Please refer to the attached word document "UnderstandingNICalibrations.doc" for screen captures and a full explaination showing how I tried to determine some answers to the questions stated below.
I want to use the Calibration Wizard feature available in MAX (via the NI-DAQmx DAQassistant), but I need to understand how the calibrations I enter are applied to the measurements. The reason I need this understanding is so I may determine the error/goodness of fit of the resulting correction from the calibration.
Please, will someone tell me how these calibration corrections work (how do I determine the error)?
I reviewed the LabVIEW help for the channel calibration property node and was able to determine that the Calibration Wizard sets up a calibration curve with the Table (10450) method. However, I do not understand what the second part of the explanation for the Table method "with all other values scaled proportionally" means. How does the calibration method interpolate/extrapolate between/beyond points on the table?
I created a NI-DAQmx task to read current measurements. In this task I specified two virtual channels that are connected to the same physical channel (the physical channel is from a simulated PXI-6225 device). My plan was to apply a calibration to one virtual channel and not the other so that I could visualize the difference between a calibrated signal and an uncalibrated signal.
In summary, I have the following questions I would greatly appreciate some answers to:
1) How do I quantify the error of the calibration correction if I use the Calibration Wizard tool?
2) For the Table calibration method, how does the method interpolate/extrapolate between/beyond points on the table?
3) Why do I not observe the expected difference in the calibrated and uncalibrated signals when I set up a task to do so?
