This is a first On Thursday, 2023-04-27, ISO published ISO 13849-1:2023, the 4th edition of the dominant functional safety standard for machinery. Usually, I would be the first to tell you that you should buy the standard as quickly as possible and start using it immediately. Today is not a normal day. As Command Module…
Read MoreUnderstanding Safety Functions: the Safety-related stop function
The most used safety function on machinery is the safety-related stop function. The requirements discussed in this post are not generally applicable to process-related stop functions unless the process and safety stop functions share the same control system hardware and software.
Read MoreIntroduction to Functional Safety Seminars
If you are interested in functional safety, and I know many readers are based on the statistics I see for my other functional safety-related posts, I think you will be interested in this. I am collaborating with the IEEE Product Safety Engineering Society’s Virtual Chapter to provide a series of three 35 minute seminars discussing…
Read MoreTrapped Key Interlocking
Many machine designers think interlocks are exclusively electrical devices; a movable mechanical guard is fitted with an electrical interlocking device, and the interlocking device is connected to the control system. Trapped Key Interlocking is an equally effective way to interlock guards that is often more appropriate in severe environmental conditions or where the guard is…
Read MoreQ & A: Category 2 and Testing Intervals
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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