session handle lost

[uhernand]

HI

I have a system developed in LabVIEW that controls at the same time different equipments: DMM, Fgen, Scope, PowerSupply and a Switch Matrix. The complete system works without problem, but sometimes, and I don't not why some instruments lost the session. For exaple, the last error was:

Error Code: -1074130544

Error Source: IviDmm Ivi Error Converter.vi

The session handle is not valid

The only one way to go over the error is closing the LabView and restart the system.... 

Why does this error happen?

How can I solve it withour stopping and restarting the whole system?

thanks

[crossrulz]

The only times I have seen this is when an instrument reset happens, typically be the software.

[uhernand]

But in our case, the instrument is always on and no one resets it.....

[nyc_(is_out_of_here)]

Instruments connected via USB?

[uhernand]

No, all the instruments are connected to the server through a LXI net

[CrisMH]

This error can also occur if you have more than one Initialize VI in your program. Only one session can be opened to your instrument at a time, so multiple Intialize VIs will produce this error. For example, if you use the Getting Started VI and then place an Initialize VI in your program, the additional session handle will be invalid.

Is it possible that you have more than one initialization happening at the same time?

[uhernand]

HI!

thank for the response!

No, I only have one initialization per instrument. The tricky thing is that only happen sometimes... I mean, it is not error that always happen... and I can not trace what is the origin of lossing the session..

Thanks!

[CrisMH]

Ok, Let's see...

The thing is that I need more information to help you finding out what is happenning. What is exactly what you want to do with the instruments ? Are you using NI-SCOPE Express VI's or NI-SCOPE API?

[uhernand]

Hi

1first of all, thank you for your help and interest 🙂

What we have is a instrumentation system with: scope, Fgen, DMM, PowerDC and a Swithc Matrix.

All the instruments are controlled by IVI drivers. That is, in the algorithm that control each one of the instrumets all th functions are IVIDmm, IVIScope, etc..

When the system is started, all of them are initialized obtaining their Session Handle that is used as input in all the IVIxxx funtions...

I don't know If I can send you any screenshot or similar... it is a quite complex system...

[CrisMH]

Yes, maybe is a good idea that you send me the VIs or make some screenshots. If you upload them it'll be very usefull