Hi,
I'm trying to define a polynomial scale for a DAQmx channel.
- I calculate the reverse coeffeicients (DAQmx Compute Reverse Polynomial Coefficients.vi)
- I Create the scale (Daqmx Create Scale - Polynomial).
- I Create the task
- I Create the channel.
My problem is the following: When i don't set the minimum value for x and maximum value for x in to calculate the reverse coefficient, the default values (-5,5) are used. If i choose the following coefficients e.g. 1,2,3 for the polynome, i get the error -200537.
"upplied forward and reverse coefficients yield inconsistent results when they are used for computations related to this property. In other words, using the result of the forward scale as input to the reverse scale does not yield the original data. Based on the forward coefficients, the value for the property is invalid.
Supply forward and reverse coefficients that yield consistent results.
Property: AI.Max
Requested Value: 321.0
Possible Values: 281.0 to 321.0
Scale Name: toto"
If i set the minimum value for x (-10) and maximum value for x (10) in to calculate the reverse coefficient I don't get the error. But I don' understand :
- why the reverse coefficients are needed to create the scale ?
- why does the function return an error with -5, 5 ? We think the reverse coefficient are bad, and therefore when we enter the min and max value for the channel this returns an error .. any explications how it really works ?
You will find enclosed the snippet of he code used
