September/October 2013

ISA Certified Control Systems Technician (CCST) program

Certified Control System Technicians (CCSTs) calibrate, document, troubleshoot, and repair/replace instrumentation for systems that measure and control level, temperature, pressure, flow, and other process variables.

CCST question

A schematic that is a representation of a complete hydraulic, electric, magnetic, or pneumatic circuit is called a:

A. process and instrumentation diagram (P&ID)

B. logic diagram

C. loop diagram

D. process flow diagram

CCST answer

The correct answer is C, loop diagram. This diagram shows complete details of a hydraulic, electric, magnetic, or pneumatic circuit, showing all of the interconnections, components, and devices that participate in that circuit.

Answer A, P&ID, is a diagram that shows the interconnection of process equipment and the instrumentation used to control the process.

Answer B, logic diagram, is a diagram used to define on/off control.

Answer D, process flow diagram, is a diagram that defines a process schematically and shows how much of each product a plant might make.

Reference: Goettsche, L. D. (Editor), Maintenance of Instruments and Systems, Second Edition, ISA, 2005.