exida explains Blog

Entries tagged with: Safety Integrity Level

Back to Basics 20 – Safe Failure Fraction, SFF

Back to Basics 20 – Safe Failure Fraction, SFF

Safe Failure Fraction (SFF) is defined as the ratio of the average rate of safe failures plus dangerous detected failures of the subsystem to the total average failure rate of the subsystem. It is defined for a single channel (no redundancy, 1oo1).

It is a measurement of the likelihood of…

Read More...

  • by Iwan van Beurden, CFSE
  • Thursday, March 21, 2013
  • Software

Changing the PVST Interval. Hey, my Architectural Constraints changed!

How to Decode an exida IEC 61508 Certificate: Part 2

Click here to read Part 1

Now that you know the step-by-step process of product certification, now let’s take a look at the actual information on the certificate. 

In the left panel (gray background) you will find an exida certification logo. …

Read More...

  • 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…

Read More...

IEC 62443: Levels, Levels and More Levels

IEC 62443: Levels, Levels and More Levels

By now we’ve all become familiar with safety integrity levels (SIL), as they have become part of our everyday lives. However, with the recent release of several cybersecurity standards in the IEC 62443 series, things are getting more complicated. This series of standards introduces two more levels…

Read More...

Why should I get my mechanical device certified per IEC 61508?

I was recently approached with a question regarding why it would be necessary to certify mechanical devices, such as valves, per IEC 61508 when it is not clearly stated in the standard that the standard is applicable to such devices.  After looking through IEC 61511 and Read More...