Vaisala WS425 - Manual (Page 44)

USER'S GUIDE____________________________________________________________________
44 __________________________________________________________________ M210361EN-E
Missing Readings
If data is missing due to a measurement problem, the NMEA messages
will only show the commas (,) between the data fields. Thus, NMEA is a
variable-length data message.
NMEA Extended Message
Vaisala extension to the standard MWV wind message is defined as
follows:
$P<id>MWV,<dir>,<ref>,<spd>,<uni>,<sta>*<chk><cr><lf>
where
$P = Fixed text
<id> = Is the data ID; A … Z
MWV = Fixed text
<dir> = Wind angle, 0 to 359 degrees
<ref> = Reference; R = Relative, T = True
<spd> = Wind speed
<uni> = Wind speed units; K = kmph [km/h],
M = mps [m/s], N = kt
<sta> = Status; A = Data Valid, V = Invalid Data
* = Fixed text
<chk> = Checksum (8-bit XOR, excluding $ and *)
<cr> = Carriage return code, ASCII 0DH
<lf> = Line feed code, ASCII 0AH
NOTE The sensor has a 20 ms timeout in receiving characters. Thus, polling
strings should be transmitted by a programmable device, not as a user
command via terminal sessions.