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7 Output
7.1 NMEA Output
NMEA compatible output is available as UDP messages and may be sent to a user specified IP address and
port. To enable NMEA output, first select ‘Use NMEA output
channel’ in the Configuration window. Now click the ‘NMEA
output settings’ button. Here you can set the specific
parameters for the local IP address where the data should be
sent. The address can be a specific destination like
‘192.168.1.123’, a broadcast address like ‘10.0.0.255’ or it can
be a multicast address as show in the example. In general
addresses in the 239.x.x.x range are known as multicast
addresses and can be received by multiple computers on the
network. Broadcast addresses can be received by computers
on the same network with the same network-mask.
All messages conform to the NMEA-0183 version 3.01 format.
All begin with $ and end with a carriage return and a line feed.
Data fields follow comma (,) delimiters and are variable in
length. Null fields still follow comma (,) delimiters, but contain no
information.
An asterisk (*) delimiter and checksum value follow the last field
of data contained in an NMEA-0183 message. The checksum is
the 8-bit exclusive OR of all characters in the message,
including the commas between fields, but not including the
$ and asterisk delimiters. The hexadecimal result is converted
to two ASCII characters (0
–9, A–F). The most significant
character appears first.
In the NMEA options window the required messages can be
selected. Note that if specific data is not available, no message
will be sent.
7.1.1 $SDDBT
–Echosounder- Depth Below Transducer
Field
Description
DataFormat
Depth, feet
Depth below transducer in Feet
dd.dd
F
The letter ‘f ‘for feet
Depth, meters
Depth below transducer in Meters
dd.dd
M
The letter ‘M ‘for Meter
Depth, fathom
Depth below transducer in Fathom dd.dd
F
The letter ‘F’ for Fathom
Example:
$SDDBT,32.81,f,10.00,M,5.47,F*39
Figure 30 Enabling NMEA output
