working with GPIB device

[Gaudier]

How do I work with a GPIB device and LabVIEW to see a current vs. voltage graph?
Were do I find the GPIB in LabVIEW and how do I use it?
Were can I find LabVIEW examples with GPIB?

[Dennis_Knutson]

The first thing you should do is try to find drivers for the instruments you're using here. Also, check the link "What is an Instrument Driver" so you know how to use any driver you download. Most drivers come with examples on how to use the functions in the driver. LabVIEW 7 and above also has the Instrument I/O Assistant to hlpe you communicate with an instrument if it doesn't have a driver. Look for low level functions on the Instrument I/O palette. You can use either VISA (preferred) or GPIB functions.

[LuI]

Zurdo,

Dennis answered the device & driver related side of your Q. There are still some other parts open.
Your first starting point for examples should be the example finder, found in LabVIEWs help menu. Search it for 'GPIB' and see if you can find anything.
As for your 'current vs. voltage graph' Q, you first need some data points I(U), that must be acquired using your device and hopefully its driver. WHen you have it, build an array of it and send this to an XY-graph or chart. Search the example finder for 'graph' and/or 'chart' to find examples on how to use those and for the difference between charts and graphs.

HTH and Greetings from Germany!
--
Uwe

[Gaudier]

I found the Instrument I/O Assistant, Im trying to communicate with a Keithley 2400.The instrument returns a timeout error. What does that mean?

[Dennis_Knutson]

You're using GPIB and you've entered the correct address of the card? In the box "Select an Instrument", you should have selected something like "GPIB0::number" where number is the GPIB address of the instrument. If that's correct, what step are you running? Is Query and Parse, Write, Read and Parse? What is the actual command you're sending? In MAX (Measurement & Automation Explorer), if you click the GPIB card listed under Devices and Interfaces and select Scan for Instruments, is the 2400 detected?

The timeout error usually means that you've requested data but there was no data returned. All of the questions I ask above is to help determine why you're seeing this error.

[Gaudier]

In the box "Select an Instrument",I selected Gpib::24::instr, Im running Query and Parse, the command Im sending is ” *rts “ to restore GPIB defaults, an error comes out that say “Timeout expired before operation completed. VISA status code :bfff0015” And the 2400 say “ error ID code : - 420”. I send the command ” :SOUR:FUNC VOLT “ to select voltage source function and the sama error comes out. Pluss “ error ID code : -113 undefined heather “.
If I click the GPIB card listed under Devices and Interfaces and select Scan for Instruments, the 2400 is detected.

The output on command works, and some others, but they show the same error.
How could I fix this?

[Dennis_Knutson]

When you do a query, that means you are requesting data back from the instrument. The instrument I/O Assistant will issue the command you specify (VISA Write), do a VISA Read, and then parse out the repsonse. In order for this to work, you actually have to issue a command that tells the instrument to return something. Instruments that use the SCPI protocol like yours, expect a "?" at the end of a request data command like :MEAS:VOLTS?. Instead of doing a Query and Parse, just try a Write.

[Gaudier]

Thanks! I can see the graph I wanted on the front panel. Instead of doing a Query and Parse, I just tried a Write. The instrument I/O Assistant did not showed error, but when I RUN the front panel the 2400 “beeped” and LabVIEW said “Error, time out expired before operation completed.”. Then I hit the “continue” option and had a good graph and good numbers on the front panel.

What does this error means?

[Gaudier]

I have the 2400 keithley driver , how do I use it?  

How do I get some data points for a  'current vs. voltage graph'?

How do I build an array of it and send this to an XY-graph ?

Greetings from Puerto Rico !

Adios!