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4 FUNCTIONS
MELSEC-QnA
4.11 Data Link Stop/Restart
The data link in the host station can be stopped or restarted.
When the data link is stopped for the master station, the data link for the entire system
stops.
(1) The link special relay used in the program is shown below:
SB0000: Data link restart request
SB0002: Data link stop request
SB0041: Data link restart complete
SB0045: Data link stop complete
(2) A program example to stop/restart the data link is shown below.
This example assumes that the module's first I/O No. is X/Y30.
1
Relationship between the programmable controller CPU and master station
Programmable controller CPU
M15 M0
to
M35 M20
to
TO
FROM
Master station
Link special relay (SB)
SB000F SB0000
to
SB004F SB0040
to
5E0
H
5E4H
2
Program example
M0
Data link stop
Data link restart
Restart command
M21 (SB0041)
FROM H0003 H05E4 K4M20 K1
Read SB0040 to SB004F
status
M2 (SB0002) data-link
stop on
M2 (SB0002) data-link
stop off
M0 (SB0000) data-link
restart on
Write to SB0000 to SB000F
SM400
Stop command
SET M2
M25 (SB0045)
SET M2
RST M2
SETSET
RST M0
TO H0003 H05E0 K4M0 K1
SM400
M0 (SB0000) data-link
restart off
POINT
SB0000 must be used to start a data link if it has been stopped with SB0002.