difference in gpib read/write

[wv]

I put together a simple GPIB read and write in my LabVIEW 7.1 and sent a *IDN? to my instrument. I get nothing but an error code 3. I downloaded Identyfy gpib[1] from this website and it works. I deleted everything else but the read, write, time out and address just like the vi I built my self, it still works and I get a result back. Then I went back to my own VI and reset the instrument but it does not work. Are there different GPIB read and writes?
NI-MAX 488.2 communicator works too.

Thanks,
WV

[Dennis_Knutson]

There are 3 different ways to do GPIB communication. There is the GPIB Read/Write on the Instrument I/O>GPIB palette, Send/Receive on the Instrument I/O>GPIB>GPIB 488.2 palette, and VISA REad/Write on the Instrument I/O>VISA palette. I personally prefer to use VISA but they should all work about the same. You can easily try VISA by dropping an Instrument Resource Name control (I/O palette) on the front panel and wiring it to a VISA Write function. Right click on the arrow on the right side of the control to view all VISA resources. It should list your GPIB instrument along with com and printer ports.

I can't say that I've ever gotten that error ("GPIB Controller not addressed correctly"), and I'm not sure what could cause it. Is the gpib controller set for address 0 and is it the only controller in the system? Is it an NI controller? What's the address of the instrument? Maybe you could post the VI that you wrote with all the values you're using set to the controls default values.

[wv]

I tried to repeat the same thing this morning, with no luck. It seems to work today. Yesterday it looked like I had an older version of the GPIB Read/write function.

Thanks for your comments Dennis.