Omron CS1W-SLK11-21 - 06-2004, Руководство пользователя

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Introduction Section 4-1
4-1 Introduction
Data links can be created between PLCs or PLCs and computers in a SYS-
MAC LINK Network to exchange data. This data is transferred between inter-
connected PLCs automatically without requiring the use of normal I/O Units.
Words in the CIO and/or DM Areas are set aside as the data link words in
each PLC that is in the data link. Some of the data link words are allocated to
the local node and the rest are allocated to other nodes. Data can be written
only to the words allocated to the local node. During data link refreshing, data
written in the local node is transferred to corresponding words in other nodes’
memory areas. The result is that each PLC in the data link has a common
data link area, the only difference being in the read/write permissions for the
various words in it.
Data Link Tables The data link words in each PLC are defined by a data link table, which
includes both common link parameters and refresh parameters. The common
link parameters define the words output by each node in the data link and are
thus the same for all nodes, and the refresh parameters define the words
input by each node and can thus be different for each node.
Data link tables can be generated automatically or manually. Automatic gener-
ation is accomplished simply by setting parameters in the DM Area. Manual
generation is accomplished by setting specific data links from the CX-Net in
CX-Programmer.
The following diagram shows the operation of a data link among four nodes in
a network. This data link was generated manually.
Data link words
Data link table
Node 2 Node 5 Node 6 Node 8
1000
1010
1030
1049
#2
#5
#6
1010
1020
1039
#2
#5
1000
1020
1039
#5
#6
1005
1015
1035
1054
#2
#5
#6
Common link
parameters
(the same in all
nodes)
Link Area Link Area Link Area Link Area
Refresh parameters
(can differ from
node to node) Refresh parameters
(can differ from
node to node) Refresh parameters
(can differ from
node to node) Refresh parameters
(can differ from
node to node)