PACS Rx3i CRU320 - variables missing between redundant controllers

[mastops]

Hi,

we are using Rx3i CRU320 redundant PLC system and we noticed a discrepancy between Primary and Secondary controller.
Couple of variables (DI) which are "high" on the Secondary controller are "low" on the Primary.

I don't have much experience with GE/Emerson Rx3i system and I am not quite sure where to start
It looks to be a problem with transfer between Secondary and Primary PLC.

Any suggestions are highly appreciated.
Thank you.

 

[Steve Bailey]

In the hardware configuration for each CPU module, there is a tab labeled "Transfer List". That's where you establish what gets shared between the primary and secondary CPUs.

 

[mastops]

Hi Steve,

thank you for your reply. I looked at the transfers list but didn't see anything meaningful there. Have a look please.

 

[Steve Bailey]

It looks like the application isn't sharing any data between the primary and secondary controllers. Just running the same program in both controllers.
What is the source of the variables that differ between the two? My first guess would be that they come from the HMI. Are they addressed variables or symbolic? I'm not sure if the GE/Emerson redundancy solution provides a mechanism for including symbolic variables in the transfer list. I'll have to do some investigating. The one redundant system I was responsible for started life as a 90-30 system and was eventually upgraded to Rx3i. Consequently, most variables were addressed.

 

[mastops]

Let me put few more details in here:

As mentioned in the first post, we are missing 3 variables in the Primary controller (they are not showing healthy "1" state in the PME):

SCP1_FR (pump fail to run)
SCP2_FR
SCP3_FR

They should be coming from the Secondary controller. This is our guess because I/O points which represent those variables are physically wired to I/O modules in the Secondary controller cabinet.

Here's the tricky part:
Even though those three variables are missing in the Primary controller, we can see their state "1" (which is normal) on both HMI displays (Primary & Secondary).

Each PLC is located in a different location and has its own (local) HMI. The whole system can be viewed from either of the HMIs.

 

[Steve Bailey]

Your system is quite a bit different from the redundant Rx3i that I'm familiar with which uses Profinet rather than Profibus.
You show three Profibus slave modules in each controller. Where is the Profibus master?
What is the IC695LRE001 module in slot 16 of each rack connected to?
GE went through several iterations of hot standby redundancy over the years. I'm going to have to do some research to wrap my head around what you have.

 

[mastops]

Hi Steve,

sorry for delayed reply. The module in slot 16 is an extension module to another Base.
We contacted GE (our vendor) and they will be looking into our issue.

Thank you for your support. It's appreciated.

 

[Steve Bailey]

The module in slot 16 is an extension module to another Base.

But the screen capture of the hardware configuration in post #3 doesn't show another base.

 

[mastops]

You are correct. The project file does not show it. It is the only project file that I have found. It is most likely not up to date.
Due to ongoing operations I am not allowed to connect to PLC and upload the latest configuration.

I will make sure that GE takes that backup once they agree to work on it.