Fluke A70M User Manual

Page of 148
 
1. INTRODUCTION 
 
Page 3 
© 2007 DH Instruments, a Fluke Company 
1.2.2 
PRESSURE MEASUREMENT SPECIFICATIONS 
1.2.2.1 
QUARTZ REFERENCE PRESSURE TRANSDUCERS (Q-RPT) 
RPM4 A70M/A20M is configured with two quartz reference pressure transducers 
(Q-RPT) modules to measure pressure. 
The Q-RPTs can measure absolute and gauge pressure.  Gauge pressure is 
defined by offsetting atmospheric pressure and applying dynamic compensation 
for atmospheric changes using the on-board barometer (see Section 3.2.2).  
Warm Up Time 
30 minute temperature stabilization recommended from 
cold power up. 
Compensated Temperature Range 
5 to 35 °C 
Operating Temperature Range 
8 to 28 °C 
 
A20M Q-RPT 
A70M-QRPT 
Maximum Range 
3 000 psi (20 MPa) 
10 000 psi (70 MPa) 
Resolution 
user adjustable to 1 ppm of Q-RPT maximum or 10 ppm 
of active AutoRange, whichever is larger, 
Precision
1
 
± 0.0175 % of reading, or 
0.13 psi, whichever         
is larger 
± 0.0175 % of reading, or 
0.44 psi, whichever         
is larger 
Predicted Stability
2
 
± 0.004 of reading 
Measurement Uncertainty
3
 
± 0.02 % of reading, or 
0.15 psi, whichever         
is larger 
± 0.02 % of reading, or 
0.5 psi whichever           
is larger 
1.  Combined linearity, hysteresis, repeatability. 
2.  Predicted Q-RPT measurement stability limit (k=2) over one year assuming regular use of AutoZero function.  
As stability 
can only be predicted and varies from Q-RPT to Q-RPT, stability for a specific Q-RPT should be established from 
experience.
 
3.  Maximum deviation of the Q-RPT indication from the true value of applied pressure including precision, predicted one 
year stability, temperature effect and calibration uncertainty (assumes calibration reference uncertainty of ±0.005% of 
reading), combined and expanded (k=2) following the ISO “Guide to the Expression of Uncertainty in Measurement.”. 
1.2.2.2 
ON-BOARD BAROMETER 
The measurement uncertainty of the on-board barometer is not significant to 
RPM4 Q-RPT measurement uncertainty.  It is used only to measure small, short 
term changes in atmospheric pressure to provide dynamic compensation of the 
Q-RPT’s atmospheric pressure offset when in gauge pressure measurement 
mode (see Section 3.2.2) 
Sensor Technology: 
Micro-machined silicon 
Warm Up Time: 
None required 
Resolution: 
0.1 Pa (0.000015 psi)