Is it possible to see GPIB traffic as caused byVISA commands?

[reddish]

Hi all,

Is it possible to snoop the GPIB traffic generated when controlling GPIB via the VISA library?

In particular, I would be interested to see the exact sequence of GPIB commands that are sent when a viAssertTrigger() is sent to a particular GPIB device.

The "NI IO Trace" utility shows the traffic in terms of VISA calls, but I want to dig deeper.

[Dennis_Knutson]

Since the VISA commands are the GPIB traffic, I'm not sure what you are looking for. To see the lowest level bus traffic, you would need a bus analyzer. NI has these and are noted with a + on the product page.

[reddish]

> Since the VISA commands are the GPIB traffic[...]

But, they are not - the VISA commands are an abstraction around the actual GPIB commands. E.g. a viAssertTrigger will translate to a small number of GPIB command bytes, including the command to make the target device a Listener, and the GET command to execute the trigger (and probably a few more).

> To see the lowest level bus traffic, you would need a bus analyzer. 

I am hoping for a software-only solution. In principe this is quite possible, the question is whether the NI VISA implementation supports it.

[Dennis_Knutson]

To view the actual command bytes, you need the analyzer. This would be true even if you used GPIB calls instead of VISA. The GPIB functions are also an abstraction to all of the bus traffic such as the handshaking.