GE Masoneilan 12420 Instruction Manual & Safety Manual page 30

7.3.2. C
ALIBRATION AT WORKSHOP WITH WEIGHTS
a. From [BAS SETUP] menu, enter the [CALIB Z S] sub-menu.
b. Enter specific gravity of calibration in level application [SG CALIB] or the low and high specific gravities in interface
application [LSG CALIB] and [HSG CALIB].
CAUTION: During the dry calibration without mechanism chamber, DO NOT ATTACH SPECIAL INTERFACE
DISPLACER (OR ITS EQUIVALENT EFFECTIVE WEIGHT) on the torque arm. Indeed, these displacers being
heavier than those for liquid level service and no mechanical stop being available without of mechanism
chamber, the torque tube and/or the instrument mechanism would be damaged.
Standard displacer characteristics
Displacer weight
Displacer volume
Fluid specific gravity
Actual volume and weight of the displacer can be read using HART communication (if data have been previously saved into
the 12400 instrument memory). Otherwise actual volume of the displacer is marked on the firm plate and displacer weight
can be measured by weighting of it.
c. Low Level [ZERO]
c1. Liquid application:
Attach to the torque arm a set of weights equivalent to the true displacer weight (i.e. 1362 g for a standard displacer) to
simulate the low level.
c2. Interface application:
Attach to the torque arm a set of weights equivalent to the displacer weight completely immersed in the liquid of Lower
Specific Gravity used for calibration [LSG CALIB] using the following formula:
c3. Enter and validate the [ZERO]: the [LEVEL:%] value indicated on the display must equal to 0.0%. If not, restart the
procedure until very close to this value. See Appendix B.
28 | GE Oil & Gas
S.I Units
907 cm
Displacer Apparent Weight for REF B =
Displacer Actual Weight - (Displacer Actual Volume X [LSG CALIB])
English Units
1362 g 3 lbs
55.34 in
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