IC-LTA_16 Datasheet, PDF (11/15 Pages) IC-Haus GmbH – 6-CH. INCREMENTAL OPTO ENCODER ARRAY

iC-LTA
preliminary
6-CH. INCREMENTAL OPTO ENCODER ARRAY
DIGITAL OUTPUT SIGNALS
Rev C1, Page 11/15
T
PA
PB
AB-gated
PZ
B-gated
T/4 T/4 T/4 T/4
ö
C
ungated
U
V
W
C/6 C/6 C/6 C/6 C/6 C/6
Figure 4: Typical encoder quadrature and motor
commutation signals.
iC-LTA’s photo-sensor array requires an external reticle
(placed either on side of the IC or on side of the LED),
and thus allows for a free definition of the optical ra-
dius and cycles per revolution for the A and B encoder
quadrature signals.
The pulse count, period length and phase shift for the
U, V, W commutation signals is also determined by the
code disc design.
Contracted code disc designs and IC packaging with
custom reticle can be offered on request; contact
iC-Haus for details.
ANALOG OUTPUT SIGNALS
GND
PB
T1
PA
PZ
VCC
R1
U
SEL
R2
Figure 5: Example of analog ABZ / analog UVW
(pin SEL = 50% VCC)
GND
PA
T1
PB
PZ
VCC
R1
U
SEL
R2
Figure 6: Example of analog ABZ / digital UVW
(pin SEL = 75% VCC)
iC-LTA features 5 principle operation modes which are
selectable by the voltage applied to pin SEL. A voltage
divider as suggested by Table 4 is the easiest way to
obtain this.
SEL
R1¹⁾ R2¹⁾
100 % VCC 0 Ω open
75 % VCC 2.7 kΩ 8.2 kΩ
50 % VCC 4.7 kΩ 4.7 kΩ
(open) (open)
25 % VCC 8.2 kΩ 2.7 kΩ
0 % VCC open 0Ω
1) Exemplary values.
Operation Mode
x2 interpolated
analog ABZ, dig. UVW
all analog
x4 interpolated
x1 comparated
Table 4: Selection of operation mode by pin SEL.
If input SEL is left open, the IC biases its input at
50% VCC and analog output signals are available for
test and alignment.
Analog output signals may also be used to increase
the encoder’s resolution by connecting an external in-
terpolation IC. In this case the analog signals are re-
quired permanently, so that noise immunity should be
improved by wiring pin SEL to an external reference
providing VCC/2.
Setting 75 % VCC may be considered to obtain analog
signals at PA/PB/PZ and NA/NB/NZ outputs feeding
the external interpolation IC, together with digital sig-
nals at U/V/W directly connecting a line driver. Special
attention to the PCB layout should be paid to avoid
cross talk; analog and digital lines should be separated
carefully.