Rockwell Automation Logix5000 Controllers Structured Text Programming Manual - Manual (Page 12)

12 Publication 1756-PM007D-EN-P - November 2012
Chapter 1 Program Structured Text
Specify a Non-retentive Assignment
The non-retentive assignment is different from the regular assignment
described above in that the tag in a non-retentive assignment is reset to zero
each time the controller:
• enters the Run mode.
• leaves the step of an SFC if you configure the SFC for Automatic reset.
(This applies only if you embed the assignment in the action of the step
or use the action to call a structured text routine via a JSR instruction.)
A non-retentive assignment has this syntax:
tag [:=] expression ;
where:
Component Description
tag Represents the tag that is getting the new value.
The tag must be a BOOL, SINT, INT, DINT, or REAL.
[:=] Is the non-retentive assignment symbol
expression Represents the new value to assign to the tag.
If tag is this data type Use this type of expression
BOOL BOOL expression
SINT
INT
DINT
REAL
Numeric expression
; Ends the assignment.