July/August 2012
Certification Review

ISA Certified Automation Professional (CAP) program

Certified Automation Professionals (CAPs) are responsible for the direction, design, and deployment of systems and equipment for manufacturing and control systems.

CAP question

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.

CAP answer

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).

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.

Reference: ISA Standard ISA-88.00.01-2010, Batch Control Part 1: Models and Terminology (ISA, 2010).