ISA Interchange

AutoQuiz: Models of Control to Describe a Batch Process

Written by Joel Don | Dec 21, 2018 2:00:52 PM

AutoQuiz is edited by Joel Don, ISA's social media community manager.

This automation industry quiz question comes from the ISA Certified Automation Professional (CAP) certification program. ISA CAP certification provides a non-biased, third-party, objective assessment and confirmation of an automation professional's skills. The CAP exam is focused on direction, definition, design, development/application, deployment, documentation, and support of systems, software, and equipment used in control systems, manufacturing information systems, systems integration, and operational consulting. Click this link for more information about the CAP program.

According to ISA-88.00.01-2010 (Part 1), which statement is true about the models of control that can be used to describe a batch process:

a) ISA-88 describes four models: process, procedural, equipment, and physical.
b) A process stage in the process model can be mapped to a unit procedure in the procedural model, which in turn is mapped to a unit in the physical model.
c) Procedural control model elements are designed to correspond to elements of the physical model.
d) A unit (physical model) may support procedures, unit procedures, operations, and phases from the procedural model.
e) None of the above

Answer A is not correct. There are only three models of control identified in ISA-88. These are the process model, the procedural control model, and the physical model.

Answer C is not correct. Procedural control model elements are designed to correspond to elements of the process model, not the physical model. Procedural control model elements (procedures, operations, and phases) are designed to carry out the requirements of the process stages, operations, and actions.

Answer D is not correct. A unit (physical model) may support unit procedures, operations, and phases from the procedural model, but not procedures, which are supported at the process cell level only.

The correct answer is B, "A process stage in the process model can be mapped to a unit procedure in the procedural model, which in turn is mapped to a unit in the physical model." An example would be "mixing stage" (process model) carried by a "mix phase" (procedural control model) executed on unit "mixer 1" (physical model).

Reference: ISA88 Batch Control standards

About the Editor
Joel Don is the community manager for ISA and is an independent content marketing, social media and public relations consultant. Prior to his work in marketing and PR, Joel served as an editor for regional newspapers and national magazines throughout the U.S. He earned a master's degree from the Medill School at Northwestern University with a focus on science, engineering and biomedical marketing communications, and a bachelor of science degree from UC San Diego.

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