IC-PR Datasheet, PDF (14/18 Pages) IC-Haus GmbH – REFLECTIVE OPTO ENCODERS

iC-PR Series
REFLECTIVE OPTO ENCODERS
INDEX DETECTION THRESHOLD
Rev A3, Page 14/18
Via tri-level pin VZ an internal threshold for the index
detection can be controlled, as described in Table 7.
Setting VZ low (maximal threshold), a safe detection
of the index pulse requires stronger illumination of the
respective photodiodes, which also results in a stronger
interference resistance against extraneous or stray light.
On the other hand, with VZ high (minimal threshold)
less illumination of the index photodiodes is required for
a safe detection. However, in this case the interference
resistance is reduced respectively. With VZ open the
threshold lies in between the other two options.
air gaps, it may be necessary to decrease the index
detection threshold.
Note: VZ affects all operation modes, no matter if the
index signal is analog or digital.
VZ
low
high
open
Description
Maximal threshold
Minimal threshold
Medium threshold
For air gap above 1.5 mm (IC to code disc), the recom-
mended value for VZ is shown in Table 8. For smaller
Table 7: Index detection controlled by pin VZ.
POWER CONTROL
iC-PR devices regulate the current through the inte-
grated blue LED, keeping the optical power constant
regardless of aging effects, varying temperature or
changes in air gap (iC to code disc).
In case of strong code disc misalignment or in the ab-
sence of any code disc, a maximum current is sent
through the LED, which corresponds to an overall sup-
ply current of typ. 80 mA.
When code disc and iC-PR are properly aligned, the
LED current is significantly reduced and mainly de-
pends on the code disc type and the actual air gap (see
Table 8 for typ. supply current values).