DESIGNER’S HANDBOOK 4189350049C EN
Page 176 of 206
The first monitor is monitoring the NMEA sentences sent on all COM ports both inputs and outputs.
When two NX2 extension modules are mounted on the XDi, there can be up to 6 active ports, that can result in a
lot of NMEA sentences to look at in the monitor.
If you are only interested in what is send or received from one of the COM ports, you can select the monitor only for
that port. Monitor COM 1.1 will only show communication on NX2, Slot1.COM1 (RX1 input and TX1 output).
In the following it is NMEA data from a wind indicator system that is used to illustrate the function of this monitor
tool, it is the Monitor all COMs that is opened.
In this case Heading , speed and wind data are received correct (RX) and the wind data sentence MWV is also
retransmitted (TX) to the NMEA output Slot 2.COM2 (TX2 output).
In a fault situation, the NMEA monitor can be a great help determining whether a given NMEA sentence is available
or not.
If you know the structure of an NMEA sentence, you can also see if data is valid or invalid.
The NMEA monitor presentation is explained in the table below.
Count
Time
COM
Sentence
Number of
received/transmitted
sentences since the
logging started
Interval
between last 2
sentences
(in seconds)
Slot number and
COM port on NX2
module receiving or
transmitting data
RX: received
TX: transmitted
NMEA sentence
content
For easy analyse of the NMEA sentence content, it is possible to freeze the screen on the NMEA monitor. Press
the OK button once to freeze and once more to return to normal mode showing every received sentence.
