exida explains Blog

How Does Stiction Affect Me?

What is Stiction?

Many studies and organizations have defined stiction, or static friction, in different ways. A few examples of the various definitions are as follows:

  • According to Entech [1], “stiction is a tendency to stick-slip due to high static friction. The phenomenon causes a limited resolution of the resulting…

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  • by Chris O'Brien, CFSE
  • Tuesday, February 05, 2013
  • Software

How Do You Handle Interposing Relays?

Many times in the design of a safety instrumented system it is necessary to utilize an interposing relay. Typically there is not a certified relay available. Since no certified product is being used it is important to follow the requirements to justify prior use and also to design…

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New Working Group (WG7) Formed for Alarm Management

The ISA-18.2 committee on alarm management has launched a new working group (WG7) that is focused on developing a standard, recommended practice, or technical report on the application of alarm management to process plants utilizing multiple packaged equipment systems. The work will be based on and complement the existing…

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Understanding Our Customers – One Step Closer to Excellence

Customer service isn’t about slashing prices or offering great rates.  Sure these types of strategies can promote new customers and generate business, but how often do the “new customers” return if the service or product didn’t meet their expectations?  It’s always said that a great sales person can sell…

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2012 - Good Progress for Cybersecurity and Functional Safety

I think it is wise for individuals to periodically review things. I like to do my professional review at the end of the year. 2012 was a good year.

Product Certification

Over 60 new products received functional safety or cybersecurity certification this year. Those products and more…

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Replace Before Failure

The solenoid valve manufacturer provides an FMEDA report that lists “useful life = 12 years.”  Useful life is a reliability engineering term that indicates a point in time when the failure rate of a device will begin increasing rather rapidly.  Why do we care about this time interval?  That…

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  • by John Yozallinas, CFSE
  • Thursday, December 06, 2012
  • Software

Spaces and Braces and Comments – Oh My!

What constitutes a good coding guideline?

Serious software development for functional safety requires a coding standard or coding guideline. Most organizations have one, but how do you know if it’s good?

You need to look beyond the boilerplate and physical code layout that are often defined in a coding…

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  • by Michael Medoff , CFSE, CISA
  • Thursday, November 29, 2012
  • Certification

Tool Qualification and Safety Standards

When building a product such as an anti-lock braking system for an automobile, or a railroad, or process control safety system, making sure that the product works as specified is a big part of functional safety. When it is time for the system to engage to prevent an accident,…

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Alarm Rationalization is “Going Green (field)”

With the growing adoption of the ISA-18.2 standard on alarm management, industry leaders are increasingly implementing alarm management best practices (such as alarm rationalization) during the upfront design, before they start up control systems for new, “Greenfield” installation. There are numerous benefits. You think alarm overload and nuisance alarms…

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  • by Dr. William Goble, CFSE
  • Thursday, November 15, 2012
  • Certification

Certification Accreditation

I am often asked “who says exida can certify a product?”  The best answer is of course “the marketplace.”  End user owner/operators ask for an exida certificate because they understand why technical competency is so important when evaluating design quality.  Then instrumentation manufacturers get an exida certificate because exida…

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  • by Dave Butler, CFSE
  • Tuesday, November 06, 2012
  • Software

IEC 61508 Compliant Module Testing: Part 4

Part 3 covered the design of tests, resulting in one or more Module Test Plans.  To execute a test plan, one would start with the test plan and a test results template (which could be a copy of the test plan as indicated previously), document the general test information…

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Industrial Control System Cyber Security – Legislation and Standards

There is a lot of concern around cyber security in Industrial Control Systems.  With new threats like Stuxnet and Flame, the perceived risk to critical infrastructure has increased dramatically.  There are increased calls for legislation and new methods for dealing with these threats.  The history of how we have…

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  • by Dave Butler, CFSE
  • Thursday, October 25, 2012
  • Software

IEC 61508 Compliant Module Testing: Part 3

The Test Plan

Assessment requires evidence that module tests are designed properly, run properly, and have been successfully run. Documented test results are also required.  In order to meet these requirements it is generally a good idea to document a test plan for each module.  Information that applies…

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  • by Dave Butler, CFSE
  • Friday, October 19, 2012
  • Software

IEC 61508 Compliant Module Testing: Part 2

Last week you learned about what exactly a module is, and examples of different types of modules. Now we will move on to interfaces, the need for module testing, and code coverage requirements.

An interface, such as the 3D printer’s communication interface, or the format of the 3D data…

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