Editing Distributed control system (section)

===The network-centric era of the 1980s===
In the 1980s, users began to look at DCSs as more than just basic process control. A very early example of a [[Direct Digital Control]] DCS was completed by the Australian business Midac in 1981–82 using R-Tec Australian designed hardware. The system installed at the [[University of Melbourne]] used a serial communications network, connecting campus buildings back to a control room "front end". Each remote unit ran two [[Z80]] microprocessors, while the front end ran eleven Z80s in a parallel processing configuration with paged common memory to share tasks and that could run up to 20,000 concurrent control objects.

It was believed that if openness could be achieved and greater amounts of data could be shared throughout the enterprise that even greater things could be achieved. The first attempts to increase the openness of DCSs resulted in the adoption of the predominant operating system of the day: ''UNIX''.  UNIX and its companion networking technology TCP-IP were developed by the US Department of Defense for openness, which was precisely the issue the process industries were looking to resolve.

As a result, suppliers also began to adopt Ethernet-based networks with their own proprietary protocol layers.  The full TCP/IP standard was not implemented, but the use of Ethernet made it possible to implement the first instances of object management and global data access technology.  The 1980s also witnessed the first [[programmable logic controller|PLCs]] integrated into the DCS infrastructure.  Plant-wide historians also emerged to capitalize on the extended reach of automation systems.  The first DCS supplier to adopt UNIX and Ethernet networking technologies was Foxboro, who introduced the I/A Series<ref>{{Cite web |url=http://iom.invensys.com/UK/Pages/Foxboro_DCSIASeries.aspx] |archive-url=https://archive.today/20120712134904/http://iom.invensys.com/UK/Pages/Foxboro_DCSIASeries.aspx |archive-date=2012-07-12 |title=Foxboro I/A Series Distributed Control System |year=2012 |access-date=October 15, 2024}}</ref> system in 1987.