exida explains Blog

exida Cyber Blog Series: 01 - What is Cyber Hygiene?

exida Cyber Blog Series: 01 - What is Cyber Hygiene?

exida would like to welcome our new director of cybersecurity services Dave Gunter.  Dave will be taking us through a multi part blog series based on general cybersecurity evolving into how it pertains to your industrial work environment and what you should do to protect your company…

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Tales from the Certification Wars - Proven In Use versus Certification
  • by Dr. William Goble, CFSE
  • Wednesday, April 19, 2017
  • Certification

Tales from the Certification Wars - Proven In Use versus Certification

Knowing Scope of Work (SOW)

Knowing Scope of Work (SOW)

There was a joke I heard many years ago that went like this…

3 workers were hired to run telephone lines.  The first part of their job was to install the poles on which the wires would run.  Each day, the foreman would ask the workers how many poles…

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What do Nuisance Alarms, the 80-20 Rule, Mental Models, and More Have in Common?

What do Nuisance Alarms, the 80-20 Rule, Mental Models, and More Have in Common?

Most everyone has heard of the “80-20 rule”.  It asserts that for many situations, roughly 80% of the effects (outcomes) come from 20% of the causes (inputs).  This rule was first proposed in the early 1900s by Vilfredo Pareto, who was an Italian engineer, sociologist, economist, political scientist, philosopher,…

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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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Nuisance Alarms and “The Boy Who Cried Wolf”

Nuisance Alarms and “The Boy Who Cried Wolf”

The purpose of an alarm is pretty straightforward - to draw the operator’s attention to an abnormal situation that requires action in order to prevent an undesired consequence. Alarms that don’t meet this principle often become nuisance alarms. A nuisance alarm is defined as:

“an alarm that annunciates excessively,…

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High Demand Diagnostic Credit?
  • by Dr. William Goble, CFSE
  • Thursday, January 19, 2017
  • Certification

High Demand Diagnostic Credit?

The IEC 61508 standard states that automatic diagnostics can only lower the dangerous undetected failure rate if those diagnostics execute 100 times faster than the expected demand rate.  That requirement has always seemed excessive to many of us here at exida.  As an accredited Certification Body we…

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Reducing Project Lifecycle Cost with exSILentia®
  • by Kate Hildenbrandt
  • Wednesday, January 18, 2017
  • Software

Reducing Project Lifecycle Cost with exSILentia®

The international functional safety standard IEC 61511 provides the safety lifecycle as a steadfast guideline to assess and mitigate risk for manufacturing processes including refineries, chemical, petrochemical, pulp and paper, and power plants. To achieve a functionally safe system, it is essential to follow each…

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IF COMPUTERS RULED THE WORLD…

IF COMPUTERS RULED THE WORLD…

What if the best minds of the world got together to generate the optimum requirements specification for human co-habitation?  And built it into one large decision matrix to run on the best super-computers?

Decisions would be made solely on objective criteria; no mental arbitration, no skipping steps, no checking…

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Conceptual Design and SIL Verification’s Ultimate Resource

Conceptual Design and SIL Verification’s Ultimate Resource

The Importance of Process Safety to the next Generation of Chemical Engineers

The Importance of Process Safety to the next Generation of Chemical Engineers

The 3rd Party Effect (Part 1)

The 3rd Party Effect (Part 1)

Have you even wondered, been involved, or WERE the little kid that didn’t listen to your parents, but always listened to a teacher?  This is called the “Third party effect.”  In business, it is well known that the power of persuasion can be the most effective by a third…

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How to become a world-class expert (the 10,000 hour rule)

How to become a world-class expert (the 10,000 hour rule)

In the book “Outliers”, Malcolm Gladwell popularized the notion that to become an expert in a field requires putting in 10,000 hours of practice.

The emerging picture from studies of expertise is that ten thousand hours of practice is required to reach the level of mastery associated with being…

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