PNI TCM 2.6 - Manual (Page 18)

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 18 of 49
Multipoint Calibration (mpcal)
Key Points
Tilt as much as possible during the calibration. This allows the compass to take full
advantage of the 3-axis magnetometer.
Move slowly, take as much as 30 seconds to complete a circle. You are trying to get an
even sampling of the magnetic field over as many headings and tilts as possible.
Pay attention to the calibration score. Performance will be compromised if you accept a
low score.
If you get a poor calibration, clear it before making a new calibration.
Procedure
1. Clear any previous calibration by sending cc.
2. Enable multipoint calibration by sending mpcal=e.
3. Put the TCM2.5/2.6 into continuous mode by sending go.
4. Begin rotating the TCM2.5/2.6 in a circle while applying pitch and roll to the unit. The unit will
have the appearance of a “wobbling top” as it is moved through the calibration routine.
Turn the TCM2.5/2.6 around at least twice changing the pitch and roll as much as possible.
Each turn should take longer than 30 seconds. The turn does not need to be a perfect
circle.
In the calibration mode, the TCM2.5/2.6 is trying to take as many different data points as
possible to determine the magnetic anomalies.
The more pitch and roll points you give it, the better it is able to determine the vertical
magnetic fields.
Apply as close to a ± 90˚ pitch and ± 90˚ roll as possible. Doing so will improve the quality
of the calibration. Do not worry about exceeding the tilt range of the unit.
5. Halt the TCM2.5/2.6 by sending h if halt=e; or h if halt=d.
6. Finish the calibration by sending mpcal=d.
7. Check the calibration score by sending lc?.
If the calibration score is not satisfactory, repeat the calibration process