analog current output problem

[elad2012]

Hi,

I have a NI PCI-6289 board. It has 4 analog outputs. I want to have one of them function as a current generator, and not as a voltage generator (so I could perform 4-probe measurements).

Does anybody know how can I do that?

Best regards,

Elad

[Kenn_N]

Elad,

Thank you for contacting National Instruments support.  This is not a supported feature of our boards and proceeding is at your own risk, that said you are not the first to ask.  There are some solutions out there that convert your voltage output to a current output. 

First, if you know the resistance of your load you will be providing current from the voltage output up to the limit of the card, so in essence you are already providing a current output.

Second, if you want to provide a fixed current output you will need some external circuitry that will provide a constant current source.  Attached is an example of circuit that does this. Again, this is not a supported circuit, it was submitted by customers, but the concept should work and people are using it.

Last,  we do have cards that provide current as an output.  I know this may not be ideal for you to purchase a new card, but they do exist and I thought I'd suggest it.

I hope this helps, let me know if you have further questions.

Regards,

[Brad.747]

I am loading a waveform from ASCII and would like to use that wave to output a current using a PCI-6289, but voltage is the only signal I am able to generate. It says there are no supported channels for current. Is there a way to output a current with this DAQ card or an accurate way to measure the current created by the generated voltage?