Mitsubishi MELSEC-A Series Programming Manual page 441

APPENDICES
Number Name
D9204
Link status
(Continue)
Loopback executing
D9205
station
Loopack executing
D9206
station
D9207 Link scan time
D9208 Link scan time
D9209 Link scan time
D9210 Retry count
D9211 Loop switching count
Table 1.5 Link special Register (Continue)
Description
• Loopback in forward loop only
• Loopback in reverse loop only
Stores the local or remote I/O station number at which loopback is
being executed.
Station executing forward
loopback
Station executing reverse
In the above example, 1 is stored into D9205 and 3 into D9206. If
loopback
data link returns to normal status (data link in forward loop), values in
D9205 and D9206 remain 1 and 3. Reset using sequence program
or the RESET key.
Stores the data link processing time with all local and remote I/O
Maximum value
stations.
• Input (X) , output (Y) , link relay (B) , and link register (W) assigned
Minimum value
• Link scan is a period of time during which data link is executed with
Present value
Stores the number of retry times due to transmission error.
Total number stored Count stops at maximum of "FFFF
RESET to return the count to 0.
Stores the number of times the loop line has been switched to
reverse loop or loopback.
Total number stored
Count stops at maximum of "FFFF
RESET to return the count to 0.
APP - 36
Master
station
Station 1 Station 2
Forward loopback
Master
station
Station 1 Station 2
Reverse loopback
Master
station
Station 1 Station 2
Forward loop
in link parameters communicate with the corresponding stations
every link scan.
all connected slave stations, independently of the sequence
program scan time.
Details
Station 3 Station n
Station 3 Station n
Station 3 Station n
Reverse loop
" .
H
".
H