Is there difference between NI VISA and HP VISA?

[Linghui]

Now I am using Labview 5.1 to compile a program for an oscilloscope (HP 54110D), and the cable connecting the instrument with PC is GPIB/USB interface. I tried to run the driver downloaded from NI, but it didn�t work. The driver used GPIB as Instrument I/O in the driver. I decide to use Labview VISA to complete it. I know the oscilloscope supports HP VISA, not GPIB. The Agilent Company suggests using VISA. I am sure that the instrument support HP VISA. I don�t know whether HP instrument support NI VISA? Is there difference between two VISAs

Thanks!

Linghui

[GerdW]

Hello Linghui,

you cannot compare VISA and GPIB. GPIB is the bus system used to communicate (like RS232 or RS485) and VISA is a driver architecture. But you can use VISA to communicate with a device connected via GPIB. And there should be no (big) difference between HP and LV VISA.

Other questions:
Can you communicate with your oscilloscope using your cable with other programs?
I'm not sure that LV5.1 supports USB. Could you check this, as I'm only having LV6.1 to 7.1 on my computer. This may be a reason for not being able to communicate. (From your posting I suspect the cable connects to a GPIB connector at the oscilloscope and an USB connector at the PC.)

Best regards,
GerdW

[Dan_Mondrik]

Linghui:

As Gerd responded, you have a choice of APIs to communicate over GPIB when using LabVIEW - the built-in GPIB (NI-488.2) functions or the VISA functions. VISA is the recommended API for all instrument drivers. But if you have an existing instrument driver for your instrument, just use it, regardless of which API it uses internally.

Which VISA you want really depends on which GPIB controller you have. If the USB-GPIB controller is from NI, then you should have NI-488 and NI-VISA installed. If it is from Agilent, then you should install Agilent I/O Libraries (both SICL and VISA).

LabVIEW will communicate with either version of VISA because they both implement a standard API. That's the whole point. And it doesn't matter from a software per
spective whether the controller and instrument are from the same company.

Also, the fact that the GPIB controller is connected via USB rather than PCI, for example, is actually moot. LabVIEW doesn't know and doesn't care because the program isn't making USB calls, it's making GPIB or VISA calls. It's the lower-level GPIB driver that handles the necessary translations.

I hope this explains things sufficiently.

Dan Mondrik
National Instruments

[Dave B]

Hi Linghui,

NI VISA is a software programming interface for use only with NI hardware.
If you are using an Agilent USB Gpib device the you definitely need to use
HP Visa. The trick is to go into MAX, and up top, select Tools>>NI
Visa>>Visa Options. Then Select Passports (My System>>Visa
System>>Passports.
Make sure that "NiVisaTulip.dll" in enabled (box checked). Once you do this,
then the usual LabVIEW Visa VI's will work.

Regards,
Dave
"Linghui" wrote in message
news:50650000000800000005010100-1079395200000@exchange.ni.com...
Now I am using Labview 5.1 to compile a program for an oscilloscope
(HP 54110D), and the cable connecting the instrument with PC is
GPIB/USB interface. I tried to run the driver downloaded from NI, but
it didn't work. The driv
er used GPIB as Instrument I/O in the driver.
I decide to use Labview VISA to complete it. I know the oscilloscope
supports HP VISA, not GPIB. The Agilent Company suggests using VISA. I
am sure that the instrument support HP VISA. I don't know whether HP
instrument support NI VISA? Is there difference between two VISAs

Thanks!

Linghui