Fluke HPMS - Manual (Page 51)

3. OPERATION
Page 41 © 2007 DH Instruments, a Fluke Company
If running AutoZ results in a value of P
offset
that is greater than ± 0.005 % FS
of the span of the Q-RPT that is being AutoZeroed, the Q-RPT and/or the reference used
as the source of P
std,0
may be out of tolerance or the AutoZ process may have been faulty.
Before activating a new P
offset
greater than ± 0.005 % FS of the active Q-RPT, check to
be sure that both the Q-RPT and the reference were in good working order, properly
vented to stable atmospheric pressure, at the same height, and reading in the same
pressure units when AutoZ was run.
When the run AutoZ selection is made, if a HEAD correction is currently active (see
Section 3.3.7) the head correction is momentarily disabled while running AutoZ to
avoid “zeroing out” the head value.
The value of P
offset
is always displayed and entered in Pascal (Pa).
Run AutoZ by Entry
Before running AutoZ in absolute mode, use <SETUP>, <2res> to set the
resolution of the active range to 0.001 or 0.0001%FS.
AutoZ by entry allows the value of P
std,0
(see Section 3.5.1,  PRINCIPLE) to be
entered manually from the RPM4 front panel. This provides a simple way of
AutoZeroing relative to an independent reference device such as a house
barometer that does not interfaced directly with RPM4.
To run AutoZ by entry press [AutoZ], <1entry>. The display is:
1. Real time pressure reading (without head
correction), pressure unit of measure and
measurement mode of the active Q-RPT.
2. Active Q-RPT position designator.
3. Entry field for the value of P
std,0
. in the current
pressure unit of measure.
14.03 psi a Hi
Pstd,0:0.00
Enter the value of the AutoZ reference (P
std,0
) in the same unit of measure as the
top line display and press [ENT]. RPM4 logs the reading and calculates a new
AutoZ offset value. The next display is:
Press [ENT] to activate the new value of
P
offset
or [ESC] to start over with entry of a
new AutoZ reference (P
std,0
) value.
Old P
offset
: 0 Pa
New P
offset
: 2745 Pa
The value of P
offset
is always in Pascal (Pa). The value of P
std,0
is entered in the
current pressure unit of measure.