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Setting Data Links Section 5-2
Note 1. Node 1 becomes the master node. Node 1 must be registered as a partic-
ipating node.
2. Only one area can be specified when using the 1 to 1 type of 1:N alloca-
tion.
3. The startup node (the node that sets the above DM parameter and starts
the data link) must be set as a participating node of the data link. If not, the
data links will not start.
4. The total number of words in data link send and receive areas must not ex-
ceed 20,000 per node when using Controller Link Units with unit Ver. 1.2
or later, or 12,000 words per node if using pre-Ver. 1.2 Controller Link
Units. The total number of words in data link send and receive areas of a
master node must satisfy the following values. Since the number of master
node words is greatest when 1:N allocation is used, the value can be esti-
mated from the number of master node words.
Total number of words in data link send and receive areas of master
node =
Number of common send words in master node +
Number of individual send words in master node
× Number of slave
nodes participating in data links +
Number of send words in slave node
× Number of slave nodes partic-
ipating in data links
5. The following values must be satisfied to ensure that the data link area is
fully contained within the specified area.
Number of common send
words per master node
Set the number of words in BCD between 0 and 1,000.
The number of common send words per master node
added to the number of individual send words per master
node multiplied by the number of slave nodes participat-
ing in the data links must not exceed 1,000.
Set to 0 if common data is not to be sent from a master
node to a slave node.
Number of individual
send words per master
node
Set the number of words in BCD between 0 and 1,000.
The number of common send words per master node
added to the number of individual send words per master
node multiplied by the number of slave nodes participat-
ing in the data links must not exceed 1,000.
Set to 0 if individual data is not to be sent from a master
node to a slave node.
Send size (number of
words) for slave node
Set the number of words in BCD between 0 and 1,000.
Set to 0 if the slave node will transmit no data.
First data link status word Set in BCD the first word used for storing data link status.
When automatic setup is used, status can be stored in
the IR or CIO Area only. The number of words used to
store status depends on the data link status storage for-
mat specification as below.
0 (*)
1 to 6128 (32 nodes max., 8-bit format: 16 words used)
*: When 0 is set, the status is saved in IR 1500 + unit
number x 25 (+ 7 to + 22).
Nodes to participate in
the data links
Set to ON (1) the bits corresponding to the nodes partici-
pating in the data links.
The data link will not start unless the startup node itself is
set as a participating node.
Item Setting range