Machine Safety

An ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis, operating efficiencies and cost savings, as well as all relevant safety standards, such as those from NFPA, ANSI, RIA, IEC, ISO and OSHA. About J.B. Titus.

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Machine safety: PLC versus PAC, is there a difference for safety?

Is PAC the newest PLC? Is there less risk for machine safety in using one or the other?

May 06, 2013


Is PAC the newest PLC? And, what’s that got to do with machine safety? What does PAC stand for? The answer is, programmable automation controller. What does PLC stand for? Everyone should know by now; that's programmable logic controller. So what’s the difference, and does a PAC have the capability to include safety logic?

 

In recent times, PLCs have grown to include unique safety certified PLCs with the capability to perform safety-related functions. We’ve also seen over the past 10 years the addition of safe controllers for various applications such as drives, motion, vision, communication, wireless, and many others. Each of these devices have, for years, been application-specific devices with unique capabilities, programming tools, and so forth. As a result, each safety-related device also required its own safety certification. Integrating these devices into one architecture on a machine was touted as easy because they would all “plug and play” on the same communications network for general automation and safety automation.

 

Then came the PAC parade. In my words, a PAC platform is designed to provide a universal capability to combine all these typical application devices plus safety-rated control for safety-related functions on a common platform. Typically this might be represented as optional modules configuring a controller (control system architecture) and programming the entire application with one tool. This advancement from automation suppliers greatly simplifies the life of manufacturers because of savings in components, spare parts inventory, training, unplanned machine downtime, re-development time for multiple machines, to mention a few.

 

A PAC solution is usually a complete machine control architecture, so it would naturally find its way to manufacturers via new machines and complete controls retrofits of legacy machines.

 

J.B. Titus, CFSE

But, do you see application possibilities about how PACs can find their way onto other installed machines? Has this presented you with any new perspectives? Add your comments or thoughts to the discussion by submitting your ideas, experiences, and challenges in the comments section below.

 

Related articles:

Siemens – PACs

Rockwell Automation – PACs

GE – PACs

Opto 22 – PACs

PACs – Plant Engineering’s Product Of The Year

Contact: http://www.jbtitus.com for “Solutions for Machine Safety”.



For more than 30 years, J.B. Titus has advised a wide range of clients on machine functional safety solutions, including Johnson + Johnson, Siemens, General Motors, Disney, Rockwell Automation, Bridgestone Firestone, and Samsung Heavy Industries. He holds a Bachelor of Business Administration degree from Oklahoma University in industrial management and an MBA from Case Western Reserve University in marketing and finance. He is a professional member of the American Society of Safety Engineers and is OSHA-certified in machine guarding. Titus is also TUV-certified as a Functional Safety Expert and serves on several American National Standards Institute, National Fire Protection Association, and National Electrical Manufacturers Association national safety and health standards committees. Reach him at jb(at)jbtitus.com and via www.jbtitus.com.