Table of Contents
Advertisement
Operands
Only the FOR_LOOP function requires operands.
Parameter Description
INDEX
The index variable. When the loop has completed, this
value is undefined.
Note:
Changing the value of the index variable within
the scope of the FOR loop is not recommended.
START
The index start value.
END
The index end value.
INC
The increment value. (Default: 1.)
For Loop Example 1
The value for %M00001 (START) is 1 and the value for %M00017
(END) is 10. The INDEX (%R00001) increments by the value of the INC
operand (which is assumed to be 1 when omitted) starting at 1 until
it reaches the ending value 10. The ADD function of the loop is
executed 10 times, adding the current value of I1 (%R00001), which
will vary from 1 to 10, to the value of I2 (%R00002).
For Loop Example 2
The value for %T00001 (START) is -100 and the value for %T00017
(END) is 100. The INDEX (%R00001) increments by tens, starting
at -100 until it reaches it end value of +100. The EQ function of the
loop tries to execute 21 times, with the INDEX (%R00001) being
equal to -100, –90, –80, –70, –60, –50, –40, –30, –20, –10, 0, 10, 20,
30, 40, 50, 60, 70, 80, 90, and 100. However, when the INDEX
(%R00001) is 0, the EXIT statement is enabled and power flow jumps
directly to the statement after the END_FOR statement.
GFK-2950C
Chapter 4. Ladder Diagram (LD) Programming
February 2018
Allowed Operands
All except constants, flow,
and variables in %S - %SC
All except variables in %S -
%SC
All except variables in %S -
%SC
Constants
Optional
No
No
No
Yes
113
Advertisement
Table of Contents
