Control Techniques UD70, User Manual

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UD70
Issue code: 70nu2
Reference 7-11
DO WHILE
Syntax 1
DO WHILE Conditional expression
Instruction
LOOP
Syntax 2
DO
Instruction
LOOP WHILE Conditional expression
Syntax 3 DO WHILE Conditional expression LOOP
This is a loop or iterative instruction which causes a block of instructions to
be repeated until a specific expression becomes false.
Syntax 1 Syntax 1 allows the conditional expression be evaluated first. If the
outcome is true, the instructions are executed. The program will continue
in the loop until the conditional expression becomes false.
Syntax 2 Syntax 2 allows the instructions be executed first, the conditional
expression is evaluated. This ensures that the instructions in the loop are
executed at least once.
Syntax 3 Syntax 3 is identical to Syntax 1, except there are no executing instructions
in the loop.
Example 1 DO WHILE #1.21 < 1000
#1.21 = #1.21 + 1
LOOP
Example 2 DO
a = a + 0.001
LOOP WHILE a < 6
Example 3 DO WHILE #3.02 > 10 LOOP
(If the value of #3.02 is greater than 10, the program will continue to loop.)
EXIT
Syntax EXIT
This is a flow-control instruction which provides a quick method of
terminating the current task.
Example CLOCK{
IF #18.22 = 1 THEN EXIT
...
(If the value of #18.22 is 1, exit from the rest of the
CLOCK
task.)