How does the NI-6581 Adapter Module differ from R-series intelligent DAQ devices?

[TomC_NGC]

How does the FlexRio + 6581 Adapter Module combination differ from say, the PXI-7842R?

The latter two modules have rather weak LVTTL drive (4 or 5mA max).

(I have also posted this question on the FlexRio community discussion board.)

[Captain_Kirby]

Hi,

This is a great question, and one many customers will be asking in the future.

The big difference between standard R-Series devices and the new FlexRIO + Adapter Module is the ability to attach any I/O you want without needing to purchase a new FPGA. In the past, if you purchased an R-Series card and later found that the I/O specifications were not sufficient for your application (or a later application,) you would have to replace the whole card, including the FPGA, which may be perfectly fine for your application. Now, you can buy one FPGA card, and attach whatever IO you want to it. With that said, we currently have only one module. But the idea is that we, as well as others will produce I/O modules for the FlexRIO that you can purchase and extend your abilities with your single board. If you have the technical abilities, you could also design your own I/O module to any specification. In that respect, if the LVTTL is not what you would like it to be in the 6581, you can just build a module to include what you want.

Beyond that, just looking at the FlexRIO as a device in itself (without considering the adapter modules,) it includes onboard RAM which the R-Series cards do not. This gives you much more space to store data onboard the card (you wont have to use precious FPGA resources to build a memory space.)

So in the end, the differences between the two product lines are fairly well defined, though in this instance, the current Adapter Module we provide will not give you the same LVTTL as the R-Series device. If you don't plan to ever reuse the product for another application, the R-Series card may be the best choice. But if you need the flexibility listed above, the FlexRIO may be a good option for the long term.

I hope this helps.

[BrowningG]

R Series devices such as the PXI-7813R and the PXI-7842R use a bus switch architecture to convert the digital output signals of the FPGA into the TTL logic levels that can be used to read from or control external devices.  This gives you direct access to the FPGA IO lines from the FPGA in your LabVIEW FPGA code. 

The NI 6581 is designed to have similar specifications as the NI 6541.  Checking out the specifications for the 6541 should give you an idea of the capabilities we are aiming for with the NI 6581.  A big difference between the using the 6581 and the 6541 will be the API used.  Like the R Series boards from above, you will need to use LabVIEW FPGA to program a FlexRIO to use the 6581 for acquisition and output.  This is done using the power of socketed CLIP.  CLIP gives LabVIEW the ability to control the IO of the 6581, so the interface is going to be a little different than the interface you use to interact with the IO on an R Series board.  It is not required that you need to know VHDL to program your FlexRIO with 6581 since the socketed CLIP is designed for you by NI.  We are still currently finishing the specifications for the 6581 so if you would like, I can contact you offline and we can discuss specifications in more detail.