The
ISA S88 and S95 standards consist of several models, for example models of the
physical structure of the enterprise, models of production procedures, models
of information flows and object models. What is the use of these models?
“A
model is a useful representation of a specific situation or thing. Models are
useful because they describe or mimic reality without dealing with every detail
of it. They typically help people analyze a situation by combining ideas with
information about the specific situation being studied. Models help us to make
sense of the world’s complexity.”
(Steven Alter, Information systems,
ISBN 0-13-043242-3)
Just
communicating about a system can be difficult because different people in the
same conversation related to an information system often attach different
meanings to common terms. S88 and S95 provide definitions of batch control
terminology and enterprise-control system integration terminology. This
terminology is presented within models, which explains the relationship between
the words. For example, in the physical mode, the process cell is place on a
higher level than the unit, which explains that a Process cell has one
or more Units.
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