SECTION IV
CALIBRATION PROCEDURE
All calibration In the PMS II system Is accomplished by changing values In the software data base. This may be done In
the field by entering the complete edit mode with the proper access combination, selecting the edit page for the
corresponding sensor and following normal edit procedures to change the values of the Offset, Span, Sensor Type, and
Calibration readings. Refer to the second page of the appropriate Sensor Specification Drawing for these values.
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NOTE: EXERCISE CARE WHEN USING THE COMPLETE EDIT MODE AS IMPROPER
ENTRIES
CAN
CAUSE
THE
SENSOR
READING
TO
BECOME
ERRATIC,
INACCURATE OR INOPERATIVE.
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Notice on these drawings that certain sensors require field calibration while others do not. If the sensor In question does
not require field calibration and its readings are Incorrect, then the sensor must be replaced. If, however, the
specification drawing Indicates that field calibration Is required, use the following procedure:
A.
Refer to the Individual Sensor Specification Drawing calibration section for special notes. Refer to the
Sensor Specification Drawing Data Base section to verify that the correct data base values are entered for
Sensor Type, Range and Calibration. Next, Insure the scale being calibrated Is linear; If so, continue.
However, if the scale Is from a non-linear lookup table, proceed to section D.
B.
Obtain two sets of upscale and downscale readings, one set from a reference gauge or measurement and
the other set from the PMS II system. Make sure that both high readings and both low readings are taken
together (at the same time) to ensure accuracy. These readings should be taken at points as far apart as
possible on the bar graph scale.
C. Calculate the new span and offset values using the following formulas.
Section 4 - Page 1
