AHRS-E304 Watson Industries, Inc
09/06/05
7
Example:
I +002.5
-05.0 273.4 +1.02 +0.15 -1.57 -00.4 +01.2 +10.4 +001.4 <CR>
^
^
^
^
^
^
^
^
^
^
^
(1)
bank angle
(2)
elev.
angle
(3)
Head.
angle
(4)
X axis
accel
(5)
Y axis
accel
(6)
Z axis
accel
(7)
X axis
rate
(8)
Y axis
rate
(9)
Z axis
rate
(10)
Velocity
(11)
(12)
space
space
space
space
space
space
space
space
space
space
space
This may be reduced to attitude and heading information to improve the update rate to almost
twice the previous rate by using special commands to modify the EEPROM of the unit.
The system is protected from inadvertent write-over of the EEPROM by requiring two spacebar
commands during the initialization interval to access the EEPROM or related functions.
The baud rate may be changed from the nominal value of 9600 baud by modifying the default
value in the EEPROM of the unit to 4800, 2400, or 1200 baud.
A text header is sent by the AHRS during initializations that identifies the unit by part number
and by serial number and gives the date of last calibration. Additionally, a line of text characters
that identifies the data channel columns is sent if the serial output is set to ASCII decimal. This
whole message can be temporarily or permanently suppressed or restored by a “*” command
from the interfacing computer.
Data transmission sent by the AHRS can also be suppressed or restored by a “+” command from
the interfacing computer.
The error overrange condition is indicated by the use of a lower case “i” or “r” when the
calculated attitude or heading error exceeds the ranges listed above. Internal functions which
require these error values are disabled while the condition exists. The system will continue to
operate in an extended time constant mode with a low level of error accumulation until the
condition is cleared. Occasional blips of this condition are expected with no detectable affect on
the resulting data.
The other output format available is a binary format. The binary format provides generally the
same information as the decimal ASCII format, but in a compact binary file format. In this
format, there are nominally 13 words sent that represent 6 fourteen-bit output channels followed
by a carriage return. Again, this may be reduced to attitude and heading information to improve
the update rate (in this case the rate would be 71.11 Hz) by using special commands to modify
the EEPROM of the unit. This format is for highly experienced users only. Consult the factory
for further details.
