Error 56

[Anil Naidu]

Hi All,

I am building my TCP communication application which will do the following.

From my Visual Basic applicaion i send a TCP command to my LabVIEW RT controller the labview process the command and sends back the results.

I am opening TCP ports and writing the data...In labview i am openings the connections for the same ports and reading the data...whereas the problem is in some ports i am able to read the data from labview but in some ports i am not able to receive the data.

I am setting TCP Read time out parameter to -1 so it has to indefentely wait till it receives the data.

I dont understand why i am not receiving any data in one of the port ??

Kindly let me know if any settings or configurations i have to make.

If anyone have faced a similar kind of problem pls let me know.

-Anil

[ehudson]

Are you sure that the non-working ports are open (i.e. not blocked by a firewall)?

[mikeporter]

Do you have tcp/ip turned on in the program options?

Mike...

[Anil Naidu]

Hi Mike,

Yes TCP/IP option has been enabled in the LV options.
The problem is LV is not able to receive the data which vb has sent. Again if any TCP action(read)takes place then i get my old data and new data. Instantly i am not able to get the data in lv once vb sends it.

-Anil

[Kristi_P]

Hello Anil,

Since you have the RT Development system, can you try running a simple TCP communication example from the LabVIEW host that will communicate with the RT controller?  A good example can be found in Help->Find Examples.  On the Browse tab, go to Toolkits and Modules->Real-Time->Communication->TCP Communication - Host Computer.vi and TCP Communication - RT Engine.vi.  Target LabVIEW to the Real-Time controller and run the RT Engine VI.  Switch execution targets back to Windows (your host) and run the Host Computer VI.  Use these VIs to ensure you can communicate over the ports properly.  If this works for you, the problem must be within your code.

I hope this helps.  If you have more questions, please post a reply.

Regards,

Kristi H

National Instruments