CSA Z432 Fourth Edition Open for Public Review!

CSA just opened public review on CSA Z432, Safeguarding of Machinery, fourth edition. If you are a user, a builder of machinery, or an evaluator of machinery, this is your opportunity to see the draft of this important standard and to make comments to help the Technical Committee improve the standard on your behalf. Note: The…

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Emergency Off (EMO) vs Emergency Stop

EMO Button, red with yellow surround. Credit: D. Nix

The concept of Emergency Off (EMO) used by the semiconductor manufacturing sector is similar in many ways to the emergency stop used in all other types of machinery, with some differences. This article covers the differences between these concepts. NOTE: This is a long post! TL;DR: EMO and emergency stop are very similar, however, there…

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Understanding Safety Functions: the start/restart function

Car engine start/stop button

After the safety-related stopping and the reset functions, the start/restart function is the next most common. Without a start/restart function, there is no way to make the machine do what it’s supposed to do. If you’re designing a machine control system, you need to understand this function.

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Understanding Safety Functions: the Safety-related stop function

A stop sign - A red octagon with a white border, and white block text reading STOP.

The most used safety function on machinery is the safety-related stop function. The requirements discussed in this post are not generally applicable to process-related stop functions unless the process and safety stop functions share the same control system hardware and software. Copyright secured by Digiprove © 2021Acknowledgements: ISOSome Rights ReservedOriginal content here is published under these license terms: X License Type:Non-commercial, Attribution, Share…

Manual reset using an HMI

A Siemens HMI displaying control functions and data.

Update: Since this post was first published in 2021, things have changed a bit. There are now some safety-rated HMIs available from big controls companies like Siemens, so if you are considering this approach, consult with your controls vendor to see if their HMIs can meet the requirements of ISO 13849-1. Ed. – 2022-05-10 Question: Can…

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