About carelandries

Thank you for your swift response.  If this is the case for your BMM150, it is quite strange that mine outputs z-axis values above 2500uT.  Nonetheless, seems like I will cap it in software to 2500uT as this is to where the device is calibrated.  Thank you for the help! ... View more

Hi, Thank you for the clarification regarding the remnant magnetic field.  Regarding the output, I think there was a miscommunication. So let me try to explain better.  The maximum magnetic field output in the z-axis is specified as +-2500uT in the datasheet.  I am using the provided API to scale the raw output to uT values. When looking at the output provided by the API, a magnetic field value of 2500uT would be represented by a integer output of 2500uT * 16 LSB/uT = 40000. So when using the int16_t formatting, this output would not be possible as int16_t can only go up to +32768. I assume this is why the API saturates the output to 32768 in software when using the int16_t formatting.  However, when using the suggested int32 formatting (from previous PDF), the output can go a lot higher, and it seems the magnetic field output on the z-axis is not capped at 2500uT by the hardware, as a magnetic field output (output of API) of way more than 2500uT is read from device if such a field is induced onto the device.  So does the ouput become invalid once it provides a magnetic field output of more than 2500uT in the z-axis? Or just non-linear? Why is the datasheet maximum specified as +-2500uT when the HW can give much higher magnetic field readings? I assume there must be a reason for this?  Thank you in advance ... View more

Hi  It also seems as if there is a remnant magnetic field on the sensor if the device was exposed to a magnetic field higher than 2500uT (the field was still well below the maximum field specified as 7 T in the datasheet).  Any thoughts on this?   ... View more

Hi,  Thanks for the prompt response.  From what i understand, the output received from the bmm15_compensate functions can be converted to uT by usng the sensitivity of 16LSB/uT (it is done like that on the GitHub repo and suggested in datasheet).  In the attached pdf "temperature calibration" you mention that 32-bit resolution can be used. This would, however, result in potential outputs in uT much larger than the datasheet specifies for the BMM150 device.  For instance, for the Z-axis, the range is specified as +-2500uT. At +2500uT this result in a integeter output of 2500 * 16 (LSB/uT) = 40000. However, if 32-bit resolution is used, the integer output could be much higher than that. In the example code you give, you saturate in software to max of in32_t.  How is this possible? Because a value of much higher than the range specifice of +-2500uT will then be received as output?  Please help to clarify? ... View more