Airmar PB200 - Manual (Page 121)

PB200 WeatherStation User Manual revision 1.000
Proprietary and Confidential
115
$PAMTC,COMP,GO
Summary
Manually initiate a user calibration sequence for the internal compass sensor.
There is an alternative to issuing the “GO” command to start user compass
calibration, called AutoCal. AutoCal is intended for users who do not have
access to a user interface which allows them to manually start user compass
calibration.
Syntax
$PAMTC,COMP,GO*hh<CR><LF>
Calibration needs to be done in calm seas, away from other boats or ferrous objects
(structures or aids to navigation). Trying to turn a 2-3 minute circle in strong currents or
congested areas will be difficult, if not hazardous.
The user calibration sequence for the PB200 is as follows:
1.
The weather station instrument is installed on the vessel. The unit under test is
powered up.
2. Manual Start: The $PAMTC,COMP,GO*hh<CR><LF> command is sent to
the weather station instrument’s NMEA 0183 input channel to initiate user
calibration mode.
AutoCal Start: Within 2 minutes of applying power to the weather station
instrument being calibrated, the vessel must start a slow circular turn. If it
completes a full circle within 2-3 minutes, AutoCal will enter the user compass
calibration procedure (See steps 3-5).
3. During the user calibration process, the vessel is rotated slowly (driven at 2-4
knots, completing a circle within 2-3 minutes), while the sensor collects data.
Once the weather station instrument has determined that enough data has been
collected for the purpose of calculating the coefficients, it transmits the
following sentence: $PAMTR,COMP,XXXX,
<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>,<9>*hh<CR><LF>
. Where
XXXX is “PASS” or “FAIL”.
4. If PASS was transmitted, then the offsets that are now in use and saved in
EEPROM are the newly calculated ones.
5. Note: During user compass calibration, heading is not valid and will be output
as NULL fields. Also, air temperature is set to 0 degrees Celsius. After
calibration is complete, heading will again be valid, and if successful, air
temperature will also return to the current temperature, but if calibration fails,
air temperature will be output as -10.0 degrees Celsius for 30 seconds.
Reply
The weather station instrument will reply immediately with:
$PAMTR,COMP,INPROCESS,
<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>,<9>*hh<CR><LF>