Factory of the Future: Virtual PLC Grids?

After Automation World columnist Jim Pinto gave his prognostications for 2012, reader Phil Christopher offered his own vision for the factory of the future. It includes a virtual grid of PLC technology and autonomous carts for assembly lines.

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In the factory of the future, several hardware servers will make up a grid that would provide the ability to add or take away programmable logic controller (PLC) processing power simply by adding or removing a server.  If one server fails, the others pick it up instantly. 

Nodes on this grid would share resources with one another, providing a large volume on which to run hundreds or thousands of virtual PLCs.  These virtual PLCs would replace the hardware PLCs on the plant floor.

So as to ensure fast, reliable communication, the components (flow meters, pressure transducers, thermocouples, drives, HMIs, etc.) would communicate via a dedicated fiber-optic channel (strand) that runs between the component and the virtual PLC on the grid in the server room. Each component would generate the fiber signal in accordance with a common standard. Fiber signals are more durable than electronic signals, especially in electronically hostile environments like some plant floors.  The communication would be faster than Ethernet because it is not going through switches and other devices that add latency. 

Some of the benefits of this architecture might be: less cost; reduced downtime; better security; improved maintainability; centralized alarm notification and improved system and data logging; improved longevity of equipment; common standards to reduce incompatibility between vendors; centralized administration and change logging.

“That is the PLC architecture vision I personally see for the future,” says Christopher. “Another innovation I can see is the development of intelligent automation.” He provides an example. 

Suppose you make dashboards for cars. What if a system could receive several orders to produce thousands of dashboards and one by one pass on each to an autonomous cart that resides in a work area with 50 other autonomous carts.  Then imagine each cart tracks where it is in the process and finds its own way to the next step, where it docks with the applicable station where the work is performed.  Imagine 50 of those carts operating independently of each other, yet aware of each other so if there is a line at a station, they prioritize based on a common set of rules. Some of those rules might be availability of dashboard parts (skin, substrate, airbag, etc.) and the urgency with which they should be manufactured.  Who knows, maybe the urgency can be further defined by availability of a truck bound for a specific customer, or an indicator at a customer’s that shows their supply of your dashboards is low. 

“Perhaps one, or both of innovations are in practice and I am simply not aware,  in which case I would be interested in hearing more about them sometime,” says Christopher. “If they are not being implemented, I could see them happening within a decade, or so.”

Phil Christopher, phil.christopher@gmail.com, is Director of IT at Linden Industries.

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