wilamowski-b-m-irwin-j-d-industrial-communication-systems-2011

13-8 Industrial Communication Systems
Business logistics
Plant production scheduling, shipping, receiving, inventory, etc.
Production capability
information
(what is available
for use)
Manufacturing operations management
Dispatching, detailed production scheduling, production tracking, etc.
Batch production
control
Product definition
information
(how to make
a product)
Continuous
production control
Production schedule
(what to make
and use)
Production
performance
(what was made
and used)
Discrete production
control
Level 4
ERP
Level 3
MES
Level 2
Level 1
ISA—IEC/ISO
interface standards
ISA 95.01
ISA 95.02
ISA functional model
ISA 95.03
IEC, OPC interface
standards
Level 0
FIGURE 13.5 Scope of ISA 95 and ISA 88.
and other enterprise functions, effectively between the ERP and MES levels of an enterprise. The scope
of the standardization work, as seen by the committee, is
• Define in detail an abstract model of the enterprise, including manufacturing control functions
and business functions, and its information exchange.
• Establish common terminology for the description and understanding of enterprise, including
manufacturing control functions and business process functions, and its information exchange.
• Define electronic information exchange between the manufacturing control functions and other
enterprise functions including data models and exchange definitions.
ISA S95 addresses exclusively the information flow between the control domain and the enterprise
domain of a company. Consequently, in the model adopted by ISA, the MES functionality is explicitly
included in the control domain (Figure 13.5). The information exchanged between the levels can be categorized
in information about the product itself (its definition), the availability of production capabilities,
and the production of the product itself (scheduling and performance information). Functions concerning
only the ERP level or the control level are beyond the scope of the standard and are therefore not covered.
ISA S95 should be regarded in connection with ISA S88 (Batch processing model), which covers the
lower levels of the automation model. Both have been developed in parallel, and they are converging in
that there are direct mappings between the two standards for models and representations. Likewise,
the reference model suggested by MESA has influenced the work, and cross references between the two
approaches are given in order to facilitate common understanding.
The standard does not describe an actual implementation; it provides only terminology, functional
requirements, and formal models. Yet, inside the standardization group, the common belief was that
XML might be a promising approach. Consequently, a working group was formed under the umbrella
of the World Batch Forum, and developed the XML schema “Business to Manufacturing Markup
Language” (B2MML). This reference implementation was released in a first version in 2002 and is constantly
being updated and enhanced.
13.5 Security Aspects in Vertical Integration
Vertical integration in the sense of connecting automation systems to a more open environment naturally
raises security questions. It has already been stated that even though network interconnection was
an essential goal of the old CIM idea, fieldbus systems were mostly developed as isolated solutions.
© 2011 by Taylor and Francis Group, LLC