ISA 5.1 PDF

General

This standard is intended to meet the different procedures of various users who need to identify and graphically depict measurement and control equipment and systems. These differences are recognized when they are consistent with the objectives of this standard, by providing alternative symbol and identification methods.

A limited number of examples are provided that illustrate how to:

a) Design an identification system and construct an identification number.

b) Use graphic symbols to construct:

1) Instrumentation schematic diagrams of the instruments, devices, and functions required for monitoring and control loops.

2) Functional diagrams of instruments, loops, and application software functions.

3) Binary logic diagrams.

4) Ladder diagrams of electrical circuits.

c) Add information and simplify diagrams.

Examples of identification and symbol applications are intended to illustrate basic concepts in the construction of the identification systems and diagrams covered by this standard that are applicable to all user industries.

Purpose

This standard establishes a uniform means of depicting and identifying instruments or devices and their inherent functions, instrumentation systems and functions, and application software functions used for measurement, monitoring, and control, by presenting a designation system that includes identification schemes and graphic symbols.