DH Instruments PPC2+, Manual

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PPC2+™ Operation and Maintenance Manual
Page 13
©2001 DH Instruments, Inc.
2.3.7 THE VENT CONNECTION (VENT PORT)
The PPC2+ VENT connection is the system vent to atmosphere point used to set zero gauge
pressure as well as to obtain reference pressure transducer measurements of
atmospheric pressure. Though a pressure hose can be connected to the VENT connection to
direct the vented gas flow, a completely unobstructed connection to atmosphere must be
maintained for PPC2+ reference pressure measurements to operate normally.
The PPC2+ VENT connection is 1/4 in. NPT female.
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2.3.8 THE ATM REF PASS THROUGH (UNLABELED)
The ATM REF pass through is connected to the on-board barometer and to the valve that
opens the Lo RPT (if present) to atmosphere when it is not in use. The ATM REF pass
through assures that the Lo RPT and on-board barometer are truly subject to atmospheric
pressure rather than to the pressure inside the PPC2+ case which may be slightly different
from ambient pressure.
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2 . 4 P O W E R - U P A N D V E R I F I C A T I O N
2.4.1 SWITCH POWER ON
Actuate the power switch on the PPC2+ rear panel. Observe the front panel display as
PPC2+ initializes, error checks and goes to the main run screen (see Section 3.1.1).
PPC2+ operating condition at power-up is VENT valve closed unless the pressure measured
by the RPT was within 3 psi (20 kPa) of atmospheric pressure.
If the PPC2+ fails to reach the main run screen, service is required. Record the sequences of
operation and displays observed.
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