FT Technologies FT742 User manual

1 FT742 (4-20mA) –DM Sensors - User Manual
FT TECHNOLOGIES LTD.
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BROOKLANDS CLOSE
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MIDDLESEX TW16 7DX
TEL: [phone]
FAX: [phone]
WEB: www.fttechnologies.com
E-MAIL: [e-mail]
A4277-3-EN
November 2017
The FT and Acu-Res logos are registered trademarks of FT Technologies Ltd.
Copyright © 2017 FT Technologies Ltd. All rights reserved.
FT742 - Analogue (4-20mA) Wind Sensor Manual
Direct-Mount Variant

2 FT742 (4-20mA) –DM Sensors - User Manual
Contents
Safety Instructions .......................................................................................4
Consignes de sécurité...................................................................................5
1INTRODUCTION ......................................................................................6
1.1 Product Overview....................................................................................................6
1.2 Build Versions & Labelling.....................................................................................6
1.3 Scope of Use............................................................................................................6
1.4 Disclaimer ................................................................................................................7
2FUNCTIONAL DESCRIPTION.................................................................8
2.1 Technical Performance...........................................................................................8
2.2 Current Loops..........................................................................................................9
2.2.1 Current Loop Characteristics................................................................................9
2.2.2 Using the Averaging Filter.....................................................................................9
2.2.3 Wind Speed Loop .................................................................................................9
2.2.4 Wind Direction Loop........................................................................................... 10
2.2.5 Changing the Wind Datum Direction ................................................................. 11
2.2.6 Error Conditions................................................................................................. 12
2.3 Heater Operation .................................................................................................. 13
2.4 Low Power Operation .......................................................................................... 13
3MECHANICAL & ELECTRICAL INSTALLATION .................................14
3.1 Connector Details................................................................................................. 21
3.2 Cable Details......................................................................................................... 21
3.3 Lightning, Surge & EMI Protection..................................................................... 22
4SERVICE, CONFIGURATION & TESTING............................................24
4.1 Inspection ............................................................................................................. 24
4.2 Fault Finding & Troubleshooting........................................................................ 25
4.3 Returns.................................................................................................................. 26
4.4 The Acu Test Evaluation PC Software............................................................... 27

3 FT742 (4-20mA) –DM 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.

4 FT742 (4-20mA) –DM 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 provides
•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.

5 FT742 (4-20mA) –DM 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
6 FT742-DM (4-20mA) –Sensors - User Manual
1 INTRODUCTION
1.1 Product Overview
The FT742-A-DM sensor is designed for general meteorological applications - particularly in harsh
environments such as areas of icing, sand, dust and offshore installation. The solid-state ultrasonic wind sensor
uses acoustic resonance airflow sensing techniques to measure both wind speed and direction. The wind
sensor has no moving parts to degrade or wear-out and is designed for applications requiring high reliability.
Mounting and aligning the sensor is simple. A compass (not supplied) can be used to align the sensor with
magnetic North (0°) using the 0° wind datum marking feature (see Figure 12). For operation in ice-prone areas,
the FT742 is 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.
FT sensors are configurable and can be factory programmed to the required customer settings, contact FT
Technologies for further details.
Note: The FT742-DM range is not suitable for turbine control applications. The FT742-FF and FT742-PM ranges
are designed for this application.
The standard FT742-DM, when installed to FT Technologies recommendations, is electrically isolated from the
mounting pole, making it unsuitable for conductively-grounded lightning protection schemes. The addition of the
FT035 grounding accessory provides a reliable, low-resistance grounding path. Refer to Section 3.3 or contact
FT Technologies for further information.
1.2 Build Versions & Labelling
Figure 1 shows how to identify a sensor, the serial number and calibration code (if applicable). Section 2.2.3
describes how you can use the wind speed scaling reference to identify the calibration of the sensor.
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 sensors are designed, manufactured and optimised for high availability.
No promise in part or full can be given to guarantee a wind 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

Section 1 - Introduction
7 FT742-DM (4-20mA) –Sensors - User Manual
•Lightning exposure
•Physical damage
•Problematic environmental conditions or combination of conditions
1.4 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.
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
8 FT742-DM (4-20mA) –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
Range 0-75m/s
Resolution 0.1m/s
Accuracy ±0.3m/s (0-16m/s)
±2% (16m/s-40m/s)
±4% (40m/s-75m/s)
Wind Direction Measurement
Range 0 to 360
Accuracy 4RMS
Resolution 1
Environment
Temperature Range -40 to +85C (operating & storage)
Humidity 0 - 100%
Altitude 0 - 4000m
Data I/O
Analogue Option 4-20mA, galvanically isolated from power supply lines and case
Format 1x 4-20mA current loop for wind speed (see Section 2.2 for scaling factors)
1x 4-20mA current loop for wind direction (4-20mA = 0 to 360°) (see
Figure 5 for offset options)
Reading Update Rate 10Hz
Configuration Port3RS485 half-duplex, non-isolated relative to power ground
Power Requirements4
Supply Voltage 24VDC nominal (12-30VDC range)
Supply Current (Heater off) 31mA typical for the sensor + 2x current loops (4-20mA)
Supply Current (Heater on) 6A (max) 5 –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 sensor is limited to 4A and
99W5by the default software settings (the current limit can be modified, see
Section 4 or contact FT for details).
Physical
Weight 380g (without size adaptors)
Material Aluminium alloy (hard-anodised)
I/O Connector 8 way
Mounting Method Pipe-Mount screw-fix (33.7mm external diameter EN10255 pipe).
Various size adaptors and pipe-inserts available.
Notes:
1.All specifications subject to change without notice.
2.Specifications calculated with default settings.
3.The Configuration Port is provided to allow the user to change the internal settings of the sensor and to
perform diagnostic testing. This interface should only be used for configuration and test purposes. This
interface is not intended for permanent connection to the computer.
4.The heater set point and current limit can be pre-configured in the factory or adjusted using the FT Acu-Test
Analogue kit.
5.See safety instruction requirements (pages 4 and 5).

Section 2 –Functional Description
9 FT742-DM (4-20mA) –Sensors - User Manual
2.2 Current Loops
2.2.1 Current Loop Characteristics
The wind sensor incorporates two galvanically isolated 4-20mA current loop outputs, one loop for wind speed
and one loop for wind direction. These current loop outputs can be converted into measurable output voltages
with the addition of external resistors.
Each loop should be powered from a DC supply in the range 12V to 30V. A positive supply must be provided to
one of the current loop wires. The other wire must then be connected through a current meter to ground. This is
because the current loops sink current, they do not source it. A common supply can be used if required. Loop
connections are polarity insensitive so that the +ve or –ve loop supply connection can be made to either of the
current loop connection pins. See example wiring in Section 4.4.
The current loops are able to operate over long cable distances; however the overall loop resistance should not
exceed the values given in Figure 2. It is recommended that twisted pair interconnection cabling should be
used. The cable should also include an overall braided screen.
Loop Supply
Maximum Loop Resistance
12V
100 Ω
20V
500 Ω
24V
700 Ω
30V
1000 Ω
Figure 2: Maximum Current Loop Resistance
The wind sensor’s current loop outputs are updated at a rate of 10 times per second. An average of several
readings should always be used for any calculations because single readings can accidentally become
corrupted (see Section 2.2.6).
2.2.2 Using the Averaging Filter
The sensor has an internal averaging filter enabled by default, which dampens the speed and wind direction
outputs by averaging previous data values. By default this feature averages the last 16 readings (1.6s), this can
be factory configured to values 0.1-6.4s in 0.1s increments. It is possible to disable the internal filter (but not
recommended) via the Acu-Test Analogue test software. Contact FT technologies for further details.
Selective Filter
In addition to the averaging filter described above, the sensor has an optional feature called the Selective Filter
that may improve data quality. 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 (see Section 2.2.6) once the number of bad readings exceeds the validity
period. This scheme can be enabled by factory configuration. The filter is turned off by default.
2.2.3 Wind Speed Loop
The default wind speed scaling is such that a change from 4 to 20mA represents 0-75m/s. This corresponds to
a scaling factor of 0.2133mA per m/s. The wind speed scaling factor can be factory programmed to the
customer requirements, contact FT for further details. Figure 3 shows the available wind speed scalings.

Section 2 –Functional Description
10 FT742-DM (4-20mA) –Sensors - User Manual
Wind Speed Scaling
References (m/s)
Value @
4mA
Value @ 20mA
Scaling Factor
(mA per m/s)
30
0m/s
30m/s
0.5333
35
0m/s
35m/s
0.4571
40
0m/s
40m/s
0.4000
45
0m/s
45m/s
0.3556
50
0m/s
50m/s
0.3200
55
0m/s
55m/s
0.2909
60
0m/s
60m/s
0.2666
65
0m/s
65m/s
0.2462
70
0m/s
70m/s
0.2286
75
0m/s
75m/s
0.2133
80
0m/s
80m/s
0.2000
85
0m/s
85m/s
0.1882
90
0m/s
90m/s
0.1778
95
0m/s
95m/s
0.1684
100
0m/s
100m/s
0.1600
Figure 3: Wind Speed Scaling Factors
On models where the full scale current has been configured above the maximum speed of the sensor, the
maximum output current will be limited to an amount equivalent to the maximum speed.
The wind speed loop can also be calibrated with non-linear scaling functions. For further information on this
advanced feature contact FT Technologies.
If a wind sensor is replaced care must be taken to ensure that the replacement sensor has
the same scaling. Otherwise the data will have reduced quality.
2.2.4 Wind Direction Loop
The wind direction scaling is such that a change from 4 to 20mA represents 360 degrees (with no dead band)
which corresponds to a scaling factor of 0.0444mA per degree.
The sensor measures the wind direction relative to the 0° datum. The 0° datum location for the sensor is shown
in Figure 4.
The default current loop output when the wind is blowing towards the 0° datum direction is 12mA. If required,
the direction loop can be set to give an output of 4mA at the datum direction. The output options are shown in
Figure 5.