What is dup visa session?

[Michelle1892773]

I have seen that many subVI of instrument company has this icon:

And not has the icon to close connection. It's correct to put this icon "dup visa session" and don't close the session? Can explain what is the meaning?

[dan_u]

When talking to instruments you usually open a connection, then use several VIs to talk to it, and at the end you close the connection. You don't close the connection after each command. Read/Write operations for instance don't (and should not!) close the VISA session. They return the VISA session (the same as you wire to the input, that's why it's called dup(licate)) so you can wire them up nicely (data flow wiring).

[Michelle1892773]

I have understand only the first part. After dup visa session I can't link the fire to an other fire... in what sense you tell that I can wire up? If I must to link this wire to an other Icont to write for exampe.. why I put dup Visa? Maybe if I use a subVI... or in a loop?

[dan_u]

How about something like that?

This is not real code, it's just to illustrate what I meant by wiring the VISA dup session to the next function.

[reikira]

Hi Michelle,

you have the DUP indicator because you are inside a subVI, so you need the indicator in order to connect it in the connector pane. In this way you can set an output for your subVI and use that output to pass the DUP wire to next VIs.

If you need further details about creating and connecting subVIs, you can have a look at this link and this one.

Best regards,

Serena

[Mehdizeinali]

I have started to work by a device from Rohed-Schwarz company(AMIQ). I want to generate my own signal and send it to the device. but all of device function has dup visa session type. it is different than my input , output signals type. so I cuold not to connect them to device function box. could you tell me how can I make addoptive function box by dup visa sesssion input output ??