Q & A: Category 2 and Testing Intervals

Logical block diagram for ISO 13849-1 Category 2 architecture.

During the Free Safety Talks with Schmersal Canada and Franklin Empire, we had a “hot question” regarding Category 2 architecture and the testing interval requirement. Category 2 in [1, 6.2.5] does not mention a minimum testing rate, but [1, 4.5.4], “Simplified procedure for estimating the quantifiable aspects of PL,” adds a requirement for test rate…

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Q & A: Can Safety PLCs be used for Lockout?

Disconnect Switch with Lock and Tag

Questions about equipment lockout using safety PLCs are more frequent these days. Can Safety PLCs be used for lockout? Safety professionals don’t always agree on this controversial topic!

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