analog output plus transconductance amplifier

[Salamandra]

Hello everybody,

sorry if I put a maybe trivial question but I'm a beginner in data acquisition yet.

I need to output a pulsed negative current from my PCI 6251 and measuring resulting voltage on load at the same time.

To do that, I've thought to ouput a pulsed voltage from AO0, sending the voltage to a transconductance amplifier, and generating a current to my load.

This is my transconductance amplifier... the load, modelled in the square, is referred to the +5V on the PCI 6251 and not to "ground", since I need current to be negative.

Now, I must read voltage on load by means of AI0 and I've got lost among grounding issues... Since the load is referred to my +5V, should I measure it in differential or single ended?? 

Thanks for your time

Denise

[sisu84 · Accepted solution]

Hi Denise,

you have to acquire in differential mode.

See http://www.ni.com/pdf/manuals/371022k.pdf pag 4-12

Ciao!

[Salamandra]

thanks a lot!