Kaman DIT-5200L - Manual (Page 9)

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Kaman Precision Products PART NO: 860522-001
www.kamansensors.com Last Revised 11/16/2012
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3.6 Target Characteristics
Target Material
Aluminum is the preferred target material for the DIT-5200L. Aluminum targets may be mounted
on materials with more stable temperature characteristics such as Invar or other substrates as
long as the target thickness guidelines are observed. Invar is an excellent target substrate as it
has a very low expansion coefficient with temperature. The figure below shows aluminum tabs
(which give optimal performance from the DIT-5200L) mounted on and Invar fixture.
Iron, nickel, and many of their alloys (ferro-magnetic targets) can be used with the DIT-5200L.
Performance to these materials may not meet standard performance specifications.
Refer to the DIT-5200L data sheet for performance specifications to aluminum
.
Figure 6 Attachment of Aluminum Targets
If the system was purchased for use with a target material other than aluminum, it has been pre-
calibrated (with pre-selected component values) at the factory using that specific material.
Changing the target material may require re-calibration or cause the DIT-5200L to malfunction.
The effect of target material is due to the resistivity and mainly affects the sensitivity of the
system. Expect about twice as much noise and drift on a system set up for a stainless steel target
as compared to one set up for aluminum.
Target Thickness
The RF field produced by the sensor is maximum on the target surface, but it also penetrates
below the surface. The depth of penetration depends on the target material used. For example,
the RF field will penetrate aluminum 0.022”. To avoid variations caused by temperature changes
of the target, use the recommended minimum target thickness in the table below: