Terms And Definitions - Omron sysmac EtherNet/IP NJ Series Connection Manual

2. Terms and Definitions

The terms and definitions used in this guide are given below.
Term
node
tag
tag set
tag data links
connection
connection type
originator and
target / scanner
and adapter
tag data link
parameters
A controller and a device are connected to an EtherNet/IP network via
EtherNet/IP ports. EtherNet/IP recognizes each EtherNet/IP port
connected to the network as one node. When a device with two
EtherNet/IP ports is connected to the EtherNet/IP network, EtherNet/IP
recognizes this device as two nodes. EtherNet/IP achieves
communications between controllers or between a controller and a device
by exchanging data between these nodes connected to the network.
A minimum unit of the data that is exchanged over the EtherNet/IP
network is called a tag. The tag is defined as a network variable or as a
physical address.
In the EtherNet/IP network, a data unit that consists of two or more tags
can be exchanged. This data unit consisting of two or more tags for the
data exchange is called a tag set.
The standard EtherNet/IP implicit communications are called tag data
links. In EtherNet/IP, tags and tag sets can be exchanged cyclically
between nodes without using a user program.
A connection is used to exchange data as a unit within which data
concurrency is maintained. The connection consists of tags or tag sets.
Creating concurrent tag data links between specified nodes is called a
"connection establishment". When a connection is established, tags or tag
sets that configure the connection are exchanged between the specified
nodes concurrently.
There are two kinds of connection types for tag data links.
One is a multi-cast connection, and the other is a unicast (point-to-point)
connection. The multi-cast connection sends an output tag set in one
packet to more than one node. The unicast connection separately sends
one output tag set to each node. Therefore, the multi-cast connection can
reduce communications load if one output tag set is sent to more than one
node.
To perform tag data links, one node requests the opening of a
communications line called a "connection". The node that requests to
open the connection is called an "originator" or a "scanner", and the node
that receives the request is called a "target" or an "adapter".
Tag data link parameters are the setting data to perform tag data links.
They include the data to set tags, tag sets, and connections.
2．Terms and Definitions
Explanation and Definition
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