Vaisala WAC155 Uživatelská příručka stáhnout pdf (Strana 34)

User's Guide ______________________________________________________________________

32 ___________________________________________________________________M210822EN-A

More than one transmitter can be connected to a single RS-485 bus.

In the case of single transmitter, the auto-transmit mode can be used (the

device transmits data messages with configured interval). If there are

several transmitters in the same bus, auto-transmission may not be

enabled, and data can be only polled by query.

Each device in the same bus has a unique configurable ID, containing

1..5 characters. Alphabetical characters a-z and A-Z (case-sensitive) are

accepted, as well as numbers 0-9.

NMEA Message Format

The NMEA specification defines wind speed and angle message MWV

as follows:

$WIMWV,<a.a>,<R>,<s.s>,<U>,<S>*<CS><cr><lf>

The comma "," is used as a separator between the fields. Here are some

examples of MWV messages output by the WAC155:

Table 4 WAC155 Default Serial Communication Settings

Property Description / Value

Baud rate 9600

Data bits 8

Parity none

Stop bits 1

where

$WIMWV = Fixed text at the start of the message

<a.a> = Wind angle, 0..359 degrees

<R> = Reference: R=relative, T=theoretical

<s.s> = Wind speed

<U> = Units: K=km/h, M = m/s, N=knots

<S> = Status: A=valid, V=invalid

* = Asterisk, indicating that the next field is the checksum

<CS> = Two character checksum for the message

1 2 ... 29 30 31 32 33 34 35 36 37 38 39 ... 59 60

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Vaisala WAC155 Uživatelská příručka Strana 34