instrument i/o assistant

[gpib_user]

As a new user to 7.1 :
I would like to use the assistant for gpib comm to my
power supply. I can successfully communicate (ie I can read/write & parse). However for my vi, I would like to make a front text control to be able to send commands. When I place the i/o assistant, only the output tokens show up, no text controls even though I have issued a write command. It does not matter if I generate visa or gpib code (on the pull down), no inputs show up.

[Dennis_Knutson]

The I/O Assistant is not capable of accepting inputs. There are a couple options that you have.

One is to convert the assistant in a normal VI by right click on it and selecting Open Front Panel. You can then modify it to add a control wired to the connector and then use that.

The second option will take a bit more work but I think might pay off in the long run. What you can do is leverage your knowledge of the instrument and commands a create a true LabVIEW instrument driver. There a couple of links on the on how to develop one. The advantage of a driver is that it's more flexible and portable. If you then go ahead and submit it to NI, others can benefit from your e
ffort.

p.s. I'm assuming you've already checked for the existance of a driver at the site above.

[JoshuaP]

This happens to be one of the limitations of the IO assistant. In order to over come this limitation you can convert the assistant into a VI by right clicking on the assistant and selecting Open Front Panel. Then open up the VI and change the constant to a control. They you can add the control as an input to the vi and then save the sub-VI. Note that once you do this you can no longer double click on the assistant to open it back up. Attached is a VI that I converted. You can place it on your block diagram to see what I mean. Then you can try to conver yours so that it looks similar.

I hope this helps out.

-Josh

[gpib_user]

Dennis & Joshua : Thanks for your responses. I was able to just change a token output to a control input
to accomplish the simple task at hand. I have much gradeur plans of writing a driver utilizing some Visa functions, but this gets me started. Thanks!

[TommyTestBoy]

As Dennis and Josh mentioned, the I/O Assistant is not capable of taking inputs in the current version. We are working on this, and realize it is a limitation of the Assistant. It will be able to accept inputs and format them into commands in a future version of the I/O Assistant.

-Tommy

[LiewSC]

Tommy,

I'm using Labview 8 and very new to it. For this version, can the I/O Assistant capable of taking inputs?

[Dennis_Knutson]

Yes.

[LiewSC]

How can I give command and wire the command to Instrument IO assistant without change it to VI?

[TommyTestBoy]

Add a Write step to your Instrument I/O Assistant task, and select "Add Parameter".  You can select the data type for the input parameter to the Express VI.  Now when you hit OK, that input parameter will be an input to your VI.  When you pass in a value at run time, it is formatted into the command string and sent to the instrument.

-Tommy

[LiewSC]

Thanks for the clear instruction, Tommy.