Ametek 682T-HP, User Manual

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Chapter 4: Calibration, Page 42
M o d e l 6 8 2 T - H P U S E R M A N U A L A T E X Z o n e 2
DENSITY is in gm/cc
The CPS variable is divided by 100 to increase the number of significant digits that are
displayed for the slope in the Calibration Coefficient Screen.
4.5.2 Alpha method
The Alpha method requires at least 4 samples with varying densities. There is no
need to hunt for the best Alpha coefficient because the calculation is done with the
best Alpha automatically. The disadvantage is that you need sufficient density
variation in the samples to produce a valid Alpha coefficient.
If you have a set of samples with varying densities and sulfur to span the expected
process conditions, and the range of sulfur is small, the Alpha method is
recommended.
EXAMPLE OF A CALIBRATION FIT WITH AN ALPHA DENSITY CORRECTION
Element: S Std. Error of Estimate: 0.0510678
Unit: % Slope: 0.007681057 Offset: 6.3331 Alpha: -4.480430635
Sample Density gm/cc CPS Given Calculated
crude 1 0.798000 30165.02 0.30 0.36592
crude 2 0.801000 24619.32 1.50 1.43753
crude 3 0.848630 27280.14 0.50 0.46126
crude 4 0.882190 23516.77 1.00 0.99969
res 5 0.902630 26691.81 0.10 0.09186
res 6 0.900380 26002.63 0.30 0.27314
res 7 0.898880 22792.95 1.00 1.03292
res 8 0.897188 20674.04 1.50 1.53768