While Loop Statement - Hitachi SJ700-2 Series Instruction Manual

- Processing cycle
Refer to the statement execution sequence indicated by parenthesized numbers in the comment fields
of the sample programs below.
(1): The "for" line is executed only once.
(2) and (3): <instruction set> is executed.
(4): <variable> is incremented in the cycle that follows the cycle in which the last instruction of
<instruction set> is executed. Then, <variable> is checked to determine whether to exit the
loop (in other words, the next statement is executed). When repeating the loop, processing
returns to the first instruction of <instruction set> in this cycle.
(5): This step is executed in the next cycle.
(6) to (10): These steps are repeated in the same way as the preceding loop execution.
(11): Processing proceeds to the following step (line).
- Sample program
for U(00)
Y(00) = 1
Y(00) = 0
next
Y(00) = 1

while loop statement

- Format
Format
while <condition>
<instruction set>
wend
- Explanation
This instruction executes <instruction set> repeatedly as long as <condition> is met. Note that
<condition> is checked before the execution of <instruction set>. If <condition> is not met, processing
proceeds to the wend statement without executing <instruction set>.
- Sample program (Condition "X (00) = 0" is met after the loop is executed twice.)
while X(00) =
Y(00) = 1
Y(00) = 0
wend
Y(00) = 1
0 3 1
Instruction to conditionally execute a pre-conditioned loop
This instruction executes <instruction set> while <condition> is met.
Note that <condition> is checked before the execution of <instruction
set>.
Is <condition> met?
Execute <instruction set>
1
Chapter 5 Instruction Words
Sequence of execution
：(1)
：(2) (5) (8)
：(3) (6) (9)
：(4) (7) (10)
：
(11)
Description
No
Yes
Sequence of execution
：(1) (5) (9)
：(2) (6)
：(3) (7)
：(4) (8)
： (10)
5 - 9