Kaman SMU9200 - Manual (Page 19)

SMU-9000 User Manual 16
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Part IV: System Performance
Part IV: System Performance
Linearity and Temperature Performance
Typically, the SMU-9000 will yield the best linearity performance
over smaller ranges. As the measuring range is increased, the
linearity of the system will decrease. For example, a sensor set up
for a measuring range equal to about 5% of it’s diameter against a
non-magnetic target will be about 1% non-linear. Increasing the
measuring range to 10% of the sensor’s diameter against the same
target, will produce a non-linearity of approximately 5%. Further
increasing the measuring range of the system to about 30% of the
sensor’s diameter will produce a non-linearity from 15% to 20%.
In general, systems with the best linearity will not yield the best
thermal stability. For example, a system with a non-linearity of
approximately 1% will typically have a thermal stability of 0.1%.
However, non-linearity will increase as the system is optimized for
thermal stability. In this case, a system that is optimized for 0.05%
thermal stability may result in a non-linearity of approximately
10%.
Fifth order polynomial curve fit linearity coefficients can be
provided for use in customer processors to achieve linearity
performance of approximately 0.1% or better. The polynomial
curve fit is applied to the linearity data and the result is a corrected
linearity. An example of this is shown in Figure 12.