Data Sheet ADIS16480
Rev. H | Page 35 of 44
Hard Iron Correction
Table 117, Table 118, and Table 119 describe the register format
for the hard iron correction factors: HX, HY, and HZ. These
registers use a twos complement format. Table 120 provides
some numerical examples for converting the digital codes for
these registers into their decimal equivalents.
Table 117. HARD_IRON_X (Page 2, Base Address = 0x28)
Bits Description (Default = 0x0000)
[15:0] X-axis magnetometer hard iron correction factor, HX
Twos complement, ±3.2767 gauss range,
0.1 mgauss/LSB, 0 gauss = 0x0000 (see Table 120)
Table 118. HARD_IRON_Y (Page 2, Base Address = 0x2A)
Bits Description (Default = 0x0000)
[15:0] Y-axis magnetometer hard iron correction factor, HY
Twos complement, ±3.2767 gauss range,
0.1 mgauss/LSB, 0 gauss = 0x0000 (see Table 120)
Table 119. HARD_IRON_Z (Page 2, Base Address = 0x2C)
Bits Description (Default = 0x0000)
[15:0] Z-axis magnetometer hard iron correction factor, Hz
Twos complement, ±3.2767 gauss range,
0.1 mgauss/LSB, 0 gauss = 0x0000 (see Table 120)
Table 120. HARD_IRON_x Data Format Examples
Magnetic Field Decimal Hex Binary
+3.2767 gauss +32,767 0x7FFF 0111 1111 1111 1111
+0.2 mgauss +2 0x0002 0000 0000 0000 0010
+0.1 mgauss +1 0x0001 0000 0000 0000 0001
0 gauss 0 0x0000 0000 0000 0000 0000
−0.1 mgauss −1 0xFFFF 1111 1111 1111 1111
−0.2 mgauss −2 0xFFFE 1111 1111 1111 1110
−3.2768 gauss −32,768 0x8000 1000 0000 0000 0000
Soft Iron Correction Matrix
The soft iron correction matrix contains correction factors for
both sensitivity (S11, S22, S33) and alignment (S12, S13, S21, S23, S31,
S32). The registers that represent each soft iron correction factor
are in Table 121 (S11), Table 122 (S12), Table 123 (S13), Table 124
(S21), Table 125 (S22), Table 126 (S23), Tabl e 127 (S31), Table 128
(S32), and Table 129 (S33). Table 130 offers some numerical
examples for converting between the digital codes and their
effect on the magnetometer output, in terms of percent-change.
Table 121. SOFT_IRON_S11 (Page 2, Base Address = 0x2E)
Bits Description (Default = 0x0000)
[15:0] Magnetometer soft iron correction factor, S11
Twos complement format, see Table 130 for examples
Table 122. SOFT_IRON_S12 (Page 2, Base Address = 0x30)
Bits Description (Default = 0x0000)
[15:0] Magnetometer soft iron correction factor, S12
Twos complement format, see Table 130 for examples
Table 123. SOFT_IRON_S13 (Page 2, Base Address = 0x32)
Bits Description (Default = 0x0000)
[15:0] Magnetometer soft iron correction factor, S13
Twos complement format, see Table 130 for examples
Table 124. SOFT_IRON_S21 (Page 2, Base Address = 0x34)
Bits Description (Default = 0x0000)
[15:0] Magnetometer soft iron correction factor, S21
Twos complement format, see Table 130 for examples
Table 125. SOFT_IRON_S22 (Page 2, Base Address = 0x36)
Bits Description (Default = 0x0000)
[15:0] Magnetometer soft iron correction factor, S22
Twos complement format, see Table 130 for examples
Table 126. SOFT_IRON_S23 (Page 2, Base Address = 0x38)
Bits Description (Default = 0x0000)
[15:0] Magnetometer soft iron correction factor, S23
Twos complement format, see Table 130 for examples
Table 127. SOFT_IRON_S31 (Page 2, Base Address = 0x3A)
Bits Description (Default = 0x0000)
[15:0] Magnetometer soft iron correction factor, S31
Twos complement format, see Table 130 for examples
Table 128. SOFT_IRON_S32 (Page 2, Base Address = 0x3C)
Bits Description (Default = 0x0000)
[15:0] Magnetometer soft iron correction factor, S32
Twos complement format, see Table 130 for examples
Table 129. SOFT_IRON_S33 (Page 2, Base Address = 0x3E)
Bits Description (Default = 0x0000)
[15:0] Magnetometer soft iron correction factor, S33
Twos complement format, see Table 130 for examples
Table 130. Soft Iron Correction, Numerical Examples
Delta (%) Decimal Hex Binary
+100 – 1/216 +32,767 0x7FFF 0111 1111 1111 1111
+200/215 +2 0x0002 0000 0000 0000 0010
+100/215 +1 0x0001 0000 0000 0000 0001
0 0 0x0000 0000 0000 0000 0000
−100/215 −1 0xFFFF 1111 1111 1111 1111
−200/215 −2 0xFFFE 1111 1111 1111 1110
−100 −32,768 0x8000 1000 0000 0000 0000