Current Measurement PXI 4065

[hegb_85]

I have a PXI 4065 under LV 8.5.1.

When a make a current measurement without the circuit under test the DMM measures 1mA. i don't know how this is possible or if this is normal.

This affects me beacause i have a circuit under test where the spected measurement is around 1mA so i don't know if the DMM acquired the correct measurement.

Any ideas? Regards

[Hillman]

Hi ethan85,

Thanks for the forum post and I hope your well today.

I noticed your post has been left unanswered for a few days now.

For example, if we left the input to a DAQ device and did a voltage reading, the value will float - and sometimes this can be noise or sometimes it can rail up/down to the range specified for the task.

What is the range for your task set too?

I guess the best way to see if this value is ok, is to test your device using a high current, and see if it still returns to 1mA.

Also with DAQ devices they make current measurements by measuring the voltage across a shunt resistor. This could well be the cause of the 1mA.

My last thought, is its usually not advisable to leave an input floating - so maybe some forum of pull down resistor could be used when the device DUT isn't connected.

Please let me know what you think,

Kind Regards, 

[hegb_85]

Hi Hillman

Thanks for your response.

I corrected this problem, I modified the range from 0.5A to 0.1A and the measurement on the floating point was of 0.17mA so this works for me.

I'll work in a application for dynamically changing the range of the DMM.

Regards

[Hillman]

hi!

Thanks for the update.

Im glad it works fine now - and glad that my advice would have got their in the end ! 😄

Best of luck with your application.

Kind regards,