DH Instruments PPC4, Руководство по эксплуатации и обслуживанию

Страница: 40 / 228

PPC4™ OPERATION AND MAINTENANCE MANUAL
© 2009 DH Instruments, a Fluke Company Page 28
Note
For information on selecting the measurement mode (absolute, gauge,
negative gauge), see Section 3.2.11.

PRINCIPLE
PPC4 allows the unit of measure in which pressure values are displayed to be changed. PPC4
supports 18 predefined pressure units of measure as well as up to five user defined units. See
Table 35, Section 9.2.1, for a listing of the available units of measure and the
conversion
factors used by PPC4.
User defined unit definitions specify the number of user units per Pascal (Pa). 1 kiloPascal (kPa),
for example, is specified by 0.001 units/Pa.
Note
•
The pressure measurement unit selected is range specific. When in a
given range, all functions and settings are represented in the current
measurement unit for that range. However, certain internal and/or
metrological functions (e.g., Q-RPT calibration coefficients) are always
represented in Pa regardless of the active range unit of measure.
•
When the active unit is an altitude unit, the range and upper limit
indications are in kPa if the unit is meters (m) and psi if the unit is feet
(ft).
•
If the pressure unit selected is a water column (inches, millimeters,
meters) the reference temperature for water density must be specified.
In the Advanced User Interface, the temperature is included as part of
the unit name, such as mmH20@4C. In the Basic Interface, the
temperature is specified in a secondary screen. For remote selections
in both Basic and Advanced Interfaces the temperature is assumed to
be 20 ºC unless specified in the Unit remote command (see Section
6.5.4).
•
In the Basic Interface, the default pressure units of measure available
under the <Unit> function depend on whether the PPC4 has been set
up as an SI or US version (indicated by SI or US at bottom right of
introduction screen). The choice of six units available under the <Unit>
function can be customized from a wider selection by the user (see
Section 4.5.6). The units available can be reset to default by reset (see
Section 3.2.25.2).

OPERATION
For Basic Interface see Sections 4.5.13.and 4.5.6.
For Advanced Interface see Section 5.7.6.1.
3.2.11 Measurement Mode

PURPOSE
To set the measurement mode (absolute, gauge or negative gauge) for the active range.

PRINCIPLE
PPC4 supports simple, one-step switching between up to three different measurement modes:
Absolute Measures pressure relative to vacuum (zero is hard vacuum). Range is
from zero absolute to full scale.