Mitsubishi MELSEC Q Series

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4.4 MELSECNET/H Module Access Function
4.4.5 Link data send/receive processing time specifications
4
FUNCTIONS
(b) How to decrease the refresh points
1) Method using refresh parameters
Up to 64 refresh ranges can be set for the C Controller module.
For the refresh parameters, set only the ranges that need to be refreshed.
2) Method using direct access
By using direct access for link devices that are less frequently used on its own
station and excluding those link devices from the link device fresh range, the
link device refresh time can be reduced.
Figure 4.35 Method using refresh parameters
Figure 4.36 Reduced link device refresh time
C Controller module
Link device internal
buffer
Link device
refresh
Link device
refresh
Link device
refresh
MELSECNET/H module
Network range
assignment parameter
Range set by
network range
assignment
Set refresh
parameters for
required part
only
Station
No.1
Station
No.2
Station
No.3
C Controller
module
Internal link device
buffers
Link device
refresh
Direct access
Direct access
Link device
refresh
MELSECNET/H module
Network range
assignment parameters
Internal
buffer access
Internal
buffer access
C Controller
module
User program
Processing to be written constantly
(Link device used frequently)
Processing to be written when
necessary
(Link device not frequently used)
Processing to be read constantly
(Link device used frequently)
Processing that performs read
when necessary
(Link device not frequently used)
Range of
transmission to
other station
Range of reception
from other station