Mitsubishi QJ71LP21 Reference Manual page 214

8 TROUBLESHOOTING
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Error history monitor
Setup confirmation test
Station order check test
8 - 3
[Status of self]
• Parameter settings
• Reserved station setting
• Transmission mode
• Duplex transmission setting
• Duplex transmission status
[Network information]
• Network Type
• Module No.
• Network No.
• Group No.
• Station No.
[Loop switching] Number of occurrences
[Transient transmission] Number of occurrences
[Forward loop]
• Retry
• Line trouble
• Communication error (UNDER, CRC, OVER, etc.)
[Reverse loop]
• Retry
• Line trouble
• Communication error (UNDER, CRC, OVER, etc.)
Error history details
Clear error history
..............................Section 7.9
Network test
.......................................Section 4.10.1
Loop test
..............................Section 4.10.2
..............................Section 4.10.3
Communication test .................................Section 4.10.4
POINT
(1) The target of the network diagnostics is the host's network designated as the
connection destination.
(2) If the connection target is specified as other station or the redundant CPU is
specified as control system, standby system, system A, or system B, the
network monitor can check only the information of the host and other stations.
(3) The network monitor cannot display correctly while the network module is
executing offline tests.
(4) When the dedicated link instruction is used to access the other station PLC
during network diagnosis, the execution of the dedicated link instruction may be
delayed.
After taking the following measures, perform network diagnosis processing and
execute the dedicated link instruction.
• Execute the COM instruction.
• Using special register SD315, secure 2 to 3ms as the communication
processing time.
REMARK
SB and SW
special relay (SB) or the link special register (SW) used for monitoring.
[Network information]
• Network Type
• Module No.
• Network No.
• Group No.
• Station No.
[Loop switching]
Station No., Factor, Switched to
[Transient transmission error]
Err. code, Error type
[Clear type]
Retry counter clear, etc,
found in the explanations of each item indicate the link
MELSEC-Q
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