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Task Flags Section 4-17
4-17 Task Flags
Task Flags range from TK00 to TK31 and correspond to cyclic tasks 0 to 31. A
Task Flag will be ON when the corresponding cyclic task is in executable
(RUN) status and OFF when the cyclic task hasn’t been executed (INI) or is in
standby (WAIT) status.
Note These flags indicate the status of cyclic tasks only, they do not reflect the sta-
tus of interrupt tasks.
Task Flag Initialization The Task Flags will be cleared in the following cases, regardless of the status
of the IOM Hold Bit.
1. When the operating mode is changed from PROGRAM mode to
RUN/MONITOR mode or vice-versa
2. When the power is cycled.
Forcing Bit Status The Task Flags cannot be force-set and force-reset.
4-18 Condition Flags
These flags include the Arithmetic Flags, such as the Error Flag and Equals
Flag, which indicate the results of instruction execution.
The Condition Flags are specified with symbols, such as P_CY and P_ER,
rather than addresses. The status of these flags reflects the results of instruc-
tion execution, but the flags are read-only; they cannot be written directly from
instructions or the CX-Programmer.
Note The CX-Programmer treats condition flags as global symbols beginning with
P_.
All Condition Flags are cleared when the program switches tasks, so the sta-
tus of the ER and AER flags are maintained only in the task in which the error
occurred.
Forcing Bit Status The Condition Flags cannot be force-set and force-reset.
Summary of the Condition
Flags
The following table summarizes the functions of the Condition Flags, although
the functions of these flags will vary slightly from instruction to instruction.
Refer to the description of the instruction for complete details on the operation
of the Condition Flags for a particular instruction.
Name Symbol Function
Error Flag 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 (A29508) will be turned ON
when the Error Flag is turned ON.
Access Error Flag 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 (A429510) will be turned ON
when the Access Error Flag is turned ON.
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