March/April 2011

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

In the maintenance of control systems, a maintenance cycle is comprised of four key activities:

  1. Completing the requested maintenance action
  2. Retesting the system
  3. Recording details of the activities carried out
  4. and ___________

A.        Replacing any panel covers removed during the maintenance action

B.         Verifying the completeness of the maintenance action with a supervisor

C.        Noting any resulting changes made to the system configuration

D.        Training operators to be able to troubleshoot the problem next time it occurs

CCST answer

The correct answer is C, noting any resulting changes made to the system configuration. Proper documentation of any and all changes to the system configuration, either in software or hardware, is essential for the continued safe and efficient operation of the system. Documentation of the "as left" condition of the control system is a basic requirement for all maintenance, calibration, commissioning, and testing tasks.

Answer A is not the correct choice since not all maintenance tasks require panel work. This is good practice, but not part of the four activities that comprise the maintenance cycle.

Answer B is not always a requirement in local plant SOPs. Completeness of the maintenance task is verified in Step 2, retesting the system.

Answer D may be desirable for small items, but training of operations personnel is not part of the maintenance cycle.

Reference: Goettsche, L. D. (Editor), Maintenance of Instruments and Systems, 2nd Edition, ISA, 2005.