Labview GPIB connection.

[ninskaya]

Hi, I would like to open a Labview window to see data from a scope (Scope Explorer) through GPIB. I have been using the attached vi which then gives me an "old VISA open" error message. Do I have to open a special VISA connection?

Thanks,
Ninskaya

[Dennis_Knutson]

An HP34401A instrument driver will not work for a LeCroy scope. I don't know why the driver uses the old VISA Open function but that's the only thing that should work in the driver assuming that you have the correct address. Do a scan for instruments in MAX to verify the address or check the scope's menu.

[ninskaya]

I have mailed this question to Dennis Knutson.

[ninskaya]

Thanks, I have already verified the GPIB address with Max so I don't know why I receive that old VISA Open error message.

Ninskaya

[Zaw]

Hello everyone,

can somebody tell me, how do i check for correct GPIB address for the equipment that i am about to control?

what if i select for wrong GPIB address and doesn't know it, how can i check it to prevent?

Thanks & Regards,

Zaw

[Dennis_Knutson]

I answered that above. You open MAX, expand Devices and Interfaces, right click on the GPIB board, and select Scan for Instruments. Assuming a modern instrument, it will respond to a *IDN? query and provide some information about itself.

You should be using VISA to communicate to your instruments and it's easy to select the correct address. The VISA Resource Name control has a little arrow on the right side. Click on the that and you will get a list of valid resources. Pick the instrument you want.

[Zaw]

Yes, I understand what you have explained. What i mean is that if I click on the scroll down menu, there is list of GPIB address. Then, from that list, i have chosen the wrong GPIB address from the list for the equipment that i want to control. So, for that, how can i make a warning or alert to the user from the program that the user have chosen for the wrong GPIB address for the equipment that the user want to control? That what i meant. So how can i program for that? Thanks.

Thanks & Regards,

Zaw

[Dennis_Knutson]

There are a couple of ways you can do that. Assuming that you have a value change event on the VISA Resource Name, do a  *IDN? on the chosen instrument. If the query doesn't match what you expect, make them change the resource. You can also make it easy to pick the correct instrument by assigning an alias to each instrument. You can give each one a more descriptive name such as Scope, DMM, Counter, etc. You assign an alias in MAX. You can right click on one of the instruments listed and select 'Rename', or on the VISA Properties page to the right, enter the alias and click the save button on top.

[Zaw]

yup. thanks you so much your help. i am working on it now. thanks alot

Thanks & Regards,

Zaw