Omron SRM1 - PROGRAMING 02-2001, Руководство по программированию

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6-3 Section Basic Ladder Diagrams
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When coding the logic block instructions together at the end of the logic blocks
they are combining, they must, as shown below, be coded in reverse order, i.e.,
the logic block instruction for the last two blocks is coded first, followed by the
one to combine the execution condition resulting from the first logic block
instruction and the execution condition of the logic block third from the end, and
on back to the first logic block that is being combined.
00000 00001 00002 00003
20002
00004 00202
Block
a
Block
b
Block
b2
Block
b1
Address Instruction Operands
00000 LD NOT 00000
00001 AND 00001
00002 LD 00002
00003 AND NOT 00003
00004 LD NOT 00004
00005 AND 00202
00006 OR LD —
00007 AND LD —
00008 OUT 20002
When determining what logic block instructions will be required to code a dia-
gram, it is sometimes necessary to break the diagram into large blocks and then
continue breaking the large blocks down until logic blocks that can be coded
without logic block instructions have been formed. These blocks are then coded,
combining the small blocks first, and then combining the larger blocks. Either
AND LOAD or OR LOAD is used to combine the blocks, i.e., AND LOAD or OR
LOAD always combines the last two execution conditions that existed, regard-
less of whether the execution conditions resulted from a single condition, from
logic blocks, or from previous logic block instructions.
When working with complicated diagrams, blocks will ultimately be coded start-
ing at the top left and moving down before moving across. This will generally
mean that, when there might be a choice, OR LOAD will be coded before AND
LOAD.
Complicated Diagrams