Rockwell Automation 8520 9/Series CNC Lathe - Manual (Page 685)

Paramacros
Chapter 28
28-11
Use this format for the WHILE-DO-END command:
WHILE [ (condition) ] DO m;
;
;
;
END m;
Where : Is :
(condition) some mathematical condition. This condition is tested by the control to
determine if it is true or false.
m an identifier used by the control to relate a DO block with an END block. The
value of m must be the same for the DO as it is for the corresponding END. This
value can be either 1, 2, or 3.
All blocks between the DO and the END command are executed until the
condition is tested as false. This set of blocks is referred to as a
WHILE-DO-END program segment.
When the condition for the WHILE-DO block is tested as false, execution
is then transferred to the block immediately following the END statement
block.
Example 28.9
WHILE-DO-END Program Segment
N1 #1=1;
N2WHILE[#1LT10]DO1
N3#1=[#1+1];
N4...;
N5...;
N6END1;
N7...;
In Example 28.9, blocks N2 through N6 are executed 9 times. At that
time, the condition in block N2 becomes false, and program execution is
transferred to block N7.
Nesting is possible with a WHILE-DO-END command. Nesting is defined
here as one WHILE-DO-END program segment executing within another
WHILE-DO-END program segment. WHILE-DO-END nesting is limited
to 3 independent segments at one time.