The V-model is a lifecycle model useful in the product development process that shows the link between the test specifications at each phase of development. Simply put, it looks like this:
The name comes from the basic shape of the model. …
exida explains Blog
- by Dave Butler, CFSE
- Thursday, August 29, 2013
- Software
Software Modeling and Functional Safety: Part 2
Part 1 of this blog entry discussed software modeling, modeling notation, and modeling tools. But, what does this have to do with Functional Safety? The IEC 61508 standard has requirements, for certain SIL levels, regarding the use of:
- “Semi-formal methods”
- Computer-aided specification and design tools
- Design standards
- Performance modeling …
- by Dave Butler, CFSE
- Tuesday, August 27, 2013
- Software
Software Modeling and Functional Safety: Part 1
Mechanical CAD and electronic schematic capture tools have been around much longer than graphical software tools. This is primarily because physical objects are more naturally represented as components in a computer-aided design program, and it was more obvious how to design those technologies at the time. The “soft” in…
- by Dr. William Goble, CFSE
- Tuesday, August 06, 2013
- Functional Safety
OREDA Data vs. FMEDA Data
A question was posed to me this week about why the OREDA failure rate for a solenoid valve was greater than the Failure Modes, Effects, and Diagnostic Analysis (FMEDA) results from exida for a specific manufacturer’s solenoid valve. The person asking the question was clearly challenging the exida…
- by Todd Stauffer
- Thursday, August 01, 2013
- Alarm Management
Alarm Rationalization: Alarm Objective Analysis (AOA)
Todd Stauffer, Director of Alarm Management at exida, takes you through a key part of the Alarm Rationalization process called Alarm Objective Analysis (AOA).
You will learn how to determine what alarms you need (and which one’s you don’t), how to eliminate nuisance alarms, and safely reduce the number…
- by Iwan van Beurden, CFSE
- Monday, July 29, 2013
- Certification
A Spring Return Scotch-Yoke Actuator with No Safe Failures! Really?
Look at the picture. What do you see? I see a spring return actuator with
- a diaphragm chamber
- a spring chamber
- the scotch-yoke mechanism
What are the high level potential failures for a ball valve?
- Scotch-yoke mechanism breaks, can no longer operate valve…
- by Iwan van Beurden, CFSE
- Monday, July 22, 2013
- Certification
A Ball Valve with Safe Failures! Really?
Look at the photo. What do you see? I see a ball valve with:
- a valve body
- a ball
- a stem that can turn the ball
What are the high level potential failures for a ball valve?
- Stem stuck, can no longer turn (dangerous) …
- by Michael Medoff , CFSE, CISA
- Friday, July 19, 2013
- Industrial Cybersecurity
Are Cybersecurity Servers Making Your ICS Less Cyber Secure?
ICS cybersecurity standards such as ISA 62443 (formerly ISA 99) and NERC CIP require operators to have policies and procedures in place to monitor and maintain their critical ICS cyber assets. For anything other than very small systems, the obvious choice is to implement systems…
- by Michael Medoff , CFSE, CISA
- Tuesday, July 16, 2013
- Industrial Cybersecurity
Cyber Security, Beyond the Internet: An Automation Engineer’s View
The world of automation has changed significantly over the past 30 years. I have fond memories of starting my career by calibrating, adjusting, and tuning pneumatic control loops while working my way through the electronic age right up to the present digital and cyber generation of automation. If you…
- by Dave Butler, CFSE
- Wednesday, July 10, 2013
- Software
Tracing and Validation Test Planning
Please see the first entry of the Requirements Management blog series here
Please see the second entry of the Requirements Management blog series here
So, you have a set of detailed safety requirements. You have derived them down to a level of detail you feel spells out…
- by Dave Butler, CFSE
- Tuesday, June 25, 2013
- Software
Allocation vs. Derivation
Please see the first entry of the Requirements Management blog series here.
The concepts of allocation and derivation are sometimes misunderstood when it comes to requirements management. This can lead to confusion and even to safety problems. The process of derivation involves the writing of a new requirement, …
- by Dave Butler, CFSE
- Wednesday, June 19, 2013
- Functional Safety
I have just one more, small change…
How many development teams have heard those few, innocent words uttered from Marketing/Management toward the end of the development phase of a project, only to have their schedule blown out of the water? The phase of development into which the change is introduced determines the size of the concentric…
- by John Yozallinas, CFSE
- Friday, June 14, 2013
- Functional Safety
Fire, Aim, Ready!
There is usually a natural order to things. But there are times when the natural order gets disrupted, and this could be for any number of reasons: we get busy, overloaded with tasks or information, tired, complacent, etc. But when you think about it, most of the excuses we…
- by Rick Smith
- Tuesday, June 11, 2013
- Functional Safety
Safety Training Benefits Safety Culture
While attending the Offshore Technology Conference, I heard a speaker make the point that studies substantiate that employees who are trained in safety are involved in fewer accidents. Those of us who promote and provide training in safety, this comes as no surprise. But it was his next…
- by John Yozallinas, CFSE
- Thursday, June 06, 2013
- Certification
If There Was ONE THING to Know About Functional Safety
Formalize your process.
Companies often have a pretty good hardware development process in place, dealing with electrical and mechanical drawings, bills of material, and the factory floor interface. Most of these processes are in place so the manufacturing department knows what to make and how to put it together. …