Rosemount P330, Инструкция по установке и эксплуатации, Страница: 51 / 92

5-11
Hardware Functions
P-Switch Contact Resistance Task Mode Procedure
1. Open the release valve on the validator.
2. Connect the pressure switch to the reference pressure port on the
validator using a 1 /
8
–27 NPT coupling device and a pneumatic
hose.
3. Set the pressure/vacuum knob to + or – as required.
4. Connect the test leads to the validator and the pressure switch
being tested as shown in Figure 5-6 above.
5. Turn on the validator and allow it to go through its self-test
process (about 15 seconds).
6. Press the
TASK
key and select
P-SWITCH
mode, if necessary. Press
ENTER
.
7. Press the
ZERO
key to zero the internal sensor.
8. Close the release valve tight.
9. Press F2 to select the Measure Resistance function. Press F1 to
run the test (Figure 5-8):
FIGURE 5-8. Running the P-Switch
Contact Resistance Test.
10. Use the pressure pump on the validator to apply pressure to just
below the expected switch operating point.
11. Screw in the fine pressure adjuster until the switch operates. The
contact state is displayed on the screen, and you hear a buzz. The
operating pressure is also displayed.
12. Screw the fine pressure adjuster out to reduce pressure until the
switch releases. The release pressure, hysteresis, and resistance
are displayed (Figure 5-9):
FIGURE 5-9. P-Switch Contact
Resistance Mode Final Display Screen.
13. Open the release valve to release system pressure before
disconnecting.
P
3
30_
55
A
P
3
30_
56A
See Safety Messages on page 5-1 and 5-2 for complete warning information.