Diagnostic Information - Mitsubishi Electric MELSEC iQ-R Series User Manual

Diagnostic information

The following is the list of special rely areas relating to the diagnostic information.
No. Name
SM0 Latest self-diagnostic error
(including annunciator ON)
SM1 Latest self-diagnostic error
(not including annunciator
ON)
SM50 Error reset
SM51 Battery low latch
SM52 Battery low
SM53 AC/DC DOWN
SM56 Instruction execution fault
SM60 Fuse Blown
APPX
646
Appendix 4 List of Special Relay Areas
Data stored
Off: No error
On: Error
Off: No error
On: Error
OffOn: Error reset request
OnOff: Error reset complete
Off: Normal
On: Battery low
Off: Normal
On: Battery low
Off: No AC/DC DOWN
detection
On: AC/DC DOWN is
detected
Off: Normal
On: Instruction execution
fault state
Off: Normal
On: Fuse blown is detected
Details
• 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.
• 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.
• 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.
• 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.
This relay has the same function as SM51 except for
switching to off after the battery voltage has been recovered
to a normal value.
• 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.)
• 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.
• 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.
Set by (setting
timing)
S (Error)
S (Error)
U/S (Status
change)
S (Error)
S (Error)
S (Error)
S (Error)
S (Error)