3. OPERATION
Page 79
© 2009 DH Instruments, a Fluke Company
While the value of P
std,0
is entered in the current pressure unit of measure, the
value of P
offset
is always in Pascal (Pa). .
If running AutoZ results in a value of P
offset
that is greater than ± 0.01 % FS of
the span of the Q-RPT that is being AutoZeroed, the Q-RPT and/or the reference used
as the source of Pstd,0 may be out of tolerance or the AutoZ process may have been
faulty. Before activating a new P
offset
greater than ± 0.01 % 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, with the same fluid heads and
reading in the same pressure units when AutoZ was run.
When running AutoZ, if a HEAD correction is currently active (see Section
3.3.7),it is momentarily disabled to avoid “zeroing out” the head value.
If the current measurement mode is absolute and a utility sensor is active
(not a Q-RPT)
, the display is:
1. ActiveRPT
designator.
2.
Current measurement mode (absolute).
3.
Selection of source of
P
std,0
reference to which
to AutoZ.
AutoZ Hi abs by:
1baro 2entry
The default selection is
<1baro>
. With this selection, when AutoZ is ON, the
PPCH on-board barometer (see Section 3.5.7.2) is used as the AutoZ reference
(
P
std,0
) and AutoZ runs automatically whenever PPCH is vented. The AutoZ
function should be ON with
<1baro>
selected unless there is a malfunction of the
on-board barometer.
Select
<2entry>
to run AutoZ manually by entering the value of AutoZ reference
(
P
std,0
) as described in
“If the current measurement mode is absolute and a
Q-RPT is active”
above.
3.5.2
<2REMOTE>
PURPOSE
To configure the PPCH COM1, COM2 and IEEE-488 (GPIB) communication ports. To test
COM1 and COM2 communications. To select remote programming communications format.
PRINCIPLE
The PPCH has two RS-232 communications ports referred to as COM1 and COM2 and a
single IEEE-488 (GPIB) port. COM1 or the IEEE-488 port is for communicating with a host
computer (see Section 4), and COM2 is reserved for communicating with an external device
(i.e. an RPM4, a multimeter, etc.). These ports’ settings can be viewed and changed using
[SPECIAL]
,
<2remote>
.
PPCH has two remote communications formats, classic and enhanced. Which of these is
active can be selected.
A self test is supplied for RS-232 communications. The self test allows verification that the
PPCH RS232 ports (COM1 and COM2) are operating properly and that a valid interface
cable is being used.
