Achieving safety isn't a risky business — if you have the right solutions and tools. That's where safety PLCs come in, as these systems can make factory floors less dangerous to people, product, the environment and other machines. But to get the most out of the technology, it helps to know the basics.
It comes down to understanding and reducing risk.
For instance, a safety PLC differs from its standard cousins in a few important respects, says John D'Silva, safety technology manager at Siemens Industry. One involves communication. For instance, Profisafe, a safe protocol layer that runs atop industrial Ethernet, has consecutive numbering of messages, time expectation with acknowledgement, a unique codename between sender and receiver, and cyclic redundancy data-integrity checks.
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