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Chapter 3 

– Mechanical & Electrical Installation

 

 

14 

                      FT742-DM (4-20mA) 

– Sensors

 - User Manual

 

3  MECHANICAL & ELECTRICAL INSTALLATION 

 
The wind sensor has no moving parts to degrade or wear-out and is designed for applications requiring high 
reliability and cold weather operation. 
 

         

 

Figure 7: Direct-Mount Wind Sensor 

 
Direct Mount sensors are mounted vertically with the cable connector routed through a 33.7mm (outer diameter) 
hollow pipe (EN10255 standard sizes). 4 M6 screws are required to secure the sensor onto the pipe (Figure 11)
The sensor body is manufactured from hard-anodised aluminium and the cavity has a water-repellent coating.  
 
A suitable compass (not supplied) can be used to align the sensor with magnetic North using th

e convenient ‘N’ 

alignment marking and the alignment flat. The magnetic North marking indicates 0° and rotates clockwise when 
viewed from above (Figure 10). The alignment flat is used with a square-sided compass for rotational alignment. 
Magnetic North should be lined up to face parallel to the 

‘N’ marking feature (Figure 12)

 
Ensure the airflow into the sensor is not obstructed or influenced by nearby objects. 
 
In order to keep the pressure within the sensor equalised with the atmospheric pressure, a small breather hole 
is located within the connector housing compartment that should not be blocked. 
 

 

See safety instruction requirements on pages 4 and 5.  

 

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 are safe and fit for purpose. Please 
see disclaimer Section 1.4. 

 

Summary of Contents for FT742

Page 1: ...7DX TEL 44 0 20 8943 0801 FAX 44 0 20 8943 3283 WEB www fttechnologies com E MAIL info fttechnologies com A4277 3 EN November 2017 The FT and Acu Res logos are registered trademarks of FT Technologies...

Page 2: ...aracteristics 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...

Page 3: ...This product complies with the RoHS2 2011 65 EU directive limination du produit Conform ment la directive europ enne 2012 19 EU relative aux d chets d quipements lectriques et lectroniques DEEE ces co...

Page 4: ...1 Standards it must be o Connected 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 o Protected by U...

Page 5: ...nnect une alimentation agr e convenablement isol e par exemple UL CSA IEC 60950 1 2005 A1 2009 A2 2013 de tension nominale 12 30 VCC et avec courant limit 6 A max o Prot g par des dispositifs de prote...

Page 6: ...trol 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...

Page 7: ...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 sens...

Page 8: ...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 senso...

Page 9: ...te 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 Averagin...

Page 10: ...lent 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 repl...

Page 11: ...ion crosses the datum In the 12mA datum current mode the output current varies linearly about the 12mA value as the wind direction moves around the datum 2 2 5 Changing the Wind Datum Direction The da...

Page 12: ...cable or wind sensor It is important that error flags are not ignored The datalogger should be able to recognise and interpret error codes within the data If errors are ongoing more than several secon...

Page 13: ...e length FT recommends cable types in Section 3 2 Since the heater circuit is thermostatically controlled the actual power being drawn from the supply will depend on the programmed set point and the e...

Page 14: ...alignment marking and the alignment flat The magnetic North marking indicates 0 and rotates clockwise when viewed from above Figure 10 The alignment flat is used with a square sided compass for rotati...

Page 15: ...the annual inspection of the sensor as detailed in Section 4 2 The FT035 grounding accessory can be fitted within the connector chamber and can provide a low resistance grounding path to the outer ed...

Page 16: ...Chapter 3 Mechanical Electrical Installation 16 FT742 DM 4 20mA Sensors User Manual...

Page 17: ...Chapter 3 Mechanical Electrical Installation 17 FT742 DM 4 20mA Sensors User Manual Figure 9 Direct Mount Wind Sensor mm...

Page 18: ...DM 4 20mA Sensors User Manual The sensor measures the wind direction relative to the central datum feature When the wind sensor is correctly aligned the wind direction measurements will be as shown i...

Page 19: ...self locking fasteners 4x part FT034 ensuring an even distribution of pressure and firm contact with the mounting pipe The fixings use a thread locking insert and will provide resistance before they a...

Page 20: ...Chapter 3 Mechanical Electrical Installation 20 FT742 DM 4 20mA Sensors User Manual Figure 12 Direct Mount Compass Alignment...

Page 21: ...1 8 0mm ODU 4 20mA Cable Side Connector 8 way plug SX2F1C P08NJH9 0001 9 2mm Figure 14 Cable Connector Sourcing Options 3 2 Cable Details The mating connectors for the sensors are suitable for use wit...

Page 22: ...or is a minimum of 30x diameter of the interceptor material The standard FT742 DM sensor has a hard anodised top surface within the connector column housing see Figure 9 When used with the plastic pip...

Page 23: ...nclosure chassis All connections from the sensor to the data acquisition system and to power should pass through the SPD s This will suppress any unwanted overvoltage transients present on the signal...

Page 24: ...hydrophobic cavity coating for wear corrosion and damage Corrosion Inspect the mounting surface of the sensor and the surfaces of other mounting parts for signs of corrosion If corrosion is present o...

Page 25: ...FT031 Size Adaptor 25mm 1 for FT742 DM includes a FT033 tapered pipe insert 4x FT034 self locking fasteners FT032 Size Adaptor 50mm 2 for FT742 DM includes a FT033 tapered pipe insert 4x FT034 self lo...

Page 26: ...ocessed in accordance with guidelines in Sections 2 2 1 and 2 2 6 Check that the measurement cavity s special coating is in a satisfactory condition Debris can be blown out or washed out with distille...

Page 27: ...lied on a CD and will work on PCs running Windows XP Vista 7 8 8 1 and 10 The sensors can be easily tested by connecting a DC ammeter in series with each current loop A positive supply must be provide...

Page 28: ...Connect the green wire wind speed 4 20mA output to an ammeter and then connect the other terminal on the ammeter to the 0V terminal on the DC power supply 6 Connect the purple wire wind direction 4 2...

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