Omron SYSMAC CJ - REFERENCE MANUAL 08-2008 Reference Manual page 1296

Task Control Instructions
Description
Note
1256
Area
Constants
Data Registers
Index Registers
Indirect addressing
using Index Registers
TKON(820) puts the specified cyclic task or extra cyclic task in executable sta-
tus. When N is 0 to 31 (specifying a cyclic task), the corresponding Task Flag
(TK00 to TK31) will be turned ON at the same time.
This instruction can be executed only in a regular cyclic task or an extra cyclic
task. An error will occur if an attempt is made to execute it in an interrupt task.
The cyclic task or extra cyclic task specified in TKON(820) will be also be exe-
cutable in later cycles as long as it is not put in standby status by TKOF(821).
Any task can be made executable from any cyclic task, although the specified
task will not be executed until the next cycle if its task number is lower than
the task number of the local task. The task will be executed in the same cycle
if its task number is higher than the local task's task number.
The specified task's task number
is higher than the local task's task
number (m<n).
Task m
Task n
TKON(820) will be treated as NOP(000) if the specified task is already execut-
able or the local task is specified.
A task in executable status can be put in standby status with TKOF(821), the
CX-Programmer, or a FINS command.
The terms executable and executing are not interchangeable. Executable
tasks are executed in order of their task numbers during cyclic program exe-
cution. An executable task will not be executed if it is put in standby status
before program execution reaches its task number.
1. The CX-Programmer's General Properties Tab for each task has a setting
(the Operation start box) that specifies whether the cyclic task will be exe-
cutable at startup. When the Operation start box has been checked, the
corresponding cyclic task will be put in executable status automatically
when the PLC begins operation. All other cyclic tasks will be in non-exe-
cutable status.
00 to 31 or 8000 to 8255 (decimal)
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The specified task's task number
is lower than the local task's task
number (m>n).
Task n
Becomes
executable
in that cycle.
Task m
Section 3-34
N
Becomes
executable
in the next
cycle.