uint64 error_count
float32 x
float32 y
float32 z
float32 range_ga
float32 scaling
float32 temperature
int16 x_raw
int16 y_raw
int16 z_raw
uint32 device_id # unique device ID for the sensor that does not change between power cycles
uint8 is_external # if 1, the mag is external (i.e. not built into the board)