Crystal MultiCal BAR/PSI - Manual (Page 5)

PN: 1763 Rev A, 4/2004
Page 5 of 7
C R Y S T A L
engineering corporation
Procedure
1. Connect the MultiCal to the pressure calibration system and to the multimeter. Be sure
that the pressure calibration system and the connection to the MultiCal is leak free.
2. Allow the MultiCal to stabilize at room temperature, away from drafts, for at least 30
minutes before proceeding with calibration. Turn on the multimeter and allow it to warm
up per the multimeter operating instruction. Set the multimeter to the appropriate DC volt
or millivolt scale.
3. Verify the condition of the battery and replace the battery if necessary. Follow the
Battery Replacement procedure to disassemble the MultiCal, but do not remove the battery
or reassemble the MultiCal.
4. Set the switch on the MultiCal to the PSI position (switch in position closest to the
banana plugs). Allow the MultiCal to warm up for two minutes.
5. The FINE ZERO potentiometer (R1) should be set to the center of its rotational range.
Adjust the COARSE ZERO pot until the output is as close to zero as possible. Trim in the
final reading to 0 mV ±0.02 mV with the FINE ZERO potentiometer.
6. Check the PSI pressure points shown on Table 2. Adjust R12 if necessary to bring the
readings to within the tolerances shown on Table 2.
Figure 1: Potentiometer locations
7. Set the switch on the MultiCal to the PSI position. Vent the system and readjust zero if
necessary.
8. Test the MultiCal at the 206 bar point. The reading should be within the tolerance shown
in Table 2.
FINE ZERO
kPa
PSI
COARSE ZERO
-
LINEARITY
R1
R12
R15