Gill Instruments Ltd
Intrinsically Safe WindObserver Anemometer
Page 34
Issue 10
Doc. No. 1360-PS-0001
May 2015
Modes 14 and 15 Road Weather Averaging Notes.
The averaging is implemented with reference to the following standard:
Guide to Meteorological Instruments and Methods of Observation – World
Meteorological 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 (1Hz output)).
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.
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).
Principle set up commands associated with this averaging mode are:-
Px:- Measurement Rate, (P1 to P3) this command sets the underlying
measurement rate from 1Hz to 4Hz.
RWASHORT xx: - Short Term Number, where xx is a number from 10 to 60.
RWALONG xx: - Long Term Number, where xx is a number from 1 to 10.
The Averaged Data Output period in seconds is:-
RWASHORT Number
Measurement Rate (P Setting Hz value)
Therefore with the RWASHORT number set for 60 (default) and P command set for 1Hz
(P1 default) the unit will output a rolling averaged reading every 60 seconds.
The Averaged Direction and Magnitude reading is based on:-
RWALONG Number * Averaged Data Output period.
