Omron CP - PROGRAMMING MANUAL 05-2007 - Cyclic Task Status; Task Execution Conditions and Settings

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Programming with Tasks Section 2-1
2-1-5 Task Execution Conditions and Settings
The following table describes task execution conditions, related settings, and
status.
2-1-6 Cyclic Task Status
This section describes cyclic task status, including extra cyclic tasks.
Cyclic tasks always have one of four statuses: Disabled, READY, RUN (exe-
cutable), and standby (WAIT).
Disabled Status (INI) A task with Disabled status is not executed. All cyclic tasks have Disabled sta-
tus in PROGRAM mode. Any cycle task that shifted from this to another status
cannot return to this status without returning to PROGRAM mode.
READY Status A task attribute can be set to control when the task will go to READY status.
The attribute can be set to either activate the task using the TASK ON instruc-
tion or when RUN operation is started.
Initial Task Execution
Flag (A200.15) and
Task Start Flag
(A200.14)
Not supported. Supported.
Index (IR) and data
(DR) register values
Not defined when task is
started (same as normal
interrupt tasks). Values at
the beginning of each
cycle are undefined.
Always set values before
using them. Values set in
the previous cycle cannot
be read.
Undefined at the beginning
of operation. Values set in
the previous cycle can be
read.
Item Extra cyclic tasks Normal cyclic tasks
Task No. Execution condition Related Setting
Cyclic tasks 0 to 31 Executed once each cycle if READY
(set to start initially or started with the
TKON(820)instruction) when the right
to execute is obtained.
None
Interrupt
tasks
Scheduled
interrupt task 0
Interrupt task 2 Executed once every time the preset
period elapses according to the inter-
nal timer of CPU Unit.
• The scheduled interrupt time is set
(0 to 9999) through the SET INTER-
RUPT MASK instruction
(MSKS(690)).
• Scheduled interrupt unit (10 ms, 1.0
ms, or 0.1 ms) is set in PLC Setup.
Input interrupt
tasks 0 to 7
Interrupt tasks
140 to 147
Executed when the corresponding
CPU Unit built-in input turns ON or
turns OFF.
• Masks for designated inputs are
canceled through the SET INTER-
RUPT MASK instruction
(MSKS(690)).
High-speed
counter inter-
rupt tasks
Interrupt tasks
0 to 255
Executed when corresponding target
or range comparison condition is met
for CPU Unit built-in high-speed
counter.
External inter-
rupt tasks
(CP1H only)
Interrupt tasks
0 to 255
Executed when requested by a user
program in a Special I/O Unit or CPU
Bus Unit.
None (always enabled)
Extra cyclic tasks 0 to 255 Interrupt tasks
0 to 255
Executed once each cycle if READY
(started with the TKON(820) instruc-
tion) when the right to execute is
obtained.
None (always enabled)