iC-MSBSAFETY, iC-MSB2
SIN/COS SIGNAL CONDITIONER WITH 1Vpp DRIVER
Rev D2, Page 22/29
The calibration range for the CH1/CH2 offset is depen-
Offset Calibration CH1, CH2
In order to calibrate the offset the reference source dent on the selected VOS12 source and is set using
must first be selected using VOS12. Two fixed voltages OR1 and OR2. Both sine and cosine signals are then
and two dependent sources are available for this pur- calibrated using factors OF1 and OF2. The calibration
pose. The fixed voltage sources should be selected for target is reached when the DC fraction of the differen-
external sensors which provide stable, self-regulating tial signals PCHx versus NCHx is zero.
signals.
OR1
OR2
Code
0x0
Adr 0x09, bit 0; Adr 0x08, bit 7
So that photosensors can be operated in optical en-
coders iC-MSB tracks changes in offset voltages via
the signal-dependent source VDC when used in con-
junction with the controlled sensor current source for
LED supply (pin ACO). The VDC potential automati-
cally tracks higher DC photocurrents. To this end inter-
mediate potentials VDC1 and VDC2 must be adjusted
to a minimal AC ripple using the selectable k factor (this
calibration must be repeated when the gain setting is
altered).
Adr 0x0A, bit 5:4
Range
x1
0x1
x2
0x2
x6
0x3
x12
Table 35: Offset Range CH1, CH2
OF1
Adr 0xA, bit 3:0; Adr 0x9, bit 7:1
OF2
Adr 0xC, bit 0; Adr 0xB, bit 7:0; Adr 0xA, bit 7:6
The feedback of pin voltage V(ACO) fulfills the same
task as source VDC when MR bridge sensors are sup-
plied by the controlled power supply output. In this
instance the VDC intermediate voltages do not need
adjusting.
Code
0x000
0x001
...
Factor
Code
0x400
0x401
...
Factor
0
0
0.00098
−0.00098
−0.00098 · OFx
−1
0.00098 · OFx
0x3FF
1
0x7FF
VOS12
Code
0x0
Adr 0x0E, bit 5:4
Type of source
0.05 · V(ACO)
0.5 V
Table 36: Offset Factors CH1, CH2
0x1
Phase Correction CH1 vs. CH2
0x2
0.25 V
The phase shift between CH1 and CH2 can be ad-
justed using parameter PH12. Following phase cal-
ibration other calibration parameters may have to be
adjusted again (those as amplitude compensation, in-
termediate potentials and offset voltages).
0x3
VDC (ie. VDC1, VDC2)
Table 33: Offset Reference Source CH1, CH2
VDC1
Adr 0x07, bit 4:0; Adr 0x06, bit 7:3
Adr 0x08, bit 6:0; Adr 0x07, bit 7:5
VDC = k · VPi + (1 − k) · VNi
k = 0.33
VDC2
Code
0x000
0x001
...
PH12
Code
0x000
0x001
...
Adr 0xD, bit 2:0; Adr 0xC, bit 7:1
Correction angle
+0
Code
0x200
0x201
Correction angle
−0
k = 0.33032
+0.0204
−0.0204
k = 0.33 + MP2 · 0.00032
k = 0.66
+0.0204 · PH12 ...
+10.42 0x3FF
−0.0204 · PH12
−10.42
0x3FF
0x1FF
Table 34: Intermediate Voltages CH1, CH2
Table 37: Phase Correction CH1 vs. CH2
ICHAUS [ IC-HAUS GMBH ]
