American Magnetics 286 Multi-Sensor Liquid Level Instrument (CE-Marked) - Manual (Page 46)

32
Calibration
Calibration Menu Reference
The intent of the approximate calibration factor is to provide the
operator with a method to transform calibrations performed in an
inexpensive and relatively safe liquid (such as liquid nitrogen) to a
more expensive or hazardous liquid (such as liquid hydrogen). It is
also useful for transforming partial length calibrations to the full
active length for extremely long sensors.
If the None option is selected, then no ratiometric transformation is
applied to the MIN/MAX calibration points.
If the Custom approximation calibration factor option is selected,
the operator may enter a calculated approximate calibration factor
as documented in the “Approximate Calibration” procedure
beginning on page 26. The approximate calibration factor is limited
to a range of 10% to 1000%. If the entered approximate calibration
factor is within the valid range, but results in an overflow of the
measuring circuits within the Model 286, then the instrument will
beep once and revert to the previous value.
Note
Approximate calibration factors must be entered in percent units,
since it is a unitless ratiometric value. The
UNITS
key is inactive
within the menu.
After selection of a preset factor or entry of a custom approximate
calibration factor, use the
MENU
key to continue.
3.3.4.3 Zero offset factor
The zero offset entry allows the operator to enter an offset value in
percentage of the calibrated span. For example, if a value of
−
10% is
entered, then a calibrated level of 0.0% (or the MIN point) will
display as +10.0% during level measurements. A calibrated level of
+90% would display as +100.0%.
b. 100% liquefied methane assumed for LNG.
A: Approx Factor
100%
A: Zero Offset
0.0 %