1 December 2005

ISA Certified Automation Professional (CAP) Program

This question is from the CAP study guide, Performance Domain IV, Development.

Definition: 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 best answer is C, Group.

A typical hierarchy is composed of displays at four levels:

Plant level - Provides information regarding the entire plant.

Area level - Provides information on portions of the plant equipment that have a working relationship.

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 that will contain several loops. Therefore, it falls into the group-level category.

Reference: Lukas, Distributed Control Systems, Van Nostrand Reinhold, 1986. y

Nicholas Sheble (nsheble@isa.org) edits the Certification department. For information about the CAP program, go to www.isa.org/cap.