FT742-SM Surface Mount Installation

FT742-SM-Surface Mount-Ultrasonic-Wind-SensorThe FT742 Surface Mount (SM) wind sensor is designed for OEM integration into a wide range of engineering systems and has a compass and heater. The sensor has been used in UAVs, drones, military vehicles, autonomous robots, handheld weather stations, CBRN detection units, drifter buoys, vehicle-mounted and ship-based meteorological systems.

The sensor can be rotated to ensure alignment with a standard reference, typically Magnetic North, or the integrated compass can calculate this automatically.

Small, low power, extremely rugged, and weighing only 252g, the FT742-SM is extensively tested and certified for vibration and shock resistance and RF immunity.


How to install the FT742-SM ultrasonic wind sensor



 - Apply non-silicon lubricant to the o-ring and correctly position in the base of the sensor.


 - Pass the cable through the mounting surface and attach it to the sensor.


 - Sit the sensor on the mounting surface and make sure the o-ring is even all around.


 - Rotate the sensor to align the mounting holes - note these are not equally spaced.


 - Fit and tighten the mounting screws (not provided), ensuring they do not exceed a depth of 5mm into the base of the sensor.


For more information and guidance on installation in lightning and salt prone areas please consult the manual.

Marking 2 displays the location of the O-ring groove (FT O-ring part number FT029, manufacturer part number: 2-127 O-Ring EPDM 70 Shore). One O-ring is supplied with new sensors. The use of lubricant on the O-ring will depend on the material selection.

The O-ring compression fit is secured using 5x M3 fixings. The internal thread depth is 4.5mm, the length of fixings should be determined taking into account the thickness of the mounting surface. Regular condition monitoring of the sealing interface is recommended.

Caution: Excessive M3 fixing length may result in damage to the sensor thread and into the sensor.


The sensor requires a supply voltage of 6V to 30V DC (10V DC minimum if the heater is required). With the heater enabled, the power supply should be capable of supplying 2A (max), otherwise 25mA (29mA with the compass enabled).

All electrical connections are made to the digital sensor via an 8-way multi-pole connector located in the base of the wind sensor housing. The connector pin designations are shown below. The connector conforms to IEC 61076-2-101.

FT742-SM-Surface Mount-Ultrasonic-Wind-Sensor





FT009 Wire Colour*





2 +VE (6-30V)  +VE (6-30V)    White
3  TX Data A -  N/C  Blue
4  RX Data A -  Data A -  Black
5  TX Data B + N/C   Grey
6  RX Data B +  Data B +  Pink
7  N/C  N/C  Violet
8  N/C  N/C  Orange

*Caution: Wire colours apply only to FT supplied FT009 cables. Other cables may use different colour schemes. Contact us for further information. 


Heater and Set Point Temperature

The sensor’s integral heater can be used to prevent icing and water condensing in the measurement cavity. This helps to maximise data availability in sub-zero temperatures and high humidity environments.

The factory default setting for the heater set point value is 99 (heater off). If icing is likely to be an issue, or if humidity levels are particularly high where the sensor is to be installed, then a heater set-point temperature of 30°C is recommended.

To use the heater, the set point value must be programmed using the HT command (refer to the user manual for more details) or alternatively it can be adjusted using our Acu-Test Packs.


Always keep the sensor’s internal filter enabled. Where the wind sensor is used for control purposes, always use filtered data. The sensor is dispatched with the internal filter enabled by default and set to a filter length of 1.6 seconds.

Status Flag (error flag)

The sensor has an internal self-checking mechanism. It signals that a reading is invalid by setting an error flag character with in the wind velocity output message:


0 represents no error has been detected. 1 indicates an invalid reading was detected. 2 indicates that an overspeed (out of range) wind speed was detected, provided this setting is enabled (default disabled).

It is important that your data logging equipment or control system can process this invalid data appropriately. See the manual for more details.


Testing of sensors is best performed with our Acu-Test Pack which allows you to connect the sensor to a PC via a USB cable and view wind speed and direction readings in real-time. The pack also allows you to change some settings such as heater set point temperature.

Acu-Test Pack for the FT742-SM wind sensorIn the case of digital sensors, a serial emulator program (such as HyperTerminal) will also function with the cable supplied in the Acu-Test Pack and is another way of testing communication. This allows you to send commands and receive messages serially to and from the sensor. Please note, however, that FT Technologies is not responsible for the content of external sites.

Further details are available in the product manual. Request a manual.

For details on Acu-Test Packs, cables and connectors please refer to Accessories.

Download the Acu-Test Datasheet for the FT742-D-SM (RS422) sensor.

Download the Acu-Test Datasheet for the FT742-D-SM (RS485) sensor.