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Programming with Tasks Section 2-1
Instruction-activated
Tasks
A TASK ON instruction (TKON(820)) is used to switch an instruction-activated
cyclic task from Disabled status or Standby status to READY status.
Operation-activated Tasks An operation-activated cyclic task will switch from Disabled status to READY
status when the operating mode is changed from PROGRAM to RUN or
MONITOR mode. This applies only to normal cyclic tasks.
Note The CX-Programmer can be used to set one or more tasks to go to READY
status when operation is started for task numbers 0 through 31. The setting,
however, is not possible with extra cyclic tasks.
RUN Status A cyclic task that is READY will switch to RUN status and be executed when
the task obtains the right to execute.
Standby Status A TASK OFF (TKOF(821)) instruction can be used to change a cyclic task
from Disabled status to Standby status.
Note The task programs for CP-series PLCs can be monitored online from the CX-
Programmer to see if they are executing or stopped. The status indications on
the CX-Programmer are as follows:
• Running: The task is in READY or RUN status. (There is no way to tell the
difference between these.)
• Stopped: The task is in INI or WAIT status. (There is no way to tell the dif-
ference between these.)
2-1-7 Status Transitions
Note (1) Activation at the start of operation is possible for normal cyclic tasks only.
It is not possible for extra cyclic tasks.
(2) A task in RUN status will be put into Standby status by the TKOF(821) in-
struction even when the TKOF(821) instruction is executed within that
task.
Standby status functions exactly the same way as a jump (JMP-JME). Output
status for the Standby task will be maintained.
INI (Disabled) status
READY status
RUN status
Executed
TKOF(821) instruction (See note 2.)TKON(820) instruction
Standby status
Right to execute obtained.
Activated at the start of
operation (See note 1.) or the
TKON(820) instruction
Standby status Jump
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