Kaman KD-5100 - Manual (Page 34)

34
Relative Sensitivity
The relative sensitivity is a way of comparing the expected resolution of the system. The relative
sensitivity is computed such that a system with a relative sensitivity of 1 would have resolution
of 0.005%FR peak-to-peak when measured at a 1kHz bandwidth with the sensors positioned at
the extreme end of the measuring range. The resolution at null is generally better by a factor of
3. A relative sensitivity of 0.5 would effectively double the noise in the system and the
temperature coefficient in the electronics as a percent of the measuring range (i.e. 1 is good, 0.5
is not as good).
This also affects the temperature coefficient of the electronics in the same relative manner. At a
relative sensitivity of 1 the electronics would have a temperature coefficient of approximately
± 0.01 to 0.02%FR/ o C (typically).
Estimated Relative Sensitivity of KD5100
0.00
0.20
0.40
0.60
0.80
1.00
1.20
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Full Range as % of Coil Diameter
R
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la
ti
v
e
S
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s
iti
v
it
y
The reason that this has an optimum around 35% of the measuring range is because of the
following:
• At large ranges the output change remains constant while the range is increasing. This
sensitivity number would obviously have a limit at ‘0’ as the range increased to infinity.
• At small ranges the output change is diminishing faster than the range is decreasing resulting
in a net loss of sensitivity as a percentage of the measuring range.