Integrated Safety - or Not! ...Plus 6 Comments; Do You Agree?

08/14/2009


We’ve all heard lots of arguments both for and against a fully integrated architecture for safety and general control. In the process world they’ve maintained a separate SIS (Safety Instrumented System) solution for safety creating a separate layer in their architecture for performing the safety functions. However, in the machine world when PLC’s were introduced in the 1970’s, standards groups rushed to exclude PLC’s from anything safety because the early technology wasn’t very reliable. Guess what happened?

Right, “anything safety” had to be hard wired relegating the safety functions to a separate layer and typically electromechanical devices. This is how the machinery world continued to live until 2002 when NFPA 79 changed allowing hardware / software devices designed, tested, and listed for safety applications. This change in the standard opened the door for options in technology, engineering, and design - to integrate safety - or not!

So, to answer the question today you have to look at your application and consider your options. Also, evaluate your risk assessment, the identified hazards, and what’s required to mitigate the identified hazards to tolerable levels. Layered safety and integrated safety are now options for you to consider along with your company’s safety policy, objectives, and business model.

IT’S YOUR OPPORTUNITY - CONSIDER IT!

Posted by J.B. Titus on August 14, 2009

COMMENTS

September 2, 2009

In response to: Integrated Safety - or Not!fatcat commented:

 

As a designer I agree with the latest comment. As the are three approaches to minimize risk - inherently safe design measures, safeguarding and complementary safety measures, and information for use, the first and most important step in the risk reduation process is inherently safe design, because protective measures inherent to the characteristics of the machine are likely to remain effective, whereas experience has shown that ever well-designed safeguarding may fail or be violated and information for use may not be followed.

September 2, 2009

In response to: Integrated Safety - or Not!Celso Valdez commented:

 

Standars are very good start point to desing, machine, control sistem, SIS etc. Depending of the risk identified and the tolerance allowed by client to the risk and the size of the sistema or machine there are lots of safety devices and solutions to implement. So The core fact from my point of view is safety must be in mind anytime someone desing and contruct any sistem or machine and the new technologies, like smarts devices, control networks, control buses etc have lots of features which when used in accordance with standars can improve safety.

September 2, 2009

In response to: Integrated Safety - or Not!Stan Lichtenberg commented:

 

That is always a hard question. Do you add a PLC to a simple machine just to integrate safety or not? There is no hard and fast line that marks the crossing from 1 to another. But I have seen a PLC added for a couple limit switches and E-Stop buttons. Was that really necessary? In my work I usually am rebuilding older equipment and I present both systems where possible to the customer and let them decide.

September 2, 2009

In response to: Integrated Safety - or Not!Krzysztof Majczak commented:

 

Certainly, it’s always better to have options – one or another.

But from my perspective, the most important achievement of functional safety is introducing standards and methodology to approach safety. Thanks to 61508/62061, 13849 most of guess-work and wishful thinking have been eliminated. The process of DFS (in my terminology – design for safety) eliminates from start most of costly mistakes and makes safety an achievable goal.

September 2, 2009

In response to: Integrated Safety - or Not!haridoz commented:

 

thanks

September 2, 2009

In response to: Integrated Safety - or Not!Steve Ludwig commented:

 

We (Rockwell Automation) agree that the safety solution is dependent on the needs of the machine, which is why we provide a full range of safety solutions including component-based, programmable and integrated safety automation systems.

Machine builders should consider safety a core design function rather than an added function after design is complete. Designing safety and sustainability into the machine reduces risk and improves machine performance.

In less sophisticated applications, simple electromechanical devices may be perfectly adequate. However, more advanced machines can now leverage control architecture that performs multidiscipline control tasks, such as motion and safety in the same controller. These systems use the intelligence and diagnostics of the automation system to operate the machine in the most efficient manner, reducing nuisance shutdowns, waste and energy consumption for the end user, and reducing the design, manufacture, programming and start-up costs of the machine builder.



No comments
The Engineers' Choice Awards highlight some of the best new control, instrumentation and automation products as chosen by...
Each year, a panel of Control Engineering editors and industry expert judges select the System Integrator of the Year Award winners.
Control Engineering Leaders Under 40 identifies and gives recognition to young engineers who...
Learn more about methods used to ensure that the integration between the safety system and the process control...
Adding industrial toughness and reliability to Ethernet eGuide
Technological advances like multiple-in-multiple-out (MIMO) transmitting and receiving
Virtualization advice: 4 ways splitting servers can help manufacturing; Efficient motion controls; Fill the brain drain; Learn from the HART Plant of the Year
Two sides to process safety: Combining human and technical factors in your program; Preparing HMI graphics for migrations; Mechatronics and safety; Engineers' Choice Awards
Detecting security breaches: Forensic invenstigations depend on knowing your networks inside and out; Wireless workers; Opening robotic control; Product exclusive: Robust encoders
The Ask Control Engineering blog covers all aspects of automation, including motors, drives, sensors, motion control, machine control, and embedded systems.
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
News and comments from Control Engineering process industries editor, Peter Welander.
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.
This is a blog from the trenches – written by engineers who are implementing and upgrading control systems every day across every industry.
Anthony Baker is a fictitious aggregation of experts from Callisto Integration, providing manufacturing consulting and systems integration.
Integrator Guide

Integrator Guide

Search the online Automation Integrator Guide
 

Create New Listing

Visit the System Integrators page to view past winners of Control Engineering's System Integrator of the Year Award and learn how to enter the competition. You will also find more information on system integrators and Control System Integrators Association.

Case Study Database

Case Study Database

Get more exposure for your case study by uploading it to the Control Engineering case study database, where end-users can identify relevant solutions and explore what the experts are doing to effectively implement a variety of technology and productivity related projects.

These case studies provide examples of how knowledgeable solution providers have used technology, processes and people to create effective and successful implementations in real-world situations. Case studies can be completed by filling out a simple online form where you can outline the project title, abstract, and full story in 1500 words or less; upload photos, videos and a logo.

Click here to visit the Case Study Database and upload your case study.