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

Process Automation 25-3
during start-up as well as in operation. Production plants with batch processes need to be more flexible
and are often connected to facilities with applied discrete processes such as bottling plants. Nevertheless,
the shown communication system architectures and requirements especially from the continuous parts
of batch processes can be applied also to continuous processes.
25.2 Structures and Models of Batch Manufacturing Systems
International standards comprise commonly agreed reference points and specifications and therefore
are of vital importance for companies to be competitive. With respect to the automation of batch manufacturing
plants, the standard ISA/ANSI S88 Batch Control and its counterpart IEC 61512 Batch Control
provide a standardized terminology and a consistent set of methods. Both standards are similar and
separated into the following four parts:
• ISA/ANSI S88.01 (IEC 61512-1) Batch Control, Part 1: Models and Terminology
• ISA/ANSI S88.02 (IEC 61512-2) Batch Control, Part 2: Data Structures and Guidelines for Languages
• ISA/ANSI S88.03 (IEC 61512-3) Batch Control, Part 3: General and Site Recipe Models
• ISA/ANSI S88.03 (IEC 61512-4) Batch Control, Part 4: Batch Production Records
Especially, Part 1 of this standard, Models and Terminology [IEC97], assists in determining the
requirements for communications systems by providing reference models for batch control as applied in
the process industries. In general, the utilization of this standard shall lead to
• A shortening of the setup time of production facilities to manufacture new products
• Easier development of tools for implementing batch control
• Enabling the users to better determine their requirements
• Easier development of recipes without the services of a control systems engineer
• A cost reduction of automating batch processes
• A decrease of life-cycle engineering efforts
According to the standard, the described models may be diminished or extended as long as the consistency
of each model remains assured. Currently employed batch control systems are based on these
models, allowing a certain grade of interoperability between these products. ISA/ANSI S88 introduces a
set of structural models that deal with processes, physical equipment, and control software. Figure 25.2
shows the correlations between the procedural control model, the physical model, and the process model.
Procedural
control model
Combined
with
Physical
model
Delivers
Process
model
Procedure
Process cell
Process
Unit
procedure
Unit
Process
stage
Operation
Process
operation
Phase
Equipment
module
Process
action
FIGURE 25.2 Procedural control mapped onto equipment to achieve process functionality. (Based on IEC TC65,
IEC 61512-1: Batch Control—Part 1: Models and terminology. International Electrotechnical Commission, 1997.)
© 2011 by Taylor and Francis Group, LLC