Kaman KDM-8200 - Manual (Page 9)

9
Kaman Precision Products
What is the KDM-8200?
System
What is the KDM-8200? Kaman Instrumentation’s KDM-8200 family of
Technology displacement measuring systems uses inductive technology to determine the
position of a target relative to the system sensor.
An AC current flows through the sensor coil, generating an electromagnetic field,
which radiates out from the sensor. As the conductive target enters this field, the
sensor induces a current flow; it produces a secondary opposing field, reducing
the intensity of the original. This opposing electromagnetic field results in an
impedance variation in the sensor coil.
The sensor coil makes up one leg of a balanced bridge network. As the target
changes position within the sensor field, the bridge network senses impedance
changes in the sensor coil and passes the information on to signal conditioning
electronics for conversion to an analog voltage. This voltage is directly
proportional to target displacement.
SYNCHRONOUS
DEMODULATOR LOG AMP
CONVERTER
OUTPUT
AMP.
TARGET
REF COIL
ACTIVE COIL
CABLE CAPACITANCE
COARSE LINEARITY
ZERO ADJUST
ANALOG
VOLTAGE OUT
GAIN
ADJUST
FINE
LINEARITY
Nonconductive materials intervening between the sensor and target have little or
no effect on system output. Because of this, environmental contaminants, such as
oil, dirt, humidity, and magnetic fields have virtually no effect on system
performance.
The function of a noncontact displacement measuring system is to monitor the
position of a target relative to some reference plane. The magnitude of the analog
output is dependent upon the relative position of the target within the sensor’s
electromagnetic field – the farther the sensor is from the target, the high the
analog output.
Reference
Plane
Reference
Plane
Target Target