GPIB communication Problem

[DaveC]

Hi All,

I am attempting to connect to an instrument using the GPIB/GPIB 488.2 library.  I have previously connected to this instrument using VISA but now I must switch to GPIB library instead.  My problem is that I am not able to get any GPIB connection commands to work.  I have tried the gpib sample "gpibrw.cws" and have found that an error occurs on the "ibdev" command (-1 is returned for the device handle), which is the same as I see in my code.  I am 100% sure I am using the correct address/slot because as I said before I have no problems communicating over VISA. 

My only thought on the problem is that I am using an agilent 82357A USB/GPIB interface between the instrument and my desktop.  However, if this is the problem, I don't know what exactly to do in order to fix it.  I know in VISA I had to turn on the tulip.dll in order for this to work, but I don't know if there is anything analogous that needs to happen with the GPIB library.

Using:

Labwindows/CVI 7.0

Windows XP SP2

[LoganS]

In general, you must use VISA with Agilent. The GPIB functions that I'm assuming you are referring to reference the GPIB-32.DLL, which is an NI-DLL, and calling into it is calling into the NI driver (which only works with NI cards).  Why are you moving from VISA to GPIB?  What additional functionality are you trying to get?  Also, what exactly is the error that you are getting?  Is it just the fact that you are getting a -1 for a device descriptor? Do you have access to an NI-GPIB interface?

Logan S.

[DaveC]

Hi Logan,

Thanks for your reply.  I actually just fixed this problem not too long ago.  I do have access to a PCI GPIB card, and I was able to get my GPIB calls working using that.  The reason that I am switching to GPIB is because I must connect to a computer remotely over a network that is accessing a GPIB device.  This computer does not have the VISA drivers installed onto it, but does have the gpib-32.dll that you mentioned before.  I don't really get any additional functionality, and I don't get the robustness of VISA either, quite unfortunately, but this is the only option I have available at the moment.  This computer is basically a black box to me and I am unable to install the VISA drivers, I can only copy .dll files piecemail and from what I have read in other discussions on this forum, installing a VISA driver is not as simple as copying a few .dll files into the correct directories, it also requires editing the registry, and I don't have the ability to do that.