Chapter 3
2 9 6
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Product description
LE 20
LE 20-Muting
Fig. 3-2: Safety evaluation unit LE 20 and LE 20 Muting
3.3
Device functions of the LE 20 and
LE 20 Muting
3 . 3 . 1
Test functions
Testing the single-beam photoelectric safety switches
The correct functionality of the testable single-beam photoelectric
safety switches are tested after switch on and after operating the
reset pushbutton. The evaluation unit sends a test signal to the
photoelectric switch sender via the TEST A and TEST B connections
and checks the reaction of the photoelectric switch receiver via the
SENSOR A and SENSOR B signal inputs. Under normal operating
conditions, the testable single-beam photoelectric switches are
tested automatically every 2 seconds. This test routine is only
Operating Instructions
Safety Evaluation Unit LE 20
8 008 685/Q913/2007-05-21