Mitsubishi Electric MELSEC iQ-R Series - Diagnostic Information

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APPX
Appendix 4 List of Special Relay Areas
Diagnostic information
The following is the list of special rely areas relating to the diagnostic information.
No. Name Data stored Details Set by (setting
timing)
SM0 Latest self-diagnostic error
(including annunciator ON)
Off: No error
On: Error
• This relay turns on when the self-diagnostics returns an
error (including the case when an error is detected by
turning the annunciator ON).
• The ON state is maintained even after the error has been
later cleared.
S (Error)
SM1 Latest self-diagnostic error
(not including annunciator
ON)
Off: No error
On: Error
• This relay turns on when the self-diagnostics returns an
error (not including the case when an error is detected by
turning the annunciator ON).
• The ON state is maintained even after the error has been
later cleared.
• This relay does not turn on when errors that are notified by
the PALERT instruction or the PABORT instruction.
S (Error)
SM50 Error reset OffOn: Error reset request
OnOff: Error reset complete
• This relay clears the error state when the mode transfers
from off to on.
• This relay switches from on to off when the error reset has
been completed.
U/S (Status
change)
SM51 Battery low latch Off: Normal
On: Battery low
• This relay switches to on when the battery voltage of the
CPU module drops below the specified value.
• The ON state is maintained even after the battery voltage
has been later recovered to the normal value.
• This relay synchronizes with BAT LED.
S (Error)
SM52 Battery low Off: Normal
On: Battery low
This relay has the same function as SM51 except for
switching to off after the battery voltage has been recovered
to a normal value.
S (Error)
SM53 AC/DC DOWN Off: No AC/DC DOWN
detection
On: AC/DC DOWN is
detected
• This relay switches to on when a momentary power failure
within 20ms is detected while the AC power supply module
is in use. This relay can be reset when power is turned off
and on. (In a redundant system with redundant extension
base unit, if a momentary power failure occurs in a module
on an extension base unit, the power failure will be
detected in both systems.)
• This relay switches to on when a momentary power failure
within 10ms is detected while the DC power supply module
is in use. This relay can be reset when power is turned off
and on. (In a redundant system with redundant extension
base unit, if a momentary power failure occurs in a module
on an extension base unit, the power failure will be
detected in both systems.)
S (Error)
SM56 Instruction execution fault Off: Normal
On: Instruction execution
fault state
• This relay switches to on when an error which can be
classified as instruction execution fault is returned.
• The ON state is maintained even after the error has been
later cleared.
S (Error)
SM60 Fuse Blown Off: Normal
On: Fuse blown is detected
• This relay is on when at least one output module is in fuse
blown state and the ON state is maintained even after later
recovering to the normal state.
• The fuse blown state check is also done for output modules
on the remote I/O station.
• In a redundant system with redundant extension base unit,
this relay is set as follows:
 If a fuse blown occurs in an output module on an
extension base unit, the on/off state is stored only in the
CPU module of the control system, but not stored in the
CPU module of the standby system.
 When the systems are switched, the state before system
switching is held.
 When the error is cleared, the CPU module of the
system where the error is cleared clears the value.
S (Error)