5. MAINTENANCE, ADJUSTMENTS AND CALIBRATIONS
Page 117
© 2005-2007 DH Instruments, a Fluke Company
At any time, a) reference pressures applied; b) associated Q-RPT readings;
c) PA and PM and P
offset
values, can be used to calculate as received and as left
values. For example, backing out PA and PM on the as left data yields the Q-RPT
readings with PA = 0 and PM = 1. Then applying the as received PA and PM and
P
offset
values to the readings calculates
as received
readings (the readings that the
transducer would have made with the old PA, PM and P
offset
). P
offset
is the offset
applied between full calibrations by the AutoZero function (see Section 3.5.1).
It is recommended that “as received” values of PA, PM and P
offset
be recorded
for each Q-RPT prior to running the calibration. The current PA, PM and
P
offset
can be viewed by pressing [SPECIAL], <8cal>, <1view>.
5.2.2
EQUIPMENT REQUIRED
The recommended calibration standard for RPM4-AD Q-RPTs is a DHI PG7601 gas piston
gauge or ADCS-601 air data calibration standard. Contact DHI for additional information.
Gas operated piston gauge (deadweight tester), with the following characteristics:
•
Measurement uncertainty of ± 0.0025 % of reading
. A standard with higher
measurement uncertainty may be used but RPM4-AD measurement uncertainty may be
degraded proportionally from published specifications.
•
Able to supply the recommended sequence of absolute pressure points in the
range to be calibrated:
See Section 5.2.4 for information on the recommended
calibration point sequence for RPM4-AD A160K and A350K Q-RPTs.
5.2.3
SET-UP AND PREPARATION
5.2.3.1
RPM4 A160K/A160K (ROTARY WING)
To set-up and prepare an RPM4-AD A160K/A160K for calibration of its Q-RPTs:
Set the RPM4-AD on a stable surface near the calibration standard at a
height as close as possible to the calibration standard’s reference height.
Consider the connections that may need to be made to the rear panel and
access to the front panel display and keypad.
Tee the calibration standard output to the
TEST(Pt)
and
TEST(Ps)
ports so that
it can apply the reference pressure to both ports simultaneously.
TEST
port
connection is AN4 M.
Use
[RANGE]
to set the active Q-RPT to
<Hi>
(see Section 3.3.1.1).
Use
[MODE]
to set the measurement mode to absolute (see Section 3.3.3).
Use
[UNIT]
to set the unit of measure to a pressure unit (not an air data unit)
(see Section 3.3.2).
Use
[DISPLAY]
,
(
<4RPT>
) to set the display to RPT (see Section 3.3.6.4) so
the Lo Q-RPT measurement is displayed on the display’s bottom line.
Use
[SDS]
to open SDS (Self Defense System) on the Hi Q-RPT (
TEST (Pt)
port) (see Section 3.3.8) so that the pressure applied by the standard will
reach the Hi Q-RPT.
Use
[SPECIAL]
,
<4SDS>
,
<1temp open/close>
,
<2Lo RPT>
to OPEN SDS
temporarily on the Lo Q-RPT (
TEST (Ps)
port) (see Section 3.5.4.1) so that
the pressure applied by the standard will reach the Lo Q-RPT.
