Specifications

Actisense

MTW – Mean Temperature of Water

Water temperature in degrees centigrade.

Format:

$xxMTW,DATA_TEMPERATURE_C,C*hh<0D><0A>

Example

Extended precision, with checksum:

$YXMTW,17.75,C*5D<0D><0A>

17.75 degrees centigrade.

VHW – Water Speed and Heading

The compass heading to which the vessel is currently

pointing, and the speed of the vessel through the water.

Format:

$xxVHW,DATA_HEADING_DEGRESS_TRUE,T,

DATA_HEADING_DEG_MAGNETIC,M,

DATA_SPEED_KNOTS,N,

DATA_SPEED_KMH*hh<0D><0A>

Example

Standard precision, with checksum:

$VWVHW, , , , ,0.0,N,0.0,K*4D<0D><0A>

No heading data provided (as not available), Water speed

0.0 Knots, and 0.0 Km/h.

VLW – Dual Ground/Water Distance

The distance travelled by the vessel, relative to the water

and over the ground. Trip distances are the distances

travelled since this value was last reset, thereby resetting

at the beginning of a trip, the trip distance is given.

Not all NMEA 0183 device that output this sentence can

have their trip distance reset - in this case, a power reset

will reset both distances.

Format:

$xxVLW,DATA_TOTAL_WATER_DISTANCE_NM,N,

DATA_TRIP_WATER_DISTANCE_NM,N,

DATA_TOTAL_GROUND_DISTANCE_NM,N,

DATA_TRIP_GROUND_DISTANCE_NM,N

*hh<0D><0A>

Example

$VWVLW,2.8,N,2.8,N*4C

Total water distance travelled 2.8 nautical miles, and Trip

water distance 2.8 NM (since last reset). The ground

distance values are not included and as the checksum has

been used to terminate the sentence, the comma and ‘N’

characters of the ground values do not need to be included

in the sentence.

This fore-shortening of the sentence by using the checksum

can be used in any NMEA 0183 sentence.