DH Instruments PPCK PLUS, Operation And Maintenance Manual

Page: 39 / 150

PPCK+™ Operation and Maintenance Manual
Page 31
©2001 DH Instruments, Inc .
3.2.2 [UNIT]

PURPOSE
To specify the pressure unit of measure and measurement mode in which PPCK+
displays pressure values.
See also Section 3.4.3.

PRINCIPLE
PPCK+ allows the pressure measurement unit and mode to be changed.
Internally, PPCK+ always operates in Pascal (Pa), the SI unit of pressure. Values of
pressure are represented in other units by the application of conversion factors to convert
from Pa (see Section 7.2.1).
PPCK+ RPTs intrinsically measure absolute pressure relative to an evacuated and
sealed reference. They are also used to measure in gauge mode by the subtraction of
atmospheric pressure. PPCK+ supports extensive on-board logic and measurements to
assure the precise atmospheric compensation of absolute RPTs to deliver achieve gauge
pressure (see Section 3.4.1,
Gauge Mode, Dynamic Compensation For
Atmospheric Pressure ). This allows simple, one step switching between gauge and
absolute measurement modes by the operator without special procedures or hardware.

OPERATION
To change the pressure unit and/or the
measurement mode, press the
[UNIT] function key.
The display is:
Select <1unit> to change pressure units or <2mode> to change measurement mode.
If <2mode> is selected, the next screen offers the choice between <1gauge>
and <2absolute> . Making a selection returns to the main run screen with the selected
measurement mode active.
If <1unit> is selected from the measurement screen, the units screen is presented.
The cursor is on the number corresponding to the
active unit for the active range. To change the
pressure unit for the active range, select the
desired unit. Pressing
[ENTER] activates the unit
and returns to the main run screen.
If the pressure unit selected is inWa, the reference
temperature for water density must be specified.
When inWa is selected as the unit, the next
display is:
Measurement: H1
1unit 2mode
1psi 2MPa 3kPa
4bar 5kcm2
Select inWa ref temp
4°C 20°C 60°F