Airmar LB150 - Manual (Page 43)

LB150 WeatherStation Technical Manual revision 0.013
Proprietary and Confidential
PRELIMINARY - DRAFT 40
_ NMEA 0183 RECEIVED SENTENCE _
$PAMTC,
BAUD
Summary
Change the baud rate for both the transmitting and receiving NMEA 0183
channels.
Syntax
One of the following forms:
$PAMTC,BAUD,4800*hh<CR><LF>
$PAMTC,BAUD,38400*hh<CR><LF>
Notes
The $PAMTC,BAUD command may be used to increase the baud rate from the
standard 4800 baud to 38400 baud. This will provide an eightfold increase in the
bandwidth of the NMEA 0183 interface, allowing more data to be transmitted in a
given period of time.
On power up, the NMEA input and output interfaces always default to 4800 baud.
It is recommended to employ the following sequence when changing the baud rate
for the WeatherStation from 4800 baud to 38400 baud. The following assumes
there is a single host device communicating with the WeatherStation:
1. Send the $PAMTX command to the WeatherStation (at 4800 baud) to
temporarily disable transmission of periodic sentences.
2. Send the $PAMTC,BAUD,38400 command (at 4800 baud) to instruct the
WeatherStation to change its baud rate to 38400. The unit will finish
transmitting any periodic sentences in progress at 4800 baud, and will then
change its interface to use 38400 baud.
3. Delay a short interval within the host to allow reception of any remaining
queued sentences from the WeatherStation at 4800 baud.
4. Change the baud rate on the host's serial port to 38400 baud.
5. Send the $PAMTX,1 command to the WeatherStation (at 38400 baud) to
resume transmission of periodic sentences.
6. All subsequent communication with the WeatherStation will be at 38400
baud, until the unit is powered down or reset, or the
$PAMTC,BAUD,4800 command is sent to the unit.
Note that a baud rate of 38400 does not comply with the NMEA 0183 standard.