Condition Flags - Omron CP1E CPU UNIT SOFTWARE User Manual

5-9

Condition Flags

Overview
These flags include the flags that indicate the results of instruction execution, as well as the Always ON
and Always OFF Flags. These bits are specified with symbols rather than addresses.
The CX-Programmer treats condition flags as system-defined symbols (global symbols) beginning with P_.
Notation
P_ ER
Condition flag name: ER
I/O memory area designator:
P_ (indicates a system symbol name)
Details
The Condition Flags are read-only; they cannot be written from instructions or from the CX-Program-
mer.
The Condition Flags cannot be force-set and force-reset.
Types of Condition Flags
Refer to 4-6 Ladder Programming Precautions for details.
Name
Always ON Flag
Always OFF Flag
Error Flag
Access Error Flag
Carry Flag
Greater Than Flag
Equals Flag
CP1E CPU Unit Software User's Manual(W480)
Name in CX-
Programmer
P_On Always ON.
P_Off Always OFF.
P_ER Turned ON when the operand data in an instruction is incorrect (an
instruction processing error) to indicate that an instruction ended
because of an error.
When the PLC Setup is set to stop operation for an instruction error
(Instruction Error Operation), program execution will be stopped and
the Instruction Processing Error Flag (A295.08) will be turned ON
when the Error Flag is turned ON.
P_AER Turned ON when an Illegal Access Error occurs. The Illegal Access
Error indicates that an instruction attempted to access an area of
memory that should not be accessed.
When the PLC Setup is set to stop operation for an instruction error
(Instruction Error Operation), program execution will be stopped and
the Instruction Processing Error Flag (A4295.10) will be turned ON
when the Access Error Flag is turned ON.
P_CY Turned ON when there is a carry in the result of an arithmetic opera-
tion or a 1 is shifted to the Carry Flag by a Data Shift instruction.
The Carry Flag is part of the result of some Data Shift and Symbol
Math instructions.
P_GT Turned ON when the first operand of a Comparison Instruction is
greater than the second or a value exceeds a specified range.
P_EQ Turned ON when the two operands of a Comparison Instruction are
equal or the result of a calculation is 0.
5 I/O Memory
Function
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