The Automation, Systems, and Instrumentation Dictionary, 4th Edition, should be used for most definitions. Here are some definitions that pertain directly to the maintenance of instrumentation and control systems.

accessible area

An area routinely or periodically entered by plant personnel in the performance of routine functions during normal plant operations and in accordance with applicable health physics procedures.

administrative controls

These are controls placed on activities through the use of permits, standard operating procedures, standard maintenance procedures, supervision, etc., to ensure safe operation and maintenance of the facility as well as the normal operations.

analog control system

Classically, a system that consists of electronic or pneumatic single-loop analog controllers, in which each loop is controlled by a single, manually adjusted device.

analytical

Having a known, reliable, reproducible relationship between the component of interest and the equipment output signal.

analytical instrument

An item of equipment that provides analytical data as its output. Liquid analysis and gas analysis are examples.

analyzer

A specialized instrument that provides a known, reliable, reproducible relationship between a component of interest and the equipment's output signal.

annunciator

A device or group of devices that call attention to changes in process conditions that have occurred. An annunciator usually points to abnormal process conditions but may be used also to show normal process status. Usually included are sequence logic circuits, labeled visual displays, audible devices, and manually operated push buttons.

ANSI

Acronym for American National Standards Institute.

API

Acronym for American Petroleum Institute.

Approved

1. Acceptable to the...