Mag3110 improper output

[deepanrajanbara]

Hi,

We are currently using imx6 based custom board which contains mag3110 magnetometer sensor.

To test the sensor we are running the evtest.

When running the evtest application for mag3110.Both the x and y axis value seemed to get either negative no matter what ever position we place the sensor.Is there any setting required to correct this. Since we tested in another board containing the mag3110 sensor, the value from the sensor seemed to change from positive to negative for x and y axis depending upon the position.

Please help us solve this issue since we are not sure what could be the reason for this behavior.

Thank you,

Deepanraj.A

[TomasVaverka]

Hi Deepanraj,

It is common that one device reads negative values and another one both positive and negative. The zero field offset is variable from unit to unit and can be either positive or negative (±100uT).

Calibration is required to eliminate the magnetometer zero field offset and the PCB hard-iron interference. The easiest method to calibrate the offset is rotating the MAG3110 in a figure of eight twisting motions for a few seconds, record the minimum and maximum magnetometer readings, compute the corresponding x- and y- offset values by using the min/max averaging and then either substract these offset values from the current magnetometer measurements or write them in the user offset registers 0x09 – 0x0E with CTRL_REG2[RAW] = 0. It has been used also in this example project.

Hope it helps.

Best regards,

Tomas

[deepanrajanbara]

Hi Tomas,

We tried the above method for eliminating the zero field offset. But it does not seem to take effect.

Is there any other method to eliminate the zero field offset.

Even thought the value of x -axis or y-axis is negative when we keep it in any direction, is it possible to find the heading using the obtained value.

Thank you