HCM370B&375B-MP
HIGH ACCURACY 3D DIGITAL COMPASS
○Inclinometer ○3D compass ○Digital inclinometer ○Accelerometer ○Gyro ○North finder ○INS&IMU
SINCE2008
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Inertial Attitude Measurement Manufacturer
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CALIBRATION DESCRIPTION
Calibration lemmas:
1) The accuracy of testing compass cannot reach the requirements.
2) compass installation environment has magnetic interference, the interference is fixed, and the
interference magnetic field and compass installation will not happen again in distance changes
(example: compass to be installed above an iron material, because the iron will have magnetic
interference, at this time then need to rotate and calibrate the iron and compass, and the iron and
compass will not be separated when using, once they are separated then need to recalibrate. If the iron
size is not fixed, or with a compass distance change is not fixed, the interference cannot be calibrated,
only can install it in a very far away, safe distance control in above 30cm).
1) correctly connect to the signal output interface, then power on.
2) Select automatic calibration mode or manual calibration mode:
Automatic calibration mode: send the command "68 04 00 44 48" (click the
SET
button after selecting
automatic calibration);
Manual calibration mode: send the command "68 04 00 43 47" (click the
SET
button after selecting
manual calibration);
Send the calibration start command in hexadecimal format: "68 04 00 08 0C" (click the start button).
3) The electronic compass will return a response command, and the compass will return a response
every time it takes a point. Please refer to the communication protocol.
4) After taking 24 calibration points according to the calibration procedure, send the stop calibration
command: "68 04 00 09 0D" (click the stop button), at this time the electronic compass pauses for about
1 second, the internal CPU automatically calculates the sampled data and returns a set of data which
represents the scoring value of the obtained data.
5) Save the calibration command: Send the command "68 04 00 0A 0E" (click the save button), the
compass will return a response command. If the save is successful, it can work normally. If the
unsuccessful message is returned, the user will recalibrate.
6) after 2) Send the calibration start command to start the calibration, keep the compass stable, and wait
for the first point to be sampled.
7) After the first point is sampled, rotate the module about 90° horizontally to keep the compass stable
and wait for the next point to be sampled.
8) Repeat the above steps until 24 points are sampled, and then send the calibration command and click
stop button.
9) Send the calibration save command to end the calibration.
When calibrating, if the distance between the magnetic interference source and the compass itself
changes, the accuracy will be affected.
Note: When starting to calibrate and take points, calibrate the compass corresponding to the following
series of calibration charts. Please note that these points are not absolute headings, but a relative
heading change value with reference to the heading which is sampled at the first point, and sampling
angle vaule error is allowed. Do not require strict accuracy.
