Kaman Aerospace Corporation
Kaman Precision Products
Copyright © 2019
PART NO: 860510-001A
Last Revised: 2019.10.22
Measuring & Memory Systems
217 Smith Street
Middletown, CT 06457
www.kamansensors.com or 860-632-4442
Page 8 of 1
2
Dwell time and Frequency
When the sensor is being inserted into a hole there is a certain period of ambiguity at
partial insertion. To avoid switching on this ambiguity a form of derivative is used to
determine whether the sensor is in motion or is at the measurement point. The system
will effectively delay
f
o
r
approximately 10-20 milliseconds after it stops moving before
it recognizes the values for the limits (the analog output does not do this and is
continuous).
Positioning/Mounting the sensor
Ideally the sensor should be just slightly smaller than (and centered in) the untapped
hole. The surface of the sensor tip should be at mid depth.
Larger
– For holes that are much larger than the sensor, the mounting can be offset so
that the sensor is near the threaded edge. While this will be able to detect the
presence or absence of a thread there are a couple of limitations. First, only a small
section of the tapped hole is being tested. Second, generally the signal strength is
lower. This results in lower resolution.
Smaller
– For holes that are smaller than the sensor, the sensor can be mounted near
the surface of the material and measure down into the hole. The main limitation here is
that there is a limited depth that the sensor can detect threads (near the max range of
the sensor). There is also a limitation on very small holes (where the diameter of the
hole is less than half the diameter of the sensor).
