More than that, they have made automation what it is today.
Since the very beginning, these networks have become known
as “fieldbus systems,” a term originally referring to the process
field in, e.g., chemical plants [1]. Apart from this ethymological
detail, the term is considerably ill defined. The “definition” that
is given in the International Electrotechnical Commission (IEC)
61158 fieldbus standard is more of a programmatic declaration
or a least common multiple compromise than a concise formulation
[2]: “A fieldbus is a digital, serial, multidrop, data bus
for communication with industrial control and instrumentation
devices such as—but not limited to—transducers, actuators and
local controllers.” In the original mission statement of the IEC
work, it was stated that “the Field Bus will be a serial digital
communication standard which can replace present signalling
techniques such as 4–20 mA... so that more information can
flow in both directions between intelligent field devices and
the higher level control systems over shared communication
medium