IC-MN Datasheet, PDF (27/59 Pages) IC-Haus GmbH – 25-BIT NONIUS ENCODER WITH 3-CH. SAMPLING 13-BIT Sin/D INTERPOLATION

iC-MN 25-BIT NONIUS ENCODER
WITH 3-CH. SAMPLING 13-BIT Sin/D INTERPOLATION
ANALOG PARAMETERS
Rev D1, Page 27/59
Signal Level Controller
By tracking the sensor’s power supply via the con-
trolled current sources (outputs ACOM, ACOS and
ACON) iC-MN can keep the sine/cosine track signals
for the ensuing sine-to-digital converter constant re-
gardless of temperature and aging effects.
When adjusting the signal conditioning a constant cur-
rent source is used in place of the controlled current
source, the set current of which can be adjusted using
ACOR_M(6:0) or ACOR_x(5:0) (x = S, N). This current
must be so low as to leave enough reserve for tem-
perature and aging effects and ensure that no unnec-
essary power dissipation is generated. However, the
source current may not be too low so as to permit a
better signal contrast and improved signal to noise ra-
tio. Using this current the signal calibration can then be
performed so that the sine/cosine signals at the sine-
to-digital converter have a (differential) value of 6 Vpp
in their calibrated state. Once calibration has proved
successful the signal level controller can be activated.
ACOC_M(4:0)
Addr. 0x0C; bit 4:0
Code
Setpoint
0x00
3.125% * Imax(ACOM)
0x01
6.25% * Imax(ACOM)
...
...
0x1E
96.875% * Imax(ACOM)
0x1F
100% * Imax(ACOM)
Table 30: Current source setpoint, ACOM output
ACOT_S(7:6)
Addr. 0x1D; bit 0
Addr. 0x1C; bit 7
ACOT_N(7:6)
Addr. 0x2D; bit 0
Addr. 0x2C; bit 7
Code
Operating mode
00
Quadratic regulation active
01
Sum regulation active
10
Constant current source mode
11
Not permitted
Table 31: Controller op. mode, ACOS/ACON outputs
There are three integrated signal level control units in
iC-MN, all of which are powered by VACO. It is thus
possible to regulate each track individually or, in opti-
cal systems with an LED, for example, all three tracks
using the master signal level controller. If the control
unit’s working range is exceeded, an error is gener-
ated.
ACOR_S(5)
Addr. 0x1C; bit 5
ACOR_N(5)
Addr. 0x2C; bit 5
Code
Current range Imax(ACOS), Imax(ACON)
0
5 mA
1
10 mA
Table 32: Current source range, ACOS/ACON outputs
ACOT_M(8:7)
Addr. 0x0D; bit 0
Addr. 0x0C; bit 7
Code
Operating mode
00
Quadratic regulation active*
01
Sum regulation active
10
Constant current source mode
11
Not permitted
*) Quadratic regulation of V()scq =
p_{(V (PSOUT − V (NSOUT ))2 + (V (PCOUT − V (NCOUT ))2}
ACOC_S(4:0)
Addr. 0x1C; bit 4:0
ACOC_N(4:0)
Addr. 0x2C; bit 4:0
Code
Setpoint
0x00
3.125% * Imax(ACOS, ACON)
0x01
6.25% * Imax(ACOS, ACON)
...
...
0x1E
96.875% * Imax(ACOS, ACON)
0x1F
100% * Imax(ACOS, ACON)
Table 28: Controller op. mode, ACOM output
Table 33: Current source setpoint, ACOS/ACON out-
put
ACOR_M(6:5)
Addr. 0x0C; bit 6:5
Code
Current range Imax(ACOM)
00
5 mA
01
10 mA
10
25 mA
11
50 mA
Table 29: Current source range, ACOM output