6229 accuracy

[KenSagem]

Hi,

The PCI 6229 Analog outputs are accurate to about 3.2mV. During our tests, we command the Analog Outputs to 5V (using DAQmxWriteAnalogScalarF64). When measured with a calibrated DMM (accurate to 3mV), value is 5.01V. During another test, an Analog Out is set to 0.75V, but typically measures 0.736V. DAQ boards are all within calibration cycle. Wondering what I am doing wrong?

[Kyle_A.]

Hi Ken,

How are you connecting your DMM to your DAQ?  Are you referencing GND for all of your measurements?  Which connector block are you using with the 6229?  Another test you can try is to reroute the output to the input on the 6229 and see if you can measure the same offset, but that should not be significantly different.  What it will tell is if you have any noise in your environment that could cause changes in your measurement. 

Other things you can check is the voltage level when AO is not outputting anything, is there an offset at 0V?  Did you try both channels on the card? 

If you feel the board is out of calibration range, there are options to send in the board for recalibration.