Vinge's "A Deepness in the Sky" can be used to explain current big industrial control systems. A typical distributed control system these days transfers data ac

Vinge's "A Deepness in the Sky" can be used to explain current big industrial control systems. A typical distributed control system these days transfers data across many different layers, transforming the data when it crosses each layer. Starting deep down in the plant: * reading the 0-10V or 4-20mA signals from sensors. * AD converters convert the values into a digital representation in field devices. * move the data to real-time controllers that run control algorithms and send outputs back to motors/valves/pumps/etc. * those controllers move the data often via raw Ethernet packets to other real-time controllers and Windows stations used for operator visualization. * some Windows workstations gather data into databases for historical usage. Sometimes this is a SQL type database, sometimes a flat database used to get better storage performance. * then data is moved to local databases that can be used by the onsite teams to analyze it in an office environment. * then that data is then moved into big data offsite/remote storage for analysis of how the medium and long term performance of the industrial installation and comparison to other installations in other parts of the world. * from that reports are made with key performance indicators and graphs. And each time the data is passed up a layer the format of the data and timestamps may be adjusted to match operating system that the data is passed to.