User`s manual

9 - 5 9 - 5
MELSEC
9 MELSEC DATA LINK LIBRARY
(From the previous page)
5) Invoke the created user application.
6) Access with the PLC CPU and communication board.
7) End the user application.
POINT
(1) Perform the processing for opening and closing a communication line (mdOpen/
mdClose) only once at the beginning and end of a program.
Repeatedly opening and closing a communication line for each transaction will
degrade the communication performance.
(2) It is necessary to perform only steps 5) to 7) above to access the PLC CPU and
communication board again using an application program that has already
been created by the user.
(3) The functions get detailed PLC information at the initial execution when the
corresponding devices are added. Therefore, the initial function execution time
gets longer than usual.
(4) When accessing multiple remote stations simultaneously from the same PC
using the CC-Link utility, Device Monitor utility, user application program or
Mitsubishi's software package (such as MX Links), limit the number of stations
to be accessed to eight or less.
If nine or more remote stations are accessed simultaneously, communication
performance may deteriorate.
(5) When creating a user application program for debugging using Visual C++
R
6.0, do not define the buffer to be used by mdReceive in static.
9.5 Channel
The following is the channel used by the MELSEC data link library:
Number Channel name Description
81 to 84
CC-Link (1st board to 4th
board)
This is used when communication via the CC-Link board.
This is set using the BD No. DIP switch on the back of the CC-Link
board.
The following will be set using the SW1 and SW2 settings.
81: OFF, OFF 82: ON, OFF 83: OFF, ON 84: ON, ON