6F3B0253
Basic Hardware and Function 99
6. Programming Information
6.8 Program execution sequence
The instructions execution sequence is shown below.
(1) They are executed in the sequence from block 1 through the final block, which
contains the END instruction (or IRET in an interrupt program).
(2) They are executed in the sequence from rung 1 through the final rung in a block
(or the END instruction).
(3) They are executed according to the following rules in any one rung.
When there is no verti cal
connection, they are
executed from lef t to right.
When there is an OR
connection, the OR logic
portion is executed fir st.
When there is a branch, they
are executed in the order from
the upper line to the lower line.
A combination of and
above.
The instructions execution sequence in which function instructions are included also
follows the above rules. However, for program execution control instructions, such as
jumps (JCS), loops (FOR-NEXT), subroutines (CALL-SUBR-RET), it will depend the
specifications of each instruction.
4321
86
7
2
5431
6
4
5
321
5
3
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