Regarding, John Rezabek's February On the Bus column: I think we are destined to have a multiplicity of protocols in our facilities. Actuators and sensors will be at the level of the not-Internet of Things; Ethernet makes no sense there. But connecting AS-interface, IO-Link, FF, HART and ProfibusPA to the Industrial Internet of Things through intermediaries to Ethernet will allow integration with IIoT. I see Profinet as the backbone, with Profinet-specified proxies mapping data from the sensor level. Profinet connects devices to the controller, then OPC UA makes sense as the protocol upwards from the controller to the cloud/big data/analytics.
