IC-MHM Datasheet, PDF (19/63 Pages) IC-Haus GmbH – 14-BIT ABSOLUTE ANGLE HALL ENCODER

iC-MHM
14-BIT ABSOLUTE ANGLE HALL ENCODER
Rev D1, Page 19/63
Offset Correction (VOSS and VOSC)
Voltage offset in the sine and cosine signals can be
corrected (compensated) using the VOSS and VOSC
parameters.
Filter Enable (ENF)
A filter is provided to suppress noise on the sine and
cosine signals. The filter cutoff frequency is set using
parameter ENF.
VOSS
VOSC
Value
0x00
0x01
...
0x3F
0x40
0x41
...
0x7F
Address 0x04; bits 6:0
Address 0x05; bits 6:0
Offset
Correction
Angle Error Correction
0 mV
0°
0.5 mV
0.06°
...
...
31.5 mV
3.7°
0 mV
0°
-0.5 mV
-0.06°
...
...
-31.5 mV
-3.7°
Table 11: Offset Correction Sine and Cosine
An offset correction range of ±31.5 mV is provided for
each channel. This will correct angle errors of up to
±3.7° due to offsets. Refer to CALIBRATION PROCE-
DURE on page 54 for information on calibrating the
offset correction values.
Gain Correction Cosine (GCC)
Parameter GCC allows trimming the gain of the cosine
channel to ensure that the amplitudes of the sine and
cosine signals are identical.
GCC
Value
0x00
0x01
...
0x3F
0x40
...
0x7F
Address 0x09; bits 6:0
Gain Correction Cosine
1.000
1.0015
exp(
ln(20)
2048
·
GCC)
1.0965
0.9106
Angle Error Correction
0°
0.04°
2.7°
-2.7°
exp(−
ln(20)
2048
·(128−GCC))
0.9985
-0.04°
ENF
Value
0
1
Address 0x04; bit 7
Cutoff Frequency
16 kHz
3 kHz
Table 13: Filter Enable
The optimal filter cutoff frequency depends on the max-
imum magnet rotation speed. In general, use a 3 kHz
cutoff frequency (ENF = 1) unless maximum magnet
rotation speed exceeds 180 kRPM.
Harmonic Calibration (HARMCAL)
After calibration of offsets and gain, a residual angle
error harmonic at a frequency of four times per magnet
revolution remains. This error can be reduced using
parameter HARMCAL.
HARM-
CAL
Value
0x00
0x01
...
0x0F
0x10
0x11
...
0x1F
Address 0x05; bit 7
Address 0x06; bits 7:4
Correction
Angle Error Correction
0 LSB
0°
1 LSB
0.05°
...
...
15 LSB
0.75°
0 LSB
0°
-1 LSB
-0.05°
...
...
-15 LSB
-0.75°
Table 14: Harmonic Calibration
Note: Parameter HARMCAL impacts the interpolator
but not the sine/cosine output signals.
Table 12: Gain Correction Cosine
A gain correction cosine range of approximately ±10%
is provided. This will correct angle errors of up to ±2.7°
due to gain imbalance. Refer to CALIBRATION PRO-
CEDURE on page 54 for information on calibrating the
gain correction cosine.