Machine Safety - Hardwired vs Integrated?
Since 2002, NFPA 79 took the lead for safety standards and eliminated the requirement that everything safety on a machine “shall be” hard wired.
Since 2002, NFPA 79 took the lead for safety standards and eliminated the requirement that everything safety on a machine “shall be” hard wired. Europe had already made the shift a few years earlier. So, with this paradigm shift for machine guarding the gates were opened for new safety technology specifically designed for and to be applied to machine safety applications.
In simple terms, machine safety was allowed to join and be fully integrated with the rest if the control technology in the architecture. Since 2002 we now have; safety PLC’s, safety drives, safe motion, safe CNC, safety networks, “intelligent” safety relays, safe wireless/cableless, and a host of safe devices such as – safe sensors, contactors, switches…..and more! The world for machine safety has dramatically opened up for opportunities in cost reduction and increased machine up time.
I’ve written several blogs and papers on this subject along with many fellow colleagues on this subject. However, I can’t recall anything written on the subject of when and under what circumstances should anyone consider converting their machine safety to full integration vs remaining hard wired.
A general guideline! It’s my opinion that someone on the supply side is in the best position to create a general guide to assist manufacturing through this process. For example, supply side companies like an OEM, a systems integrator, or an automation supplier In my years on the supply side I heard suggestions like:
- If you have four or more safety devices on your machine
- If you have six to eight safety point in your machine logic
- If you need to frequently re-configure your machine for production runs
- If you’re proceeding to update the machine control system.
I could add more....
Have any of you come across a document like this that you could share? This is one of the frequently asked questions from both small and medium sized companies.
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