Link Device Access; Internal Buffer Access; What Is The Internal Buffer Access?; Internal Link Device Buffers - Mitsubishi Electric Q12DCCPU-V User Manual

5
ACCESS VIA NETWORK MODULES
5.3.2

Link device access

Link device data of a MELSECNET/H module controlled by a C Controller module can be
read or written from a user program on the C Controller module.
To access from the user program to the link devices, two different methods are available:
the internal buffer access and the direct access.
/* Data write */
ret = QBF_WriteLinkDevice();
or
ret = mdSend();
ret = mdRandW();
ret = mdDevSet();
ret = mdDevRst();
/* Data read */
ret = QBF_ReadLinkDevice();
or
ret = mdReceive();
ret = mdRandR();

(1) Internal buffer access

(a) What is the internal buffer access?
(b) Internal link device buffers
C Controller module
User program
Internal
buffer access
Figure 5.13 Link device access
The internal buffer access is a method of accessing the internal link device buffers
in the C Controller module.
To use this method, the refresh parameters must be previously set in the
<<Parameter settings>> tab of MELSECNET/H utility.

1) Internal link device buffers

• The internal link device buffer is reserved for each of four MELSECNET/H
modules.
• Each of the internal link device buffers (LX, LY, LB, and LW buffers) has
the same area size as the corresponding link device (LX, LY, LB, and LW).
Set refresh ranges on the Refresh parameter settings screen activated
from the <<Parameter settings>> tab of MELSECNET/H utility.
• The internal link device buffers are refreshed with the link device data by
link device refresh.
Q12DCCPU-V
Direct
access
Internal link
device buffers
Link device
refresh
LX buffer
LY buffer
LB buffer
LW buffer
5.3 MELSECNET/H Module Access Function
5.3.2 Link device access
Q06CCPU-V Q06CCPU-V-B
MELSECNET/H module
Link devices
LX
LY
LB
LW
*1
SB
*1
SW
*1 Link device refresh is not
available for the link
devices SB/SW.
Use the direct access.
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