Mitsubishi MELSEC-A Series Reference Manual page 271

9. PROGRAMMING
Device
Name
Number
Station number
D9243 data of the station
itself
Slave station
D9244
number data
Receive error
D9245
detection count
D9248
Local station
operating status
D9249
D9252
Local station error
status
D9253
Table 9.8 List of MELSECNET/B special link registers
Data
Stores a station number
(0 to 64)
Stores a slave station
number
Stores the accumulated total
number of receive errors
Stores the status of
No.1 to No.16
Stores the status of
No.17 to No.31
Stores the status of
No.1 to No.16
Stores the status of
No.17 to No.31
9 - 25
• Stores the station number assigned to the host station itself.
• Used by a local station to check the host station number.
• Used by a local station to check the total number of slave stations
in the loop.
• Stores the accumulated number of times that the following errors
are detected in the loop line currently being used:
"CRC", "OVER", "AB.IF"
• Errors are counted up to "FFFF
• Execute the reset operation to clear the data to "0".
• Stores station numbers of the local stations, excluding the host
station , whose status is either STOP or PAUSE.
• If a local station except for the host station goes down, data
before the failure will be held.
When the corresponding bit in D9252 to D9255 is "0", the relevant
bit in the above special registers is validated.
• Even If the host station (master station) goes down, the data
before the failure will be also held.
• When the status of a local station is either STOP or PAUSE, the
corresponding bit is set to "1". When the status of the local station
changes to RUN or STEP RUN, the bit is automatically reset to
"0". The bit status of remote I/O station always remains "0".
Example: When the statuses of local stations No.7 and No.15 are
either STOP or PAUSE, "1" is set to bit 6 and bit 14 of
D9248. When D9248 is monitored, its value is "16448
(4040 )".
H
• The bit corresponding to the station itself is not set regardless of
the status of the station itself. (alawys "0" is stored)
• Detects station Nos. of faulty local stations except for the host
station in the loop and then stores the data into the corresponding
bits in the special registers (for link) as shown below.
• Error detection is performed only for local stations other than the
host station. The status of remote I/O stations remains "0".
• Bits corresponding to the station Nos. of faulty local stations
(except for host station) turn to "1".
Example:When local No. 12 is faulty, "1" is set to bit 11 of D9252.
When D9252 is monitored, its value is "2048 (500
• 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".
Description
" and then counting is stopped.
H
)".
H