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NI 9265 not outputting a constant 10uA in all channel

I am using the 9265 to output a current of 10uA to measure temperature from thermistor, but when I used a multimeter to read the current output from all the channels I noticed that some channels weren't outputting a constant currents. A couple of channels were outputting 6uA. is there a way to get a constant current from all the channel in the 9265 without a fluctuation of the current?. I using a 24VDC to supply power to the 9265

 

thanks

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What is the resistance range of the thermistor? The max load the 9265 can handle is 600 ohms. If your thermistor is above that it may be affecting the performance of the other channels. Can you repeat the test with loads under 600 ohms to see how the channels behave?

 

-AK2DM

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"It’s the questions that drive us.”
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the thermistor resistance is at 100kOhm at 25C. The current used to test 100kOhm thermistor is 10uA.

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If you look at the error specifications, you will see that you are doing quite well. Typical error at 25 C after calibration is Gain error = 0.11% of reading + Offset error = 0.19% of range. The gain error would be negligible at 10 uA, but the offset error may be larger than 39 uA.

 

This device does not appear to be suitable for your application.

 

Lynn

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