Certified Automation Professionals (CAPs) are responsible for the direction, design, and deployment of systems and equipment for manufacturing and control systems.
Which of the following explains why ANSI/ISA-88.01-1995 (S88) treats control modules as a separate entity?
A. A control module is inextricable from its equipment.
B. Each control module is encapsulated so it can be reused.
C. Each control module has a phase and directs a set of final control elements.
D. A control module is partitioned to prevent the phase from commanding other control modules within an equipment module.
The correct answer is B, each control module is encapsulated so it can be reused. One of the major documented benefits of ISA-88 is its definition of separate equipment module and control module functions. This allows code for a single control module, for example, a two-way on/off valve, to be programmed, validated, and then reused for each instance of a two-way on/off valve in the process. These reusable control modules streamline code development, simplify documentation, and allow for consistent operator interactions.
Reference: Trevathan, Vernon L., A Guide to the Automation Body of Knowledge, Second Edition, ISA, 2006.
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