From: Stuart & Ruth Parker <s.parker@...>
To: Lacrosse_weather_stations at yahoogroups.com
Sent: Saturday Oct 21, 2006 3:18 pm
Subject: [LacrosseWS] Re: WS2300-15 anemometer power supply?
The serial protocol is as follows-
a.. Approx 1.2mS bit time >> 833 bps
b.. inverted data - 0V = logic 1, +3.3V = logic 0
c.. one long (20 bit) stream with start frame and end checksum
d.. issued every 2 seconds while /CE is true (held at 0V)
e.. 00100bbbbvvvvvvvvvvvvcccc
f.. 00100 start frame
g.. hhhh bearing, lsb first, 0-15 cardinal points from North, clockwise
rotation, 0=N, 1=NNE, etc
h.. vvvvvvvvvvvv velocity, lsb first, 0-4096, turbine counts over previous 2
second period, non accumulating
i.. velocity count appears somewhat nonlinear- the turbine is quite sensitive
to small gusts below 5 knots that would not move a conventional cup anemometer,
but less so at higher speeds
j.. knots = velocity/8 seems to be a reasonable approximation across typical
wind speed ranges
k.. cccc checksum, appers to be simple XOR of the 4 bbbb, vvvv,vvvv,vvvv
nibbles
Hope this is of value,
Regards,
Stuart Parker
ZK-JAW Airborne Edge 582
www.sparxfly.co.nz

each 'transmitting burst' is a train of 6 bursts of 0.12 msec, bursts are 8 when raining