Less programming, greater flexibility, less cost, and simpler installation at the user facility are the key benefits ascribed to this approach.
But some OEMs are reluctant to go this route, says Dan Throne, Food & Packaging Industry Manager at industrial automation controls manufacturer Bosch Rexroth Corp.
“While some machinery builders do embrace the notion of a combined motion and logic controller, I still see OEMs who are using separate motion and logic controllers to run their machines,” says Throne. “I don’t think they’re satisfied with integrated motion and logic capabilities from some suppliers because they are still scan-based PLC architectures, which can be too slow to handle today’s high-speed applications compared to event-based system architectures that come from the motion-centric servo controls world. So these OEMs still use a servo-based motion controller to do their tightly synchronized motions and then include a simple PLC for the safety guarding, the light stack, the horns, the recipe management, and so on. They keep the motion control separate and sacred. That way they have a guaranteed machine performance, based on using the same high-performance motion solution each time, and they can put on whatever PLC their customer prefers without affecting their machine performance level. This gives the freedom to the OEMs sales force to be able to adhere to whatever PLC preference the end user wants and still have a high-performance machine regardless of the customer PLC preference.”