Rockwell Automation 8520-MUM 9/Series CNC Mill Operation and Programming Manual Documentation Set - Manual (Page 710)

Paramacros
Chapter 28
28-10
When block N2 is read, parameter #3 is compared to the value -1.5. If the
comparison is true, then blocks N3 and N4 are skipped, and execution
continues on from block N5. If the comparison is false, then execution
continues to block N3. When block N6 is read, parameter #4 is compared
to the value 3. If the comparison is true, then execution is transferred to
block N1; if it is false, execution continues to block N7.
Unconditional DO-END
The unconditional DO-END command is rarely used. The lack of a
condition here causes the control to loop indefinitely until reset or
<CYCLE STOP> is pressed, or until some other transfer of control
command forces execution out of the loop.
The format for the unconditional DO-END command is as follows:
DO m;
:
:
:
END m;
Where : Is :
m a loop identifier used 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
indefinitely or until execution is stopped by some external operation such
as by pressing <E-STOP> or <CYCLE STOP>, or when a block delete is
performed if programmed.
Conditional WHILE-DO-END
The conditional WHILE-DO-END command is dependant on whether a
mathematical condition is true. If this condition is false, execution will
transfer to the block immediately following the END statement block.
28.3.3
DO-END and
WHILE-DO-END Commands