When the Inert Gas System is running normally, the output of the I/P converter is connected to the final control element (e.g. control valve, auto choke valve). 

Whether the terminal input is connected to DCS or PLC depends on the system being used. 

The I/P converter can be separated into two parts: electronic part (electronic card) and pneumatic part (pneumatic relay).

I/P Converter (Image Credit: Giantech)

The electronic card is used to process the mA input signal and convert it to correspond to pneumatic output. The pneumatic relay is used to amplify the signal output so as to avoid delaying pressurization.

To calibrate the I/P converter, follow the steps below:

1. Inject 4mA input signal from a current injector to I/P converter, and check the output pressure reading on the pressure gauge. It should show 0.2bar/3psi. 

• If the reading is higher than 0.2bar/3psi, reduce the output pressure by turning the ZERO adjustable knot in clockwise direction until it shows 0.2bar/3psi. 

• If the reading is lower than 0.2bar/3psi, increase the output pressure by turning the ZERO adjustable knot in counterclockwise direction until it shows 0.2bar/3psi.

2. Inject 20mA input signal from a current injector to I/P converter and check the output pressure reading on the pressure gauge. It should show 1bar/15psi. 

• If the reading is higher than 1bar, reduce the output pressure by turning the RANGE adjustable knot in counterclockwise direction until it shows 1bar/15psi. 

• If the reading is lower than 1bar/15psi, increase the output pressure by turning the RANGE adjustable knot in clockwise direction until it shows 1bar/15psi.

Do you require further information? 

Feel free to contact Sze Jia Lim at [email protected] 

GIANTECH’s service engineers are always happy to help.

About the author

GIANTECH specialises in the life cycle management of marine equipment. It is a leading marine engineering company with an experienced international service team specialising in inert gas systems, inert gas generators, nitrogen systems, boilers and burners, pressure-vacuum valves, incinerators and compressors on-board vessels.

For more information, please visit https://www.igiantech.com/services/inert-gas-system-servicing/

Note: This article provides general information only and does not represent formal advice or the positions of any equipment maker.