November 2009

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.

The following question comes from the CAP study guide, Performance Domain IV, Development, Software development and coding

CAP question

The graphic display for a distillation column in a refining train would BEST fit in the HMI Display hierarchy at which level?

A. Plant

B. Area

C. Group

D. Loop

CAP answer

The correct answer is C, the group level.  

A typical hierarchy has displays at four levels:

Plant level: Provides information regarding the entire plant

Area level: Provides information on portions of the plant equipment that is related in some way

Group level: Provides information for the control loops and data points relating to a single process unit within a plant area

Loop level: Provides information that deals with individual control loops, sequences, or data points

A distillation column refers to one piece of equipment in the distillation process, which will contain several loops. Therefore, it falls into the group-level category.

Reference: Lukas, Michael P., Distributed control systems: Their evaluation and design, Van Nostrand Reinhold Co., 1986