exida explains Blog

Are Collaborative Robots Inherently Safe?

Are Collaborative Robots Inherently Safe?

No! They are not Inherently Safe!

A collaborative robot is intended to work “collaboratively” with a person. i.e. share a common workspace. It is force and speed limited by design to minimize any potential hazard. Collaborative robots fit the application where the task cannot be easily or cost effectively…

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The Undetected Detective; PVST

The Undetected Detective; PVST

Have you ever wondered why some dangerous failures are classified as undetected and others are classified as detective?  Aren’t dangerous failures all dangerous? Why do we classify them differently?

Let's say we have a plant that is running in normal operation mode and the system needs to trip. The…

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Industrial Robots – Easy Pickings!

Industrial Robots – Easy Pickings!

As robots populate factories and plants around the world at a brisk pace, security and safety are often overlooked. Numerous vulnerabilities plague industrial robots as seen in automotive assembly or autonomous transporters (found in larges on-line retailers that tout  efficient warehouse fulfillment operations.) Not to be forgotten, Cobots (Collaborative…

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Random versus Systematic Faults: What’s the difference?

Random versus Systematic Faults: What’s the difference?

I saw and responded to a LinkedIn discussion on this very issue, where someone had asked “if I have a misaligned limit switch that fails dangerously, then is it random or systematic? “.  This is an intriguing question because many view human error as being systematic and, whereas, this…

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Cloud Robotics – Safe & Secure?

Cloud Robotics – Safe & Secure?

Cloud computing, huge potential! That’s what the automation, automotive, and robotics industries are all excited about.

So, what is cloud computing and how does it affect safety?

Cloud computing utilizes servers on the internet to process, store and manage data. There is a much longer NIST definition

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Why Proof Test Coverage Is So Important For A SIF to Achieve Its Target SIL?

Why Proof Test Coverage Is So Important For A SIF to Achieve Its Target SIL?

This is a question I often get asked when I’m teaching our FSE100 course on Functional Safety, when we discuss the purpose of Proof Testing and coverage.  It’s amazing how many end users assume perfect proof testing (i.e. 100% coverage), that is capable of finding, all the…

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Outer Banks: How Could This Massive Power Outage Happen?

Outer Banks: How Could This Massive Power Outage Happen?

I, like many others, was stunned to hear that there was a major power outage covering the Outer Banks. Being an engineer, my instincts were to immediately investigate what happened and what steps occurred to lead to that point. Even before I did research, my mind was already asking…

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Making the Most of Customer Feedback

Making the Most of Customer Feedback

Your organization gets information, feedback, and requests from customers all the time.  It’s up to you to do some preliminary analysis and determine what the customer really wants.  Do they want to buy something?  Do they want to complain about something?  Do they have a need for which no…

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IEC 61508 is flexible, but is it Agile?

IEC 61508 is flexible, but is it Agile?

Agile development is a much better fit with IEC 61508 compliant software development than one might think at first blush.

Agile is not a methodology but rather a set of values and principles stated in the Agile manifesto. These principles are designed to force introspection and reflection…

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Why Run-to-Fail Is Not A Good Maintenance Strategy For SIS

Why Run-to-Fail Is Not A Good Maintenance Strategy For SIS

Making Use of Leading and Lagging Indicators – Are You Using These for Functional Safety?

Making Use of Leading and Lagging Indicators – Are You Using These for Functional Safety?

Some of you reading this may not be aware or familiar with the terms “leading” and “lagging” indicators, when applied to Functional Safety.  The concept isn’t new but does provide significant benefit when applying this to Functional Safety because, if used correctly, these indicators can help significantly improve performance. …

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Why Is Functional Safety An Important Piece of Process Safety Management?

Why Is Functional Safety An Important Piece of Process Safety Management?

It’s interesting to note that with the release of the 2016 edition of IEC61511, there’s more emphasis being placed on the need for better functional safety management.  Having taught many courses on Functional Safety over the past few years, I find that most of the…

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Functional Safety Standards - IEC 61508 vs. IEC 61511

Functional Safety Standards - IEC 61508 vs. IEC 61511

IEC 61508 is considered a basic or “umbrella” standard for functional safety.  It is generic and sometimes even vague.  IEC 61508 was intended that various industry sectors provide their own specific standards and guidelines as needed.  Here we can see the relationship between 61508 and other standards, such as…

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So what does Interference-Free mean?  And why do we care?

So what does Interference-Free mean?  And why do we care?

An Interference-Free component, either as an interface or a defined functional area, is a system component that is neither safety critical (C3) nor safety relevant (C2), but interfaces with such subsystems. 

If a component has been shown to be interference free (C1), then it has been demonstrated that no…

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Getting Good Proof Test Coverage Numbers

Getting Good Proof Test Coverage Numbers

Several years ago we recognized that proof test coverage was an important variable that must be considered when doing PFDavg calculations. We ran some models and discovered that the difference between “perfect” proof test coverage (100%) and a very good 90% could mean a whole SIL

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