Selection Of Internal Buffer Access Or Direct Access - Mitsubishi Electric Q12DCCPU-V User Manual

5
ACCESS VIA NETWORK MODULES
(c) Selection of internal buffer access or direct access
POINT
Remark
Select a suitable access method referring to the following.
1) Data suitable for internal buffer access
If a link device is used frequently or the block data assurance per station is
needed for a link device, the data of the link device are suitable for internal
buffer access.
For this kind of data, set refresh parameters to utilize them for internal buffer
access.
2) Data suitable for direct access
Data of a link device that is not used so frequently are suitable for direct
access.
Exclude these data from the refresh parameter setting, and utilize them for
direct access.
To enable the block data assurance per station, set as follows.
1) Select "Block send data assurance per station" or "Block receive data
assurance per station" in Parameter settings (Supplementary settings) for
MELSECNET/H module (control station).
This Parameter settings (Supplementary settings) can be configured in
MELSECNET/H utility when the control CPU of the MELSECNET/H module
(control station) is a C Controller module, or in GX Works2/GX Developer
when the control CPU is a programmable controller CPU.
2) In the <<Parameter settings>> tab of MELSECNET/H utility, set 10 or higher
for "Link device refresh cycle" and configure "Refresh parameters" settings.
If 0 is set for "Link device refresh cycle" with "Block data assurance per
station" enabled, cyclic transmission will not be performed properly and a data
link error may occur.
For MELSECNET/H utility, bus interface functions, and MELSEC data link
functions, refer to the following.
C Controller Module User's Manual (Utility Operation, Programming)
5.3 MELSECNET/H Module Access Function
5.3.2 Link device access
1
2
3
4
5
6
7
8
5
- 19