Spying Non-NI GPIB systems

[MarcDub]

I have a customer who would like to get data from a non-NI system that uses GPIB. The system is operational and the customer does not want to (and cannot) change anything on the computer that controls the instrument by GPIB for various reasons. However, he would like to be able to import the data from the instrument by "spying" the GPIB communication. I found that document that says that it is possible using GPIB analyzer. Any idea if it is possible to do it in a manner where the data would be imported within Labview so that the data can be processed, analyzed, and displayed in real time?

[Blokk]

I did something similar a few years ago: I had a very old system (old PC with GPIB ISA card), and we wanted to "spy" the communication between a multimeter and the PC (running a closed source EXE under DOS).

It worked, we were able to get and see the data and command sequences. However we did not try to automatize it, I only recorded some minutes of data using the NI MAX.

I am sure it is possible to use for example the NI-GPIB-HS+ device from NI, and connect to the existing line. After this, you only need to program an application in LabVIEW, which probes the GPIB line and interprets the raw data.

So I only used the NI GPIB Analyzer from MAX, and captured the raw data in ascii file. I would contact an NI engineer to request help how to do the same programmatically...

Maybe someone else in the forum knows a way...?

edit: I would try first to use the low level GPIB functions (I never used these before, since all of my GPIB devices have LV driver...) in order to read raw data from the line. After that you just need to write an interpreter for your very application...

edit2: so the main question is: How to get the same raw data from a LabVIEW application as you can get via the NI GPIB Analyzer?

edit3: it looks like no API for the NI GPIB Analyzer to access it from LV:

http://forums.ni.com/t5/Instrument-Control-GPIB-Serial/What-is-the-best-way-to-monitor-GPIB-bus-acti...

This link suggests a trick how to read the data, but as I understand it can disturbe the existing line if configured wrong...

[Blokk]

or you could try to "hack" the NI GPIB Analyzer 🙂 Maybe via some Windows API you could access the text field of the program to monitor the incoming data real time... or using frequent screenshots + character recognizer 😄 hmm, I think these options are a bit crazy, but once I have seen similar workaround... 😄

(of course these would only work if the real data rate is the same as the screen refresh rate...i guess?...)

[keroba]

Hello there,

According what I researched you can do what are you planning to do, 

Please take a look of this:

Can I share one GPIB device with 2 PCs?

GPIB spying

Regards

[MarcDub]

Thanks for the effort. I will look into this and let you know if I can make it work.

[Dennis_Knutson]

The first link does not seem to apply at all and the second link merely says that the + versions have an analyser capability. There is still no api for the analyser.