Omron SYSMAC CJ1W-EIP21, Operation Manuals

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7 Tag Data Link Functions
7-14
CJ-series EtherNet/IP Units Operation Manual for NJ-series CPU Unit (W495)
• Not Setting Refreshing Tasks for Tags (Network Variables)
Concurrency of the tags in the tag set is not maintained.

The timing of updating network variables that are assigned to tags is
synchronized with the execution period of the program that accesses the
network variables.
Set the refreshing task for the network variables assigned to the tags to the task that contains the
program that accesses those network variables.
• Difference between the Operation of Tags with a Refreshing Task and Tags without a Refreshing
Task
When you set a refreshing task for tags (network variables) that is the same as the task that con-
tains the program that accesses them, those tags are refreshed at the same time as the execution
of the program. Refreshing of tags (network variables) that have no refreshing task is handled by
the system service with the lowest execution priority, and therefore it is not synchronized with the
execution of the program.
Connection
Tag data links updated.
NJ-series Controller NJ-series Controller
Refreshing task Refreshing task
EtherNet/IP
100
10
10
Value of variable
100
→
10
Value of variable
Variable c
Variable b
Variable a
Variable c
Variable b
Variable a
Tag set
Variable f
Variable e
Variable d
Tag set
100
→
10
100
→
10
Not refreshed.
Refreshed.
Refreshed.
The
values of
tags in
the tag
set are
not
refreshed
at the
same
time.
Execution
priority
Primary period
Task period
UPG IO
Task period
UPG
High
Low
IO UPG M C
UPG IO
System service
IO UPG M C IO UPG M C IO UPG M C IO UPG M C
Primary
periodic task
Priority-16
periodic task
Priority-17
periodic task
(3)
(1) (2) (1) (2) (1) (2) (1) (2) (1) (2)
*: Refreshed during system common processing 2 in the task processing.
.....
(1) Execution timing of the program
(2) Refresh timing of network variables (tags) with the primary periodic task* set as the refreshing task*
(3) Refresh timing of network variables (tags) that do not have the primary periodic task set as the refreshing task
The system service is executed
during free time between task execution.