3. OPERATION
Page 57
© 1998-2007 DH Instruments, a Fluke Company
When the run AutoZ selection is made, if a HEAD correction is currently active
(see Section 3.6.8) 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
AutoZ by entry allows the value of
P
std,0
(see Section 3.4.4.4, PRINCIPLE) to be
entered directly from the molbox RFM front panel. This provides a simple way of
AutoZeroing relative to an independent reference device such as a house
barometer that does not interface directly with molbox RFM.
To access run AutoZ by entry press
[TARE]
,
<4AutoZ>
,
<4run>
,
<1Entry>
.
The display is:
1.
Real time reading (without head correction) of
upstream (1, Hi) RPT in unit of measure on
line 2.
2.
Real time reading (without head correction) of
downstream (2, Lo) RPT in unit of measure on
line 2.
3.
Entry field for the value of
P
std,0
. in the current
pressure unit of measure.
96.772 kPaa 96.778
Pstd,0:96.7752
Enter the value of the AutoZ reference (
P
std,0
) in the same unit of measure as the
display and press
[ENT]
. molbox RFM logs the readings and calculates a new
AutoZ offset value. The next display is:
1. Current/previous value of
P
offset
for the
upstream (1, Hi) RPT.
2. Current/previous value of
P
offset
for the
downstream (2, Lo) RPT.
3.
New value of
P
offset
for the upstream (1, Hi)
RPT for the AutoZ that was just run.
4.
New value of P
offset
for the downstream (2, Lo)
RPT for the AutoZ that was just run.
Old: 0.0 Pa 0.0
New: 3.7 Pa 2.6
Press
[ENT]
to activate the new values of
P
offset
or
[ESC]
to start over with entry
of a new AutoZ reference (
P
std,0
) value.
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.
Run AutoZ by COM2
AutoZ by COM2 allows a
DHI
RPMx Reference Pressure monitor connected to the
molbox RFM COM2 to act as the AutoZ reference (source of
Pstd,0
) (see Section
3.4.4.4, PRINCIPLE). The RPMx is read and the new
P
offset
is calculated automatically.
To access run AutoZ by COM2 press
[TARE]
,
<4AutoZ>
,
<4run>
,
<2COM2>
.
For molbox RFM to communicate with an RPMx connected to its COM2 port,
the molbox RFM and the RPMx RS-232 interfaces must be set up properly
(see Section 3.6.6.1). If, the molbox RFM is unable to locate an RPM ON COM2
when running AutoZ by COM2, it times out after 6 seconds and displays an
error message.
