Safe Drive Control, including STO Motor drives are everywhere, some with Safe Torque Off (STO) capabilities and many without. 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 have given machine designers unprecedented capabilities when compared…
Read MoreISO 13849-1 Analysis — The 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.
Read MoreISO 13849-1 Analysis — Part 8: Fault Exclusion
Post updated 2019-07-24. Ed. Fault Consideration & Fault Exclusion ISO 13849-1, Clause 7 [1, 7] discusses the need for fault consideration and fault exclusion. Fault consideration is examining the components and sub-systems used in the safety-related part of the control system (SRP/CS) and making a list of all possible faults. This is a non-trivial exercise!
Read MoreISO 13849-1 Analysis — Part 3: Architectural Category Selection
Post updated 2019-07-24. Ed. 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). I will discuss selecting…
Read MoreISO 13849-1 Analysis — Part 2: Safety Requirement Specification
This article was updated on 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 analyze and design the safety systems for your machinery. Note that I am assuming that you are doing…
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