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 a recent exchange, I thought I would share the reasons for why this is such a bad idea. The short answer The short answer is an unequivocal NO. Don’t […]
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 […]
This article was updated 2019-04-26, adding specific details related to IEC 60947 – 5 – 5. When it comes to emergency stop devices there is no doubt that the red mushroom-head push button is the most common – they seem to be everywhere. The second most common emergency stop device is the pull-cord, and like the light-curtain in safeguarding […]
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 […]
In Part 2 of this article, I looked at the pressure-sensitive devices (safety edges) themselves. This part explores the stopping performance requirements that engineers and technologists need to consider when applying these devices. Copyright secured by Digiprove © 2018Acknowledgements: As cited in the text.Some Rights ReservedOriginal content here is published under these license terms: X License Type:Non-commercial, Attribution, Share AlikeLicense Summary:You may copy this content, […]
In Part 1 of this article, I looked at the pressure-sensitive devices (safety edges) themselves. This part explores the design requirements that engineers and technologists need to consider when applying these devices. Copyright secured by Digiprove © 2018Acknowledgements: As cited in the text.Some Rights ReservedOriginal content here is published under these license terms: X License Type:Non-commercial, Attribution, Share AlikeLicense Summary:You may copy this content, create […]
Safety Edges are often forgotten as safeguarding devices. Most machinery engineers and designers are familiar with interlocking devices and light curtains, but once we step away from the familiar, our understanding of how to apply safeguarding devices like a safety edge becomes a bit foggy. Copyright secured by Digiprove © 2018Acknowledgements: SafeInd, IEC, ISO, Rockwell Automatio more…Some Rights ReservedOriginal content here is published […]
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. In the short video below, Doug answers that question. If you have more questions or felt something wasn’t clear in the video, leave us a comment and […]
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 […]
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 […]