Hi Rodrigo Schneiater.
 
 
Thank you for answer me. I'll clarify the scenario for you.
 
Beyond the hardware that I had listed before, we have a scxi 1305 terminal block for current signal input.
 
We did some tests, in a frequency range between 60 up to 400Hz, like you sugested me. We used a current clamp, that have a constant phase error for all range of the test (comproved by oscilloscope measurements). This is the result for, discounted the error by the current clamp (3°):
 
 
60Hz - phase shift of 6.40° between voltage and current signal;
 
120Hz - phase shift of 11.15°;
 
180Hz - phase shift of 16.50°;
 
240Hz - phase shift of 21.66°;
 
300Hz - phase shift of 26.40°;
 
360Hz - phase shift of 30.70°;
 
400Hz - phase shift of 33.30°;
 
 
 
Thank you for help us.