Appendix 3 List Of Special Relay (Sm) Areas - Mitsubishi Electric MELSEC iQ-R Series User Manual

Appendix 3
The following table shows how to read the special relay (SM) list.
Item
No.
Name
Data stored
Details
Set by (setting timing)
Do not change the values of special relay set by the system by an engineering tool. Doing so may result in
system down or communication failure.
Diagnostic information
The following table lists the special relay areas relating to the diagnostic information.
No. Name
SM0 Latest self-diagnostic error
SM1 Latest self-diagnostic error
SM50 Error clear
SM53 AC/DC DOWN
SM60 Fuse blown
List of Special Relay (SM) Areas
Description
Special relay number
Special relay name
Data stored in the special relay and its meaning
Detailed description of the data stored
Set side of data (system or user) and timing when data is set by the system
<Set by>
• S: System
• U: User (via network or by test operation from an engineering tool).
• U/S: User and system
<Set timing>
• Every END: Data is set every time END processing is performed.
• Initial: Data is set when initial processing is performed (e.g. powering on the system, changing the operating status from
STOP to RUN).
• Status change: Data is set when the status is changed.
• Error: Data is set when an error occurs.
• Request: Data is set when requested by a user (using the special relay).
• Writing: Data is set when a user performs a writing operation.
• Power-on to RUN or STOP to RUN: Data is set when the operating status changes from power-on to RUN or from
STOP to RUN.
• Copy start: Data is set when memory copy is started.
• Copy end: Data is set when memory copy is completed.
Data stored
Off: No error
On: Error
Off: No error
On: Error
OffOn: Error clear request
OnOff: Error clear
complete
Off: No AC/DC DOWN
detection
On: AC/DC DOWN
detected
Off: Normal
On: Fuse blown detected
Details
• This relay is turned on when the self-
diagnostics returns an error.
• The ON state is maintained even after the
error has been later cleared.
• This relay is turned on when the self-
diagnostics returns an error.
• The ON state is maintained even after the
error has been later cleared.
• This relay clears the error state when the
mode transfers from off to on.
• This relay is turned on and off when the error
clear has been completed.
• This relay is turned on when a momentary
power failure within 20ms is detected while
the AC power supply module is in use. The
ON state is reset when the system is powered
off and on.
• This relay is turned on when a momentary
power failure within 10ms is detected while
the DC power supply module is in use. The
ON state is reset when the system is powered
off and on.
• This relay is turned 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.

Appendix 3 List of Special Relay (SM) Areas

Set by (setting timing)
S (Error)
S (Error)
U/S (Status change)
S (Error)
S (Error)
APPX
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