The fourth revolution in manufacturing and process automation， often referred to as Industry 4.0， will advance on the backbone of connected systems： sensors， actuators， and control systems， all linked through networks via the internet protocol. Sensor data will be analyzed to optimize manufacturing， predict failures， schedule maintenance and automatically replenish inventory. This poses a considerable challenge for programmable logic controller （PLC） design engineers who are required to pack more functionality into enclosures that keep getting smaller. Higher input/output （I/O） density and smaller form factors also add to the design challenge in another basic way： the system must be more power efficient than ever to prevent the PLC from overheating， especially in an application where fans and vents are generally not acceptable.