Direct Access - Mitsubishi Electric MELSEC Q Series User Manual

13.2.2

Direct access

Direct access is a method to directly access network module link device(s) from the user program.
C Controller module
User program
(1) Function to use
The dedicated function is used from the user program to access link device(s).
Functions used for direct access are indicated below.
(a) Bus interface functions
Function name
QBF_WriteLinkDevice
QBF_ReadLinkDevice
(b) MELSEC data link functions
Function name
mdSendEx
mdRandWEx
mdDevSetEx
mdDevRstEx
mdReceiveEx
mdRandREx
● Proper use of dedicated function libraries
To access to module(s) in the same C Controller module, use of bus interface functions better improves the user program
processing performance.
In case of CC-Link, use MELSEC data link functions. Access by the bus interface function is not allowed.
CHAPTER 13 FUNCTIONS ACCESSED VIA A NETWORK MODULE
Q24DHC-V
Network module
Link
Direct access
device
Writes data directly into network module link device(s).
Reads data directly from network module link device(s).
Writes data directly into network module link device(s).
Reads data directly from network module link device(s).
Q24DHC-LS Q26DHC-LS
Q24DHC-VG
Network module
Link
Link
device
scan
Function
Function
Q12DC-V
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