Precautions; Condition Flags - Omron SYSMAC CS Series Programming Manual

Precautions

2-2

Precautions

2-2-1

Condition Flags

Using Condition Flags
52
Rewrite the rungs on the left. They cannot be executed.
The arrows show signal (power flow) flow when the rung consists of control relays.
A B
E
C D
Conditions flags are shared by all instructions, and will change during a cycle
depending on results of executing individual instructions. Therefore, be sure
to use Condition Flags on a branched output with the same execution condi-
tion immediately after an instruction to reflect the results of instruction execu-
tion. Never connect a Condition Flag directly to the bus bar because this will
cause it to reflect execution results for other instructions.
Example: Using Instruction A Execution Results
Correct use
Condition Flag
Example: =
The same execution condition (a) is used for instructions A and B to execute
instruction B based on the execution results of instruction A. In this case,
instruction B will be executed according to the Condition Flag only if instruc-
tion A is executed.
ncorrect use
Condition Flag
Example: =
R1
R2
Instruction A
Reflects instruction A
execution results.
Instruction B
Preceding rung
Instruction A
Reflects the execution results of
the preceding rung if instruction
A is not executed.
Instruction B
Section 2-2
A B
R1
C E
A E D
R2
C
Mnemonic
Instruction Operand
LD a
Instruction A
AND =
Instruction B