Crystal nVision Lab Reference User Manual
Page 23
Modules
21
nVision Operation Manual
Differential Pressure Measurement Uncertainties without Tare
The total nVision Reference Calibrator measurement uncertainty in the ΔP mode configuration will need to consider the uncertainties of both pressure mod-
ules. We recommend the module uncertainties to be combined with the preferred square root of the sum of the squares (or “root sum squares”) method.
The following table lists the possible combinations of combining Pressure Modules (PM) with different accuracy statements. The uncertainties reported below
are without using the Tare feature which will greatly improve your measurement uncertainty.
Upper Pressure Module Uncertainties
(of Static Line Pressure) (of Reading)
0.025%
0.05%
0.10%
Lower Pressure
Module Uncertainties
(of Static Line Pressure)
(of Reading)
0.025%
0.035%
0.056%
0.103%
0.05%
0.056%
0.071%
0.112%
0.10%
0.103%
0.112%
0.141%
Differential Pressure Measurement Uncertainties with Tare
The Tare function can improve measurement uncertainties on two modules with the same full scale pressure range installed into one nVision Reference
Recorder.
The following specifications apply to the measurement system with a logging interval of 1 reading/second or slower:
Full Scale Range of Both Sensors
The Greater of (+/–)
PSI
bar
kPa/MPa
kg/cm
2
PSI
mbar
inH
2
O
mmH
2
O
% of DP Reading
30
3
300
3
0.0005
0.04
0.014
0.4
or
0.025%
100
10
1
10
0.0015
0.10
0.04
1.0
or
0.025%
300
30
3
30
0.005
0.4
0.14
4.0
or
0.025%
1000
100
10
100
0.02
1.0
0.4
10.0
or
0.05%
3000
300
30
300
0.05
4.0
1.4
n/a
or
0.05%
10000
700
70
700
0.2
10.0
4.0
n/a
or
0.1%
15000
1000
100
1000
0.3
15.0
6.0
n/a
or
0.1%
Unit must be enabled in CrystalControl