Altimeter Product Manual
0286-SOM-00001, Issue: 09
23
© Tritech International Ltd.
4. Operation
4.1. General Guidelines
Notes
The output from the altimeter can be in serial or analogue format. This section
only covers applications which use the data in serial format.
Altimeters configured with a 10m range may give false readings (neither zero or
max range) when operating in air.
Output Strings
The serial output is either interrogated (i.e., the software asks for a response) or is free-
running and will continuously send out acoustic pulses and supply the output from the
altimeter to the connected computer even if the software is not running.
The output is an ASCII data string terminated with a carriage return and line feed (
<CR><LF>
)
and will be in one of three formats depending on the hardware settings. These formats are
as follows:
2P3
xx.xxxm<CR><LF>
xx.xxx
= range in metres to 3 decimal places
m
= units label for metres
<CR><LF>
= carriage return and line feed terminators.
3P2
xxx.xxm<CR><LF>
xxx.xx
= range in metres to 2 decimal places
m
= units label for metres
<CR><LF>
= carriage return and line feed terminators.
3P3
xxx.xxxm<CR><LF>
xxx.xxx
= range in metres to 3 decimal places
m
= units label for metres
<CR><LF>
= carriage return and line feed terminators.
NMEA
$DBT
$PADBT,xxx.xx,f,yyy,yy,M,zzz.zz,F*hh<CR><LF>
xxx.xx
is the range in feet
yyy.yy
is the range in metres
zzz.zz
is the range in fathoms
