GE Masoneilan 12420 Instruction Manual & Safety Manual page 29

♦ Calibration of transmitter for interface application:
The level transmitter is used to measure the interface level of two immiscible liquids of different specific gravities. The displacer
must always be fully immersed.
The electronic circuit is calibrated towards two reference levels (REF L and REF H). See schematic below.
REF L corresponds to the displacer completely immersed in the liquid of Lower Specific Gravity used for calibration [LSG

CALIB].
REF H corresponds to the displacer fully immersed in the liquid of Higher Specific Gravity used for calibration [HSG CALIB].

The loop current corresponding to REF L may be set through [MA LO:mA] via [VAR SET]; it is generally 4mA.
The current corresponding to REF H may be set through [MA HI:mA] via [VAR SET]; it is generally 20mA.
The value of [MA HI:mA] must always be higher than the value of [MA LO:mA].
The level indication corresponding to REF L is set through function [LRV] via [VAR SET]; it is expressed in the unit set through
[UNIT] function; if UNIT is "%", [LRV] must be 0.00%.
The level indication corresponding to REF H is set through function [URV] via [VAR SET]; it is expressed in the unit set through
[UNIT] function; if UNIT is "%", [URV] must be 100.00%.
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