Instruction Manual

26 UPS3000/UPS3110/UPS3210 Operation and Maintenance Manual
3.7.2 For UPS3110 Absolute/Gage Switch Selectable Units ONLY
If the current barometric pressure is below 14.7 PSIA, the offset is positive, see Example 1. If the current
barometric pressure is above 14.7 PSIA, the offset is negative, see Example 2. If the current barometric pressure
is 14.7 PSIA, then no offset is needed.
Example 1:
If the current barometric pressure is lower than 14.70 PSIA, subtract the current barometric pressure from 14.70.
14.70 PSI: UPS3110 reference point
-14.55 PSI: Current barometric pressure
0.15 PSI: Positive Delta Offset
Complete the following steps (refer to Figure 2-2 on page 5 and Figure 2-5 on page 7):
1. Open the VENT valve (12) and close the INPUT (10) valve.
2. Using the RANGE SELECT switch (6), select the lowest pressure range on the UPS3110.
3. Press the ENTER push-button, as shown in Figure 3-2 on page 20, on the UPS3110. The display reads
zero. Repeat this step for the middle and high ranges.
4. Close the VENT valve (12). Select the lowest pressure range of the UPS3110.
5. Turn the VERNIER (11) of the UPS3110 clockwise, creating a pressure until the display reads the value of
the Positive Delta Pressure, 0.15 PSI as in this example.
6. Depress the ENTER push-button on the UPS3110. The display reads zero. Without touching the VERNIER
(11) knob repeat this step for the middle and high ranges.
7. Using the STEPPER push-button, as shown in Figure 3-2 on page 20, place the unit into SHUNT RESISTOR
CALIBRATION mode. The display will be as shown in Figure 3-5 on page 23.
8. With UPS3110 RANGE SELECT switch (6) switched in the high range, depress the ZERO push-button on
the front panel. Verify that the display reads 0.00. Upon release of the push-button the display will be as
shown in
Figure 3-5 on page 23.
9. Depress the ENTER push-button. The display will respond with “[] [] [] [] [] []” until the button is
released.
10. Pressing the STEPPER push-button bring the indicator back to its initial Data Recall display condition as
shown in
Figure 3-2 on page 20. The display shows 1 XXX (three arbitrary digits).
11. Depress the DATA ENTER switch, S2, located approximately in the middle of the circuit board. See Figure
2-7 for the switch location
12. If the data is accepted, the three-digit number on the right side of the display will indicate 377 for as long
as the DATA ENTER switch, S2, is depressed.
13. The barometric offset is now complete and CALIBRATE/OPERATE switch, S3, must be returned to its
normal operating positions as shown in
Table 3-1 on page 20.
Example 2:
If the current barometric pressure is above 14.70 PSIA, subtract the current barometric pressure from 14.70.
14.70 PSI: UPS3110 reference point
-14.75 PSI: Current barometric pressure
-.05 PSI: Negative Delta Offset
NOTE: Normally the negative offset is small enough to prevent the need of a vacuum pump.
Complete the following steps (refer to Figure 2-2 on page 5 and Figure 2-5 on page 7):
1. Open the VENT valve (12) and close the INPUT (10) valve.
2. Using the RANGE SELECT switch (6), select the lowest pressure range on the UPS3110.
3. Press the ENTER push-button, as shown in Figure 3-2 on page 20, on the UPS3110. The display reads
zero. Repeat this step for the middle and high ranges.
4. Close the VENT valve (12). Select the lowest pressure range of the UPS3110.
5. Turn the VERNIER (11) of the UPS3110 counter-clockwise, creating a vacuum until the display reads the