METEK GmbH uSonic-2
5 NMEA protocol
A special output protocol type NMEA0183 is offered by the uSonic-2 in order to
make the usage in marine applications as easy as possible. Because the NMEA-
format requires certain interface adjustments usage of the following commands
should be done only if the usage of the NMEA format is essential. As mentioned in
chapter 6 there are some options available for this protocol. In general the system is
switched to NMEA format mode by entering:
PR=1
The data set is changed according to the NMEA-standards printing out wind velocity
and wind direction.
This requires that the parameter assigning the type of data set is adjusted to the
value "2" automatically.
OD=2
If BR equals zero, the serial interface is automatically switched to a baud rate of
4800. In NMEA mode the system does not accept any commands except
PR=0
which will switch the device back to normal operation. So options for the NMEA
protocol must be selected before entering PR=1. These options refer to the setting
of the parameters OD, FR and NO (see chapter 6).
The format of the data output is shown in the following example:
Example: $WIMWV,176,R,2.8,M,A
This line is started by an initializing text string, indicating by the characters MWV
that is an information about wind velocity and wind direction is following. The wind
direction is displayed with an accuracy of one degree as a three-digit number,
followed by the character R for relative angles. The wind velocity is displayed in
meters (unit indicated by the character M) as a three-digit number and with an
accuracy of one tenth. The validity of the line is signalled by the trailing character A.
Invalid lines are marked with the character V. The unit of the wind velocity and the
can be selected by the parameter NO. This parameter can as well
activate/deactivate the output of the MWV sentence (refer to table in chapter 5.1).
A second line (indicated by MTA) prints the current temperature as a three-digit
number with a resolution of 1°C:
Example: $WIMTA,024,C
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