R&S SMT signal Generator locksup when Labview triggers a frequency sweep

[stamp41]

I'm interfacing Labview to a R&S SMT signal Generator via the GPIB bus, when i run a frequency sweep, the SMT locks up, it won't switch back to local mode and Labview gets a timeout when it tries to talk to it, any ideas what might cause this?

i trigger the sweep and the SMT will perform the sweep, but then it won't respond to anything else when the sweep is completed. i can stop Labview and it won't switch back to Local, and if i try to wtiye to it again with LAbview the write command times out. I'm using Labview 7.1, and a NI PCI-GPIB card

[Brooks W.]

Hi stamp41,
What do you mean when you say the SMT won�t switch back to local mode? Do you mean that it won�t switch back to being a listener on the GPIB bus?

Here are a couple of utilities that you can use to troubleshoot:
1. Go to Measurement and Automation Explorer (MAX) and send the sweep command using the NI-488.2 communicator. You can access the NI-488.2 communicator by going to MAX, right clicking on the GPIB device and choosing communicate with Instrument. This utility will allow you to write commands to the instrument without going through LabVIEW. After the sweep completes try writing another command to the device. This will let us know if LabVIEW is the source of the problem.
2. The other thing you can try is using IBIC to communicate wi
th the device. You will want to read over the following web page (link below) and ultimately what you want to do is write the sweep command to the SMT and then see if you can continue to communicate with it by writing and reading other commands and responses.

http://www.ni.com/support/gpib/max/ibic.htm

Let me know the results. Hope this helps!

Have a great day!
Brooks W.
National Instruments

[stamp41]

Thanks for your help,
what i meant by switching back to local mode, was when i tried to take the SMT out of remote mode and into local control,as in use the SMT's actual physical controls, it would not respond, normally if i push the local button it would instantly switch back to local mode and i would be able to change settings from the SMT itself, and not use the GPIB bus or Labview.

From using MAX i discovered that the device only froze if the command to leave sweep mode came from within a while loop, i made some changes to the code and it is working fine now.
I'm still not sure what exactly was happening with the SMT. The GPIB bus didn't seem to be the problem because after the SMT locked i queried my spectrum Analyzer and got a response, which w
ould leave me to believe that the problem is something within the SMT itself.

Again, thanks for your help