DSM250 User’s Manual
Page 156 Revision 1.4.16a
The last line in the menu enables you to program the lifetime of the variation data received by the
SSC200. In Figure 167, you can see that the “Variation Time” has been programmed to 5.0 seconds.
This means that if the compass has not received magnetic variation for five seconds, it will no longer
transmit true heading data, as the variation data it has received is now expired. On the NMEA2000
side, the Heading PGN has separate fields for heading sensor reading and variation. The SSC200
always has magnetic heading available; when variation is not available (timeout or invalid) the
variation field is set to N/A. The default value of 5.0 seconds should be adequate for the majority of
applications, but it may need to be increased for variation sources that transmit less frequently.
Figure 167 – SSC200 NMEA 0183 Sentence/Rate Selection Screen
6.22.1.3.3 Load Default Sentence / Rate Selection
The Load Default Sentence / Rate Selection option will reset the NMEA 0183 sentence
enable/disable status, along with transmission intervals and variation time, to their factory default
settings.
Figure 168 – SSC200 Load Default Periodic Rate Selection
