FAQ No. FAQ02328
Question
Why is the
F3SN /
F3SH Safety Light Curtain
control output always use light-ON operation?
Answer
Safety Sensors and Safety Light Curtains need to be designed from
a failsafe perspective so that control devices do not start operation on
the dangerous side when any error or fault occurs.
With the light-ON output, the machine will operate using the NO contacts
of a relay. In other words, the NO contacts will be open even if power is
interrupted, e.g., by an error or fault, and the machine will not operate,
i.e., the operation will be safe.
On the other hand, with a dark-ON output, the machine would operate using
the NC contacts of a relay. The NC contacts would remain closed even if
power was interrupted, so the machine would operate and operation would
not be safe.
That is why, from a safety perspective, Safety Sensors and Safety Light
Curtains use light-ON outputs.
Other Safety Sensor
FAQs
 What is the difference between F3SN/F3SH and F3W Area Sensors?
What is the self-diagnostic function?
What is the protective height?
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