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Fake Fact: Diagnostics are useless

Fake Fact: Diagnostics are useless

The idea that diagnostics are useless contradicts everything I’ve ever learned and taught about diagnostics. 

Diagnostics help identify problems. Diagnostics can turn a fault that is unrevealed during normal operation into a detected fault, which allows me to take action. That action could be an automatic transition to the…

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Functional Safety Assessment of Valve Assemblies (Part 2)

Functional Safety Assessment of Valve Assemblies (Part 2)

In Part 1, I covered the emerging trends in the valve assembly market, how these trends relate to IEC 61511 requirements, and the anatomy of final elements.

Now let’s discuss why we need to show requirements traceability down through the design of the safety instrumented function and then…

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Do You Measure the Performance of Your SIS?

Do You Measure the Performance of Your SIS?

It always amazes me that when teaching our FSE 100 Functional Safety Engineering course, the number of times I find that end users in the class are not really measuring the performance of their SIS. In most cases, they are doing some measurements, but not thoroughly.

It…

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Does Everyone Really Ignore Failure Rates?

Does Everyone Really Ignore Failure Rates?

While discussing functional safety certification of an integrated valve assembly with a manufacturer, exida stated that all devices (actuator, pneumatic parts, valve, etc.) must be IEC 61508 certified. The manufacturer said this was no problem, and provided a set of exida and TÜV certificates. 

Of…

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Fake Fact: IEC 61508 Does Not Affect Me As an End User

Fake Fact: IEC 61508 Does Not Affect Me As an End User

Though this is largely true, I want to discourage people from completely ignoring the good things that IEC 61508 does for the end user.

IEC 61511 is the process industry functional safety standard derived from IEC 61508. In the very first section of IEC 61511 (“Scope”), the standard describes…

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MISRA Compliance Static Analysis Results for a Real-world Automotive Project

MISRA Compliance Static Analysis Results for a Real-world Automotive Project

Splint is offering to present a “special reward” to the “first person to produce a real program that produces no errors with strict checking.” Here’s a summary of a recent real-world automotive project attempting this.  

TL;DR: We were not successful, but we learned a few things about MISRA compliance. Feel free to skip to the Observations section to learn more. 

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Which FSAs Do I Have to Perform?

Which FSAs Do I Have to Perform?

The new release of IEC61511:2016 has caused some confusion when it comes to the Functional Safety Assessments (FSAs). Which ones are mandatory?

The confusion comes from the wording in the standard and the clarifications in the notes. The relevant clause in the standard 5.2.6.1.4 states:

A FSA team…

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Dreaming of a Better Tomorrow?

Dreaming of a Better Tomorrow?

When I was a kid, I liked watching the Jetsons.  I felt certain that by the year 2000 we’d all be enjoying those flying saucers and futuristic homes.  Imagine my disappointment that in 2018 we still drive on 4 wheels… and my home cannot elevate itself above bad weather……

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Fake Fact: Final Elements should not be included in SIF evaluation

Fake Fact: Final Elements should not be included in SIF evaluation

Ehh… If your safety action is stopping flow/closing a valve, how are you going to accomplish this if you consider that the remote actuated valve is not part of your SIF ?

So, what is this myth based on? The title of IEC 61508 reads “Functional safety of electrical/electronic/programmable…

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You want what??  You want it when??

You want what??  You want it when??

Estimating time and cost for a project, or even part of a project, can be tricky.  Breaking down the tasks into subparts must be done or you don’t stand a chance.  Given enough time, you can develop an accurate estimate and put a good plan in place.  But sometimes…

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Software Metrics

Software Metrics

Both IEC 61508 and ISO 26262 highly recommend a modular approach to software development. One question that comes up regularly asks if there are quantitative targets for determining whether sufficient progress has been achieved by software engineers.

IEC 61508-3 Table B.9 Modular approach

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What Managers Need To Know About Functional Safety

What Managers Need To Know About Functional Safety

If you’re a manager in the process industries then you should be familiar with the concept of Functional Safety and the need to have well defined processes and procedures in place.  If not, then how else will you be able to ensure that your Safety Instrumented System and plant…

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Frequently asked questions about ANSI/CSA 22.2  No. 336 for Robotic Engineers

Frequently asked questions about ANSI/CSA 22.2 No. 336 for Robotic Engineers

On January 5th CSA Group published the first edition of particular requirements for rechargeable battery-operated commercial robotic floor treatment machines with traction drives.  CSA 22.2 - 336 is a National Standard of Canada.

Why Should I Care?

If you are a robotics engineer working for a company planning to…

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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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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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