
in the coil and produces a force between the coil and the
flapper valve, which controls the servo pressure and the
output pressure.Zero adjustment of the unit is made by
turning a screw that regulates the distance between the
flapper valve and the air nozzle. Span adjustmentis made by
varying a potentiometer,which shunts input current past the
Is This Answer Correct ?    41 Yes 4 No
M M Chotrani
# 4
mA ---> Kg/Cm2 ---> % Valve Open

4 ---> 0.2 ---> 0%
8 0.4 25%
12 0.6 50%
16 0.8 75%
20 1.0 100%
Is This Answer Correct ?    9 Yes 2 No
Mayank Rathod
# 5
I/P is input (requirement of process/operator) at which
valve needs to be operated.Positioner gives output
(feedback) to control loop about actual position of valve.
Conclusively-I/P-requirement, Positioner-job done
Is This Answer Correct ?    21 Yes 15 No
Rk Singh
# 6
it's work to forced balanced
Is This Answer Correct ?    6 Yes 2 No
Chetan Jodatti
# 7
I/p converter is a heart of
control valve. Positioner is
like a blood circulation.
Is This Answer Correct ?    2 Yes 3 No
# 8
i/p means current to penumatic converter its gives 4-20ma
and hi regulate the penumatic pressur
Is This Answer Correct ?    2 Yes 8 No
Rahul D Bhoir
# 9
I/P works on Motion Balance and Positioner works on Force
Balance priciples
Is This Answer Correct ?    5 Yes 16 No
Parag Pathak
# 10
basic working principle on frequency circuit 
Is This Answer Correct ?    4 Yes 33 No

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