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FT702LM wind sensor


Overview   Technical Specification   Installation   Market Sectors






The FT702LM is an ultra-compact anemometer which uses our patented Acu-Res®  airflow sensing technology to measure accurately both wind speed and direction.

Our OEM (Original Equipment Manufacturer) wind sensor is designed for integration into a wide range of engineering systems.

The LM2 Version includes an electronic compass.


FT702LM ultrasonic anemometer





  • Designed for integration into OEM equipment
  • Ultra-compact (70mm x 78mm)
  • Low power consumption (66mW)
  • Light weight (234g), rugged and portable
  • Built in self-regulating anti-icing heaters
  • Sealed to IP67
  • NMEA 0183 compatible
  • Corrosion resistant surface finish
  • Optional integrated compass - FT702LM2
  • Wind speed output in m/s, km/h or knots available

Interface and Data format

The sensor can output up to 5 readings per second via a RS422 or RS485 interface. There is a 10-way connector in the sensor’s base for the power and data connections.

Data is transmitted in digital with serial messages in ASCII. The sensor is NMEA 0183 (MWV sentence) compatible and wind speed measurement in knots is now available, making it ideal for use with other marine electronic devices. (Wind speed measure in knots only available in software version 3.8. Please contact FT for assistance with updating sensor software.)


Its small size, light weight, robust construction and ease of integration give designers maximum flexibility.



FT702LM datasheet






If you have any technical enquiries or require a quotation, please contact us.





Overview   Technical Specification   Installation   Market Sectors



Technical specification

Sensor Performance


Measurement principle

Acu-Res® Technology Acoustic Resonance (compensated against variations in temperature, pressure and humidity)

FT patented Acoustic Resonance airflow measuring system

Wind Speed Measurement

Range:  0-50m/s
Accuracy:  ±4%
Resolution:  0.1m/s
Zero Error:  ±0.1m/s

Wind Direction Measurement

Range:  0° to 360°
Accuracy:  ±4°
Resolution:  1°

Compass Accuracy (FT702LM2 ONLY):  ≤ 5° RMS

Data I/O

Interface:  RS-422 or RS-485

Format:  Full range of user programmable functions. NMEA 0183 (MWV sentence) ASCII data output format.

Data Update Rate: 5 measurements per second


Power requirements


FT702LM1: 4.4V to 30V dc @15mA (typical – exclude data o/p drive current)
FT702LM2: 4.4V to 30V dc @16mA (typical – exclude data o/p drive current)

Heater: 10V to 30V dc @ 2.5A (max)


Dimensions: 70mm x 78mm (nominal dia. x height)

Weight:  233.5g (sensor stand alone) 250g (with accessories: gasket)

Material:  Aluminium alloy, hard anodised.

I/O Connector:  10 way connector (p/n Harwin M80-867 1022). Mating connector (p/n Harwin M80-8891005)

Mounting Method:  Threaded holes (M4) x6 in base


Environmental specification   

Operating Temperature Range:  -40° to +85°C

Storage Temperature:  -40° to +85°C

Humidity:  0-100%

Dust and Immersion:  Sealed to IP67 (when correctly installed with supplied gasket)



EN 61000-6-3 (2007 inc. A1:2011)  Emission standard for residential, commercial and light-industrial environments

EN 61000-6-2 (2005)  Generic Standard - Immunity for Industrial Environments

EN 61000-4-2 (2009)  Electrostatic discharge immunity test

EN 61000-4-3 (2010)  Radiated, radio-frequency, electromagnetic field immunity test

EN 61000-4-8 (2010)  Power frequency magnetic field immunity test

EN 61000-4-9 (2009)  Pulse magnetic field immunity test

EN 61000-4-10 (1994; A1:2001)  Damped oscillatory magnetic field immunity test



Overview   Technical Specification   Installation   Market Sectors



Installation: mounting and connections

Mounting details

The wind direction datum is indicated by a small circular indentation on the lower half of the sensor (located below sensor label). The datum is offset by 6deg from the 60deg pitch of the fixing holes (see right).

The sensor should be mounted using the supplied gasket to ensure adequate sealing is achieved.

FT702LM mounting details



The six fixing holes are M4 threaded. Maximum screw depth is 5mm (plus 1.6mm to allow for gasket thickness).


Electrical connections

Electrical connections to the FT702LM are made via a Harwin 10 way connector.

Wind sensor connector Harwin p/n M80-8691022

Connector pin details RS-422

 FT702LM connector pin details RS422

The LM wind sensor with RS-422 serial digital interface uses a differential pair Rx to receive information (2 wires A&B) and a differential pair Tx to transmit information (2 wires A&B). You can transmit and receive at the same time, as the transmit wires are separate to the receive wires.


View of the fixed connector looking at base of wind sensor (RS-422)


Connector pin details RS-485

FT702LM connector pin details RS485

The FT702LM wind sensor with RS-485 serial digital interface uses the same differential pair (2 wires Data A and Data B) to transmit and receive information. Each device (sensor and controller) must take it in turns to listen and talk otherwise the communications will be corrupted.


View of the fixed connector looking at base of wind sensor (RS-485)



Voltage supply
Sensor 4.4V to 30V dc @12mA (typical excluding data output drive current)
Heater 10V to 30V dc @ 2.5A (max)



Overview   Technical Specification   Installation   Market Sectors




Market sectors and OEM applications

Existing OEM applications

The FT702LM is used in a wide range of fixed and mobile systems. Examples include:

  • Vehicle mounted meteorology systems
  • CBRN (Chemical, Biological, Radiological and Nuclear) integrated monitoring systems
  • Ship based meteorology systems
  • Fixed and portable weather stations


We are discussing potential applications in many sectors including:

  • Military and Civil defence
  • Semiconductor manufacturing
  • Naval Engineering and Oceanology Research
  • Marine meteorology
  • Infrastructure (cranes, bridges, roads, airports)

If you think that the FT702LM series could help you in your project please contact us.











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