What just happened and why ? - Unravel the domino effect with SOEs in SCADA

The Domino Effect

From at least the early 1990s when I discovered SCADA so to speak, I wondered what on earth SCADA meant by Sequence of Events and tended to reject the whole idea until I understood why ?

I had come myself from a world of real-time control when everything was current to the actual time and data from one controller was highly sequenced with that of another.  The era of the PLC and it's great contribution to sequencing of - read inputs, calculate logic, write outputs was a pretty fundamental design I had thought.