Gill Instruments Ltd
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WindObserver 65
Page 32
Issue 4
Doc. No. 1390-PS-0039
June 2016
7.6.2 Modes 14 and 15 Road Weather Averaging (RWA).
The averaging is implemented with reference to the following standard:
•
Guide to Meteorological Instruments and Methods of Observation – World
Meterological Organization WMO-No8 seventh edition 2008 ISBN 978-92-63-
10008-S
The direction and magnitude outputs are derived from the vector sum of U and V over the
RWALONG averaging period (default 10 minutes in P1).
The gust output is derived from the vector sum of U and V over 3 readings (3 seconds in
P1), and the max gust is the maximum of the gust value over the RWASHORT period
(default 60 seconds in P1). The max gust value is reset to zero at the end of each
RWASHORT period.
RWA
Default settings
are:-
P (Output rate Hz) = 1
RWASHORT
= 60
RWALONG
= 10
Therefore:
Anemometer output period
= 60/1 =
60 seconds
(the WindObserver will output a
reading every 60 seconds).
Averaged direction and magnitude reading
= 10 x 60 =
600 seconds
(this is the time
the readings will be averaged over).
When the average building period has been completed, the average reported thereafter will
be a rolling average derived from the last averaged direction and magnitude time period.
Mode 15 – Averaging Data in Continuous mode.
Averaged Digital Data Output comprises of.
<Start of String>, Node, Mode, Averaged Direction, Averaged Magnitude, units,
Maximum Gust Direction, Maximum Gust Magnitude, Status, <End of String>,
checksum.
e.g.
(status code 51 shows measurement average building, non-heat enabled units only).
(status code 00 code shows measurement average building period complete and normal
operation, non-heat enabled units only).
