The plant I work at is running Honeywell Experion PKS R410.2 with C200E controllers (yes, I know it’s old). There are two servers running in redundancy - Server A and Server B. Server A is typically primary, and Server B is backup. We typically switch between working on each one via KVM switch.

Electricians wanted to perform a PlantScape backup up on the servers which has been done multiple times in the past. They always start by performing a manual failover from Server A to Server B, so the backup can first be performed on A. During this recent manual failover, we have experienced some connectivity issue that’s not allowing us to see Server A anymore. No backup has been made yet because we didn’t want to go any further until we fixed this issue.

Symptoms:

• From Server B Station, we can make the two servers synchronize on the Redundant Server status screen
• When working on Server A (the faulty one now), we cannot open Station. It is just a blank screen and eventually gives us a warning of “Unable to connect. Not primary host.”
• I can open Configuration Studio on Server A
• When switched to Server B, the Flex Station screen shows Server A is “offline”

What I’ve Done So Far:

• Restarted Experion services (System Repository, Server System, Server Replication, Server Service Framework, StationDisplayService, GCL Name Server, & CDA-SP Service)
• Confirmed I can ping Server A from B, and vise versa
• The classic ‘turn it off and back on again’

We’re currently running with Server B as the main one and no backup redundant server. Anyone have any insight? This is a rather critical issue that I plan on tackling this week.

 

Forgive if this covers items you have checked or know. you may want to check your connection files. On experion systems i have seen all flex stations connect to the primary server which is now the B server since the switchover to B was done. Often a default connection file exists that is configured to look at itself. The file should also have an entry for an alternate file that is configured to look at the B server. the default file is not always configured completely or the file for the backup is not always configured.

 

Forgive if this covers items you have checked or know. you may want to check your connection files. On experion systems i have seen all flex stations connect to the primary server which is now the B server since the switchover to B was done. Often a default connection file exists that is configured to look at itself. The file should also have an entry for an alternate file that is configured to look at the B server. the default file is not always configured completely or the file for the backup is not always configured.

Okay so I'm looking into the Connection Properties and found that I can make Server A (ARKDESTNA), Station #10, function normally if I list the "Server" as "arkdestnb" and make the "Auxiliary Setup File" point to 'default'. I have a feeling this is not correct though.

On Server B (ARKDESTNB), Station #11, it is functioning normally setup the exact same way.

If I change Server A, Station #10, to any other Server name or auxiliary setup file, it will not function normally anymore. Hope that makes sense.

 

Welp....on a whim I decided since the Server Redundancy page was showing Server A & B to both be in sync and operational, I'd perform another manual failover back to Server A. Everything is working as it should now and the System Management Display is showing ARKDESTNA to be online now.

Only issue I'm stuck with is now when I use the KVM switch to swap to Server B, I get that same "Unable to connect. Not primary host" error. I have to go into the Connection Properties window and manually tell it to point to the active server. I've never had to do that in the past so not sure how to correct it.

 

Good show. let’s look at the pictures you posted. First the picture of the A server connection file called default.stn file. It is configured to look at ARKDESTNA Server and uses 10 as the flex station number. But look at the aux setup file name. It is also default.stn. It is the same file. it needs to be a different .stn file that is configured to look at ARKDESTNB as the server. If properly set up when switching from A to B server Station using default.stn file will realize A server is not primary, disconnect from A, try the Aux setup file,and connect to the B server. You will see the name of the stn file used at top of the station window. Look in the client\station directory for a partner file. It could be labeled defaultb.stn configured for B server and station number 10. I would have the files named like ESTN_10A and ESTN_10B

If you have other flex stations you may have example A and B .stn files.

now to your B server station. Server A running as primary. you use the kvm to switch to work on the server B.
You open station trying use defaultB File shown in your second picture. But Server B is not the primary Server Station should see this and try the aux file default.stn that is in the configuration picture. That file should have serverA ARKDESTNA configured. i would suspect the default.stn file on ARKDESTNB was configured with ARKDESTNB as the server. That will work if B is primary but not if A. Don’t know why that file would change. But it is not hard to change if there is access Check the file date.It may trigger memory. These are text files so pulling a copy over and viewing side by side can sometimes help.

couple cautions. make copies of the .stn file if modifying. Cheap recovery insurance for this type of work. Two check the switchover if ever rolling out new configs.