OMC-131 True wind display
Users’ manual
V1.14
Page 18
TDC-April-2017
3.3 Communication and ports
Starting from firmware v3.1 the speed information in the VHW message can be read on this port. The
heading information on this port is ignored, HDT from gyro is expected on port 3.
If you would like to use the VHW speed AND heading data , you must use port 3. This will replace the gyro
(HDT) input.
Expected input message, VHW Water speed and direction.
$GPVHW,xxx.x,T,xxx.x,M,xx.x,N,xx.x,K,*hh
T
= Heading in degrees true
M
= Heading in degrees magnetic
N
= Speed knots
K
= Speed km/h
$GPHDT,xxx.x,T*hh<CR><LF>
T
= Heading degrees true
When only ships heading is available via NMEA-
183 protocol the pulse input of input 6 can be
used for ships speed input
