Kaman KD-2440 User Manual
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Noncontact Displacement Measuring
System User’s Manual
This apparatus, when installed and operated per the manufacturer’s recommendations, conforms
with the protection requirements of EC Council Directive 89/336/EEC on the approximation of the
laws of the member states relating to Electromagnetic Compatibility. Please refer to the KD-2440
Declaration of Conformity or contact Kaman Precision Products for details.
2.357
(59.9)
1.902
(48.3)
KD 2440
KAMAN
Instrumentation
1.23 (31.24)
.984
(24.99)
PIN SIGNAL
2 SWITCH
3 SWITCH
.610
(15.5)
4,7 V IN
5 COMM
9 V OUT
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KD-2440
Kaman Precision Products’ Displacement Measuring
System Model KD-2440 is a noncontact linear proximity
measuring system. This low-cost, easy-to-use system
makes precision static and dynamic measurements of
metal targets, and thickness measurements of nonconductive material backed by metal. The system
includes a switching output that will track RPM
measurement to 10Khz.
Features Summary / Advantages
•••• Outstanding Precision: Static Resolution to 12
Microinches
•••• Easy to Adjust
•••• Excellent Performance with Ferrous Targets
•••• Variable Voltage Input from 12 to 24 Volts DC
•••• Adjustable Gain for up to 22 Volts Output with 24
Volts Input
•••• Compact Rugged Electronics and Sensors
•••• Temperature Tolerant Sensors (to 400°F)
•••• Level Adjustable Switched Output to 10Khz for
Process Control
•••• Drop in Replacement to Kaman’s KD-2400 with
Accessories Kit
KD-2440 Unit
The KD-2440 system consists of three subassemblies:
the sensor with integrated cable, the signal conditioning
electronics module, and the power and output cable.
The KD-2440 electronics uses a standard DB-9
connector to bring +12 Vdc to +24 Vdc into the
electronics and provide outputs for the analog voltage
and switch functions.
12345
6789
Electronics DB-9
Connector Face
54321
9876
I/O Cable DB-9
Connector Face
DB-9 Connections and Power I/O Cable
Color Chart:
Wire Color Pin Signal
1 N/C
BLU 2 SWITCH RX
WHT 3 SWITCH TX
GRN 4 VIN (ALTERNATE)
BLK 5 COMM
6 N/C
RED 7 VIN
8 N/C
ORN 9 VOUT
CLR - CABLE SHIELD
Electronics
The KD-2440 electronics has two potentiometers
accessible through openings in the enclosure for
adjusting the GAIN and SWITCH SET POINT level.
An LED indicates when the optically-isolated switch is in
the closed position. The KD-2440
electronics and sensors utilize SMA type coaxial
connectors: female on the electronics, and male on the
sensor cable. Two production-sensor configurations
are available, the 9C and the 5CM. Data for these two
sensors is shown on the following pages. The sensor
must be attached snugly (finger tight) to the electronics
assembly for the unit to function properly.
Mounting Instructions
Mounting the KD-2440 electronics module can be done
using either of the two holes in the enclosure, and an M3 or 4 screw. It is preferable not to remove both screws
from the case for mounting purposes. An easier
mounting method may be to use a cable tie wrap or zip
tie.
Positioning the electronics module so that it is not the
low point in the cable will keep liquids from running
down the cable and into the electronics. Take care to
route the sensor cable to avoid crushing or crimping it
during use. Damage to the sensor cable may affect the
desired set points and overall operation of the
electronics.
Theory of Operation
The KD-2440 system operates on a traditional Colpitts
oscillator circuit where the sensor acts as the resonating
coil for the oscillator. The proximity of the target to the
sensor face pulls
and amplitude of modulation, controlling a variable gain
oscillator section within the electronic circuit.
the oscillator, changing its frequency
5CM Sensor Response Data:
5CM Sensor Response Data:
2 7
The signal is half-wave rectified and filtered to
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obtain an analog voltage proportional to the target
position or displacement. The analog voltage
output can be varied by adjustment of the gain. The
input power is diode protected and regulated to
provide a clean low-noise signal. The output is
short-circuit current protected.
Adjustment and Calibration
The KD-2440 is instrumented with a ten volt
regulator to provide a clean repeatable output
signal. The input voltage must be maintained at a
minimum of twelve volts for the regulator to
function.
The gain (ratio of output voltage to target
displacement) is used to adjust the output slope
(output per displacement). W hen changing types of
target materials or power supply voltages, it will be
necessary to readjust the gain for the desired
output voltage.
The KD-2440 can easily be adjusted or “calibrated”
to obtain maximum output per displacement,
maximum range, or any variation in between. Note
that when the KD-2440 is adjusted for maximum
output per displacement, it is at a minimum usable
range, whereas a minimum gain gives a voltage
change throughout the largest displacement for the
same sensor, target, and range as depicted in the
following graph:
4130 Steel Output for 12 & 24 Volt Inputs
18
16
14
12
10
DC Output Voltage
The minimum gain is defined as being the lowest
gain obtainable without pulling the circuit into
saturation. Minimum gain can be obtained by
setting the sensor displacement to a point within
the usable
slowly decreasing the gain potentiometer
(clockwise) until the output saturates. At this point,
increase the gain slightly to a point just above
24 volt input w ith high gain
12 volt input w ith
high gain
8
6
4
2
0
0 50 100 150
Displacem ent, Mils
12 or 24 volt input
with low gain
range (preferably mid range), then
saturation (the output begins to change with a gain
increase).
Example Calibration
To maximize the output slope for an application using a
5CM sensor with a .010” offset and a range of .040”,
follow these steps:
1. Adjust the sensor / target to its maximum
displacement, plus the offset, plus approximately
20% of the range (.058”).
2. Adjust the gain potentiometer to its minimum point
(adjust clockwise until the analog output saturates)
3. Slowly increase the gain potentiometer (counter
clockwise) until it saturates at its maximum point.
this will be approximately two volts below the input
voltage.
4. At this point, the module is calibrated to a
maximum output per displacement condition. As
the sensor is moved toward the target from
approximately .058”, the output will decrease. If the
sensor / target displacement is increased beyond
.058”, the output will saturate at approximately two
volts below the input.
Switched Output Operation
The KD-2440’s switched output is a simple on / off
switch with a corresponding LED indicator lamp. The
switch is in a closed condition when the LED is
illuminated. The switch can be adjusted to trip
anywhere along the sensor range using the “Switch
Setpoint” potentiometer.
CLEANING
The KD-2440 is not designed to be immersed or
operated while immersed in liquids. Solvents may
damage electronics module, sensor, or power I/O
cable. Clean the unit with a damp cloth.
EMI PERFORMANCE
The KD-2440 conforms with the applicable standards
of Council Directive for Generic for Light Industrial and
Commercial Use. Under some EMI environments, at
specific frequencies, the KD-2440 unit may experience
a change in output voltage. In general, when exposed
to those environments covered by the EMC directive,
the user can expect less than 5% deviation of output.
Contact Kaman Instrumentation for
recommended solutions if you experience problems
with the KD-2440.
specific data or for
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