Kaman KD-5100 - Manual (Page 7)

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2-5. This differential configuration achieves its high resolution by eliminating the noise and drift
any intervening summation and Log amplifiers normally add to the system.
2-6. Maximum performance depends upon advanced sensor technology. Factors critical to the
high resolution of the KD-5100 are tighter manufacturing control, using significantly larger coils
for a given range of operation, and electrically matching the sensors.
2-7. By using electrically matched sensors on opposing legs of the same bridge, temperature
effects common to the sensors and cabling of a differential sensor pair tend to be cancelled. This
is true for the mechanical aspects of the sensor/target system also. Assuming the thermal
characteristics of each sensor track together, slight changes in sensor length due to temperature
tend to be cancelled.
3. OPTIMUM PERFORMANCE
3-1. To optimize the performance of a KD-5100 system, a high (d) to (s) ration is desired: (d) is
the sensor coil diameter and (s) includes: the null gap, the positive measuring range, and ½ of
the coil depth (Figure 2).
Figure 2 Sensor and Target Geometry
3-2. The 15N sensor used over the specified ±0.009” measuring range provides a d/s ration of
3.08. The ration for the 20N is 10.68. Therefore, if mounting space and target size permit, the
20N offers better performance over the specified measuring range.