Mitsubishi Electric MELSEC iQ-R Series User Manual page 159

Differences from link refresh
Item
Number of steps
Processing speed
Cyclic data assurance
*1 For the instruction processing time when the link direct device (J\) is used, refer to the following.
 MELSEC iQ-R Programming Manual (CPU Module Instructions, Standard Functions/Function Blocks)
Shortening the transmission delay time
The transmission delay time can be shortened by reducing the number of link refresh points and shortening a communication
cycle interval. ( Page 526 Communication cycle intervals)
The following methods can be used to reduce the number of link refresh points.
• In "Refresh Settings" under "Basic Settings", set only the link devices frequently used in the CPU module as the link refresh
range. ( Page 77 Refresh Setting)
• Remove infrequently used link devices in the CPU module from the link refresh range, and directly read or write the
corresponding data from the program by direct access.
Link refresh is performed in END processing of the sequence scan of the CPU module.
Precautions
■Cyclic data assurance
The direct access to link devices does not provide station-based block data assurance. Use 32-bit data assurance, or if cyclic
data of more than 32 bits needs to be assured, use interlock programs. ( Page 158 Cyclic data assurance)
■Mounting multiple modules of the same network number
When multiple CC-Link IE TSN Plus modules of the same network number are mounted, the target of the direct access to link
devices is the module that has the smallest slot number in the base unit.
■Link direct device in a multiple CPU system
In a multiple CPU system, link direct devices cannot be used for the CC-Link IE Controller Network-equipped module
controlled by another CPU module.
Access method
Link refresh
1 step
High speed
Available
Direct access
2 steps
*1
Low speed
Not available
9 FUNCTIONS
9.2 Cyclic Transmission
9
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