User Manual

Modules  21
nVision Operation Manual
Dierential Pressure Measurement Uncertainties without Tare
The total nVision Reference Calibrator measurement uncertainty in the ΔP mode conguration 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.
T
he following table lists the possible combinations of combining Pressure Modules (PM) with dierent 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%
Dierential 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 specications 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