Application Functions; Direct Access To The Link Devices - Mitsubishi Electric SW0DNC-MNETH-B User Manual

12 APPLICATION FUNCTIONS

12 APPLICATION FUNCTIONS
Basic
Cyclic transmission function
functions (Periodical communication)
RAS function
Application
Direct access to link devices
functions
Cyclic transmission function
(Periodical communication)
Transient transmission function
(Non-periodical communication)
Multiple transmission function (optical loop system)

12.1 Direct Access to the Link Devices

The link devices (LB, LW, LX, LY, SB, SW) of the MELSECNET/H board can be
directly read from/written to the user program by the driver setting.
By directly accessing the link devices, the link refresh time and the transmission delay
time can be shortened.
However, in direct access, since block guarantees are not applicable in station units, it
is necessary to establish an interlock.
For the direct access setting, set it in the "Driver" in the MNETH utility.
The direct access of the link devices LX/LY is limited to the communication with the
block I/O master station set with the common parameters. By limiting the
communication, data cannot be shared among multiple stations, such as link device
LB/LW, but 1:1 communication between predefined stations is allowed.
12 - 1
Communication LB/LW
Communication LX/LY
Automatic return function
Control station switch function
Control station return control function
Loopback function (optical loop system)
Prevention of station failure by using external
power supply (optical loop system)
Diatnostic function
Driver WDT function ······································································· Section 4.3
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Low-speed cyclic transmission
Communication function
Routing function
Group function
POINT
Refer to Q Corresponding
MELSECNET/H Network System
Reference Manual
(PLC to PLC network)
········································································· Section 6.5
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MELSEC
12
Section 12.2
Section 12.3.1
Section 12.3.2
Section 12.3.3
Section 12.4
12 - 1