Mitsubishi MELSEC-A Series Reference Manual page 264

9. PROGRAMMING
Device
Name
Number
D9224
D9225
Initial
communication
between local and/
or remote I/O
D9226
stations
D9227
D9228
D9229
Local station or
remote I/O station
error
D9230
D9231
Table 9.5 List of MELSECNET special link registers (Continued)
Data
Stores the status of
No.1 to No.16
Stores the status of
No.17 to No.32
Stores the status of
No.33 to No.48
Stores the status of
No.49 to No.64
Stores the status of
No.1 to No.16
Stores the status of
No.17 to No.32
Stores the status of
No.33 to No.48
Stores the status of
No.49 to No.64
• Stores station Nos. of local stations or remote I/O stations, which
are exchanging initial setting data for data link processing, into
the corresponding bits in D9224 to D9227 as shown below.
• When a local station or a remote I/O station is communicating
initial setting data (link parameters), the bit corresponding to the
station number is set to "1".
Example: When No. 23 and No. 45 are communicating initial setting
data (link parameters), "1" is set to bit 6 of D9225 and bit
12 of D9226. When D9225 is monitored, its value is "64
(40 )"and when D9226 is monitored, its value is "4096
H
(1000 )".
H
• When the communication of initial setting data is complete, the bit
is automatically reset to "0".
• The master station detects the number of a faulty local or remote
I/O station on data linking loop, and the information is stored in
the corresponding bit of the data register as shown below.
• A station is determined to be faulty if the data returned from it to
the master station is not received within the specified length of
time.
• When data is not received within the specified length of time, the
bit corresponding to the station number of the local station is set.
Example: When an error at No. 3 causes it to fail to return the data
to the master station, "1" is set for bit 2 of D9228. When
D9228 is monitored, its value is "4".
• When the loop line becomes faulty, "1" is set for the bits if the
stations downstream the faulty point or for all local stations.
• When the master station becomes faulty or the setting for the
monitoring time is too small, "1" is set for the bits corresponding
to all local stations.
• When the faulty station recovers normal operating status or when
the loop line is switched so that the data link returns to normal
operating status, the bit is automatically reset to "0".
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Description