How can I find Output Impedance in National Instruments?

[tonyshaw]

I have built a circuit but need to find the output impedance of it, how can I Find it? Please help me in detail

Update: The circuit is built in the NI and want to know how can i find the Ro(output Impedence) with National instrument. 
(I don't want to calculate Ro) 
Is there any function in NI that i can use? 

The question does not depend on a specific circuit, it can be any circuit. How can i get the Ro in National Instrument

[altenbach]

National Instruments is a company. Please explain what the terms "National Instruments" or "NI"  mean to you.

[rizardus]

If I understand you correctly you have to check the datasheet for the device that you are using.