Omron CP1E CPU UNIT SOFTWARE User Manual page 88

5 I/O Memory
Name
Less Than Flag
Negative Flag
Overflow Flag
Underflow Flag
Greater Than or
Equals Flag
Not Equal Flag
Less than or Equals
Flag
Using the Condition Flags
The Condition Flags are shared by all of the instructions. Their status may change after each
instruction execution in a single cycle.
Therefore, be sure to use Condition Flags on a branched output with the same execution condition
immediately after an instruction to reflect the results of instruction execution.
Example: Using Instruction A Execution Results
Precautions for Correct Use Precautions for Correct Use
The Condition Flags are shared by all of the instructions. This means that program operation can
be changed from its expected course by interruption of a single task. Be sure to consider the
effects of interrupts when writing ladder programs to prevent unexpected operation.
5-20
Name in CX-
Programmer
P_LT Turned ON when the first operand of a Comparison Instruction is less
than the second or a value is below a specified range.
P_N Turned ON when the most significant bit of a result is ON.
P_OF Turned ON when the result of calculation overflows the capacity of the
result word(s).
P_UF Turned ON when the result of calculation underflows the capacity of
the result word(s).
P_GE Turned ON when the first operand of a Comparison Instruction is
greater than or equal to the second.
P_NE Turned ON when the two operands of a Comparison Instruction are
not equal.
P_LE Turned ON when the first operand of a Comparison Instruction is less
than or equal to the second.
Instruction A
The result from instruction A
is reflected in the Equals Flag
Condition Flag
Example: =
Instruction B
Function
Instruction Operand
LD
Instruction A
AND =
Instruction B
CP1E CPU Unit Software User's Manual(W480)