Lenze ELCAMZIxxx4SNNPSNN (LCU122) - Manual (Page 109)

Safety engineering
Basics
Overview of sensors
7
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109 EDSLCMX3024-SPS EN 5.0
7.1.7 Overview of sensors
Passive sensors
Passive sensors are two-channel switching elements with contacts. The connecting cables
and the sensor function must be monitored.
The contacts must switch simultaneously. Nevertheless, safety functions will be activated
as soon as at least one channel is switched.
The switches must be wired according to the closed-circuit principle.
Examples of passive sensors:
ƒ Door contact switch
ƒ Emergency-off control units
Active sensors
Active sensors are units with two-channel semiconductor outputs (OSSD outputs).
Drive-based safety integrated in this device series allows for test pulses < 1 ms to monitor
the outputs and cables.
P/N-switching sensors switch the positive and negative cable or signal and earth cable of
a sensor signal.
The outputs must switch simultaneously. Nevertheless, safety functions will be activated
as soon as at least one channel is switched.
Examples of active sensors:
ƒ Lightgrid
ƒ Laser scanner
ƒ Control