Fluke Calibration RPM4, Operation And Maintenance Manual

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5. MAINTENANCE, ADJUSTMENTS AND CALIBRATIONS
Page 119
5.2.4 RECOMMENDED CALIBRATION POINT SEQUENCE
Calibration adjustments to RPM4 Q-RPTs are made by altering calibration coefficients,
PA and PM (see Section 5.2.1.1). To adjust these coefficients to optimum values giving the
best results over the Q-RPTs complete operating range, specific calibration point sequences
are recommended. The recommended point sequence depends upon whether the Q-RPT
being calibrated is a Standard or Premium Class (see Section 1.2.2.1). The class of the
RPM4 Q-RPTs is indicated in the model number on the product label and on the rear panel
Q-RPT label (
<s> for standard, <p> for premium, for example A7Ms or A7Mp).
Prior to running the calibration point sequence, the Q-RPT should be exercised by:
a) Setting full scale pressure.
b) Dwelling at full scale pressure for 5 minutes.
c) Returning to atmospheric pressure (vented). If the Q-RPT is a gas operated Axxx type,
use vacuum rather than atmospheric pressure.
d) Dwelling for twenty minutes.
A dwell time after setting the pressure of at least 60 seconds before taking data at each point
is recommended.
Section 5.2.4.1 gives calibration point sequences for Standard Class Q-RPTs and Section 5.2.4.2
gives calibration point sequences for Premium Q-RPTs.
It is not required that the calibration pressure standard apply precisely the nominal
pressure value of each calibration point as long as the exact value of the applied pressure
is known. Best results are obtained if the actual applied pressure is within 2 % of the
recommended nominal point.
5.2.4.1 STANDARD CLASS Q-RPTS
See additional information in Section 5.2.4 concerning exercising the Q-RPT and
dwell time at pressure points.
Table 22. Calibration Point Sequence, Standard Class,
Axxx and Gxxx Q-RPTs
CALIBRATION
SEGMENT
POINT
NO.
POINT
[% OF SPAN]
Ascending
1 Lowest Pressure
1
2 25 %
3 50 %
4 75 %
5 100 %
Descending
6 75 %
7 50 %
8 25 %
9 Lowest Pressure
1
1. In absolute mode, the lowest point that can be set reliably by
the reference piston gauge, or atmospheric pressure for ranges
> A1.4M. Zero (vented) in gauge mode.
Axxx (absolute) Q-RPTs that will NOT be used in absolute or
negative gauge measurement modes may be calibrated in
gauge measurement mode with a gauge pressure standard.
Axxx (absolute) Q-RPTs calibrated in gauge measurement
mode should be used in gauge mode only (see Sections 3.3.3,

PRINCIPLE, 5.2.5).