Omron CS1G/H-CPUxx-EV1 Programming Manual page 79

Basic Concepts
General Structure of the
Ladder Diagram
Left bus bar
Mnemonics
A ladder diagram consists of left and right bus bars, connecting lines, input
bits, output bits, and special instructions. A program consists of one or more
program runs. A program rung is a unit that can be partitioned when the bus is
split horizontally. In mnemonic form, a rung is all instructions from a LD/LD
NOT instruction to the output instruction just before the next LD/LD NOT
instructions. A program rung consists of instruction blocks that begin with an
LD/LD NOT instruction indicating a logical start.
Special
Input bit
instruction
Connecting line
A mnemonic program is a series of ladder diagram instructions given in their
mnemonic form. It has program addresses, and one program address is
equivalent to one instruction. Program addresses contain six digits starting
from 000000.
Program Address
000000
000001
000002
000003
000004
000005
000006
000007
000008
000009
Output bit
Right bus bar
Rungs
Example
Instruction (Mnemonic)
LD
AND
LD
AND NOT
LD NOT
AND
OR LD
AND LD
OUT
END
Section 2-1
Instruction blocks
Operand
000000
000001
000002
000003
000100
000101
000200
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