DESIGNER’S HANDBOOK 4189350049C EN
Page 169 of 206
Even if the dot is green, it is a good idea to look through the automatic selection and check that needed data has
the right source assigned.
In this case the compass group is green, so everything looks to be good. All data types in the group have a source
assigned, but in some cases where there are multiple instances of the same data type, it may be necessary to
change some of the automatic selections made.
If we press OK on the highlighted compass group to open it, we can see which NMEA port and sentence is used to
provide data.
In this case, GYRO 1 using
“Heading T1” (True heading instance 1) and GYRO 2 using “Heading T2” (True
heading instance 2), are both automatically selected to use the same input source.
The HTD sentence received from input port 2.1, provided by talker with ID: HE.
Mag.Com. 1: $HEHDG,265.5,03.0,E,25.0,E*44
GYRO 1:
$HEHTD,A,0.0,L,M,T,45.0,25.0,0.5,3275.0,200.0,1.0,250.0,T,A,A,A,270.0*67
GYRO 1:
$HEHDT,293.5,T*22
GYRO 2:
$IIHDT,271.6,T*20
Why has XDi made this selection of HTD for both?
When XDi makes an automatic selection, it has a priority list of sentences to choose from.
For True heading the sentence priority list is: HMR, THS, HTD, VHW, HDT.
Because the HTD sentence has a higher priority than HDT it is automatically selected even though there is other
heading sentences of type HTD.
RED dot
means that no external sources are
available, in this case for the dimmer data
group.
YELLOW dot
means that sources are available
for some data in the group, but it should be
checked. Some data types may need manual
selection or some may be missing.
GREEN dot
means that all data types in this
group have been assigned a source.
