Compass Calibration (Compcal.exe) - YSI SonTek ADVField Technical Documentation Manual

SonTek/YSI
Section 6. Compass Calibration (COMPCAL.EXE)
A program ( ) has been provided that lets you calibrate the optional compass/tilt
COMPCAL.EXE
sensor. Calibration minimizes the effects of ambient magnetic fields on compass data. We rec-
ommend you perform a compass calibration before each ADV deployment.
gives a graphical display of instrument orientation that can be used to ensure the com-
COMPCAL
pass and tilt sensors are functioning correctly. To run the calibration program, make sure the in-
strument is powered up and connected to a computer serial port. Here is the command syntax.
COMPCAL [com port] [baud rate]
The parameter is the communication port being used on your computer (i.e.; 1 for
[com port]
COM1, 2 for COM2); is the ADP communication rate (9600 is the default).
[baud rate]
Once started, shows a graphical display of compass orientation. At this point, the com-
COMPCAL
pass is not in calibration mode; it is in a monitoring mode where instrument orientation is output
in real-time. The graphical display provides three perspectives. To the right is a compass that in-
dicates the direction the X-axis is pointing. To the left are tabular and graphical displays of pitch
and roll. In the center is a 3D box with an X on the side corresponding to north. When this side is
facing into the screen, the instrument X-axis is facing north.
To begin the calibration, press <F1>. will put the compass in calibration mode, the dis-
COMPCAL
play will resume, and instructions are provided for instrument rotation at the bottom of the
screen. The calibration procedure involves rotating the ADV slowly through two complete circles
while varying the pitch and roll as much as possible. Each turn should take about one minute; the
exact starting and ending orientations are not important.
To end the calibration, either press <F1> again (to remain in the graphical display) or press
<Esc> to exit with the calibration results. Pressing <Esc> at any time will exit the program and
display the results of the most recent calibration. See the ADVField Operation Manual for more
information about compass calibration and for information on how to interpret the calibration
score.
ADVField Software Manual (September 1, 2001) 31