Chapter 8. Structured Text (ST) Programming
GFK-2950C
February 2018
367
8.1.4
Structured Text Syntax
The syntax of the ST implementation for PACSystems follows the IEC 61131-3 standard.
▪
Structured Text statements must end in a semi-colon (;).
▪
Structured Text variables must be declared in the variable list for the target.
These symbols have the following functions.
:=
assigns an expression to a variable
;
required to designate the end of a statement
[ ]
used for array indexing where the array index is an integer. For example, this sets the third
element of an array to the value j+10:
intarray[3]: = j + 10
;
(* *)
designates a comment. These comments can span multiple lines. For example,
(*This
comment spans
multiple lines.*)
// or ‘
designates a single line comment. For example,
c :=a+b; //This is a single line comment.
C
:=a+b; ‘This is a single line comment.
Содержание PACSystems RX7i
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