nVision
Operation Manual
•
Page 27
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X
Measurement.Uncertainties.for.two.Pressure.(PM).Modules.using.Tare.
Function
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:
The greater of
Full Scale Range
of Both Sensors
PSI
PSI
mbar
inH2O
% of DP Reading
30
0.0015
0.10
0.042
or
0.025%
100
0.0040
0.28
0.11
or
0.025%
300
0.015
1.0
0.42
or
0.025%
1 000
0.04
2.8
1.1
or
0.05%
3 000
0.15
10.3
4.2
or
0.05%
10 000
0.4
27.6
11.1
or
0.1%
Due the additional digit of resolution in differential mode some units may be inappropriate due
to the noise floor of the reading.
The following chart indicates the expected resolution on the appropriate units:
PSI
bar kPa/MPa kg/cm
2
PSI
kg/cm
2
inHg
inH
2
O mmHg mmH
2
O
kPa
bar
mbar
MPa
30
3
300
3
0.0001 0.00001 0.0001 0.001
0.001 0.00001
0.01
100
10
1
10
0.0001 0.00001
0.001
0.01
0.001 0.00001
0.01
300
30
3
30
0.001
0.0001
0.001
0.01
0.01
0.0001
0.1
0.00001
1 000 100
10
100
0.01
0.0001
0.01
0.01
0.01
0.0001
0.1
0.00001
3 000 300
30
300
0.01
0.001
0.01
0.1
0.001
0.0001
10 000 700
70
700
0.1
0.001
0.1
0.001
0.0001
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X
Measurement.Uncertainties.for.two.Pressure.(PM).Modules.without.Tare
The total nVision Reference Calibrator measurement uncertainty in the ∆P mode configuration
will need to consider the uncertainties of both pressure modules. Crystal Engineering recom-
mends 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%
Summary of Contents for nVision Lab Reference Recorder
Page 1: ...C R Y S T A L engineering corporation Operation Manual Reference Recorder Lab Reference ...
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