D Type Fibre Optic Displacement Sensor

D Type Fibre Optic Displacement Sensor

D models (Reflectance Dependent) are used for single axis vibration and stroking motions, where the target reflectivity is constant.
The output voltage function for D model sensors includes a near side region where the voltage rises with increasing distance, an optical peak region, and a far side region where the voltage output decreases with increasing distance. Operation in the near side region gives high sensitivity with limited operating range. Operation in the far side region gives moderate sensitivity with greater operating range.

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The D type fibre optic sensors are a family of very high performance non contact displacement sensors. With resolutions down to 0.004µm and measuring ranges from 20µm to 50mm, these units also have 100Hz, 20kHz and 200kHz + frequency capability. Their rugged construction and compact size means they are suitable for measurements inside of mechanisms, submerged in fluids and hostile environments. The sensors can measure any surface that reflects light. They are commonly used in applications where the target moves in the sensor axis such as vibration monitoring.

Model NoLinear Range Near sideResolution at 100Hz
Near side
Linear Range Far sideResolution at 100Hz
Far side
Tip DiameterTotal Range
  • Compact measuring tip down to 0.81mm diameter means sensors can be placed inside mechanisms
  • Fibre optic principle means complete insensitivity to magnetic fields and high voltage electrical fields
  • Can be used where inductance or capacitance sensors do not work
  • Rugged construction; for use in all types of difficult environments such as vacuum, high pressure, cryogenic temperatures, high temperatures, in fluids or explosive atmospheres
  • High frequency capability 200kHz +
  • High resolution down to 0.004µm
  • 0-5 VDC analogue output
  • Actuator stroke
  • Bearing vibration
  • Diaphragm deflection
  • Displacement in fluids
  • Read/write head tracking
  • Piston stroke
  • Solenoid travel
  • Ultra sonic vibration
  • Valve dynamics
  • Piezoelectric crystal vibration
AProvides temperature stabilised electronics for low drift & high accuracy
BConnects sensor system with inline connector (D6, RC12 n/a). *Oprion B is also required for use with vacuum passthru flanges & assemblies Bv2, Bv3, Bv4, BvF
2BConnects sensor system with two inline connectors. Not available for all models..
B1Connects sensor system with bulkhead connector (D6, RC12 n/a)
Bv1Connects sensor system with single channel vacuum passthru for 10 E-7 torr. Includes ultra-torr compression fitting (D6, RC12 n/a)
Bv133Same as Bv1 with 1.33” diameter mini-CF type flange for bulkhead mounting
Bv22 port single channel vacuum passthru flange for D models for 10 E-11 torr (D6 n/a) *also requires option B
BvFMulti-channel high vacuum passthru assembly for 10 E-7 torr. provides fused fiberoptic passthru and multi-channel vacuum flange assembly. Can accommodate 8 D Ype or 5 RC type sensors. (D6, RC12 & RC20 n/a) *also requires option B
Standard Jacket: PVC Monocoil -PVC over a steel helical winding. semi-crush-proof, liquid-tight, not autoclavable or MRI compatible. Good to 105C.
C1Jacket: stainless steel interlock, crush proof, not liquid tight. good to 850c.
C2Jacket: silicone – mri and bio-compatible, autoclavable, flexible, liquid-tight, not crush-proof. good to 200C
C3Jacket: silicone over ptfe wrap – semi-crush-proof. good to 200c. short lengths only
C4Jacket: corrugated – all plastic. semi-crush-proof, liquid-tight, light-weight, mri compatible. Good to 85C.
C5Jacket: ptfe over stainless steel interlok – vapor barrier, liquid-tight, crush-proof. good to 260c.
C51Jacket: ss interlok over ptfe – vapor barrier, liquid-tight, crush-proof, poor flexibility, good to 260c.
C6Jacket: PVC over nylon wrap – semi-crush-proof, liquid-tight, EMF compatible. good to 105c.
C7Jacket: ptfe tubing – autoclavable, MRI & EMF compatible, vapor Barrier, liquid-tight. good to 260c.
C8Jacket: pvc – polyvinyl chloride – very flexible, liquid-tight, EMF & MRI compatible, not autoclavable, not crush-proof. good to 105c.
C9Jacket: annealed (semi-rigid) stainless steel tubing. liquid tight. good to 850c.
C10Jacket: silicone over ss interlok sheathing. liquid-tight, crush-proof. good to 200c.
C11Jacket: polyolefin shrink tubing – thin wall moisture/vapor barrier, not crush-proof, poor flexibility. good to 150C.
C12Jacket: polyolefin over ss interlok – thin wall moisture/vapor barrier, crush-proof, flexible. good to 150c.
E1Extra length of fiberoptic cable (some models limited to 10 feet or to 49 feet); any fiber bundle < Ø 2.5mm
E2Extra length of fiberoptic cable (some models limited to 10 feet or to 49 feet); any fiber bundle > Ø 2.5mm
Fv1Low vacuum passthru for 10 E-4 torr – provides solid section on fiberoptic cable, compression fitting, and stainless steel interlok sheathing on vacuum side
Fv2Low vacuum passthru, same as fv1, provides Ø 0.250” x 3”l solid section on fo cable
Fv3Low vacuum passthru, same as fv1, provides Ø 0.500” x 3”l solid section on fo cable
G1Additional output, DC coupled with 10x gain and adjustable DC offset
G2Additional output, AC coupled with 10x gain
H1High frequency amplifier for d models up to 200KhZ bandwidth
H2High frequency amplifier for d models above 200KhZ to 1 mhZ bandwidth
0Additional output for D models with bandwidths up to 200KHZ
0Additional output for D models with bandwidths up to 1MHZ
LLow frequency amplifier ( < 20Khz), 100hz std
+LAdditional output with low frequency bandwidth ( < 20Khz), 100hz std
MDigital display – DC volts
OAdjustable DC offset
PPolynomial curve fit to specified calculation range
QConnects AC/DC power adaptor and BNC output
R1Ambient light rejection
R2Blue light sensor, 470nm
T1Tip: straight, customised
T2Tip: threaded
T3Tip: non-metalic, (torlon or peek)
T4Tip: 90° tubing
T5Tip: 90° square body, unthreaded end
T6Tip: 90° square body, threaded end
T7Tip: made to customer specifications
T8Tip: high temperature, 350°c max.
T9Tip: high temperature, 480°c max.
T10Tip: high temperature, >480°c (quartz fibers)
T11Tip: non-magnetic (brass or aluminium)
T12Tip: invar (low expansion coefficient)
VProvides sensor amplifier with 0 – 10 volt output
WWindow: recessed sapphire epoxied into tip for high pressure or vacuum
WbWindow: sapphire brazed to sensor tip for high pressure or vacuum