User manual
Table Of Contents
- 1 FOREWORD
- 2 INTRODUCTION
- 3 PRINCIPLE OF OPERATION
- OPTIONS AND SPECIFICATION
- INSTALLATION REQUIREMENTS
- INSTALLATION
- 7 MECHANICAL
- 8 OUTPUT FORMATS
- 9 ANALOGUE OUTPUTS AND OPTIONS
- 10 METPAK SDI-12
- 11 MAINTENANCE & FAULT-FINDING
- 12 TESTS
- 13 APPENDICES
- CS215_jun06.pdf
MetPak Doc No 1575-PS-0001 Issue 02 CN 4240 March 2006
3 PRINCIPLE OF OPERATION
3.1 Wind Speed and Direction Sensor
The MetPak uses the WindSonic wind speed and direction sensor. WindSonic measures the times taken for an
ultrasonic pulse of sound to travel from the North transducer to the South transducer, and compares it with the time for a
pulse to travel from S to N transducer. Likewise times are compared between West and East, and E and W transducer.
If, for example, a North wind is blowing, then the time taken for the pulse to travel from N to S will be faster than from
S to N, whereas the W to E, and E to W times will be the same. The wind speed and direction can then be calculated
from the differences in the times of flight on each axis. This calculation is independent of factors such as temperature.
Figure 1 Time of Flight details
4