how to measure the analogy voltage from different source?

[dragondriver]

Hi all,

  I am trying to measure the voltage generated from a function generator ranged from -2V to +2V. I am trying to use a PCI-6023E for analogy input. I directly connect the voltage output from the generator to one of the analogy input channel, but the reading is not that accurate, it should be 2.4V but sometimes it read 2.6V and sometimes 2.2V or less. I am thinking if anything to do the the ground? Where should the ground of the BNC from the generator should connect to? Someone suggests to use differential input but I have no experience of doing that, any suggestion or example?

[Joshua-B]

Hi dragondriver,

I'm providing below links to 2 documents that discuss wiring considerations that are applicable to your device.  Hopefully this information is helpful!

E Series User Manual

http://www.ni.com/pdf/manuals/370503k.pdf

Field Wiring and Noise Considerations for Analog Signals

http://www.ni.com/white-paper/3344/en#toc5

[dragondriver]

Thanks a lot. It seems to be a good materials for me to start. By the way, I am using LV7 and traditional DAQ for long time and I have DAQmx installed weeks ago. But didn't get a chance to see how to use the DAQmx. I am currently working on using  analogy input to mesure the voltage of battery (constant 2.5V), is any simple example to show how to use DAQmx to achieve that?

[Dennis_Knutson]

Just like everything else, you start by going to Help> Find Examples.

And please, it is analog - no y at the end.