Page 41 - Sensors and Control Systems in Manufacturing

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Cha p te r
O n e

Too often, the implementations of CIM have created a compatibil-
ity nightmare in today’s multivendor factory-floor environments.
Too many end users have been forced to discard previous automation
investments and/or spend huge sums on new equipment, hardware,
software, and networks in order to effectively link together data from
distinctly dissimilar sources. The expense of compatible equipment
and the associated labor cost for elaborate networking are often pro-
hibitive.
The claims of CIM open systems are often misleading. This is
largely due to proprietary concerns, a limited-access database, and
operating system compatibility restrictions. The systems fail to pro-
vide the transparent integration of process data and plant business
information that makes CIM work.
In order to solve this problem, it is necessary to establish a clearly
defined automation program. A common approach is to limit the
problem description to a workable scope, eliminating those features
not amenable to consideration. The problem is examined in terms of
a simpler workable model. A solution can then be based on model
predictions.
The danger associated with this strategy is obvious: If the simpli-
fied model is not a good approximation of the actual problem, the
solution will be inappropriate and may even worsen the problem.
Robust automation programs can be a valuable asset in deciding
how to solve production issues. Advances in sensor technology have
provided the means to make rapid large-scale improvements in prob-
lem solving and have contributed in essential ways to today’s manu-
facturing technology.
The infrastructure of an automation program must be closely
linked with the use and implementation of sensors and control sys-
tems, within the framework of the organization. The problem becomes
more difficult whenever it is extended to include the organizational
setting. Organization theory is based on a fragmented and partially
developed body of knowledge, and can provide only limited guid-
ance in the formation of problem models. Managers commonly use
their experience and instinct in dealing with complex production
problems that include organizational aspects. As a result, creating a
competitive manufacturing enterprise—one involving advanced
automation technology utilizing sensors and control systems and
organizational aspects—is a task that requires an understanding of
both how to establish an automation program and how to integrate it
with a dynamic organization.
In order to meet the goals of integrated sensory and control
systems, an automated manufacturing system must be built from
compatible and intelligent subsystems. Ideally, a manufacturing sys-
tem should be computer-controlled and should communicate with
controllers and materials-handling systems at higher levels of the
hierarchy, as shown in Fig. 1.3.