Section 2
Functional Description
9
FT702LT Flat Front Wind Sensor Manual
2 FUNCTIONAL DESCRIPTION
2.1 Technical Performance
Sensor Performance
1
Measurement Principle
Acoustic Resonance (compensated against variations in temperature,
pressure and humidity)
Wind speed Measurement
Range
0-50m/s
Accuracy
0.5m/s (0-15m/s),
4% (>15m/s)
Resolution
0.1m/s
Wind Direction Measurement
Range
0 to 360
Accuracy
2
(within
10
of 0
datum),
4
(beyond ±10
⁰
of 0
⁰
datum)
Resolution
1
Environment
Temperature Range
-40
to +85
C (operating), -40
to +85
C (storage)
Humidity
0-100%
Data I/O
RS485 Option
Interface
Digital RS485, galvanically isolated from power supply lines and
case
Format
ASCII
data, polled or continuous output modes
Data Update Rate
5 measurements per second
Power Requirements
3
Supply Voltage
20V to 30V DC (24V DC nominal)
Supply Current (Heater off)
30mA
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 and sensor power
consumption is limited by default to 99W
2
.
*Only 4A (max) power consumption possible for sensors prior to build
version 22.
Physical
Weight
320g (max)
Material
Aluminium alloy, hard anodised
I/O Connector
5 way (RS485 option),
Mounting Method
Self aligning, single screw fixing
Notes:
1. All specifications subject to change without notice
2. The heater set point, current limit and maximum power limits can be configured by programming the
sensor
’s internal parameter settings (only available from Version 22 and above)
3. See safety instruction requirements (page 4)
