Kaman’s high-temperature displacement sensors provide accurate non-contacting measurement of conductive surface motion in hostile environments. Thermal  compensation techniques that maintain sensitivity and linearity with small zero shifts make these accurate high temperature measurements possible.

Kaman’s sensors feature laser-welded Inconel construction, making them perfect for a variety of extreme environment applications. The sensors use the versatile KDM-8200 family of signal conditioning electronics. Single channel systems are available in the NEMA-enclosed KDM-8200 or bench-top/rack-mountable KDM-8200. The NEMA enclosure houses an internal power supply, digital panel meter and window kit. Up to eight measuring channels are available in the rack-mountable KDM-8200. (See Kaman’s KDM-8200 data sheet for a complete description and additional specifications for these electronics.)

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Measuring range* (maximum mechanical offset 0.001 inch)
KD-1925 0.050 inch (1.27 mm)
KD-1925M** 0.035 inch (0.9 mm)
Electronics KDM-8200
Power input (120 Vac)
Output (electrical zero offset up to 50% of measuring range)
KD-1925 0-2 Vdc nominal (50 mV/mil)
KD-1925M** 0-1.75 Vdc nominal (50 mV/mil)
Resolution (at mid range)
Static 30 μinch (0.00003 inch)
[0.00076 mm]
Dynamic 50 μinch (0.00005 inch)
[0.0013 mm]
Repeatability 30 μinch at mid range
Operating temp. range -320°F TO +77°F or
+77°F to +1000°F (+538°C)
Nonlinearity Within ±1.5% FSO at customer
selected calibration temp.
Typical temperature coefficients (over maximum specified
thermal range)
Zero shift 0.03%/°F FSO (0.054%/°C FSO)
Sensitivity shift 0.03%/°F FSO (0.054%/°C FSO)
Frequency response 0-10 kHz (3 dB)
30 kHz available on request
Sensor material Corrosion resistant high temp.
nickel chrome alloy (Inconel 718)
welded and hermetically sealed
Cable material Nickel chrome alloy (Inconel
600) sheathed, mineral insulated
Standard cable lengths
Hardline 10 feet
Softline 5 feet
Target material Conductors – nonmagnetic
and magnetic
Operating pressure range To 5000 psi
Standard mounting
configurations 1. 5/16-24 thread mount
2. Flange mount, smooth body
*Change from standard may degrade specifications.
**For magnetic targets.

Each sensor has dual coils inside the corrosion resistant case. In operation, an electromagnetic field generated by the active coil penetrates the front of the sensor to induce eddy currents in a conductive target within the sensor’s range. Changes in target displacement result in impedance variation in the active coil. This variation is detected by the signal conditioning electronics and converted to a linear analog output signal. The symmetrical design of the dual coils compensates for constant and slowly changing temperatures from -320°F to +77°F or from 77°F to +1000°F. Measurement quality is unaffected by most corrosive gasses and liquids and most other environmental contaminants such as oil, dirt, radiation, and stray RF and magnetic fields. The cabling has two sections joined by a LEMO® transition connector: a high-temperature metal sheathed, mineral insulated section designed to the same environmental specifications as the sensor, and a flexible section of Teflon® jacketed, twisted pair, coax cable for connection to the electronics unit.