NI-VISA is not detecting my LXI instrument????

[IVI]

hi,

 we are using NI-visa resource find to detect all the instrument connected to our station,

 but it is not detecting the LXI instruments in the LAN!!!

 We used NI-MAX to configure the new LXI device and then it was listed in MAX explorer.

 NI-VISA resoursefind is detecting the LXI instrument after doing this.

 why does it happen???

 do i need to configure in NI-max every time i add a new LXI instrument to get detected in NI-VISA resourcefind???

thanks

bharathi

[JoshuaP]

Yes, you need to us MAX to find your LXI devices before NI-VISA will be able to see them.  NI-VISA does not search for LXI devices when viFind is called.  If it did the call would be 100 times slower.  If you know the IP of your instrument you can manually enter it in the VISA resource string and NI-VISA will try to open it.  However, if you want the resource to show up in the LabVIEW control you will have to add it in MAX first.

-Josh

[IVI]

hi, thanks a million for ur reply.

is there any other means to find LXI instruments programatically???

does NI support any API's to do this???

thanks

bharathi

[JoshuaP]

Currently there isn't a way to programmatically find LXI devices, but NI does provide an example how to programmatically add them if you know the IP address.

http://zone.ni.com/devzone/cda/epd/p/id/4161

Note that you may need to modify the example to point to the location of your visaconf.ini file.  I would also suggest filing a product suggestion on the ability to programmatically find them.  Also can you elaborate on why you want to be able to programmatically find them and why adding them in MAX doesn't work for your application.

-Josh

[IVI]

thanks for ur reply,

[IVI]

We need a way to detect all kind of instrumens like LXI,PXI,GPIB etc,

for all these we planned to use NI-VISA COM in .net environment which can detect all kind of instruments except LXI.

hence we thought of maintain a uniformity to detect all the kinds of instruments including LXI,rather user need to start NI-MAX and find LXI resourses.

hence we searched for a API (hope VXI-11 Server)which can do this detection.

thanks

bharathi

[Makoto]

As JoshuaP replied, NI-VISA does not search for LXI/VXI-11 instrument at runtime when you call viFindRsrc() or viOpen().  This is because network devices in general may take several seconds to respond.  Instead, NI-VISA requires you to pre-configure all the LXI instruments you will use with NI-MAX.  After configuration, VISA viFindRsrc() and viOpen() will work based on the configured LXI instrument list.

If you want to search for LXI or VXI-11 instruments without NI-VISA or NI-MAX software, the simplest way is directly call SUN ONC RPC.  To use this method, you need send a broadcast packet of RPC's GET_PMAP procedure through the UDP port #111.  The RPC's GET_PMAP procedure (program# 100000, version#2, procedure #3) will take additional parameters of program # 0x0607AF (=VXI11 core program# ), and version #1.  This will search for LXI / VXI-11 compatible instruments.  After that, the hit instruments will respond to this broadcast message with replying the actual mapped port# info.  This method is not so easy for Windows socket programming, but most of VISA implementation must use this or similar approach.

[Dan_Mondrik]

Note that with the latest version of NI-VISA (4.4) we added this feature:

Added automatic detection of LXI (TCP/IP) devices that support the mDNS and DNS-SD technologies.

This will now auto-discover LXI devices that conform to the latest LXI 1.2 spec.

This means you no longer have to manually go into MAX before using it in NI-VISA.

Dan

[FreddyNI]

I have installed ni488281.exe, i.e.  Version 2.8.1

and am using it with Visual Studio 2010 and the .Net support.

Both example projects "FindResources" and "VisaicNS" build/run and detect the lone GPIB power supply I have on the GPIB-HS-USB adapter.

As well, "FindResources" and "VisaicNS" can show the ethernet connected Tekronix DPO3054 LXI oscilloscope if I enter the IP address.

Also from C# code I can retrieve the devices with FindResources:

   var z = NationalInstruments.VisaNS.ResourceManager.GetLocalManager().FindResources("?*");

This will return a array of strings:  "ASRL1::INSTR", "ASRL10::INSTR", "GPIB0::INTFC", "GPIB0::5::INSTR"

But if does not return my TCPIP oscope device.

The MAX utility Add Network Device can Auto Discover the oscope.

What DotNet VisaNS statements/commands do I need to use to Auto Discover like the MAX utility is able to do?

[IVI]

LXI autodiscovery uses a "VXI11" Protocol for discovering instruments.

I hope VISA FindResources wont detect the LXI instruments.

I hope NI-MAX uses VXI-11 protocol implementation for LXI discovery.

but i have seen once the LXI instruments is autodetected and configured in NI-MAX,VISA FindResources detects it.

Thanks

Bharathi