# I/P Converter

In this post, we will discuss I/P converter ( Current to Pressure Converter), Current to Pressure Converter plays an important role in the controlling through a pneumatic control valve. Current to pressure converter works as an actuator for a control valve.

I/P Converter (Current to pressure Converter)

A current to pressure converter (I/P Converter) converts an analog signal (4 to 20 mA) to a proportional linear pneumatic output (3 to 15 psi or 0.2 to 1.0 Kg/cm^2). Its purpose is to translate the analog output from a control system into a precise, repeatable pressure value to control pneumatic actuators/operators, pneumatic valves. The supply air for Current to Pressure Converter (I to P Converter) is 20 psi.

I to P Converter Table

Input (m Amp)            output(Kg/cm^2)

4                               0.2

8                               0.4

12                              0.6

16                              0.8

20                              1.0

This output is given to a pneumatic positioner of a control valve and from this pneumatic positioner control valve is connected.

I/P converter works on electromotive force balance principle.

Calibration of I/P Converter-

We all know that the supply air for I to P converter is 20 psi. So, first of all, we will set supply air 20 psi. We will connect a pressure gauge in the output of I to P converter.

The procedure of calibration of Current to Pressure Converter (I to P converter)

• Apply 4 milliAmperes at the input of I to P converter, its output should be 0.2 kg/cm^2.
• Apply 8 milliAmperes at the input of I to P converter, its output should be 0.4 kg/cm^2
• Apply 12 milliAmperes at the input of I to P converter, its output should be 0.6 kg/cm^2
• Apply 16 milliAmperes at the input of I to P converter, its output should be 0.8 kg/cm^2
• Apply 20 milliAmperes at the input of I to P converter, its output should be 1.0 kg/cm^2

4-20 milliAmperes signal can be provided to I to P converter using a milliAmpere source or we can also use a PID Controller to provide the 4-20 milliAmperes signal.

If we are not getting the desired output, we can set it by the Zero and Span screws.

4 milliAmperes are set using the Zero screw and 20 milliAmperes are set using the Span screw.

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