PPCH™ OPERATION AND MAINTENANCE MANUAL
© 2009 DH Instruments, a Fluke Company
Page 74
3.5
[SPECIAL]
PURPOSE
[SPECIAL]
accesses a menu of PPCH settings, adjustment and features that are less commonly used or
not normally used in regular operation.
OPERATION
Press
[SPECIAL]
from the MAIN RUN screen to access the
SPECIAL menu. The display is:
1AutoZ 2remote 3head
4reset 5pref 6Punit
7internal 8cal 9log
Some screens, such as the SPECIAL menu, go beyond the two lines provided by the display. This is
indicated by a flashing arrow in the second line of the display. Press the cursor control keys to move the
cursor to access the lines that are not visible or directly enter the number of the hidden menu choice if you
know it.
SPECIAL menu choices include:
<1AutoZ>
Manage AutoZero function for the active Q-RPT or utility sensor (see Section 3.5.1).
<2remote>
View and edit PPCH COM port (RS-232) and IEEE-488 interface settings (see Section 3.5.2).
<3head>
Set HEAD function fluid and height unit of measure (see Section 3.5.3).
<4reset>
Access PPCH’s various reset functions (see Section 3.5.4).
<5pref>
View and set screen saver time, keypad sound frequency, unit ID number, time/date,
security protection level (see Section 3.5.5).
<6Punit>
Customize
the
[UNIT]
key pressure unit of selections (See section 3.5.6).
<7intern>
Access internal functions including control configurations, on-board barometer viewing,
pump and reservoir functions (see Section 3.5.7).
<8cal>
View and adjust RPM3 utility sensor, Q-RPT and barometer calibration coefficients (see
Sections 3.5.8 and 5.2).
<9log>
View the PPCH incident log (see Section 3.5.9).
3.5.1
<1A
UTO
Z>
PURPOSE
To offset the PPCH system Q-RPTs relative to a reference value in order to compensate for
possible changes in Q-RPT zero between full recalibrations.
PRINCIPLE
AutoZ Purpose and Principle
The main component of the change over time of the PPCH Q-RPTs is change in zero or
offset, independent of span. Offsetting or “rezeroing” PPCH Q-RPTs relative to a reference
between recalibrations allows measurement uncertainty specifications to be maintained with
less frequent full calibrations. The PPCH AutoZero function (AutoZ) provides full on-board
support for the rezeroing process to simplify its application by the user.
The AutoZero function uses three values:
1.
P
std,0
:
The pressure value indicated by the AutoZ reference, the device that is acting as
the reference relative to which to offset the Q-RPT.
