ABB AC 800M, Manual

Page: 184 / 200

Automatic Switch-Over to Backup CPU Section 4 Operation
184 3BSE036351-510 A
Controller Reset
The system stops. The application program and variables are erased.
To initiate Controller Reset, press and hold the Controller INIT push button (more
than three seconds) until the Run LED begins to flash. A Controller Reset must be
performed if the system is in an undefined position and consequently unavailable to
the user.
Controller Reset in Redundant Configuration
Follow the steps below to perform a Controller Reset in redundant configuration:
1. Perform a Controller Reset of the backup CPU. The system will go single CPU
state.
2. Wait a few seconds and then perform a Controller Reset on the Primary CPU.
Automatic Switch-Over to Backup CPU
In a redundant configuration an automatic switch-over from the Primary CPU to the
Backup CPU occurs in the following situations, provided they are in synchronized
state (DUAL LED is lit):
• Memory error in the Primary CPU.
• Other HW-error in the Primary CPU, which causes CPU crash.
• Severe communication errors on the Control network, that is, loss of both
network ports in the Primary CPU.
• Severe communication errors on the ModuleBus (if ModuleBus is part of the
HW configuration) that is, loss of clusters in the Primary CPU.
Note that a Backup CPU with severe communication errors on the ModuleBus
will be rejected (if ModuleBus is part of the HW configuration) and
synchronized state will never be reached as long as error remains.