1 August 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 question

All of the following are basic components of a PLC system EXCEPT:

A. Processor

B. I/O system

C. Power supply

D. CRT monitor

CCST answer

A programmable logic controller (PLC) has a microprocessor, and it controls industrial processes. It communicates with other process control components through data links, handles simple switching tasks, PID (proportional-integral-derivative) control, complex data manipulation, arithmetic operations, timing, process, and machine control-all without a CRT (cathode ray tube) or video monitor. Engineers program it and leave it alone. The correct answer is D.

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