Mitsubishi Q12PRHCPU - Page 121

5
REDUNDANT SYSTEM FUNCTIONS
5.3 The System Switching Function
5.3.1 System Switching Method
5 - 38
1
OVERVIEW
2
SYSTEM CONFIGURATION
3
TRACKING CABLE
4
PROCEDURE FOR STARTING UP A REDUNDANT SYSTEM
5
REDUNDANT SYSTEM FUNCTIONS
6
REDUNDANT SYSTEM NETWORKS
7
PROGRAMMING CAUTIONS
8
TROUBLESHOOTING
(2) Manual System Switching
Manual system switching means the system switching that is done manually by the
user while the system is running.
2 types of manual system switching are available: system switching using GX
Developer and that by the system switching instruction (SP.CONTSW instruction).
The manual system switching is performed for the control system CPU module.
(a) System switching using GX Developer
When executing the system switching in the control system CPU module using
GX Developer, the system switching operation is done at END processing.
1) System switching using GX Developer is done in the following
procedure:
• Turn on the "Enable/disable user system switching" flag (SM1592) in the
control system CPU module.
• The system switching request is issued to the control system CPU module
by the redundant operation of GX Developer.
Diagram 5.26 System Switching Operation by GX Developer
System A -
Control
System
System B -
Standby
System
System switching
Calculating Stopping calculation
End calculation Begin calculating
Execute system
switching operation
on the control system
GX Developer
GX Developer
Tracking cable
Tracking cable
System B
END
Control
system
Standby
system
RUN
(Execute program)
Normal Standby
RUN
(Stop program)
System
switching
requested by GX
Developer
System A -
(Control System
Standby System)
System B -
(Standby System
Control System)
System A
System
switching
Normal Standby
RUN
(Stop program)
Standby
system
Control
system
RUN
(Execute program)