7 Tag Data Link Functions
7-10
NJ-series CPU Unit Built-in EtherNet/IP Port User’s Manual (W506)
When you use multiple connections to communicate with one specific node, the information in the Con-
troller status is stored in the following variables if the Controller status is specified in the input tags and
the output tags for all connections.
Additional Information
Even if you specify including the Controller status in the output (produce) tags, you do not neces-
sarily need to include it in the input (consume) tags. If you do not include the Controller status in
an input (consume) tag, the contents of the Controller status is not updated in the Target PLC
Operating Mode and Target PLC Error Information variables, but it is sent in the input (consume)
tag. Therefore, you can use the Controller status data that was received in the input (consume)
tag as receive data.
To maintain the concurrency of data in a tag data link, you must set a refreshing task for each network
variable that is assigned to a tag.
• Maintain concurrency in the tag data in a tag set.
• 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.
Additional Information
A refreshing task maintains concurrency of the value of a global variable from all tasks that
access that global variable. This is achieved by specifying a single task that can write to that glo-
bal variable and not allowing any other task to write to that global variable. For details on refresh-
ing tasks, refer to the
NJ-series CPU Unit Software User’s Manual (Cat. No. W501).
z Maintaining Concurrency in the Tag Data in a Tag Set
To maintain concurrency in the values of multiple tags in a tag set, the tags (variables with a Network
Publish attribute) must satisfy the following three conditions.
(1) The tags must be assigned to the same tag set (connection).
Controller status Variable name Description of operation
Controller Operating Flag _EIP_TargetPLCModeSta
(Target PLC Operating
Mode)
This flag shows the operation information of the Controller at the
target node.
When the Built-in EtherNet/IP Port Is the Originator of the Con-
nection
The array element that corresponds to the target ID at the target
is TRUE when all information for all connections of the relevant
target node is shows operating status. You can change the target
ID of the IP address from the Network Configurator. This status
information is enabled when the Controller status is included in
the communications data in both the originator and target node.
This variable is updated when necessary.
Controller Error Flag _EIP _TargetPLCErr
(Tar-
get PLC Error Information)
This variable shows the error status (logical OR of fatal and non-
fatal errors) of the target node Controllers.
When the Built-in EtherNet/IP Port Is the Originator of the Con-
nection
You can change the target ID of the IP address from the Network
Configurator. The Controller Error Flags are enabled when the
Controller status is included in the communications data for both
the originator and target. This variable is updated when neces-
sary.
7-1-7 Concurrency of Tag Data Link Data
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