Mitsubishi MELSEC-Q Series User Manual page 97

4
FUNCTIONS
(c) Selection between internal buffer access and direct access
POINT
(3) Link device access functions
The following functions are available for link device access.
Data write to link
device
Data read from link
device
Remark
When selecting the access method, refer to the following.
1) Data suitable for internal buffer access
Data suitable for internal buffer access are those of the link devices that are
used frequently or whose data must be secured in units of stations.
For these data, set the link device refresh parameters and utilize them by
internal buffer access.
2) Data suitable for direct access
Data suitable for direct access are those of the link devices that are not used
frequently.
Exclude these data from the link device refresh parameter setting and utilize
them with direct access.
Make the following setting to validate the secured data setting.
1) Select "Secured data send" or "Secured data receive" in the parameter
setting (supplementary setting) of the MELSECNET/H module (control
station).
Make the parameter setting (supplementary setting) on the MELSECNET/H
utility ( Section 9.4.6 (5)) when the control CPU of the MELSECNET/H
module (control station) is a C Controller module, or on GX Developer when
the control CPU is a programmable controller CPU.
2) On the <<Parameter setting>> tab of the MELSECNET/H utility, set the "Link
device refresh cycle" (
( Section 9.4.6 (3)).
Table4.9 Link device access function list
Function Function name
QBF_WriteLinkDevice
mdSend
mdRandW
mdDevSet
mdDevRst
QBF_ReadLinkDevice
mdReceive
mdRandR
Refer to Chapter 10 for details of the bus interface functions and MELSEC data
link functions.
Section 9.4.6 (1)) and "Refresh parameters"
Writes data to link devices of the
MELSECNET/H module.
Reads data from link devices of the
MELSECNET/H module.
4.4 MELSECNET/H Module Access Function
4.4.2 Link device access
Description
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