That circuit will not work as you have drawn it. It will work if you rearrange the circuit like the attached 'circuit.bmp' and use these equations.
I[R] = I[1k] = (5V-U2)/1k
R = I[R] x U2
Also note that you cannot always guarantee the supply voltage to be exactly 5V or even stay the same under load conditions. It may pay to set aside a channel to measure the 5V supply. Of course this really depends on the accuracy and repeatablility of the measurement.
Vadim Gnatkovsky wrote:
> Hello. > I have DAQCard-1200 and LabVIEW 5.0.1f. > I should measure resistance in range 100 - 1000 kilohms. > Can I do it? Please advice me. Can I use +5V from pin 49 in my DAQCard for > this task? > > Is circuit (see attachment) will be work? > Ohm's l aw. > > Thank you. > Vadim Gnatkovsky. > > Name: circuit.bmp > circuit.bmp Type: Bitmap Image (image/bmp) > Encoding: x-uuencode