NI 9203 and NI 9264 resistance measurement

[ozancanzihni@gmail.com]

Hi, 

I am a mechanical engineer with limited familiarity in the domain of resistance measurement. I have four test specimens that require concurrent resistance measurements during a tensile test. Is it feasible to perform these resistance measurements utilizing the NI9203 and NI 9264 instrumentation? Your insights on this matter would be greatly appreciated.

[santo_13]

Tell us more about the resistance you're trying to measure.

Looks like you're not qualified to develop this test setup, perhaps request for a qualified engineer to design and develop this test apparatus to get it correct.

[ozancanzihni@gmail.com]

Hi, 

Thank you for your answer.

The resistance is roughly 200 ohm for each sample.  Can you please tell me can I measure the 4 samples with NI 9203 and  NI 9264 or I need to have another equipment?

[santo_13]

200 ohms sounds a lot like a strain gauge, are you trying to measure the strain on the object under test using 4 strain gauges in a full bridge config?

https://www.ni.com/en/shop/data-acquisition/sensor-fundamentals/measuring-strain-with-strain-gages.h...

What does the resistance represent in the physical quantity? are these custom built or off-the-shelf?

[Henrik_Volkers]

in principle it possible to measure a resistance with a voltage source and a current meter....

HOWEVER

your specified voltage source  can only deliver 16 mA in total and 4 mA per channel typical...

usually you want a low current to not heat the resisitors, but you didn't tell about the needed uncertainty and range, so that migth be no problem.

since your current meter measure the current with a buildin 138 Ohm resistor , you build a voltage devider , but math can help here.

If you need to use the 9203 ( It's build for industrial sensors that have represent current sources)  , I would think about using one voltage source for all your 'sensors' and an additional known and constant reference resistor of 200Ohm. If self heating is no problem ,say we want to settle at about 10 mA . the internal sense resistor and your load give 138+200=338 Ohm .  with 10 mA you need a 3.38 V power source .. I would choose a 3.3V fixed voltage regulator (or  the good old LM317 with some more resistors) .

the exact voltage can be calculated with your reference channel. If do the math, it will end up in ratios of measured currents

I wouldn't go much higher with the voltage , if you have a shortcut in your resistor (0 Ohm) , the maximum current is ~24 mA  and will not fry your 9203.

digging into the specs and do an uncertainty budged is your homework 😉

 and don't forget the error you get by the resistive change in the cables ( look up two and four wire resistor measurement)

not a good way to measure resistance, but the joy of engineering is to do what you want, with the stuff you can get 😄