Omron Sysmac NY512-1300, User Manual

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7 Tag Data Link Functions
7-14 NY-series Industrial Panel PC / Industrial Box PC Built-in EtherNet/IP Port User’s Manual (W563)
(2) Tag (network variable) without a refreshing task
The values are written to the variables in a system service.
Additional Information
Relationship between Refreshing Tasks and Data Concurrency in Tag Data Links
If you do not specify a refreshing task for global variables in tag data links, the following may
occur.
1. When the data is sent for the output tag set, another task may have already written different
values before that data is sent, depending on the timing of the task.
2. When data is received by an input tag set, another task may write different values after that
data is received, depending on the timing of the task.
Therefore, to maintain the concurrency of data in tag data links, you must specify the same
refreshing task on both the output Controller and the input Controller.
Primary period
Task period
Tag data is read
from the tag set.
The values are written to the network variables (tags)
in a system service.
Task period
Interrupted.
High
Low
MC IO UPG MC IO UPG MC IO UPG MC IO UPG MC IO UPG
UPG UPG
UPG
Execution
priority
Priority-16
periodic task
Priority-17
periodic task
Primary
periodic task
System
services
Tag data link
service
NJ/NX-series CPU Unit
Connection
Tag data links
updated.
NY-series Controller
Refreshing
task
Refreshing
task
EtherNet/IP
Variable c
Variable b
Variable a
Tag set
Variable f
Variable e
Variable d
Tag set
This variable may
already be written
by another task
before you send
the data.
This variable
may be written
by another task
after you receive
the data.
Data concurrency is not maintained
unless you assign the same
refreshing task for both the output
and the input tags.