Omron CQM1H-CLK21 - Manual (Page 133)

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What Are Data Links? Section 5-1
Using Offsets
For automatically set data links, all of the send words transmitted by a node
are received by other nodes with no change in size. For manually set data
links, the size of a receive area can be restricted by specifying a number of
words from the beginning word of the words sent by another node.
However, the above system does not guarantee that only the desired words
will be received and therefore the receive node may receive unnecessary
data.
Offsetting enables specification of a more specific range of receive data by
indicating both the number of words and the starting word position from the
beginning of the area. The offset refers to the starting word position counted
from the beginning of the area.
Offsetting Image
Application Example of
Using Offsets In the following example, the send data from node 1 is split into three parts
and each part is received by a different node, i.e., each of the other nodes
receives only part of the send data from node 1. This enables effective use of
data link memory areas without wasting space. In this way, a type of message
service (i.e., specific data to a specific node) can be achieved through data
links.
Manually set
data links
A node can specify the num
ber of words to receive from
the beginning send word.
# 1
# 2
# 3
# 2
# 3
# 2
# 3
# 3
# 2
# 1
# 1
# 3
# 2
# 1 # 1
# 3
# 2
# 1
# 1 # 2 # 3
# 1 # 2 # 3
Automatically set
data links
# 1
# 2
# 3
# 3
# 1 # 3
# 2
# 2
# 1
# 1 # 2 # 3
Offset from the beginning
Number of words to be received
Restricted reception
from node 1 by
specifying an offset Restricted reception
from node 2 by
specifying an offset
#1 Data
I only need this. I need all of it.
#1 Data