36
Time Out
This setting allows you to set the time it takes before sentences from a lower priority input are passed.
SeaTalk Priority
This sets the priority of the SeaTalk data. It can be either Highest (SeaTalk - In1 - In2 - In3) or Lowest
(In1 - In2 - In3 - SeaTalk).
Channel Information
These options insert channel number information in the NMEA stream that is sent to the host interfaces.
Channel numbers allow distinguishing between similar data from different instruments, like two depth
sounders on the same boat.
When “STN Sentence” is enabled, each received NMEA sentence is preceded by a $MXSTN sentence to
indicate on which NMEA input the following sentence was received. The example in Figure 37 shows that
an IIGGA sentence was received on In1, a GPGGA sentence on In2, an IIGLL sentence on In1 and an
HEHDT sentence on In3.
$MXSTN,01*71
$IIGGA,143357.999,5301.0061,N,00635.5479,E,1,06,1.9,90.0,M,,,,0000*2E
$MXSTN,02*72
$GPGGA,143357.999,5301.0061,N,00635.5479,E,1,06,1.9,90.0,M,,,,0000*39
$MXSTN,01*71
$IIGLL,5301.0061,N,00635.5479,E,143357.999,A*22
$MXSTN,03*73
$HEHDT,67.0,T*1E
The $MXSTN sentence is defined by the NMEA standard and a description can be found in the Technical
Reference at the back of this manual.
When “TAG Block” is enabled, the multiplexer adds an NMEA 0183 V4.0 TAG block to each sentence. This
TAG block contains a source identification parameter indicating on which input that sentence was
received. Figure 38 shows the same data as above, but with TAG blocks added.
\s:MX02-1*42\$IIGGA,143357.999,5301.0061,N,00635.5479,E,1,06,1.9,90.0,M,,,,0000*2E
\s:MX02-2*41\$GPGGA,143357.999,5301.0061,N,00635.5479,E,1,06,1.9,90.0,M,,,,0000*39
\s:MX02-1*42\$IIGLL,5301.0061,N,00635.5479,E,143357.999,A*22
\s:MX02-3*40\$HEHDT,67.0,T*1E
See the Technical Reference section for a description of the TAG block.
NMEA Conversions.
NMEA Conversions allow you to convert specific NMEA sentences into new NMEA sentences. The
originating sentence used for a conversion is forwarded as usual but if desired, it can be blocked using
the sentence filter. The conversion results are available on a virtual input called “NMEA
Conversions” on
the “NMEA Inputs/Outputs” page and on input C on the “Sentence Filtering & Routing” page. They can be
routed anywhere using the default route and the Sentence Filter.
Magnetic to True Heading (HDG, HDM -> HDT)
If this option is enabled, the multiplexer will generate an HDT sentence (true heading) when an HDG or
HDM sentence (magnetic heading) is received. If the originating HDG sentence contains a magnetic
variation, it is used to calculate the true heading from the magnetic heading. Otherwise the magnetic
heading value is just copied.
This option can be useful when a device needs a true heading while only a fluxgate compass is available
on board. Many satellite telephones for instance need a true heading to be able to direct their antenna to
the right communications satellite.
GPS Speed to Log Speed (VTG -> VHW)
If this option is enabled, the multiplexer will generate a VHW sentence (water speed and heading) when a
VTG sentence (course over ground and ground speed) is received. The VTG sentence is generated by a
GPS and the VHW sentence by a log. Often the paddlewheel of a log gets stuck when fouled and this
option offers a solution to substitute the log data with GPS data.
Reverse Heading (HDT)
This option allows you to reverse the true heading in a received HDT sentence. When an HDT sentence is
received, the multiplexer generates a new HDT sentence with 180° added to the original heading. This
Figure 37
Figure 38
