I have Silicon diode Si 410 which will measure very low temperature from 300 K to 4 K. I will be using LabVIEW data acquisition system. As the Silicon diode is RTD, it needs excitation current. The manufacturer of Silicon diode mentioned that the excitation current should be of 10 micro ampere and this is very low current. The LabVIEW module PXIe 4357 will give excitation current in terms of mili ampere. How to deal with this situation? Is there any solution that can make me comfortable to use LabVIEW to measure low temperature by SIlicon diode?
Paresh,
I would build a hardware constant current source, and use the LabVIEW devices purely to sense the voltage drop.
Same here. You can get very accurate constant current source for not much and measure the differential voltage drop across the diode.
Paresh, you can build a constant microampere current source yourself. For example, put a 1 Mohm resistor in series with a 10 VDC battery or any other suitable ohm-V combination. Metal film resistors are quite stable to changes in ambient temperature and could be used for such a purpose.
As others have suggested - you will not go to very precise measurement with biuilt-in excitation. Use part like LM334S (http://www.linear.com/product/LM334S) to obtain a steady current source.
Take care about proper shielding of your sensor wires if you want to get reasonable SNR.
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