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21 DEVICES
21.5 Link Direct Device
Specification range
All the link devices of the network module can be specified. The link devices which fall outside the range specified with
"Refresh Setting" can also be specified.
Specification range for writing
Writing should be done for the range which is within the link device range specified as a sending range of network parameters
and outside the range specified as a refresh range for "Refresh Setting". Writing for a range specified as the refresh range
overwrites link device data of the link module during refresh process. When writing data to a writing range of another station
using the link direct device, data is overwritten with received data during data reception from another station.
Specification range for reading
Data can be read from all the range of link devices of the network module. There is only one network module for which writing/
reading is allowed with the link direct device for each network number. When more than one network module with the same
network number is mounted, the network module with the lowest slot number is the target for writing/reading by the link direct
device.
Difference from link refresh
The following table shows the difference between the link direct device and link refresh.
Item Link direct device Link refresh
Description method
in program
Input Jn\K4X0... X0...
Output Jn\K4Y0... Y0...
Link relay Jn\K4B0... B0...
Link register Jn\W0... W0...
Link special relay Jn\K4SB0... SB0...
Link special register Jn\SW0... SW0...
Access range in relation to network module All the link devices for each network module The range specified in "Refresh Setting"
Guarantee range of access data In word (16-bit) units In word (16-bit) units
LB0B0
CPU module
Network module
Link range
Sending range
Write range
Refresh
range
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