problem with transfering data from multi RT (CVS) through DataSocket

[Little Bird]

Hello Everyone,

I am trying to transfer data from multi RT (10 CVS, Compact Vision System) to one host machine though Datasocket. The datasocket server is running on the host machine.

Now my problem is the datasocket operation goes very slow on the RT (Open datasocket and Write datasocket) and gives error 63 or error 56. I think maybe the datasocket server is too busy to communicate with RT, so I set the time out as -1. Theoretically the Open and Write Datasocket operation should wait forever to finish. However, it does not help at all. I still only get data from 7 RT and lose others.

I don’t know why. By the way we use Labview 7.1.1.


Thanks a lot for any input.



Anne

[Ricardo_SR]

Hello,

Check if you have any problems in the network like collisions. About the time out error, even if you specify -1, since it uses in the end the Ethernet protocol, all server client connections cannot last too much time without packets coming and going. You might want to try using TCP communication, but I really think the problem could be somewhere in your network. If you use a crossover cable, will it improve the performance?

Ricardo S.
National Instruments

[Little Bird]

I choose to use Datasocket because I need to buffer data. With TCP, I have to take care it by myself.


Unfortuantely, I could not change to crossover cable because I have 10 RT.


More ideas?

Anne

[Johnner]

Anne,

I agree with Ricardo that you may have a lower-level network configuration issue that is masquerading as a DataSocket problem (maybe DNS is configured incorrectly on some of the machines, or maybe there are protocols or protocol options enabled that are not appropriate, etc.).

Even if you don't intend to use the lower-level TCP functions for your final product, you might want to create a quick test app that does a basic client/server communication among the machines in question. If you still see slow behavior in that case, then you can be certain that DataSocket is not your problem, and you can take a closer look at the network configuration issue.

Regards,
John

[Little Bird]

Now my system is up and running happily.

I put very long timeout setting and trap errors (56 and 63) and warnings (1182).

It still takes time (more than a minute) to establish all the DS connections. (10 clients and 2 DS connections for each.)

As soon as they are established, everything seems OK.




Before it did not work because I did not trap warning 1182. Aactually it should be an error instead of warning because it caused the program working incorrectly, especially for multi clients cases.


Thanks a lot for your help and suggestions.

Anne