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The disappearing field bus
Field bus is a term used in the industrial automation world to describe the
communication between controller and controlled components, and sometimes
between controllers. Modbus is one example of such a field bus that may be
familiar to railroaders. These field bus systems are historically supplier-specific and
largely incompatible.
Industrial ethernet is a term used for some time in the automation community
although its meaning is rapidly evolving. Industrial ethernet used to be used for
controller to controller communication in automation networks, but its use is now
being extended into the field bus. That means that a discreet, controller-specific
field bus is being replaced by a single ethernet network for the entire control
system(s). That could also be the same network that is used for a normal
business network. From the business network to the field elements, the same
physical infrastructure can be utilized. The obvious advantages of using industrial
ethernet include:
-high speed communications
-distributed system architectures
-relatively low cost
-ease of connection of field data to business network (buzzword: enterprise
connectivity)
While there continues to be some in the automation community who continue to
defend the advantages of a dedicated, independent field bus, the speed with
which industrial ethernet technology is progressing seems to indicate that this shift
would be difficult to stop.
As anyone familiar with this issue knows, I am not even scratching the surface on
a topic that you can dedicate years to understanding, there are of course many
other aspects to this issue and many predictions of what the future may hold.
Because this site is dedicated to railroaders I have not dedicated much space to it.
If you are interested in this topic look here or here or check out my links page to
find more information.
