4
FUNCTIONS
4.4 MELSECNET/H Module Access Function
4.4.2 Link device access
4 - 24
1
OVERVIEW
2
SYSTEM
CONFIGURATION
3
SPECIFICATIONS
4
FUNCTIONS
5
SETTING AND
PROCEDURES
6
I/O NUMBER
ASSIGNMENT
7
MEMORIES AND
FILES
8
INSTALLING /
UNINSTALLING
(c) Selection between internal buffer access and direct access
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.
POINT
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 (1)) and "Refresh parameters"
( Section 9.4.6 (3)).
(3) Link device access functions
The following functions are available for link device access.
Remark
Refer to Chapter 10 for details of the bus interface functions and MELSEC data
link functions.
Table4.9 Link device access function list
Function Function name Description
Data write to link
device
QBF_WriteLinkDevice
Writes data to link devices of the
MELSECNET/H module.
mdSend
mdRandW
mdDevSet
mdDevRst
Data read from link
device
QBF_ReadLinkDevice
Reads data from link devices of the
MELSECNET/H module.
mdReceive
mdRandR
To Next Page
Loading...
Need help?
General
