You can use comments to annotate your code, which helps others to understand the intention of the program or function.

Comments can be placed in any location where a space is acceptable. Comments are not significant in terms of program execution.

Single Line Comments

Single line comments begin with two consecutive forward slash (/) characters. The remainder of the text in the line, up to and including the end of line, is the comment.


// Calculate flow rate:

Multi-line Comments

Multi-line comments begin with a left parenthesis (() character followed by an asterisk (*) character. A multi-line comment ends with an asterisk (*) character followed by a right parenthesis character ()).

Example 1:

(* Calculate flow rate *)

Example 2:

* Calculate flow rate

Standards Compliance

Table 3.1 - IEC 61131-3 2nd Edition.

Table 3.1 & 3.2a - IEC 61131-3 3rd Edition.

Further Information

Common Elements

To learn about other IEC 61131-3 Common Elements.


For definitions of the terms used in Fernhill SCADA.