“Maybe this will solve this problem I have over here,” they say to themselves. Networking is one of those tools.
A customer told me once that he would never run a wire from a machine programmable logic controller (PLC) to something outside the system. It would create untold safety and security problems, he thought. Within five years of that statement, I quoted a system that would network all of the PLCs on one of his lines to a central computer on the floor that would capture data for maintenance analysis purposes.
Suppliers have given engineers technologies for wireless networking and have adapted common Ethernet for manufacturing purposes. Engineers immediately set out to extend applications for these networking technologies. Suppliers said their wireless networks were meant only for data acquisition. Engineers said, “I bet these could be used for some simple control problems”—and they installed them and it worked.
Ethernet suppliers have actually perpetuated this situation. Engineers asked why they couldn’t use Ethernet for their input/output systems as well as for data handling. That way, they only had to manage one network type. Many suppliers have developed deterministic Ethernet networks specifically for use in machine control to help solve that problem.
This month, series Contributing Editor Terry Costlow looks at the technologies, topologies and applications that have extended Ethernet into this realm of deterministic networking for machine control.
Check out an on-demand Webcast on the strengths and weaknesses of Industrial Ethernet variants for common industrial applications at www.automationworld.com/webcast-7946.
