LabVIEW, GPIB-USB-HS

[AM33]

My LabVIEW program hangs up on one of my Read GPIB steps which causes the active light to go out. From there I get no usable data. Any ideas?

[Emily-C]

Hi AM33,

Could you please give more details on your application:

What device are you connecting to?

Does Read GPIB work at other parts of your program?

Which active light are you referring to?

What happens when it hangs up? Do you get an error?

You say you get no usable data. Are you not getting any data at all, or are you getting incorrect data?

The more information you can provide, the easier it will be to help narrow down what's going wrong.

Thanks! 

[AM33]

Hello Emily,

Thank you for the reply and questions. I have the questions answered in the order presented:

1) For the failed step, I am connected to an O-scope. Although, I am also connected to a Lock-in for other steps as I am taking homodyne measurements.

2) Yes, there are two Read GPIB steps, it only fails the last one

3) When it hangs up, I get an error and the light dilluminates

4) I have two graphs on the Front Panel: there is a lock-in graph, and an O-scope graph. The O-scope gives me a flat-line

I suspect that either the second Read GPIB is not getting the correct information from the Write GPIB or the O-scope. Thank you again for the reply.

[billko]

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@AM33 wrote:

Hello Emily,

Thank you for the reply and questions. I have the questions answered in the order presented:

1) For the failed step, I am connected to an O-scope. Although, I am also connected to a Lock-in for other steps as I am taking homodyne measurements.

2) Yes, there are two Read GPIB steps, it only fails the last one

3) When it hangs up, I get an error and the light dilluminates

4) I have two graphs on the Front Panel: there is a lock-in graph, and an O-scope graph. The O-scope gives me a flat-line

I suspect that either the second Read GPIB is not getting the correct information from the Write GPIB or the O-scope. Thank you again for the reply.

---

Does the equipment being read stream data, or do you need to send a command?  If you need to send a command and you have two reads, the second one will never get anything to read.  (This is assuming you are trying to read twice from the same equipment.)

It would be helpful to see the code, too.

[AM33]

I will send the vi once I get back to the lab. I am unfortunately not in a position to do that at this moment.

[AM33]

I am sorry that it took so long and I appreciate the assistance. I unfortunately had my GPIB "borrowed" by a fellow lab member. Rather than taking turns, I decided to use a different GPIB. However I have attached the vi code if you still want to look at it.

[Emily-C]

Hi AM33,

From looking at  your code, it seems like you mean it's the :meas:vav? command that's not getting results read back. Can you please clarify what you mean when you say it "hangs"? Does this step ever work, then stop working at some point during execution? Please post a screenshot of the error you see when it hangs up.

I'll still need more information to help you troubleshoot this issue. Can you please give me as much information as you can on the overall behavior?  Please try to clarify what works originally, when something stops working, and what behavior you see once something stops working.

If the :meas:vav? results are never being read back, please try taking that section out of the rest of the program and try running it on its own to see if you can ever collect that data.

Thanks!

[AM33]

Hello Emily,

Unfortunately, I cannot take a screen shot as the GPIB-HS has been "borrowed" by a fellow lab member and will be getting used for doctorial research.

The second read GPIB step does not ever work. The GPIB "Active" LED illuminates during execution, but eventually goes out before the execution of the entire program has cycled through one time. After this occurs, I get a straightline (0 mV) on my graph. 

I am now using a Prologix GPIB. The problem that I am having with that is that I am getting a straight line on my Lock-in and Multimeter (Oscope) graphs. Another problem is that the GPIB only reads for a short amount of time. This causes me to restart the program frequently to get a respectable amount of data. However, all that I am getting at this time is a straight line anyway. Should I close this discussion as solved and start a new one, or should I continue here? I have attached the vi to this message in the event that it would be useful. Also, if it is useful, I have error code 1073676294. Since the straightline data seems to be a problem with both GPIB's, I may also look into checking the recency of the windows updates as the internet is not connected on that computer.  

Thank you very much for your help so far.  I will try to apply your suggestion to the Prologix suggestions.

[Emily-C]

Hi AM33,

Once you have your GPIB-HS back, please try running the write and read commands separately from the rest of the program and see if you can collect valid data. As well, please get a screenshot of the error you are seeing. 

I can continue to help you here, but if you have a new issue with your Prologix you may get more responses creating a new thread as well. 

Thanks,

[AM33]

Will do. Thank you