About the visa resource name!

[JAN_2000]

Just these days,as a greenhand,I am busy devoloping the labview drivers for a DAQ card,pci-1712,which is made by ADVANTECH CO..

 In MAX, I can see the device,of course,which goes with the excalmatory mark. In labview ,however,I cannot get any information from the visa resource control.Why? 

[Dennis_Knutson]

I'm surprised that it is even displayed in MAX as that is a utility for NI DAQ boards. The board is not listed as a VISA resource because it's not the type of board that would be listed as such as far as I can tell. It seems like it is a DAQ board that competes with NI products and they don't show up as VISA Resources either. They are programmed with NI-DAQ or NI-DAQmx functions. Also, according to http://www.advantech.com/local_inc/search_to_fulltextsearch.asp?id=1002129&keywords=1712&pageid=r&mo..., there is a LabVIEW driver already.

[JAN_2000]

Thanks for your answer!

But I just wanna learn how to devolop  labview drivers with non-NI cards. According to your opinions, there are no possibility to do such a thing,really?

[Dennis_Knutson]

Of course there is a possiblity to develop drivers for non-NI boards. The fact that Advantech has a driver already available proves that it's possible. You just can't configure and test it from MAX. But, just like the LabVIEW drivers are based on calls to the DAQmx dll, your driver would be based on calls into the dll that Advantech provides. It would be possible to create a VISA interface to the board but you would need a lot of details from Advantech on register location and other functionality that they likely won't provide. Have you actually tried the driver that they provide? Is there a problem with it or is this some academic excersise?

[JAN_2000]

Thank you again for your answers!
Yes,I have tried the drivers provided by Advantech many times,both in vc++ and in labview, and met with no problem.
According to NI Application Note 006--Developing a LabVIEW Instrument Driver,and NI Application Note 111--LabVIEW Instrument Driver Standards, however,users  can devolop drivers for non-NI products with only G language. Moreover,in the new edition labview (above 8.0),there is "instrument driver devoloping project" menu newly added, which aims to devolop drivers for non-NI products (All NI products have exist labview drivers ),and many templates are accessible. How to  understand all these?

[Dennis_Knutson]

There is a big difference between instruments and DAQ boards. All of the app notes and documentation you refer to are talking about traditional external instruments. These are instruments that are connected via GPIB, VXI, Ethernet, etc and that have some defined programming interface such as SCPI. The connection to the communication bus is handled by VISA and the commands to the instrument are read from the vendor's manual and made into a driver. Things such as GPIB, VXI, Ethernet, SCPI, VISA, IVI, are standardized and as long as vendors follow the standard, everything goes pretty smoothly. There is no standard for a pc-base DAQ board besides what exists for pci/isa boards in general. That is why you program an NI DAQ board with DAQmx and vendor A's board with their own dll. VISA is not involved at all. You can create a VISA interface with some work and that is what NI has done with their instrument boards such as scope, dmm, etc. this was done to make these boards interchangeable with the traditional stand-alone instruments. Over on the DAQ forum, you will find some complaints from DAQ users as to why they can't use DAQmx with an NI scope or dmm board. I am using some cPCI boards designed internally with VISA but I also have access to the designers and know each and every register location and usage so that I could write the driver. If you can get that from Advantech, then you can use the VISA register access functions.

[JAN_2000]

Oh,I am extremely grateful to you for your generous help!
I learned so much knowledge from your answers! Thank you very much!