2. INSTALLATION
Page 13
© 2007 DH Instruments, a Fluke Company
Minimizing the length of the test connection tubing will enhance control
performance and reduce pressure setting time. For normal operation, the optimum
total volume of the device or system under test including connecting tubing is 50 cc
(3 in
3
) and should be less than 100 cc (6 in
3
) for standard dynamic control mode.
Up to 500 cc is acceptable for other control modes.
PPCH-G pressure control will not operate properly if there are excessive leaks
in the system connected to its TEST port. In general, the maximum acceptable leak
rate for optimal PPCH-G automated pressure control operation and to assure in
tolerance measurements with default pressure control parameters is 0.002 % of
reading/second. In DYNAMIC CONTROL mode, to handle higher test system leak
rates, increase the hold limit using CUSTOM CONTROL (see Section 3.4.6.1) or use HI
VOLUME DYNAMIC CONTROL (see Section 3.2.2.2).
2.3.8
CHECK/SET SECURITY LEVEL
PPCH-G has a security system based on user levels. By default, the security system is set
to “low”, which includes certain access restrictions, and there is no password required to
change the security level. See Section 3.5.5.5 for information on the security level system.
As part of the PPCH-G startup, determine the security level that is appropriate for the PPCH-
G and set a password if desired.
PPCH-G is delivered with the security level set to “low” to avoid inadvertent altering of
critical internal settings but with access to changing security levels unrestricted. It is recommended
that the low security level be maintained at all times and password protection be implemented if
control over setting of security levels is desired.
2.3.9
TURN OFF ABSOLUTE MEASUREMENT MODE
PPCH-G Q-RPTs can operate in both absolute and gauge measurement modes (see Section
3.3.3). If the PPCH-G will only be used in gauge mode, absolute measurement mode may
be turned off for its Q-RPT(s) so it is no longer accessible. This can avoid confusion and/or
accidental use of the wrong measurement mode. See Section 5.2.5 for complete information
on turning off absolute measurement mode.
2.4
POWER-UP AND VERIFICATION
2.4.1
SWITCH POWER ON
Actuate the power switch on the PPCH-G rear panel. Observe the front panel display as
PPCH-G initializes, error checks and goes to the MAIN RUN screen (see Section 3.1.1).
PPCH-G power-up condition is Internal, Hi Q-RPT or utility sensor active, VENT ON unless the
pressure measured by the Hi Q-RPT is more than 1 MPa (150 psi) away from standard
atmospheric pressure.
If the PPCH-G fails to reach the MAIN RUN screen, service is required. Record the sequence of
operations and displays observed. Contact a DHI Authorized Service Provider (see Table 28).
