VISA Closes deletes termination character?

[ehrlich]

I am currently working on a remote control of a laser using VISA and the actor framework. My Actor (basically an object) holds a VISA address and upon startup the termination character in a "Configure.vi" (see attachement). The object is then passed on and the first query always works but all subsequent ones fail, reason beeing that the termination character is reset from 13 to 10.

Also in the attachements is how I currently send my commands to the VISA device. I just write the command, read some data back (it shouldn't really read 256 bytes but that is why I use the termination character) and close the VISA session. So does one of these steps reset the termination character setting of the VISA device? Note that I do not store the VISA address back so I would expect it to be a copy of the one stored in my object. So even if something would change its settings, that should not affect the origial one. But I am clearly missing something here.

[Albert.Geven]

Simply

only close the visa session when you leave the program, not every call.

Closing means stop that reference (including the reference to the endchar) and open the next time a new reference.

[crossrulz]

Closing the reference resets the settings.  You should only open the session once at the beginning of your program and only close it at the end.  This is a good practice for all references.

[ehrlich]

Thank you for the clearification. I thought it would be cleaner to close the session after each request. Learning every day!

[SnowMule]

Opening/closing a ton of references leaks a bit of memory too... code's more efficient if you create the reference on init and just pass that around.