Vaisala WS425 - Manual (Page 20)

USER'S GUIDE____________________________________________________________________
20 __________________________________________________________________ M210361EN-E
specify a direction coast speed between 0.0 and 9.9 units of
measurement. Use 0.0 if coasting is not required.
For example, making the direction coast speed = 2.0. The consecutive
measurements are presented in Table 6 below.
Table 6 Wind Direction Coasting
Measured Wind Speed Measured Wind
Direction
Wind Direction Used
for Averaging
3.5 350 350
2.5 340 340
2.2 340 340
1.9 175 340
(coasting)
1.2 045 340 (coasting)
2.1 345 345
Gust Wind Speed and Direction Over
Time
The gust wind speed and direction are available in SDI-12 submode B. It
is the highest wind speed and direction recorded during the averaging
interval. The gust averaging count can be specified, which is the number
of measurements (one measurement each second) average to produce the
gust values for speed and direction. It has a range of one to nine counts.
As a gust averaging count is specified as one, the reported wind gust is
the highest instantaneous reading. An example of a gust averaging count
of five will follow. In this example of 14 measurements shown in Table 7
below, measurement 13 has the highest instantaneous wind gust reading.
Table 7 Gust Wind Speed and Direction Over Averaging Time
Measurement 1 2 3 4 5 6 7 8 9 10 11 12 13 14
Wind speed 8 7 6 3 5 3 4 9 8 7 6 10 12 11
Highest sum of 5 - - - - 29 29 29 29 29 31 34 40 43 46
Gust averaging
sum of last 5 [29] [24] [21] [24] [29] [31] [34] [40] [43] [46]
Gust wind speed
(sum of highest
5) divided by 5 - - - - 5.8 5.8 5.8 5.8 5.8 6.2 6.8 8.0 8.6 9.2
Sum of all wind
speed 8 15 21 24 29 32 36 45 53 60 66 76 88 99
Average wind
speed 8 7.5 7.0 6.0 5.8 5.3 5.1 5.6 5.9 6.0 6.0 6.3 6.8 7.1