Digital Multimeters (DMMs) and Precision DC Sources

[wykoman]

We are designing a product that requires supplying a programmable voltage and measuring the current or supplying a current and measuring the voltage.  Right now we are using a Keithley Sourcemeter.  This is big, expensive, and has a lot of capability we don't use.  A PXI-4110 would do the job.  Is there a way to use this without having to put it into an enclosure?  We want to include it in our power supply chassis and have it be controlled by the system computer.  Using a PXI enclosure would make it as big and almost as expensive as the Keithley.

Is there a small, cheap, 1 slot enclosure?  Or maybe a USB to PXI converter that could just be plugged onto the back of the PXI-4110 (we can arrange operating power)?  Is there some similar product that's made for stand-alone use?  If all these answers are no, then I'll be designing a board custom tailored to our needs; that's OK but a buyout would be preferable.

Thanks,

Jim

[kirsch]

PXI is a superset of PCI in a different mechanical form factor. So it is possible to plug in a PXI board to a PCI slot assuming you have an adapter and can make it all fit. But I'm no hardware engineer, so I don't know if this has any cooling or shielding/noise implications, or worse, safety issues. A quick Google search for such adapter returned no results.

[Now_With_Under…]

Hey Jim,

NI doesn't sell an enclosure, adapter, etc, but as Marcos mentioned, PXI is based on the PCI standard.  In general, you'll lose all the triggers, but this doesn't matter with the 4110, since it doesn't have any... there are a few other signals that don't route through, but nothing that would prevent the module from working just fine in a PCI slot.  You can find the pinouts for PCI online, and the pinouts for PXI from the spec sheet of any of our chassis (e.g. table B5 of a 1045).  From there, it would be simple to build an adapter board that adapts from PCI to PXI.  

Caveats:

-the PXI chassis uses forced air cooling; you would want to add fans to your adapter board.

-PXI boards can pull more power than PCI can deliver; however, the 4110 only pulls 20W max, so it's within PCI spec.

-you'll need a mechanical solution to hold the board in place

-the board will stick awkwardly out the side of the computer.  

Confidence level that the 4110 will work with a properly designed adapter: 100%

Mechanical difficulty getting the 4110 mounted in a PCI system: Moderate

Thoughts: Time to launch Eagle/Mentor/insert-PCB-design-SW

[wykoman]

This is the result I expected.  Too bad.

Thanks everyone,

Jim

[Now_With_Under…]

Hey Jim,

Compared to designing a CV/CC power supply from scratch, creating a simple adapter board is a trivial task.  From my previous post, there are a few mechanical concerns, but overall the adapter is quite trivial.  I'm surprised nobody makes an adapter.

[wykoman]

True, an adapter would be simple but the result wouldn't look like anything someone would want to buy and it probably wouldn't pass emission testing.

Jim