Allen-Bradley Logix5000 Reference Manual

Rockwell Automation Publication 1756-RM003N-EN-P - October 2011 687
Structured Text Programming Appendix C
FOR…DO
Use the FOR…DO loop to do something a specific number of times before doing
anything else.
Operands:
Structured Text
Operand Type Format Description
count SINT
INT
DINT
Tag Tag to store count position as the FOR…DO
executes
initial_ value SINT
INT
DINT
Tag
expression
Immediate
Must evaluate to a number
Specifies initial value for count
final_ value SINT
INT
DINT
Tag
expression
Immediate
Specifies final value for count, which
determines when to exit the loop
increment SINT
INT
DINT
Tag
expression
Immediate
(Optional) amount to increment count each
time through the loop
If you don’t specify an increment, the count
increments by 1.
IMPORTANT
Make sure that you do not iterate within the loop too
many times in a single scan.
• The controller does not execute any other statements
in the routine until it completes the loop.
• If the time that it takes to complete the loop is greater
than the watchdog timer for the task, a major fault
occurs.
• Consider using a different construct, such as IF...THEN.
FOR count:= initial_value TO
final_value BY increment DO
<statement>;
END_FOR;

Allen-Bradley Logix5000 Specifications

General

Brand	Allen-Bradley
Model	Logix5000
Category	Controller
Language	English