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
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
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
a pressure transmitter with a range of 0 to 2500kpag has a specified accuracy of
0.5 % of span.It is to be calibrated using a comparison gauge to have an accuracy
of 0.1% of span.The comparison gauge has a range of 0 to 3000kpag
What is the accuracy ratio? is this ratio acceptable?
IS IT POSSIBLE TO CALIBRATE A LEVEL TRANSMITTER INDICATOR(ABB)
USING HART COMMUNICATOR.? I MEAN TO CHANGE FROM ONE UNIT TO
ANOTHER WITHIN INDICATOR (EG. INCH TO FEET)...? PLZ NOTE
THAT I HAVE MADE THE UNIT CHANGE IN TRANSMITTER USING HART
COMMUNICATOR..BUT WHAT ABOUT THE INDICATOR..?