Cannot connect to cFP-2120 via FTP

[volker_sbk]

I am using several cFP-2120 running LV RT 8.2.1 with the FieldPoint drivers version 5.0.1. for process control and data acquisition. All data are logged to a file and broadcasted via network-shared variables. The data files can be downloaded using an external ftp client. Lately, two of our units have been giving me some trouble as I sometimes can not access the cFP2120s via ftp. I can ping the unit on the network though, all programs are still running and I can still access the network-shared variables. Only a reset of the controller seems to solve the issue.

Any pointers would be greatly appreciated.

Volker 

[KHartley]

Volker,

Do the cFP-2120s give an error when you try to connect via ftp? What is the error? Which ftp client are you using? Is anyone else able to access the cFPs besides you? Could someone else be logged into it? Are you able closing the connections safely, or just closing the ftp client?

[volker_sbk]

Thanks for the reply.

Here are some answers to yoru questions.

> Do the cFP-2120s give an error when you try to connect via ftp? What is the error?

The error message is your generic ftp connection error. Using Windows FileExplorer to connect to the cFP, the error reads:

Windows cannot access this folder. Make sure you typed the file name correctly and that you have permission to access the folder. Details: The connection with teh server was reset."

> Which ftp client are you using?

We have tried Filezilla, Windows FileExplorer etc. with the same result. No connection to the cFP is possible once the it stops responding. 

> Is anyone else able to access the cFPs besides you? Could someone else be logged into it?

The access to the cFPs is not restricted. However, in order to rule out any networking issues we ended up having someone hook directly into the affected cFP with an Ethernet cross-over cable giving the connected laptop a static IP address on the same subnet as the cFP, unfortunately with the same result.  

> Are you able closing the connections safely, or just closing the ftp client?

Typically just closing the ftp client.

Volker

[KHartley]

Volker,

Can you only connect one time after you reset and it stops working if you try to reconnect shortly there after or does it work for awhile and then eventually it stops working? Are you using the controller to perform any other tcp communications with an other servers, besides the network shared variables? 

Whats your memory usage on the cFP? Do you have the System State Publisher software loaded? Try connecting with DSM and see how much CPU and Memory usage you are using.

Can you check the timeouts in MAX to make sure they didn't get changed? Right click on the cFP and select Communication Timeout Settings. From stock they should be 15000 ms.

Are these cFP dedicated to just this one task or are they reconfigured from time to time?

[volker_sbk]

Kyle,

Thanks again for contributing.

> Can you only connect one time after you reset and it stops working if you try to reconnect shortly there after or does it work for awhile and then eventually it stops working?

After we reset the controller it seems to always work for awhile before it stops working again.

> Are you using the controller to perform any other tcp communications with an other servers, besides the network shared variables? 

Our system is configured as a slave on a Modbus TCP network and is queried typically once a minute.

> Whats your memory usage on the cFP? Do you have the System State Publisher software loaded? Try connecting with DSM and see how much CPU and Memory usage you are using.

No, I havent done this yet. I think this was instroduced with LV8.6? I just upgraded to the latest LV version and will investigate. This will take a week though.

> Can you check the timeouts in MAX to make sure they didn't get changed? Right click on the cFP and select Communication Timeout Settings. From stock they should be 15000 ms.

The timeout in MAX is still 15000ms.

> Are these cFP dedicated to just this one task or are they reconfigured from time to time?

We only reconfigure these units when we upgrade the software. This has been less frequent lately and happens maybe once a year.

All the best,

Volker

[Wayne.C]

I've seen a very similar issue with a cFP that runs standalone for long periods of time.  Application does not use any Shared Variables.  The FTP server on the cFP stops running.  You can ping the IP and that's it.  All other functions including the remote front panel continue to run normally.  Just can't get my data files via FTP. 

Suspect that the FTP runs at a lower priority and gets shutdown during some period of high resource utilization.

[KHartley]

Volker,

Like Wayne.C suggested, the network traffic runs at a lower priority so please check the resource utilization when you first start your deployment then monitor it when the device stops working. If memory usage is up too high around >90% that could be the cause. Make sure your code doesn't have any open references. Make sure you're not reallocating arrays everytime you read in values.

Please let me know if you're still having issues.