Model 202BG Test Report - Paroscientific, Inc.

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use a conventional gauge dead weight tester to calibrate the 202BG, but only if thecommon-mode corrections are known beforehand.Conformance with CEC Standard202BG Deviation (Pa)3.002.251.500.750.00-0.75-1.50-2.25-3.00-20 -15 -10 -5 0 5 10 15 20Reference Pressure (kPa)The standard pressure equation is a quadratic polynomial in frequency squared. We noteda somewhat systematic deviation between the test unit and the reference pressure thatlooks like an S-curve. We added a small cubic term to the pressure equation to bestmodel the sensor. The residual rms error was 0.2 Pa, including repeatability andhysteresis. The shown data is the same as in the previous plot.Best Conformance Fit to CEC Standard202Bg Deviation (Pa)3.002.251.500.750.00-0.75-1.50-2.25-3.00-20 -15 -10 -5 0 5 10 15 20Reference Pressure (kPa)
Stability:Even though long-term stability is generally not important in calibration equipment thatcan be zeroed easily, as is the case with the 202BG, we perform routine longer-termstability tests at 0 psig to identify anomalies. Stability test data is shown below.Stability Test Data1.510.5Pa0-0.5-1-1.53/5/00 3/15/00 3/25/00 4/4/00 4/14/00 4/24/00 5/4/00 5/14/00DateIn the stability test setup, a Paroscientific 216B is used to correct the common-modesensitivity for atmospheric pressure variations of up to 4 kPa. As shown in the data, aresolution of better than 0.01 Pa and week-long stability of better than 0.1 Pa can beachieved.
Page 1 and 2: A New High-Precision Low-RangeBi-Di
Page 3: 2 kPa. Offset and linearity adjustm
Page 7: APPENDIX B: Pressure EquationDefini

Model 202BG Test Report - Paroscientific, Inc.

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