Mitsubishi Electric Q12DCCPU-V - Direct Access; What Is Direct Access?; Directly Accessible Devices

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5.3 MELSECNET/H Module Access Function
5.3.2 Link device access
5
ACCESS VIA NETWORK MODULES
(2) Direct access
(a) What is direct access?
The direct access is a method of directly accessing a link device of a MELSEC/H
module from a user program on the C Controller module, independently of the link
device refresh.
Since direct access does not use any internal link device buffer, the link device
refresh cycle and refresh parameters need not be set in MELSECNET/H utility.
(b) Directly accessible devices
The following devices are directly accessible.
Table 5.6 Directly accessible device list
Access method Accessible device
Direct access
LX
LY
LB
LW
SB
SW
Figure 5.16 Direct access
MELSECNET/H module (Fourth module)
MELSECNET/H module (Third module)
MELSECNET/H module (Second module)
User program
ret = QBF_WriteLinkDevice();
ret = mdSend();
ret = mdRandW();
ret = mdDevSet();
ret = mdDevRst();
or
/* Data write */
ret = QBF_ReadLinkDevice();
ret = mdReceive();
ret = mdRandR();
or
/* Data read */
Direct access
SB
SW
LW
LB
Link devices
LX
LY
MELSECNET/H module (First module)C Controller module