Owner's manual

Operation  3
MultiCal mmHgA/PSIA Pressure Module Manual
Readings may change when the MultiCal is shifted from a vertical to a horizontal orientation. This is due to the oil lling that transmits the pressure signal
from the stainless steel diaphragm to the silicon sensor. The magnitude of the shift is typically less than 0.15 mmHgA.
The MultiCal is calibrated in a horizontal orientation. To compensate for position you can use the method below.
1 To insure best performance the MultiCal should be checked at zero pressure or compared against a reference barometric standard. This should be done at
least once a month, or more often in critical applications.
2 To check at zero pressure, use a vacuum pump and a thermocouple type vacuum gauge.
3 Set the Multical to the mmHgA scale.
Note: Typically, vacuum gauges are calibrated in millitorr. 1 millitorr = 0.001 mmHgA.
4 “Zero” the MultiCal when the vacuum achieved is 10 millitorr or less. With a small screwdriver adjust the small trimming potentiometer on the end of the
MultiCal until your meter reads precisely zero.
Another way to adjust zero is to compare the barometric reading with a barometric reference standard. If any dierence is noticed between the MultiCal and
the reference, the zero trimming potentiometer can be adjusted so the readings match.
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BATTERY REPLACEMENT
1 Set the power switch to the OFF position.
2 Disconnect the MultiCal from the multimeter and any pressure connections.
3 Turn the MultiCal so the power switch is facing down. Remove the single screw located between the banana plugs.
4 Grasp the one case half in each hand. Pull the two halves apart, beginning at the end with the banana plugs.
5 Remove and replace the battery.
6 Reassemble the MultiCal. To reassemble, mate the two case halves at the end opposite the banana plugs, then "snap" the two halves together.