Machinery Safety 101

Safe Drive Control including Safe Torque Off (STO)

Graph illustrating STO Function
This entry is part 12 of 16 in the series Emer­gency Stop

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,… 

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How to do a 13849 – 1 analysis: Complete Reference List

This entry is part 8 of 9 in the series How to do a 13849 – 1 analysis

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… 

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ISO 13849 – 1 Analysis — Part 8: Fault Exclusion

This entry is part 9 of 9 in the series How to do a 13849 – 1 analysis

Post updated 2019-07-24. Ed. Fault Con­sid­er­a­tion & Fault Exclu­sion ISO 13849 – 1, Chapter 7 [1, 7] dis­cusses the need for fault con­sid­er­a­tion and fault exclu­sion. Fault con­sid­er­a­tion is the pro­cess of examin­ing the… 

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ISO 13849 – 1 Analysis — Part 7: Safety-Related Software

General architecture model of software
This entry is part 7 of 9 in the series How to do a 13849 – 1 analysis

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… 

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An update on CE Marking Electrical Cable

CE Mark­ing Wire and Cable In an earli­er post, I wrote about the require­ments for CE Mark­ing wire and cable and dis­cussed the <HAR> mark. In 2016, the Con­struc­tion Products Reg­u­la­tion 305/2011…

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ISO 13849 – 1 Analysis — Part 6: CCF — Common Cause Failures

This entry is part 6 of 9 in the series How to do a 13849 – 1 analysis

Post updated 2019-07-24. Ed. What is a “Com­mon Cause Fail­ure”? There are two sim­il­ar-sound­ing terms that people often get con­fused: Com­mon Cause Fail­ure (CCF) and Com­mon Mode Fail­ure. While these… 

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ISO 13849 – 1 Analysis — Part 5: Diagnostic Coverage (DC)

A graph showing the theoretical "bathtub curve" for product failure rate over the lifetime of the product.
This entry is part 5 of 9 in the series How to do a 13849 – 1 analysis

Post updated 2019-07-24. Ed. What is Dia­gnost­ic Cov­er­age? Under­stand­ing Dia­gnost­ic Cov­er­age (DC) as it is used in ISO 13849 – 1 [1] is crit­ic­al to ana­lys­ing the design of any safety func­tion assessed… 

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ISO 13849 – 1 Analysis — Part 4: MTTFD – Mean Time to Dangerous Failure

This entry is part 4 of 9 in the series How to do a 13849 – 1 analysis

Post updated 2019-07-24. Ed. Func­tion­al safety is all about the like­li­hood of a safety sys­tem fail­ing to oper­ate when you need it. Under­stand­ing Mean Time to Dan­ger­ous Fail­ure, or MTTFD, is… 

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ISO 13849 – 1 Analysis — Part 3: Architectural Category Selection

This entry is part 3 of 9 in the series How to do a 13849 – 1 analysis

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… 

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ISO 13849 – 1 Analysis — Part 2: Safety Requirement Specification

This entry is part 2 of 9 in the series How to do a 13849 – 1 analysis

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… 

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