Problem with GPIB connected device adress when using more than one card.

[Chamakits]

    I've been working with Labview 7.0 with mostly Keithley instruments.  So far i hadn't had much problem until we started using a second GPIB PCI card.  As most of you know, Labview automatically detects the first GPIB card.  So if you were to connect a device to that card with adress "8", all you have to write in the adress string of the GPIB read(or write) input and it would detect its that device.  On the other hand, if I connect it to the second GPIB card, it doesn't detect it automatically.  I've read around that the syntax for going around this is typing in the adress something like "GPIB1::8::INSTR". 

    I've tried this, not only that, but I've cheked the instruments properties with the program "Measurement and automation" and thats the same thing it says that identifies the device.  Also, if I try "GPIB0::8::INSTR" when its connected to the first GPIB card, it doesn't work either, meaning I must be doing something wrong.  Can some one please help me out.  I know that the information may seem kind of vague, and if so, tell me what other details you need, or I may have said something wrong, but thats what i've understood so far.  If so, correct me please.  Thanks in advance, ask me for any other information I may need to give.

[Dennis_Knutson]

I'm a little confused about your question. You say that you are using the GPIB Write but then you mention GPIB1::8::INSTR which would be the syntax for a VISA Write resource name. Are you using VISA or the GPIB functions? If it's VISA, then the syntaz you mention is correct and if you had it connected to the first card GPIB0::8::INSTR would work as well. If you are really using the GPIB functions, then have you read the on-line help for GPIB Write which says:

When there are multiple GPIB Controllers that LabVIEW can use, a prefix to address string in the form ID:address (or ID: if no address is necessary) determines the Controller that a specific function uses. If a Controller ID is not present, the functions assume Controller (or bus) 0.

LabVIEW doesn't detect any card automatically. It's just that the default for the GPIB Write (and VISA Write for that matter), is controller 0.

You might want to consider switching to VISA in any case. For quite some time, that has been the standard for which all instrument drivers are written with. With a VISA Resource Name control/constant, you can also just pick your instrument from a list. The list is populated from your Scan for Instruments in MAX.

[Chamakits]

Thanks for the instructions about the ID for the GPIB.  I was using GPIB and the syntax was the ID:address (in my case 1:8).  Thanks alot man.  Could you give me the site for that online help that you mentioned.  Thanks in advance, and thanks again.

[Dennis_Knutson]

There is no "site" for the on-line help. It's the LabVIEW help available on your pc. Go to the Help menu in LabVIEW and select Show Context Help or VI, Function & How-To Help, or on the diagram, right click on any function and select "Help".

You should have context help turned on just about all of the time when you are programming.

You should also think about switching to VISA.