Mitsubishi Electric Melsec QJ71LP21 Reference Manual page 457

APPENDICES
No. Name
3
Redundant system status
SB01F4
(1)
(500)
3
Redundant system status
SB01F8
(2)
(504)
3
Redundant system status
SB01FC
(3)
(508)
3: Valid only when the SB0047 is off. When it turns on (error), the last data are retained.
App - 18
Table 3 Link special relay (SB) list (continued)
Description
Indicates the operation mode of each station's CPU.
Off: CPUs of all stations in backup mode
On: Separate mode
(excluding reserved stations and stations of the number
exceeding the maximum)
This relay turns off when all of SW01F4 to SW01F7 are "0."
In the separate mode, the status of each station can be checked
by Redundant system status (1) (SW01F4 to SW01F7).
Depending on the timing of the link refresh, Redundant system
status (1) (SW01F4 to SW01F7) and the update may be offset
by one sequence scan.
Indicates the pairing setting status of each station.
Off: No pairing setting
On: Pairing set station exists
(excluding stations after the maximum station number )
This relay turns off when all of SW01F8 to SW01FB are "0."
When a pairing set station exists, the status of each station can
be checked by Redundant system status (2) (SW01F8 to
SW01FB).
Depending on the timing of the link refresh, Redundant system
status (2) (SW01F8 to SW01FB) and the update may be offset
by one sequence scan.
Indicates the operation status of each station's CPU (control
system/standby system).
Off: Control system CPUs on all stations
On: Standby system CPU exists
(excluding reserved stations and stations after the maximum
station number)
This relay turns off when all of SW01FC to SW01FF are "0."
When a standby system CPU exists, the status of each station
can be checked by Redundant system status (3) (SW01FC to
SW01FF).
Depending on the timing of the link refresh, Redundant system
status (3) (SW01FC to SW01FF) and the update may be offset
by one sequence scan.
Use permitted/prohibited
Control Normal
station station
Loop Bus Loop Bus
[Availability column] Loop: optical loop, Bus: coaxial/twisted bus
MELSEC-Q
Remote
Remote I/O
master
station
station
Loop Bus Loop Bus
: Available, : Not available
App - 18