scaling analog inputs

[Moni]

Hello, I´ve got one question for you. I use PCI 6221. If I understand  my analog input range is -10V - +10V and my card  has 16-bit ADC convertor, so my  resolution is 20V/(2^16) = 0,000305176. And if I´m  using your  example  for  data acquisition  (Cont Acq&Graph Voltage-  To File(Binary).vi )  and  for reading Graph  Acquired Binary Data.vi. the scaling coefficients for my channels is directly 0,000305176. It ´s ok. But my problem is when I use Custom scale (for example linear scaling y=2*x+0) for each channel my scaling coefficients are 0,000152588. Why it is two times smaller and no two times bigger ? Can you explain it to me,please? Thank you Monika

[Moni]

Hello, It´s right, my scaling coefficients are good (divided with gain), but I see that my data have  same values with gain 2 or without scaling. Where could be problem? I use unscaled integer 16. Monika

[TheWoost]

Hi Monika,

Do you have the maximum and minimum for the input signal range defined for the post-scaled values?  Also verify that your custom scale is saved with the correct values in Measurement and Automation Explorer.  Please provide any additional information that you have about your application.

Regards,
Andrew W
National Instruments