Tucked away in the rolling hills of rural America, the Slumbertown paper mill had been operating efficiently since it opened its doors back in the spring of 1911. The mill started with a single paper machine but was expanded and updated over the years and now operates three state-of-the-art production lines, mainly producing specialties paper for high-end printing applications as used for magazines and calendars.

George has been with the mill since 1970. He started as a paper machine technician and evolved into a mill Information Technology (IT) and Operational Technology (OT) professional to accommodate the evolving technology needs of the expanding mill operations. When he started at the mill, all process systems were standalone islands of controls, with relay and timer circuits being the norm. But the acquisition of paper machine number 2 in 1987 changed all that. It came with a sophisticated network of servers, Terminals and PLCs, forming what is known as a Distributed Controls System, or DCS.

The DCS oversaw every aspect of the paper machine process and streamlined the entire operation of the machine. George liked the DCS system. He liked it so much that he lobbied for replacing the antiquated relay and timer controls of the wood yard and pulp mill systems with a DCS. And by 1992, all relay and timer circuits of the plant were replaced by Programmable Logic Controllers, which were part of one of the three DCS systems that now ran the entire mill process.

Along with the most recent acquisition of paper machine 3, the decision was made to invest in a manufacturing execution system (MES) to start tracking the effectiveness of the production systems. To this end, the 4 DCS systems and some lingering local controls were going to have to be able to communicate with the MES data and application servers. George had spent a lot of effort in getting all the OT systems on a shared (ICS) network. The setup maintained a separation between OT and IT systems by not directly connecting the two networks together but having some dedicated computers connected to both networks.

These computers were used to interact with the OT systems and devices for tasks such as programming and troubleshooting. It was decided to keep this trend and have the MES servers fitted with dual Network Interface Cards, or NICs, so they could communicate with both the OT systems on the ICS network as well as MES client computers on the business network. The following figure depicts the resulting architecture:

With this setup, the MES servers can collect and send data to and from the Industrial control systems and devices. Maintenance people can program and troubleshoot equipment with their workstation attached to the ICS network. Engineering people can access systems on the ICS network as well as the business network and computers on the business network can access MES data via client software or web portals and reporting services via the business side of the MES servers.