BS 1646-4:1984

This standard BS 1646-4:1984 Symbolic representation for process measurement control functions and instrumentation is classified in these ICS categories:

• 01.080.40 Graphical symbols for use on electrical and electronics engineering drawings, diagrams, charts and in relevant technical product documentation
• 25.040.40 Industrial process measurement and control
• 01.080.50 Graphical symbols for use on information technology and telecommunications technical drawings and in relevant technical product documentation

This Part of BS 1646 specifies symbols for the representation of process computer and shared/control functions in the field of process measurement and control.

The symbols established in this part have been developed to be used in conjunction with the symbols devised in BS 1646-1 and BS 1646-2 and are supplementary.

They are intended to provide a means to illustrate process computer and/or shared display/control functions in the field of process measurement and control and may be used separately or combined with the symbols of BS 1646-1 and BS 1646-2. They will enable users to show and identify in a simple form the functions of instruments, the process computer and shared display/control functions or any combination of these.

It is permissible to use the basic symbol for computer based functions (see 3.1) throughout for any software based digital system. This is not intended to preclude the use of the basic symbol for shared display/control functions (see 3.2) if the user considers this to be appropriate.

The symbols are intentionally limited to the identification on process flow diagrams, etc and do not provide a means of illustrating specific instruments or parts thereof.

The letter code for function identification is given in the Tables of BS 1646-1 and BS 1646-2.

The application methods are shown in the examples.

NOTE The titles of the publications referred to in this standard are listed on Inside back cover.

Specifies symbols to illustrate process computer and/or shared display/control functions in process measurement and control, e.g. on process flow diagrams. The symbols may be used in conjuction with the symbols given in Part 1 of BS 1646 but they do not provide a means of illustrating specific instruments or parts thereof.