[?]: Quantum Unity Hotstandby PLC-B goes to halt

[leofarhan]

Hello,

I am facing a prolem in Quantum Unity Hotstandby 140CPU67160.
Both the controllers have same logic,
the PLC-A execute the logic perfectly,
while when PLC-B is Primary it goes to halt within 12-15 hours with stop code 8190.
And the reason of the halt in the PLC Diagnostic View is Watchdog overflow.

Kindly help to resolve this issue.
I have checked the logic there is no problem in the logic.

Best Regards

Leo-Ali

[Schtiel]

And the reason of the halt in the PLC Diagnostic View is Watchdog overflow.

Watchdog overflow means that task execution time becomes greater than the maximum execution time declared in the task properties.

How many tasks do you use? What execution times are set?

[leofarhan]

We are using Master Task only contains 79 sections.
The watchdog timer is 1000ms cyclic for MasterTast, but normal scan time is 41 ms.
But problem is this problem occurs only on PLC-B since last three months.
We have tested PLC-A for more than 30 days continious operation, but never found this problem in PLC-A.

[Schtiel]

But problem is this problem occurs only on PLC-B since last three months.

Looks like bug in PLC-B (either hw or sw). Try to update its firmware - if it doesn't help, then contacting Schneider is the only option (but it can last for ages ).

[leofarhan]

HEllo,

We have test the problem by replacing the PLC-B with Spare Processor. The problem remains in PLC-B.

Then it was decided to replace PLC-B by PLC-A, so that it is to be clarify the problem is in PLC or rack/Modules on rack. The problem still remain in PLC-B.

Further I would like to ask, We have used same logic in both the PLCs, and have not used any condition for PLC-A & PLC-B seperately. My question is still there is chance of Task Overflow in the PLC-B.

Thanks for your reply.

Best Regards

Leo-Ali

[leon78]

What is in first section? Only first section is running in Standby PLC.

[leofarhan]

Hello Leon,

The first section contains logic for the status of standby PLC and its modules, but I have blocked this section by a condition.

Further the standby PLC is not going to Halt, only PLC-B is going to halt whenever it is primary.

Best Regards

Leo-Ali

[leofarhan]

Hello!

I would like to confirm, the number of allowable error counts on Remote I/O Network?
And if it increase from the maximum allowable error count what will happen in this case.

Is there any possibility that Quantum Unity Hot standby PLC go to halt mode due to Remote I/O error.
If so then what will be the message on PLC?
What will be the stop code?
And what will appear in diagnostic viewer?

Thanks for reply.

Best Regards

Leo-Ali

[leofarhan]

Hello All!,

All the problem have been solved by upgrading the fimware (OS: 2.7 to 2.8 & Co-Pro: 2.7 to 2.81).
Thanks you all for support.

Best Regards

Leo-Ali