how to read current using labview 7.1 from Keithley 2400

[Joycezh]

Hi, All,

I am trying to read current out from labview 7.1. The program I wrote is attached (program.gif). But when I run this program, the error message poped out when it reach the function of GPIB write (error.gif). Can anybody help to point out what's wrong with this program?

Thanks a bunch!

Joyce

[Dennis_Knutson]

Could you provide the information on how you are doing the addressing since that is what the error message is saying is the problem? Obviously we cannot see your front panel.

Is this an NI GPIB controller? Is it the only one? What is it's address.

p.s. When you say you attached code, actually attach code. An image is not code unless it's a png code snippet created in 2009.

[Joycezh]

Hi, Dennis,

Thanks for replying. You reminded me of putting 24, which is the GPIB address of Keithley 2400, in the front panel. Now this error doesn't occur, but it failed when it's trying to scan the result.

I attached the program in this post. I attached the figure because i thought people couldn't open the code if they don't have the right version of LV. 🙂

Thanks,

Joyce

[Dennis_Knutson]

You fail because the have the incorrect format string. You have no format string. No way of telling what is correct. How do you know what is correct? You don't have an indicator to look at the returned string from the GPIB Read. Did you probe the output?

If you want help with this new problem, you will have to provide the exact string that is being returned. One way is to add an indicator like I mentioned. Run the VI, go to edit>Make Current Values Default, save the VI, attach the saved VI.

p.s. It is recomended that you use VISA functions. It makes for portable code.

[Joycezh]

Hi, Dennis,

Here you go. I put the indicator of the output data at the right side of the wavechart.

I want to my wavechart to show the second result only.

Thanks

Joyce

[Dennis_Knutson]

So use a format string of %f,%f. In case you change your mind and want all the data, use %f,%f,%f,%f,%f