IEN: What trends are you seeing today?
Ross: We see factory bus communication moving down to the control device level. In the early days, fieldbus and Ethernet networks connected the factory at the machine level. Now the trend is to connect individual control components to the network.
One reason for this is that machinery is more modular, requiring more communication between modules. Another reason is the desire to obtain diagnostics information on each component. Yet another is the desire to communicate operational status to factory control software or HMI (Human Machine Interface).
A good example is a multi-loop temperature controller that is interfaced to a programmable logic controller (PLC). The controller takes care of the analog processing, and the PLC handles the logical processing and connects to the HMI. Because different makes of PLCs may use different fieldbus protocols, controller vendors need to provide a choice of protocol interfaces.
Our MLC 9000+ multi-loop temperature controller (shown here) is available with a choice of several communication bus interfaces, including Ethernet. Because Ethernet networks reach into the plant from the front office, operations executives can access statistical information for quality and value stream analysis.