Error -420 Query UNTERMINATED (from USBTMC)

[Yang91]

Hi, I am using Labview to control a Keithley 2450 to make I-V measurements.

Right now I'm having trouble connecting the Keithley with Labview. I get the the error message: Error -420 Query UNTERMINATED (from USBTMC) and Error -111 Header separator error.

I'm wondering what to do to solve this problem.

Thanks!

Yang

[billko]

This is not a LabVIEW error.  (It's not a Keithley error, either - it's a SCPI error).

Check out this useful link: http://www.keithley.com/data?asset=4072

[Dennis_Knutson]

You have said of you are using the driver from Keithley and if you are, which one. If you aren't, you have not provided your code or even the command you are sending. It's hard to provide a solution with so little information.

[Yang91]

Hi Bill,

Thanks for the advice. I look into those solutions but I can not get an idea out of that.

I just downloaded the Labview and connected a Keithley 2450 with the computer through a USB.

I downloaded the driver for Labview of Keithley 2450 from the Keithley website and it is version 2013.

I have not written any scripts so I can not read those solutions as they are about something wrong in scripts.

So I am really looking for some step by step tutorial to make them communicate.

Thank you again!

Best,

Yang Lu

[Yang91]

Hi Dennis.

Thanks for the responding.

I just downloaded the Labview and connected a Keithley 2450 with the computer through a USB.

I downloaded the driver for Labview of Keithley 2450 from the Keithley website and it is version 2013

Thank you agian.

Best,

Yang Lu

[Dennis_Knutson]

And what functions are you calling? Can you attach a snippet? A snippet is a special type of image. Read the help to learn how to create one.

[Yang91]

Hi DennIs,

I loaded the project from the driver and ran an example program.

It can find the instrument but has the error in communicating with that instrument.

Thank you!

Yang Lu

[Dennis_Knutson]

You did not attach a snippet.

Open the Configure Measurement function and probe the VISA Resource into the Error Query function. See if this is valid. Note that this is a different error than what you said previously. Did you edit the VI?

[Yang91]

Oh, I want to explain that. When I try to connect the Keithley with the Labview, I first tried to use a software, which comes with Keithley, Test Script Builder. This software has a direct button of connecting the instrument. And when I click the button, the errors I mentioned before were prompted out on the Keithley screen. And the software delivered a message said that it failed to connect to the Keithley.

Then I turned into Labview, and after I installed the drive, I chose a example program to run but the error prompted out and there is no reaction on Keithley which makes me doubt that the instrument is still not connected properly.

And I saw the messages are similar so I just attached the message.

I am going to try your advice right now.

Thank you

Yang

[Dennis_Knutson]

Let's take a step backwards. Is the instrument visible in MAX? When you ran the VI, did you select it from the VISA resource name pull-down menu? What version of NI-VISA did you install?