Acquiring analog voltages

[hansell]

HI all.

I am using a NI 7330 PCI card to for motion control of a stepper motor.

I am trying to use this card also to capture an analog input.  The 7330 has many analog inputs, but I do not know how to acces them on LABVIEW (i.e I dont find the vi necessary to achieve this)

I am also using the  UMI-7764 interface.

Thank you

[jslouie]

Hi Hansell,

Thank you for using National Instruments forums.  The Analog Inputs can be used by using the Enable ADC.vi and the Read ADC.vi.  WIth these two VIs you can read any analog input.  I would definitely recommend looking into the detailed help to see how the Read ADC.vi works because it does not simply output a voltage.

Hope this helps.

Justin Louie

[Buechsenschuetz]

I remember that NI once told us that the ADC inputs of the motion controllers are NOT recommended for precision measurement, since the layout of the ADC section is not optimized for noise immunity. They are rather supposed to work as auxiliary ADC channels in case you just have to measure a voltage with acceptable accuracy.

[hansell]

You are right!! I tried and the accuracy is very poor.  I think is more for feedback purposes that for actual precision measurements.  Thank you all for your collaboration.