Connection Of Several Safety Switches In A Cascade - SICK TR4 Instrucciones De Operación

GB
Chapter 5
WARNING
150
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Electrical installation
5.3.3 Connection of several safety switches in a
cascade
Several TR4 safety switches can be cascaded (connected in series).
The number of safety switches in a cascade is almost unlimited.
However it will have an effect on the response time of the system (see
section 9.1.2 "Response time for multiple cascaded TR4 safety
switches" on page 163). It is therefore recommended not to use more
than 30 safety switches in a cascade.
Use external device monitoring!
The TR4 has no external device monitoring. To achieve SIL3/PL e you
must therefore implement external device monitoring with the aid of
suitable higher level safety evaluation.
The actual performance level or SIL claim limit achieved depends on
the external circuit, the design of the wiring, the selection of the control
switch and its placement on the machine.
Evaluate both safety outputs!
To ensure safety it is imperative you evaluate both safety outputs
(Out A and Out B) (see Fig. 5).
Prevent tampering!
On the usage of TJplug connectors for cascading you must mount the
connecting cables such that simple bypassing of the safety switch is
not possible.
Operating Instructions
TR4
8014465/2012-05-07
Subject to change without notice