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…
Read MoreUnderstanding Safety Functions: the start/restart function

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.
Read MoreUnderstanding Safety Functions: the Safety-related stop function

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

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…
Read MoreUnderstanding safety functions: Manual Reset

Following the risk assessment, risk reduction is the next step. Whenever the control system is called upon to reduce the risk, a safety function is needed. Safety functions are defined in safety requirement specifications. ISO 13849-1:2015 [1] offers descriptions of some of the more common safety functions. One of the most poorly understood is the…
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