For novice gauge technicians: issues regarding the numerical values displayed by flow meters and level gauges
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For the differential pressure flow meters here, as well as the single and double flange level gauges, the displays show pressure values and percentages. For differential pressure flow meters, does the percentage indicate pressure or flow rate? And for single and double flange level gauges, does the percentage represent the liquid level or pressure?
Take the EJA transmitter as an example; by default, it displays pressure and percentage when it leaves the factory. The pressure displayed is definitely the actual measured pressure, while the percentage represents the percentage of the range.
Differential pressure transmitters display pressure (whether as a pressure value or a percentage); as for whether you want to measure flow rate or liquid level, that is achieved through a secondary instrument.
The differential pressure flow transmitter displays the volumetric flow rate; it is necessary to determine whether taking the square root makes the flow rate scale linear or nonlinear
The pressure displayed is also a percentage, representing a percentage of the pressure range. The meter or system can display the flow rate
For example, in the case of a single-flange level gauge, if the display shows 10%, does that mean the current liquid level is indeed 10%? What about double flanges?
10% for single flange refers to 10% of the liquid level, while for double flange it refers to 10% of the liquid level between the two flanges
The percentage displayed is the liquid level, while the pressure shown is the pressure value measured after migration.
What to display can be set in the table header
The units and data format displayed in this header can be changed using HART475. You can use 475 to check which variable’s percentage is being displayed!