PG7000™ OPERATION AND MAINTENANCE MANUAL
© 1998-2008 DH Instruments, a Fluke Company
Page 62
The
tare
and
reference
PG7000s must have nominally identical piston-cylinders.
The two PG7000s operate together with the
reference
acting as “master” and
the
tare
as “slave”. For communications between the two to occur, COM2 of the
reference
must be connected to COM1 of the
tare
with a valid RS232 cable and
proper settings must be made on both interfaces (see Section 3.11.5.1).
For high line differential mode operation up to 11 MPa (1 600 psi) in gas, an
MPC1-D and the PK-7100-MPCD-DIF Interconnections Kit P/N 401645 should
be used to provide the DUT high and low test connections and support line
pressure and differential pressure setting procedures (see Figure 10). For
operation at pressure greater than 11 MPa, GPC1 for gas, OPG1 or MPG1 for
oil, and custom interconnecting hardware are used in a functionally similar setup.
PG7000 high line differential measurement mode manages the data acquisition
and handling necessary to support differential mode operation. Differential mode
operation requires setting the line pressure including crossfloating the two
PG7000 piston gauges and then setting differential pressures at the line
pressure. These two independent operations are supported under
[MODE]
,
<3HLdif>
,
<1run>
.
High line differential mode relies upon the very high sensitivity of PG7000 gas
operated piston-cylinders to set and stabilize low differential pressures relative to
very high line pressures. To meet the full performance potential of PG7000 high line
differential mode operation, external influences on the piston gauges must be
minimized. Air currents and vibrations are the most significant possible influences.
Do not operate near an active air conditioning or heating duct, avoid opening and
closing doors or any movement of personnel around the system. Consider putting
the PG7000s in an electrostatic free enclosure if the environment cannot be
adequately controlled.
See Section 7.2.1 for information on the exact calculations used by PG700 to
obtain the differential pressures defined in high line differential mode.