
75
These six basic instructions correspond to the conditions on a ladder dia-
gram. As described in 3-4 Basic Programming, the status of the bits assigned
to each instruction determines the execution conditions for all other instruc-
tions. Each of these instructions and each bit address can be used as many
times as required. Each can be used in as many of these instructions as re-
quired.
The status of the bit operand (B) assigned to LD or LD NOT determines the
first execution condition. AND takes the logical AND between the execution
condition and the status of its bit operand; AND NOT, the logical AND be-
tween the execution condition and the inverse of the status of its bit operand.
OR takes the logical OR between the execution condition and the status of
its bit operand; OR NOT, the logical OR between the execution condition and
the inverse of the status of its bit operand. The ladder symbol for loading TR
bits is different from that shown above. Refer to 3-4-3 Ladder Instructions for
details.
There are no flags affected by these instructions.
3-7-6
AND LOAD and OR LOAD
Ladder Symbol
AND LOAD - AND LD
0002
0003
0000
0001
Ladder Symbol
OR LOAD - OR LD
0000
0001
0002
0003
When instructions are combined into blocks that cannot be logically com-
bined using only OR and AND operations, AND LD and OR LD are used.
Whereas AND and OR operations logically combine a bit status and an ex-
ecution condition, AND LD and OR LD logically combine two execution con-
ditions, the current one and the last unused one.
In order to draw ladder diagrams, it is not necessary to use AND LD and OR
LD instructions. They are used to convert the program to and input it in mne-
monic form.
In order to reduce the number of programming instructions required, a basic
understanding of logic block instructions is required. For an introduction to
logic blocks, refer to 3-4-6 Logic Block Instructions.
There are no flags affected by these instructions.
3-7-7
OUTPUT and OUTPUT NOT - OUT and OUT NOT
B: Bit
Output bits, work bits, DR, LR
Ladder Symbol
Operand Data Areas
OUTPUT - OUT
B
Description
Flags
Description
Flags
Instruction Set
Section 3-7