1 November 2005

ISA Certified Control Systems Technician (CCST) Program

This question is from the Level III study guide, Domain 2, Loop checking.

Level III represents a professional who has a 13-year total of education, training, and/or experience.

CCST questions

1. All of the following allow specific information to be extracted from an electronic database EXCEPT:

A. Filter

B. Report

C. Template

D. Query

2. The continuous sequence of steps or "operating cycle" performed by a PLC processor is known as:

A. Updating

B. Scanning

C. Polling

D. Rectifying

CCST answers

These two questions test the CCST test taker's knowledge of nomenclature.

A filter is a program that accepts a certain type of data as input, transforms it in some manner, and then outputs the transformed data. For example, a program that sorts names is a filter because it accepts the names in unsorted order, sorts them, and then outputs the sorted names. Utilities that allow you to import or export data are also sometimes called filters.

In this context, a report is a formatted and organized presentation of data. Most database-management systems include a report writer that enables one to design and generate reports.

A template is something that establishes or serves as a pattern for reference.

A query is a request for information from a database. There are several different ways to pose a query.

Scanning is the process by which a computer collects data from process sensors for use in calculations. It is the sequential interrogation of devices or lists of information under the PLCs control.

While the PLC may in fact update values, poll devices, and rectify aspects of the process in response to data it encounters during its routine, the best term for this continuous sequence is scanning.

The correct answers are C, template, and B, scanning.

Nicholas Sheble explains the answers to CCST questions. For information about the CCST program, go to www.isa.org/ccst.