A graphical linking of function blocks is commonly used to configure process control systems, historically DCS style systems but now with IEC 61131 one of the f

A graphical linking of function blocks is commonly used to configure process control systems, historically DCS style systems but now with IEC 61131 one of the five languages used by PLC's is function block diagram. Some of these systems can be reasonably complicated, we are talking oil refineries, LNG processing plants, large mineral processing facilities, chemical plants etc. The reasons they are programmed this way are many and varied, many historical/legacy, but essentially much of it boils down to limiting variability of the language and creating a "bridge" language that the specialist engineers focusing on the chemistry of the process can more easily discuss and work with. This probably isn't changing in a hurry as the industry is also very slow to adapt. The sort of facilities are plant worth tens of billions of dollars and multi-millions of dollars lost per trip or hour of downtime. Owners are understandably risk adverse to experimenting with a new paradigm that may work a little better, but may also create problems. Additionally, plant owners factor in availability and decades of experience in the existing pool of labor that has the specialist skills related to optimisation and real time control of the process as the primary value add.