LabVIEW RT 2009 - Ethernet connection

[plessnick]

Hello,

I have updated a LabVIEW RT 8.5 application running on PXI-8106 chassis to LabVIEW RT 2009 .  The application is using ethernet to connect to remote display panels and Ethernet modbus to exchange information with a PLC.  The application is monitoring the number of Modbus connection using the "MB Ethernet Connection Manager.vi".

Since the update, the number of connections (1 by default) is often 2 or 0 for about 100 ms and I'm also getting more errors "56" with my displays.

Does default Ethernet parameters in LabvIEW RT 2009 changed?  Has something changed in Farlaps as the "drop ethernet connection timeout" is normally related with the system.

The application is still working fine in 2009 but the customer is "afraid" with the log file where all these ethernet and modbus stuff are logged.

Thanks,

Patrick 

[Logan_H.]

Patrick,

When it comes to this Error 56 with your FieldPoint, this typically comes from network starvation. There are two usual ways to fix this which are to 1) increase your timeout or 2)increase the sleep time of your time critical loop. A quick reference on this error code can be found in this Knowledge Base.

As for the default settings of the network timeout settings changing between versions of LabVIEW RT, I honestly don't know. No matter though, because we can change them to what we want in the Communication Timeout Settings in MAX.

This Knowledge Base covers a different error code but describes the method we can use to change the Timeout and Connect Timeout settings.

Let us know how things go!

Logan H

[Ben]

Who is the client and who is the server when you get those errors?

What is the CPU usage when the errors occur?

Where did you get the code used for the Modbus protocol running on the RT paltform?

Ben

[plessnick]

Hello Ben,

We are using the NI Modbus 1.1 (I'm not quite sure about the version, I will verify on Thursday when going back to thge office).

The application is slave for all connections 

The error 56 between the PXI and the display panels were on my side and were probably there since the beginning of the project but we are now seeing them now as the last application update was related with improvement in the error management.

However, the Modbus implementation has not changed between the version.  I will comeback again on Thursday with the detail Modbus implementation.

Thanks,

Patrick  

[plessnick]

Hello All,

Sorry for you time everybody.  The customer IT department changed an IP switch the same day we upgraded to LabVIEW 2009.  The network is the cause of the problem. 

Patrick

[plessnick]

It is not the customer network that caused the disconnection issue.  I'm now seeing it at all other sites as soon as the application is updated to 2009 RT. 

I'm planning to add logging functions to the "MB Ethernet Wait on Query.vi" next week to trace the issue.

Patrick