FT Technologies acures FT722 User manual

FT TECHNOLOGIES LTD.
SUNBURY HOUSE
BROOKLANDS CLOSE
SUNBURY-ON-THAMES
MIDDLESEX TW16 7DX
TEL: [phone]
FAX: [phone]
www.fttechnologies.com
E-MAIL: [e-mail]
A4266-4-EN
February 2019
The FT and Acu-Res logos are registered trademarks of FT Technologies Ltd.
Copyright © 2019 FT Technologies Ltd. All rights reserved.
FT722 & FT742 –Digital (RS485) Wind Sensor Manual
Flat-Front & Pipe-Mounted Variants

Section 1 Introduction
2 FT722 & FT742 (RS485) –FF & PM Sensors –User Manual
Contents
Product Symbols......................................................................................................4
Safety Instructions...................................................................................................5
Consignes de Sécurité.............................................................................................6
1INTRODUCTION................................................................................................. 7
1.1 Product Overview ................................................................................................................7
1.2 Build Versions and Labelling .............................................................................................7
1.3 Scope of Use........................................................................................................................7
1.4 Major Changes Compared to Previous FT702LT Digital Products.................................8
1.5 FT722 and FT742 differences .............................................................................................8
1.6 Disclaimer.............................................................................................................................8
2FUNCTIONAL DESCRIPTION ...........................................................................9
2.1 Technical Performance .......................................................................................................9
2.2 Wind Speed Calibration ....................................................................................................11
2.3 Wind Speed and Direction Filtering.................................................................................11
2.4 Electronic Rotation of the Datum Direction....................................................................12
2.5 Selective Filter Scheme.....................................................................................................12
2.6 Error Detection...................................................................................................................12
2.7 Overspeed Warning Scheme............................................................................................12
2.8 Heater Setup.......................................................................................................................12
2.9 Acoustic Temperature.......................................................................................................13
3MECHANICAL INSTALLATION & LIGHTNING PROTECTION...................... 14
3.1 Flat-Front Sensors.............................................................................................................14
3.1.1 Mechanical & Electrical Integration .................................................................................14
3.1.2 Connector Details............................................................................................................18
3.1.3 Cable Details...................................................................................................................18
3.1.4 Lightning, Surge & EMI Protection..................................................................................20
3.2 Pipe-Mount Sensors..........................................................................................................25
3.2.1 Mechanical & Electrical Integration .................................................................................25
3.2.2 Assembling the Pipe Mount Adapter...............................................................................29
3.2.3 Connector Details............................................................................................................30
3.2.4 Cable Details...................................................................................................................30
3.2.5 Lightning, Surge & EMI protection ..................................................................................32
4SERVICE, CONFIGURATION & TESTING...................................................... 37
4.1 Inspection...........................................................................................................................37
4.2 Fault Finding & Troubleshooting.....................................................................................38
4.3 Returns ...............................................................................................................................39
4.4 The Acu-Test Evaluation Kit.............................................................................................40
4.4.1 Software Installation........................................................................................................41
4.4.2 Acu-Vis 2.0 Software Operation......................................................................................42

Section 1 Introduction
3 FT722 & FT742 (RS485) –FF & PM Sensors –User Manual
4.4.3 Command Line Terminal Programs (Including Tera Term) ............................................47
5SENSOR COMMUNICATION........................................................................... 49
5.1 Introduction........................................................................................................................49
5.2 RS485 Protocol ..................................................................................................................49
5.3 Configuring the Sensor.....................................................................................................50
5.4 Communication..................................................................................................................50
5.4.1 Conventions used in this manual ....................................................................................50
5.4.2 Data Transmission ..........................................................................................................51
5.4.3 Message Format..............................................................................................................51
5.4.4 Listener and Talker Identifiers.........................................................................................52
5.4.5 Calculating the Message Checksum...............................................................................52
5.4.6 Disabling the Checksum..................................................................................................52
6PARAMETER SETTINGS ................................................................................54
6.1 Command Types................................................................................................................54
6.1.1 Set Commands................................................................................................................54
6.1.2 Query Commands ...........................................................................................................55
6.2 User Calibration Table.......................................................................................................56
6.3 Timing Constraints............................................................................................................57
6.4 Command Parameters.......................................................................................................58
6.4.1 AM: Set or Query the Anemometer Mount Orientation...................................................58
6.4.2 AT.1: Query the Acoustic Temperature...........................................................................59
6.4.3 AT.2: Set or Query the Acoustic Temperature Units.......................................................60
6.4.4 AT.3 Set or Query the Acoustic Temperature Filter Length............................................61
6.4.5 BR: Set or Query the Serial Interface Baud Rate............................................................62
6.4.6 CF: Set or Query the Wind Datum Offset Angle .............................................................63
6.4.7 CU: Set or Query the Continuous Update Setting...........................................................64
6.4.8 DF: Set or Query the Wind Velocity Data Format ...........................................................65
6.4.9 DG: Query the Run-time Counter....................................................................................66
6.4.10 DL: Set or Query the Command Delay Interval ..........................................................67
6.4.11 ER: Query or Reset the Error Report..........................................................................68
6.4.12 FL.1: Set or Query General Filter Settings .................................................................69
6.4.13 FL.2: Set or Query Filter Lengths................................................................................70
6.4.14 FL.3: Set or Query the Selective Filter........................................................................71
6.4.15 HT.1: Set or Query General Heater Settings.............................................................72
6.4.16 HT.2: Set or Query Delay Heater Settings.................................................................73
6.4.17 HT.3: Set or Query Limit Heater Settings ...................................................................74
6.4.18 ID: Set or Query the Listener & Talker Identifiers.......................................................75
6.4.19 MM: Reset or Query the Min/Max Recorded Wind Speed..........................................76
6.4.20 OS: Set or Query Overspeed Warning Scheme........................................................77
6.4.21 RS: Reset the Sensor .................................................................................................78
6.4.22 SN: Query the Serial Number and Platform Version ..................................................79
6.4.23 SV: Query the Software Version.................................................................................80
6.4.24 UC.1: Set or Query General User Calibration Settings...............................................81
6.4.25 UC.2: Clear User Calibration Table Record................................................................82
6.4.26 UC.3: Set User Calibration Table Record...................................................................83
6.4.27 UC.4: Save and Read User Calibration Table............................................................84
6.4.28 UC.5: Set & Query User Calibration Table Label .......................................................85
6.4.29 US: Set or Query Saved Parameters..........................................................................86
6.4.30 WV Polar: Query the Wind Velocity Reading..............................................................88
6.4.31 WV NMEA: Query the Wind Velocity Reading............................................................89

Section 1 Introduction
4 FT722 & FT742 (RS485) –FF & PM Sensors –User Manual
Product Symbols
The following symbols may be used upon the product and within the manual.
Meaning / Description
Symbol
Signification / Description
Warning/ Caution
An appropriate safety instruction should be
followed or caution to a potential hazard
exists
Avertissement / Attention
Une instruction de sécurité doit être
suivie ou attention portée à un
danger potentiel qui existe.
DC Current only
Equipment operates under Direct Current
(DC) supply only.
Courant continu uniquement
L'équipement fonctionne sous une
alimentation en courant continu (CC)
uniquement.
Product Disposal
In accordance with European directive
2012/19/EU on Waste Electrical and
Electronic Equipment (WEEE), these
product components must be recycled. This
should be done by returning the product to
FT Technologies or by using an appropriate
waste disposal company. This product
should not be disposed of in general waste
of landfill. This product complies with the
RoHS2 (2011/65/EU) directive.
Élimination du produit
Conformément à la directive
européenne 2012/19/EU relative aux
déchets d'équipements électriques et
électroniques (DEEE), ces
composants du produit doivent être
recyclés. Cela doit être fait par le
retour du produit à FT Technologies
ou en utilisant une entreprise
d'élimination de déchets. Ce produit
ne doit pas être éliminé avec les
ordures ménagères ou en décharge.
Ce produit est conforme à la
directive RoHS2 (2011/65/EU).
Recognized Component
Sensors marked with the ETL label indicate
that the product conforms to UL Standard
61010-1 and is certified to CSA Standard
C22.2 No. 61010-1.
4000105
Composant Reconnu
Les capteurs marqués avec
l’étiquette ETL indiquent que le
produit est conforme à la norme UL
61010-01 et est certifié à la norme
CSA22.2 61010-01.
CE Mark
The EU Declaration of Conformity complies
with the essential requirements of the
following applicable EMC Directive
2014/30/EU, and carries the CE Marking
accordingly.
Marquage CE
Déclaration de conformité CE de la
compatibilité électromagnétique
(EMC) et marquage CE
conformément à la directive CE
2014/30/EU.

Section 1 Introduction
5 FT722 & FT742 (RS485) –FF & PM Sensors –User Manual
Safety Instructions
English
•To ensure the safe installation and operation of this product the equipment must be installed and
integrated:
oUsing suitably qualified and trained personnel
oIn accordance with any regional electrical codes
oIn accordance with the instructions set out in this manual, observing all information, warnings
and instructions
oIn accordance with any other instructions or guidance FT Technologies provide
•To ensure that the product remains compliant with the electrical safety requirements of the UL / CSA
61010-1 Standards it must be;
oConnected to an appropriately approved isolated power supply (for example UL/CSA IEC
60950-1:2005 + A1:2009 + A2:2013) rated 12-30VDC and be current limited (6A Max)
oProtected by UL 1449 listed surge protection devices
oConnected with an approved interface cable (for example UL/ CSA recognised AWM style
21198, rated 300V, 80°C)
•The equipment must only be operated within the range of the specified technical data and used for the
purposes for which it was designed.
•The equipment should always be transported in packaging which is appropriate, that will prevent any
accidental damage from occurring.
•Always ensure that any failures or errors from the product cannot cause any damage to any other
equipment or property or cause any other consequential effects.

Section 1 Introduction
6 FT722 & FT742 (RS485) –FF & PM Sensors –User Manual
Consignes de Sécurité
Français
•Pour assurer la sécurité de l'installation et le fonctionnement de ce produit, l'équipement doit être
installé et intégré :
oÀ l'aide de personnel qualifié et formé
oConformément à tous les codes électriques régionaux
oConformément aux instructions figurant dans ce manuel et en observant toutes les
informations, avertissements et instructions
oConformément à d'autres instructions ou directives que FT Technologies fournit
Pour garantir que le produit reste compatible avec les exigences de sécurité électrique de l'UL/CSA
61010-1 normes, l'équipement doit être;
oConnecté à une alimentation agrée convenablement isolée (par exemple UL/CSA IEC 60950-
1:2005 + A1:2009 + A2:2013) de tension nominale 12-30 VCC et avec courant limité (6 A max)
oProtégé par des dispositifs de protection UL 1449 contre les surtensions
oConnecté avec un câble d'interface (par exemple UL/CSA reconnu AWM style 21198, de
valeur nominale 300 V, 80°C)
•L'équipement doit être utilisé uniquement dans la plage des données techniques spécifiées et utilisé
aux fins pour lesquelles il a été conçu.
•L'équipement doit toujours être transporté dans un emballage qui est approprié, qui permettra d'éviter
qu'un quelconque dommage accidentel ne survienne.
•En toutes circonstances, garantir que les défaillances ou les erreurs du produit ne puissent pas causer
des dommages à d'autres équipements ou autres biens ou provoquer d'autres effets indirects.

Section 1 Introduction
7 FT722 & FT742 (RS485) –FF & PM Sensors –User Manual
1 INTRODUCTION
1.1 Product Overview
The FT722 and FT742 are solid-state ultrasonic wind sensors using a patented Acoustic Resonance
airflow sensing technique to measure accurately both wind speed and direction. The sensors have been
specifically designed to operate in harsh environments including offshore, lightning and ice-prone areas.
The wind sensor has no moving parts to degrade or wear-out and is designed for applications requiring
high reliability. They help reduce costly down-time and unscheduled maintenance visits.
Mounting and aligning the sensor is very simple. A 0° wind datum marking can be used to align the
sensor to a reference point. For operation in ice-prone areas, the FT722 and FT742 are fitted with a
highly-effective thermostatically controlled all-body heating system. A three element heater is used to
ensure heat is evenly distributed over the entire surface area.
1.2 Build Versions and Labelling
The electrical interface is the same as our previous range of FT702LT (RS485) sensors. The same pin-
outs and RS485 communication standard is used.
Figure 1 shows how to identify the sensor platform version and individual serial number, depending on
the attached main labels:
Additional labels may be attached. Only sensors marked with the Intertek label conform to the UL Standard
61010-1 and are certified to CSA Standard C22.2 No. 61010-1.
Figure 1: Examples of Main Sensor Labels
1.3 Scope of Use
The sensor is designed, manufactured and optimised for high availability.
No promise in part or full can be given to guarantee a sensor’s continuous operation, as exceptional
circumstances can occur that may result in the failure of the output from a sensor. Exceptional
circumstances can include:
•Poor installation
•Inadequate inspection
•Power supply failures
•Poor quality electrical connections
•Lightning exposure
•Problematic environmental conditions or combination of conditions
•Physical Damage
Typically higher levels of wind speed and wind direction data availability are achieved through the use
of an additional FT sensor or alternative sensor. Control strategies or algorithms, which compensate in
whole or in part, for any temporary interruption of data from individual sensors should also be applied.
The choice and implementation of such methods is entirely the Purchaser’s responsibility.

Section 1 Introduction
8 FT722 & FT742 (RS485) –FF & PM Sensors –User Manual
1.4 Major Changes Compared to Previous FT702LT Digital Products
•The FT742 has a higher speed range available (0-75m/s)
•New optional Overspeed Warning Scheme introduced (see Section 2.7). By default this feature
is disabled to match legacy behaviour
•This product has a faster data output rate (was up to 5Hz, now up to 10Hz)
•By default, the averaging filter now samples over the same time period, but averages twice as
many data points
•A new innovative mechanical design incorporating a series of “turbulators” (patent pending)
which condition the air flow to deliver improved accuracy
•An optional Selective Filter can be enabled (see Section 2.5), which rejects invalid wind data
from entering the averaging filter, thus improving data quality and reducing error flags. This
feature is disabled by default to match legacy behaviour
•The Acoustic Temperature and Anemometer Mount features were introduced in software V7.5
It is strongly recommended that customers carry out their own product validation before deployment of
the FT wind sensor.
1.5 FT722 and FT742 differences
The FT722 is capable of recording 0-50m/s wind speeds.
The FT742 is capable of recording 0-75m/s wind speeds.
Since the maximum speeds are different, the optional overspeed warning is triggered at different
speeds.
1.6 Disclaimer
There are no warranties, representations or conditions, expressed or implied of any kind given in this
manual for any particular design application. The Purchaser should independently undertake sufficient
testing to confirm validity and suitability of any design. The Purchaser assumes all risks and liability in
conjunction with the use of the information given.
Any warranty given by FT Technologies in respect of the Equipment is conditional upon the sensor
being handled, installed, integrated and operated in accordance within the guidelines given in this
manual.
FT Technologies can take no responsibility for the effectiveness of any sensor lightning protection
scheme implemented. The wind sensor has passed a wide range of EMC tests but FT Technologies
does not warrant the sensor to survive lightning strikes.
Information supplied by FT Technologies Ltd. shall not be construed as permission to license to operate
under, or recommendation to infringe any existing or pending patent, patent applications or trademarks.

Section 2 Functional Description
9 FT722 & FT742 (RS485) –FF & PM Sensors –User Manual
2 FUNCTIONAL DESCRIPTION
2.1 Technical Performance
Sensor Performance1 & 2
Measurement Principle Acoustic Resonance (compensated against variations in temperature,
pressure and humidity)
Wind speed Measurement
FT722 FT742
Range 0-50m/s 0-75m/s
Resolution 0.1m/s 0.1m/s
Accuracy ±0.3m/s (0-16m/s) ±0.3m/s (0-16m/s)
±2% (16m/s-40m/s) ±2% (16m/s-40m/s)
±4% (40m/s-50m/s) ±4% (40m/s-75m/s)
Knots and km/h options available.
Wind Direction Measurement
Range 0 to 3600 to 360°
Accuracy 2RMS (within 10of 0) 2RMS (within 10of 0)
4RMS (beyond 10of 0) 4RMS (beyond 10of 0)
Resolution 1(both models)
Acoustic Temperature Measurement5
Units Celsius, Fahrenheit or Kelvin
Resolution 0.1°
Accuracy ±2°C under the following conditions:
Wind speed between 5m/s and 60m/s
Temperature Difference < 10°C (Sensor Temp. vs Air Temp.)
Operating (air) temperature between -20°C and +60°C
Environment
Temperature Range -40 to +85C (operating & storage)
Humidity 0-100%
Altitude 0-4000m
Data I/O
RS485 Interface Digital RS485 (half duplex), galvanically isolated from power
supply lines and case
Format ASCII data, polled or continuous output modes
Data Update Rate Up to 10 measurements per second (10Hz)
Power Requirements3
Supply Voltage 24VDC nominal (12V to 30VDC)
Supply Current (Heater off) 31mA (typical)
Supply Current (Heater on) 6A (max) –The heater is thermostatically controlled. Heater power
consumption will depend on the heater energy required to keep the sensor’s
temperature at a user determined set point. The heater is limited to 4A and
99W by the default software settings 4.
Physical
Weight Flat-Front 320g (max). Pipe-Mount 350g (max. excluding adaptor)
Material Aluminium alloy, hard anodised
I/O Connector 5 way (RS485 option)
Mounting Method Flat-Front or Pipe-Mount options. Self-aligning, screw fixing

Section 2 Functional Description
10 FT722 & FT742 (RS485) –FF & PM Sensors –User Manual
Notes:
1.All specifications subject to change without notice.
2.Specifications calculated with the default settings and filters enabled.
3.See safety instruction requirements (page 5 & 6).
4.The heater set point, current, operational voltage and maximum power limits can be configured at the
factory or by programming the sensor’s internal parameter settings, see Sections 6.4.15 and 6.4.17,
or contact FT technologies for further information
5.Acoustic Temperature accuracy can be affected by the wind sensor heater –user calibration may be
required

Section 2 Functional Description
11 FT722 & FT742 (RS485) –FF & PM Sensors –User Manual
2.2 Wind Speed Calibration
The wind sensor is calibrated in our wind tunnels before dispatch. As the sensor has no moving parts, there is
no need to recalibrate a sensor over its lifetime as no measurement degradation will occur. The sensor’s compact
strong monolithic shape is designed to prevent accidental transducer movement or damage. FT Technologies’
calibration procedure and wind tunnels are designed to give a calibration profile that is within the accuracy limits
set in the product technical specification (see Section 2.1). Periodically the accuracy of FT’s wind tunnels are
compared with the accuracy of an independent wind tunnel to ensure that no drift has occurred.
In exceptional circumstances users may wish to apply additional calibration factors. The sensors have an option
to set a User Calibration Table, which can modify the wind sensor’s wind speed output (see Section 6.4.24).
The User Calibration Table can be programmed with up to 64 correction factors which are maintained in non-
volatile memory. When enabled, the uncorrected wind speed output is adjusted according to the stored User
Calibration Table records using linear interpolation. The adjustments are applied to wind speed readings
regardless of wind direction.
For further details on user calibration modification using the Acu-Vis 2.0 program please contact FT Technologies.
2.3 Wind Speed and Direction Filtering
It is important that the system does not rely exclusively on a single wind reading for any control decision. A single
reading may be inaccurate due to measurement error, turbulence, corruption or interference. It is recommended
that an average of wind readings is used. In addition if 100% data availability is required then a second FT sensor
or alternative wind sensors should be fitted in addition.
The sensor has optional internal filtering available. This is a digital finite impulse response (FIR) filter, which works
by calculating the moving average of a fixed number of previous readings. If filtering is being applied externally,
the sensor’s output filters can be disabled. If filtering inside the sensor is preferred, the length of the averaging for
both wind speed and direction can be independently set (See Sections 6.4.12 & 6.4.13).
Figure 2: Examples of FIR Filtering
Always use an average of several readings for any calculations or control decisions because
single readings can accidentally become corrupted.

Section 2 Functional Description
12 FT722 & FT742 (RS485) –FF & PM Sensors –User Manual
2.4 Electronic Rotation of the Datum Direction
The datum direction of the sensor can be offset electronically by using the CF command (Section 6.4.6). This
facility can be used to adjust the datum direction in case of any mechanical misalignment within the mounting
arrangement. To offset the datum direction, in either the clockwise or anticlockwise direction, use the CF
command (Section 6.4.6). Once the offset has been set it will be retained in the sensor Flash memory.
2.5 Selective Filter Scheme
In addition to the averaging filter described in Section 2.3, the sensor has a feature called the Selective Filter. The
scheme allows the user to set a “validity period”, during which the sensor will exclude invalid readings from
entering the averaging filter. The output will freeze on the last previous “good” reading and only raise an error flag
once the number of bad readings exceeds the validity period. This scheme can be enabled by factory configuration
or by using the FL software command (see Section 6.4.14). The filter is turned off by default to match legacy
behaviour.
2.6 Error Detection
The sensor has a self-checking mechanism which can detect if a reading is invalid. On very rare occasions where
an invalid reading may have been detected, this is signalled to the computer or data logger by setting an error
flag character within the wind velocity output message (see Sections 6.4.30 & 6.4.31).
When an error is detected, the error flag character is set to a value of: 1.
Note: An optional Overspeed Warning Scheme can be enabled (but is disabled by default). See Section 2.7 for
further details.
It is important that error flags are not ignored. Data associated with an error flag should not be processed as valid
wind data. The system should be capable of riding through rare periods when data may be temporarily unavailable.
If errors are ongoing (more than several seconds), a reset of the sensor should be applied (see Section 6.4.21 for
instructions on sending an RSU command).
It is recommended that errors are monitored and logged. If the frequency of errors has recently increased, then
inspection of the sensor for physical blockages may be required (see Section 4.1).
2.7 Overspeed Warning Scheme
During periods where the sensor detects wind speed beyond the rating of the sensor, the sensor will (by default)
indicate a general error flag status.
An additional Overspeed Warning Scheme can be enabled: if an overspeed condition is detected (above the
highest speed rating), the error flag character will be set to: 2 (see Sections 6.4.30 and 6.4.31) unless a general
error condition is also detected. Not all high speeds can be detected and may report as the regular error flag 1
instead.
To comply with legacy behaviour, this scheme is disabled by default.
The Overspeed Warning Scheme can be enabled by software commands (see Section 6.4.20), via the Acu Vis
PC software program (see Section 4.4) or enabled in the factory before despatch.
2.8 Heater Setup
The sensor is fitted with an integral three-element distributed heater that can be used to prevent icing-up of the
sensor in freezing temperatures. The heater is controlled automatically by the sensor using a user programmable
‘set point’ temperature. The sensor uses a control scheme which dynamically changes the current supplied to
each individual heater element in order to maintain the programmed set point temperature.
It is important to consider the resistive losses in the cable and rate the cable appropriately. In general, power
losses in the cable should be minimised in order to maximise the available heating power to the sensor. A heater
setpoint temperature of >30°C is recommended for most applications. To change the heater set point or to disable
the heater use the Acu-Vis test software or the HT RS485 software command (see Section 6.4.15).

Section 2 Functional Description
13 FT722 & FT742 (RS485) –FF & PM Sensors –User Manual
Since the heater circuit is thermostatically controlled, the actual power being drawn from the supply will depend
on the programmed set-point and the environmental conditions (i.e. ambient temperature, wind speed,
precipitation etc.). The maximum power that the sensor can consume is by default software limited to 99W (with
the heater enabled). The power supply must be rated to provide the maximum power that the sensor can consume.
The maximum current limit of the sensor can be adjusted between 0.1 and 6.0 Amps (from the default of 4 Amps
and in increments of 100mA). By default the heater requires a minimum of 11VDC for operation. The heater
activation voltage and the maximum current limit can be changed at the factory, using the Acu-Vis test software
or the HTL software command (see Section 6.4.17).
If the sensor is powered up and there is a possibility it has become iced, it is recommended that the sensor is
allowed to heat up for 30 minutes, followed by a User Reset Command (see Section 6.4.21) to permit the sensor
to initialise correctly without ice blockage.
2.9 Acoustic Temperature
The Acoustic Temperature feature takes a measurement of the ambient temperature via measurable acoustic
properties of the airflow. Sections 6.4.2, 6.4.3 and 6.4.4 describe related software commands.
The averaging system can be performed for 0 to 50 seconds (in increments of 10 seconds), or between 1 to 10
minutes (in increments of 1 minute).
See Section 2.1 for details regarding operating specifications. Operation with high temperature gradients
(between sensor body and ambient airflow), extreme humidity levels and low wind conditions (below 5m/s) may
result in reduced accuracy.
Caution: The acoustic temperature feature requires calibration at FT Technologies. If the sensor has had a
software upgrade to 7.5 (or above) then the data will be uncalibrated and may not comply with the official
specification. Testing is recommended to confirm suitability for the application.

Section 3 Mechanical Installation & Lightning Protection
14 FT722 & FT742 (RS485) –FF & PM Sensors –User Manual
3 MECHANICAL INSTALLATION & LIGHTNING PROTECTION
Two mounting options are available and have different mechanical dimensions and properties. The Flat-Front
sensor allows for simple mounting against a flat bar using a single screw, nut and washer. The Pipe-Mount sensor
offers enhanced cable protection from environmental factors and an improved low-impedance ground path for
lightning protection - the pipe mount sensor may be preferred for difficult or lightning-prone areas. See Section
3.1 for Flat-Front sensors, Section 3.2 for the Pipe-Mount sensors.
Ensure the airflow into the sensor is not obstructed or influenced by nearby objects. We recommend a minimum
clearance distance of 20cm between the sensor and other objects.
•See safety instruction requirements on pages 5 & 6.
•The wind sensor installation must be properly designed to ensure the correct
operation of the sensor. This section is for guidance only. It is the responsibility of
the designer and installer to ensure that the installation and its design is fit for
purpose. Please see the Disclaimer in Section 1.6.
3.1 Flat-Front Sensors
3.1.1 Mechanical & Electrical Integration
The flat-front model has a flat contact area used to attach the sensor onto a mechanical bracket.

Section 3 Mechanical Installation & Lightning Protection
15 FT722 & FT742 (RS485) –FF & PM Sensors –User Manual
Figure 3: Flat Front Wind Sensor
The sensor measures the wind direction relative to the mounting flat and bar. When the wind sensor is correctly
aligned the wind direction measurements will be as shown in Figure 4.

Section 3 Mechanical Installation & Lightning Protection
16 FT722 & FT742 (RS485) –FF & PM Sensors –User Manual
Figure 4: Correct Sensor Alignment

Section 3 Mechanical Installation & Lightning Protection
17 FT722 & FT742 (RS485) –FF & PM Sensors –User Manual
The Flat-front option is designed to be mounted using an M6 socket head cap screw, nut and washer made from
galvanised steel.
The mounting flat on the support tube of the sensor (see Figure 5) allows for firm fitting against a flat surface. The
preferred material of the mounting bar is an appropriate grade of aluminium. As an alternative hot dipped
galvanised steel can be used (aluminium is preferred as it provides superior thermal conduction in icing
conditions). If galvanised steel material is selected, the mounting bar should have a minimum galvanising
thickness of 50µm to ensure long-term protection against corrosion. The galvanising quality should conform to
ASTM A123, Standard Specification for Zinc (Hot-Dip Galvanised) Coatings on Iron & Steel Products.
The mounting flat of the sensor is provided free of coatings to allow for a good electrical connection between the
body of the sensor and ground through the mounting bar. In order to protect the mounting surface against
corrosion, a very thin layer (<0.2mm) of electrical joint compound should be applied. An example of this could be
AFL Global’s Electrical Joint Compound # 2. It should be applied directly to the sensor’s mounting surface, whilst
avoiding the fixing hole. Use of an electrical joint compound will also help to maintain long-term low impedance
connection to ground. This connection should be checked as part of a service inspection of the sensor, as detailed
in Section 4.
Some electrical joint compounds contain fluoride etchants which may react with certain materials. Material
compatibility should therefore be checked prior to application (refer to the electrical joint compound manufacturer’s
data).
In order to keep the pressure within the sensor equalised with the atmospheric pressure, a small breather hole is
located within its support tube. It is therefore important that the airway to this breather hole be kept clear. This can
be achievable by cutting a small 3mm channel in the mounting bar as shown (see Figure 5).
Figure 5: Sensor Installation
It is recommended that a protective sleeve be fitted over the base of the sensor and the connector. This will
provide environmental protection as well as stress-relief from vibration. Heat shrink or cold shrink would be
suitable for this purpose. FT offers a cold shrink solution which is available on request (part number FT909). The
sleeve should cover the lower part of the support tube, the connector itself and at least 25mm of cable (see Figure
6).
Figure 6: Flat-Front sensor with protective sleeve

Section 3 Mechanical Installation & Lightning Protection
18 FT722 & FT742 (RS485) –FF & PM Sensors –User Manual
3.1.2 Connector Details
All electrical connections are made to the digital sensor via a 5-way multipole connector located in the base of the
wind sensor housing. The connector pin designations are shown in Figure 7 and the connector/mating connector
manufacturer’s part numbers in Figure 8.
Figure 7: Sensor Connector Pin
Manufacturer
Connector Type
Connector
Description
Manufacturers Part
Number
Maximum Outer
Cable Diameter
W.W.Fischer
RS485 Cable
Side Connector
5 way plug
SE104Z053-130/8.7
8.0mm
ODU
RS485 Cable
Side Connector
5 way plug
SX2F1C-P05NJH9-0001
9.2mm
Figure 8: Connector Sourcing Options
3.1.3 Cable Details
The mating connectors are suitable for use with cables with overall diameters as per the table above and for
individual cores of diameters of up to 1.2mm. Cable such as SD980CPTP 3x2x0.5mm² from SAB Brockskes or
similar types may be used. Care must be taken to ensure that the cable is suitable for the environment it will be
used in and is adequately approved, for example AWM Style 21198.
In an area with a moderate or severe lightning strike exposure the cable shield may not provide sufficient
protection. In this case the cable will require further shielding such as being enclosed in a metal pipe or conduit.
FT can supply cables with a mating connector leading to bare wires at the other end, for connection to user
systems. The digital version of the -FF and -PM sensors use either the FT001 (15m) or FT007 (5m) digital cable.
Note: 4-20mA sensors use a different (8-way) connector and will require an alternative cable.
Please ensure that when sourcing cables from alternative sources that the cables are suitable for the requirements
and the cable wiring is equivalent. The sensor is protected against common miswiring events within the operating
range of the sensor.
For further details of cables and accessories please visit the FT website at https://www.fttechnologies.com/Wind-
Sensors/Accessories
FT can also provide Acu-Test cables allowing operators to view wind speed and direction data with the Acu Vis
software. These cables are intended for short testing periods and are not suitable for long-term datalogging.
Please see Section 4.4 for further details.

Section 3 Mechanical Installation & Lightning Protection
19 FT722 & FT742 (RS485) –FF & PM Sensors –User Manual
Figure 9: Cable Specifications

Section 3 Mechanical Installation & Lightning Protection
20 FT722 & FT742 (RS485) –FF & PM Sensors –User Manual
3.1.4 Lightning, Surge & EMI Protection
It is important to install the sensor with appropriate protection against lightning and other sources of
electromagnetic interference in order to maximise its chance of survival and continued operation during and after
exposure.
Protection against direct lightning effects
The sensor installation must be designed in such a way that a protection zone is created around the sensor so
that its body can never be subjected to a direct lightning strike.
Figure 10: Direct lightning strike
Figure 11: Indirect lightning strike
This level of protection is achievable through the use of conductive structural parts known as “lightning
interceptors”. These help to create the protection zone and to divert the majority of the lightning current away to
ground.
The lightning interceptor must have a direct connection to ground through metal parts with a minimum cross-
sectional area of 50mm2(see Figure 13). The length of any grounding wire or strap must be kept to a minimum.
This will help to provide the lowest possible impedance path to the ground reference.
The recommended clearance distance between the sensor and the lightning interceptor should be 30x the
diameter of the interceptor material, but never less than 20cm (due to aerodynamic factors and an increased risk
of lightning flashover).