[joshxdr]

I am making a simple control API for a piece of equipment that has a GPIB port. I am trying to decide to use VISA or GPIB. My understanding is the only advantage to VISA is that you don't need to rewrite your code if you use the same API for serial or GPIB. Is there any other benefit to using VISA? I will never use serial communication for this project.

[Mark Yedinak]

VISA is the recommend solution because it is the current technology and it is the supported method for communications. GPIB is the older technology and while supported it is not actively being worked on (new features). Also, you never know when you will need to use some other communications interface. At the moment you may only need GPIB but if this application lives on it may need to use other interfaces in the future. (Think you equipment dies and the only option is to replace it with something that doesn't have GPIB. Most new equipment use USB or Ethernet these days.)

[crelf]

I don't think there's much extra work implementing in VISA than raw GPIB, so I'd go for VISA. That's said, it's been a while since I've used raw GPIB. Also, there are a handful of oddities with each physical layer, so your application *might* require you to use GPIB only, but those oddities are very very rare, and VISA does have GPIB-specific properties, so you should be good.

[ChrisClark]

A while ago I heard that the GPIB primitives now are wrappers around VISA functions anyway. You could check out ni.com/idnet for instrument driver-y development info and style.
cc

[rolfk]

ChrisClark, on 08 March 2010 - 05:59 PM, said:

A while ago I heard that the GPIB primitives now are wrappers around VISA functions anyway. You could check out ni.com/idnet for instrument driver-y development info and style.
cc

Not sure about LV2009 but until 8.6 they clearly went straight to the ni488.dll It wouldn't make much sense anyhow since the VISA interface eventually calls into the ni488.dll anyhow for GPIB devices.

But learning VISA is definitely easier than the GPIB primitives and also more useful as you can use it for all other instrument communication too, if you ever happen to need it. The special GPIB features mentioned earlier are almost all also available through VISA and really only used for either very old or somehow non-compliant GPIB devices.

[crelf]

rolfk, on 10 March 2010 - 07:55 AM, said:

The special GPIB features mentioned earlier are almost all also available through VISA and really only used for either very old or somehow non-compliant GPIB devices.

Exactly. Bottom line: go with VISA.