DH Instruments PPC4, Руководство по эксплуатации и обслуживанию

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PPC4™ OPERATION AND MAINTENANCE MANUAL
© 2009 DH Instruments, a Fluke Company Page 52
3.2.27.4 Purge

PURPOSE
To enable and disable the PURGE function which automate use of the optional
Self Purging Liquid Trap (SPLT) (see Section 3.2.17).

Caution
When the purge function is enabled, PPC4 makes background
use of valve driver channel #8 independently of user actions
(see Sections 3.2.17, 3.2.23).
3.2.27.5 Log

PURPOSE
To view and/or clear the PPC4 event log.

PRINCIPLE
PPC4 records to a log each time one of the following events occurs:
•
Pmax! of an internal PPC4 Q-RPT or utility sensor is exceeded (see Section
3.2.21.1).
•
A memory fault occurs.
Note
Over pressure events on external Q-RPTs are not logged on the
PPC4. They are logged in the RPM4’s log (see the RPM4
Operation and Maintenance Manual).

OPERATION
For Basic Interface, see Section 4.5.9.
For Advanced Interface, see Section 5.7.12.4.
3.2.27.6 TEST (-) Vent

PURPOSE
To cause a PPC4 or external RPM4’s Gxxx or BGxxx Q-RPT TEST (-) vent valve
to stay open or closed rather than open and close automatically.
Note
This feature is active only when the active Q-RPT is a Gxxx
(gauge) or BGxxx (bi-directional gauge) Q-RPT.

PRINCIPLE
A PPC4 or an RPM4 equipped with a Gxxx (gauge) or BGxxx (bi-directional
gauge) Q-RPT has a TEST (-) vent valve in its Q-RPT module (see Figure 13).
The TEST (-) vent valve connects the TEST (-) port to the VENT port which also
connects the Q-RPT and the device or system under test low side to atmosphere.
In normal PPC4 operation, the TEST (-) valve is closed automatically whenever
the PPC4 is performing fine pressure control to isolate the TEST (-) circuit from
fluctuations in ambient pressure. The valve is opened at all other times. This
ensures that the pressure in the TEST (-) circuit does not move too far away from
atmospheric pressure as it might if it were permanently shut off. In normal RPM4