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Entry type: FAQ Entry ID: 76676971, Entry date: 04/30/2021
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Contact expansion of a fail-safe controller with 3SK1 and 3RQ1

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Contact expansion of a fail-safe controller with 3SK1


QUESTION:

How can I multiply the outputs of a fail-safe controller with minimum wiring effort and expand the switching capacity of a fail-safe controller?

 

ANSWER:

The SIRIUS 3SK1 safety relays offer such an option with their basic unit and output expansion modules. This means you can increase the number of contacts as well as expand the switching capacity of the fail-safe controller up to 10 A. Another advantage is that the devices are already certified to the applicable safety standards.

Further reasons for decoupling the fail-safe outputs from downstream actuators may be the requirement for galvanic isolation or protection against EMC feedback.

This FAQ shows the different options for using the 3SK1 device series as contact expansion modules.

For applications with lower demands on the number of switching contacts, the positively driven coupling relays 3RQ1 in the variant with certification up to SIL 3 / PL e (3RQ12) are also suitable. These are therefore also described in this FAQ.

For applications with lower functional safety requirements, the positively driven coupling relays 3RQ1 in the variant with certification up to SIL 2 / PL c (3RQ10) are also suitable. These are therefore also described in this FAQ.

  FAQ_76676971_Contact_expansion_of_a_fail-safe_controller_with_3SK1_V14_en.pdf (889,2 KB)

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