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 the fundamentals of functional safety. The…
Read MoreTrapped Key Interlocking
Many machine designers think of interlocks as exclusively electrical devices; a switch is attached to a movable mechanical guard, and the switch is connected to the control system. Trapped Key Interlocking is a way to interlock guards that is equally effective, and often more appropriate in severe environmental conditions. Copyright secured by Digiprove © 2018Acknowledgements: As cited.Some Rights ReservedOriginal content here is published under…
Q & A: Category 2 and Testing Intervals
During the Free Safety Talks that we did with Schmersal Canada and Franklin Empire, we had a “hot question” come up regarding Category 2 architecture and the testing interval requirement. The definition of Category 2 in 6.2.5 does not include any mention of a minimum testing rate, but 4.5.4 “Simplified procedure for estimating the quantifiable aspects of PL”…
Read MoreFive reasons you should attend our Free Safety Talks
Reason #1 – Free Safety Talks You can’t argue with Free Stuff! Last week we partnered with Schmersal Canada and Franklin Empire to put on three days of Free Safety Talks. We had full houses in all three locations, Windsor, London and Cambridge, with nearly 60 people participating. We had two great presenters who helped…
Read MoreSafe Drive Control including Safe Torque Off (STO)
Ed. Note: This article was revised 25-Jul-17 to include information on safe standstill. Safe Drive Control including STO Motor drives are everywhere. From DC variable speed drives and indexing drives, through AC Variable Frequency drives, servo drives and stepper motor drives, the capabilities and the flexibility of these electronic systems has given machine designers unprecedented…
Read MoreHow to do a 13849 – 1 analysis: Complete Reference List
Post updated 2019-07-24. Ed. As promised in previous posts, here is the complete reference list for the series “How to do a 13849 – 1 analysis”! If you have any additional resources you think readers would find helpful, please add them in the comments. Copyright secured by Digiprove © 2017 – 2018Acknowledgements: As cited.Some Rights ReservedOriginal content here is published under these license terms: X License Type:Non-commercial, Attribution,…
ISO 13849 – 1 Analysis — Part 7: Safety-Related Software
Post updated 2019-07-24. Ed. Safety-Related Software Up to this point, I have been discussing the basic processes used for the design of safety-related parts of control systems. The underlying assumption is that these techniques apply to the design of hardware used for safety purposes. The remaining question focuses on the design and development of safety-related software…
Read MoreISO 13849 – 1 Analysis — Part 3: Architectural Category Selection
Post updated 2019-07-24. Ed. At this point, you have completed the risk assessment, assigned required Performance Levels to each safety function, and developed the Safety Requirement Specification for each safety function. Next, you need to consider three aspects of the system design: Architectural Category, Channel Mean Time to Dangerous Failure (MTTFD), and Diagnostic Coverage (DCavg). In…
Read MoreISO 13849 – 1 Analysis — Part 2: Safety Requirement Specification
This article was updated 2019-07-24. Ed. Developing the Safety Requirement Specification The Safety Requirement Specification sounds pretty heavy, but actually, it is just a big name for a way to organize the information you need to have to analyze and design the safety systems for your machinery. Note that I am assuming that you are doing this in…
Read MoreISO 13849 – 1 Analysis — Part 1: Start with Risk Assessment
This post was updated 2019-07-24 I often get questions from clients about how to get started on Functional Safety using ISO 13849. This article is the first in a series that will walk you through the basics of using ISO 13849. Keep in mind that you will need to hold a copy of the 3rd edition of ISO 13849 – 1 [1]…
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