Vaisala WINDCAP WS425 Guide de l'utilisateur télécharger pdf (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.

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Vaisala WINDCAP WS425 Guide de l'utilisateur Page 44