AC800M Controller fault - error code 4030

In one of the customer sites, there is a PM866 in redundant configuration. The backup CPU has suddenly gone in to fault mode. We have tried to init restart the backup controller. But it come back in fault mode. Since the log points at module bus inaccessible, We checked the optic fibre connectivity and looks like there is no breakage.

We checked the RCU link between the primary and backup controllers and it seems fine.

The log reads the error codes as below:

E 2018-01-31 13:00:06.151: 4008 P:RCUMessHalt Lower CPU
E 2018-01-31 13:00:06.047 Unit= _SWTargets XXXSS_~troller 4030 Stopped ModuleBus inaccessible Backup CPU
E 2018-01-31 13:00:06.149 Unit= _SWTargets XXXSS_~troller 4004 P:BkpNotAlive in Synch
E 2018-01-31 13:00:06.150 Unit= _SWTargets XXXSS_~troller 4008 P:RCUMessHalt Lower CPU

The 'RCUMessHalt Lower CPU' is logged first. However as per the time stamp the error code 4030 occurred first.

Can you please help me what could possibly be the issue.

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asked 3 months ago




Following may be reasons of failure:

1. Loose CEX Bus connection.

2. AC800m Controller may be faulty

3. baseplate of Controller may be faulty.

What you can do:

1.Check CEX extension cable and other modules installation(Should not be losse)

2.replace CEX Bus extension cable

3. Replace RCU Link cable

4. Replace BC810(lower)

and at last replace controller.

My strong doubt will be on BC810 module.

Also if possible for you, check controller healthiness by powering suspected/faulty controller seperately.


answered 3 months ago


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Stopped due to ModuleBus inaccessible from Backup CPU

This event is issued from the MBTestMC unit if the Backup CPU has been stopped

due redundancy supporting modules on the module bus turned out to be inaccessible

from the Backup CPU.


Basappa G   

answered 3 months ago


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You could connect a serial cable to the backup controller and read from the terminal if it gives you more information during boot. Did you check the power supply voltage, maybe it is too low. As mentioned before, if all connections are ok, replace the components.

Good luck solving this issue.


answered 3 months ago


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