Terahertz Technologies Inc.Terahertz Technologies Inc.
(888) U.S.-OTDRS
LT-880 Laser Tachometer

The LT-880 Fiber Optic Laser Tachometer is a non-contact instrument designed to measure rates of rotation by sensing the presence of absence of a reflective surface in its optical beam. These are typically provided by affixing an easily made black and white encoder to the surface of the rotating component. A TTL signal is asserted whenever a reflective surface is sensed. The output signal may be read directly from the display or used in conjunction with a spectrum analyzer to sense linear translation, RPM, and angular vibrations. A five meter fiber optic cable enables the optical sensor to be placed in hazardous environments and/or inaccessible spaces where a conventional unit cannot be used. The LT-880 adds the additional flexibility of a multi-functional readout.

Encoders may be made easily with a laser printer and any drawing or CAD program.


Remote Sensing of RPM and Angular Vibration
No Special Reflective Tape Required
Large 6 Digit LCD Display
Sensing Rates to 40,000 PPS
Ni-mH Powered with Fast Charger
Measures RPM, RPS, PPS
Entry of Number of Encoder Sectors
Ordering Information
LT-880 Fiber Optic Laser Tachometer (Includes 5 Meter Cable with Reflective Sensor Head
LT-880-10 Fiber Optic Laser Tachometer (Includes 10 Meter Cable with Reflective Sensor Head)
LT-880-T Fiber Optic Laser Tachometer (Includes 5 Meter Cable with Transmissive Sensor Head)
LT-880OH-RF 5 Meter Cable w/ Reflective Sensor Head for use with LT 880
LT-880OH-T 5 Meter Cable w/ Transmissive Sensor Head for use with LT 880
RAA-LT-880 Right Angle Adapter for use with LT-880 Reflective Optical Head
LT-880 Laser Tachometer Specifications
Units of Measurement Revolutions per Second, Revolutions per Minute, Pulses per Second
Measurement Update Rate Twice per Second
Readout Uncertainty ± .02 % of Reading, ± .1 LSD
Maximum Measurement Rate 40,000 PPS
Range from Sensor to Target 12 to 125 mm (Using White Copier Paper)
Laser Wavelength 650 nm ± .10 nm
Laser Output Power < 2 Milliwatts
Laser Spot Size < 1.9 mm @ 13 mm Range
Laser Beam Divergence < 13 Milliradians
Display Six Digit LCD, 0.375 Height, Six LED Annunciators
Frequency Output Port TTL Pulse for Each Reflective Sector Sensed, (0 to 5 Volts)
Output Impedance 100 Ohms
Standard Fiber Optic Cable Length 5 Meters
Standard Fiber Types Receiver: 400 um Core
Transmitter: 62.5 um Core
Standard Connector Type ST Type
Batteries Supplied Four AA NimH, ≥ 2500 mAH
Charger Power Requirements 95 - 260 VAC, 50-60 Hz Universal, < 10 VA
Mains Connectors Supplied North American, Great Britain, Continental Europe, Australian
Charging Time Approximately Two Hours
Dimensions (Controller) 200 mm L x 98 mm W x 38 mm D
Dimensions (Sensor) 40 mm L x 13 mm Diameter, 1/2 by 20 Thread, Jam Nuts Included
Operating Temperature Electronics: 0° to 50°C
Sensor Head: -40° to 120°C
Weight 0.46 Kg
Accessories Provided Carrying Case, Batteries, Power Supply/Charger, Operating Manual
Standard Warranty Two Years, Components and Workmanship
30 Day Satisfaction Guarantee

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