Logix 1756 5575 Redundancy Issue -- Urgent Help Requested

[QasimFSH]

Guys, please help me with this urgently.

We have Logic 5575 installed in hot n standby setup. For some reason, the primary now cannot sync with secondary. Sync starts, but gets stuck at 54%, every time.
We have tried rebooting secondary chassis, replaced the CPUs, as well as changed the RM module there as well. Simply cannot understand what's causing this, especially since its been working fine for some time.

 

[robertmee]

What does the Redundancy Configuration Tool show in the event logs?

Are both processors on a DLR ring? Check the health of the DLR if so.

 

[QasimFSH]

Yes, they are. But we have other PLC pairs here as well and they are working fine. Can it still be an issue with a DLR?

 

[robertmee]

Yes, they are. But we have other PLC pairs here as well and they are working fine. Can it still be an issue with a DLR?

Yes....there's a tech note about if you lose one leg of the DLR, that can cause a hang up in the synchronization. Have no idea if that's what's going on, but unless you're monitoring DLR health, the Ring will still work for other devices with one leg lost, but could cause issue with the Redundancy synch. Also, what are the event logs saying in the configurator?

 

[asenior]

Do you happen to recall the tech note ID? I would like to read through it.

Thanks…

 

[dalporto]

Last time I saw something like that I had a faulty EN2TR in one of the racks.

 

[QasimFSH]

The only error in the Event Log is

 

[QasimFSH]

Last time I saw something like that I had a faulty EN2TR in one of the racks.

How did you narrow it down though? I am resuming the rectification works so any help now would be greatly appreciated.

 

[tarik1978]

Check this tech note:
ID: BF28577 | Access Levels: Everyone

1756-RM/RM2 Redundancy Module: COMM ERR PRT and COMM RSRC ERR PRT errors​

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[QasimFSH]

Check this tech note:
ID: BF28577 | Access Levels: Everyone

1756-RM/RM2 Redundancy Module: COMM ERR PRT and COMM RSRC ERR PRT errors​

Sign In

Checking now. Thanks mate

 

[QasimFSH]

Not much of help. We tried all of this but did not help. Ended up reboot the primary PLC (after setting up the other one as primary), and that resolved the issue. No clue yet about the real cause of this