Mitsubishi Electric Melsec QJ71LP21 Reference Manual page 350

7 APPLICATION FUNCTIONS
SM255 (distinction between regular/standby network)
Module 1 SM256 (Refresh from the network modules to the CPU)
SM257 (Refresh from the CPU to the network modules)
SM260 (distinction between regular/standby network)
Module 2 SM261 (Refresh from the network modules to the CPU)
SM262 (Refresh from the CPU to the network modules)
CPU
Station
No. 1
Station
No. 2
Station
No. 3
Station
No. 4
CPU
Station
No. 1
Station
No. 2
Station
No. 3
Station
No. 4
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[When the regular network is faulty]
The CPU module does not control the special relay (SM) automatically; thus, must be
controlled by the sequence program.
Signal
Station No. 1
Regular Standby
SM257
Station Station
SM262
No. 1 No. 1
Station Station
SM261
No. 2 No. 2
Station Station
SM261
No. 3 No. 3
Station Station
SM261
No. 4 No. 4
Regular Standby
Station Station
SM261
No. 1 No. 1
Station Station
SM261
No. 2 No. 2
Station Station
SM261
No. 3 No. 3
SM257
Station Station
SM262
No. 4 No. 4
Station No. 4
Status
Off (Regular)
On (Does not refresh)
Off (Refreshes)
On (Standby)
Off (Refreshes)
Off (Refreshes)
Station No. 2
CPU
Station
SM261
No. 1
SM257
Station
SM262
No. 2
Station
SM261
No. 3
Station
SM261
No. 4
Cable
disconnection
CPU
Station
SM261
No. 1
Station
SM261
No. 2
SM257
Station
SM262
No. 3
Station
SM261
No. 4
Station No. 3
MELSEC-Q
Remarks
Controlled by the CPU.
Controlled by the user.
(Initially controlled by the CPU)
Controlled by the CPU.
Controlled by the user.
(Initially controlled by the CPU)
Regular Standby
Station Station
No. 1 No. 1
Station Station
No. 2 No. 2
Station Station
No. 3 No. 3
Station Station
No. 4 No. 4
Regular Standby
Station Station
No. 1 No. 1
Station Station
No. 2 No. 2
Station Station
No. 3 No. 3
Station Station
No. 4 No. 4
7 - 126