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

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 MoreInstructions for Use – the New ISO 20607

Instructions are one of the basic items that users expect to get when they purchase a product, and yet these important documents are often poorly written, badly translated, and incomplete. Key…
Read MoreCan Emergency Stop be used as an “on/off” control?

Every couple of months I get an email asking me if there is any reason why e‑stop functions can’t be used as the primary power control (on/off button) for machinery. Following…
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.…
Read MoreDo-It-Yourself Safety Labels, Signs and Tags

One of the great challenges that all product designers face is the sourcing of appropriate product safety labels. There are many sources for off-the-shelf labels including some of the biggest…
Read MoreEmergency Stop Pull-Cords

This article was updated 2020-06-13, adding links to the Rockwell Automation and Schmersal pull-cord data, and on 2019-04-26, adding specific details related to IEC 60947 – 5‑5 [7]. Additional vendor links and…
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…
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