Mitsubishi MELSEC-A Series Reference Manual page 265

9. PROGRAMMING
Device
Name
Number
D9232
D9233
D9234
D9235
Local station or
remote I/O station
loop error
D9236
D9237
D9238
D9239
Receive error
D9240
detection count
Table 9.5 List of MELSECNET special link registers (Continued)
Data
Stores the status of
No.1 to No.8
Stores the status of
No.9 to No.16
Stores the status of
No.17 to No.24
Stores the status of
No.25 to No.32
Stores the status of
No.33 to No.40
Stores the status of
No.41 to No.48
Stores the status of
No.49 to No.56
Stores the status of
No.57 to No.64
Stores the total number of
receive error occurrences
• Stores the station number of the local and remote I/O stations at
which an error is detected in the forward loop line or reverse loop
line.
• If a local station goes down, data before the failure will be held.
When contents of D9224 to D9227 and D9228 to D9231 are
ORed and the relevant bit is "0", the corresponding bit in the
above special registers is enabled.
• Even If the host station (master station) goes down, the data
before the failure will be also held.
• When an error is detected at a local station and/or remote I/O
station in the forward loop line or the reverse loop line, the
corresponding bit is set to "1".
Example: When an error is detected in the forward loop line at No.
5, "1" is set for bit 8 of D9232. When D9232 is monitored,
its value is "256 (100
This error will have been caused by one of the following:
(a) A faulty connection of the forward loop cable
connecting No. 4 and No. 5
(b) A fault of the forward loop receiver of link module on
No.5
(c) A fault of the forward loop transmitter of link module on
No.4
• With errors other than loop line errors, such as hardware errors
and data communication errors, only the error involved with the
loop line currently being used will be detected. The error status is
retained.
• When data link is executed again with the loop line in which an
error was detected, the bit data is automatically reset to "0"
provided that the fault has been removed.
• Stores the number of times that the following errors are detected
in the loop line currently being used:
"CRC", "AB.IF", "OVER"
• Counting stops if the number of receive error occurrences
exceeds the maximum limit "FFFF
• Execute the reset operation to clear the data to "0".
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Description
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