The effect of air trap to the precision of measurement level using differential pressure transmitter

The Differential Pressure Transmitter is an instruments for measuring water-level on Pressurizer and Steam Generator of Reactor Thermalhydraulic Loop. This instrument works base on difference pressure of two sides The difference pressure of two sides e.g : Reference pressure sides and processing pressure sides. The difference pressure of two side of transmitter equivalent to water level which to be measured, according to equation P ρ g h. The output of transmitter is electrical current that equivalent to the difference pressure appeared. Air trap on water level measurement system caused a difference output current, comparing to the out put current without air trap, on the same water level. Increasing the height of air trap causes increasing the measurement error, where the indicated level will be low that the real level