DSM570
User’s Manual
Page 162
Revision 1.8.3
The last line in the menu enables you to program the lifetime of the variation data received by the
SSC200/SSC300. In Figure 170
, 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/SSC300 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 170
– SSC200/SSC300 NMEA 0183 Sentence/Rate Selection Screen
6.23.1.3.3
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 171
– SSC200/SSC300 Load Default Periodic Rate Selection
