Machinery Safety 101

Manual reset using an HMI

A Siemens HMI displaying control functions and data.
This entry is part 2 of 3 in the series Under­stand­ing Safety Functions

Ques­tion: Can a safety-related stop func­tion, for example, be reset via a graph­ic­al object rep­res­ent­ing a reset but­ton on an HMI? The short answer: No, with an excep­tion. Read on if you’d like… 

Read More

What exactly is PELV?

Photo of the interior of an electrical control cabinet showing the components and wireways on the backplane.

What exactly is PELV? Elec­tric­al design­ers run into all kinds of spe­cial­ized ter­min­o­logy as part of their work. IEC is notori­ous for cre­at­ing spe­cial­ized terms that are not famil­i­ar to… 

Read More

Force and injury — How hard is too hard? ISO/TR 21260 will help

ISO/TS 15066 body model
This entry is part 5 of 5 in the series Hier­archy of Controls

Force rep­res­ents the mech­an­ic­al energy that causes injury to the human body. ISO/TC 199 has been work­ing on answer­ing that ques­tion since 2012.

Read More

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… 

Read More

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… 

Read More