I'm working with the same type of sensors (lakeshore Cernox). I want to calibrate a sensor by myself. To do this, I want to measure the resistance of an uncalibrated sensor, and in a same time the temperature from a calibrated sensor. So I will have an 2D array, consisting of Temperatures and Resistances. Then, I want to calculate Chebychev coefficients (like A0, A1...), similar to the .pdf you joined.
But I didn't find any function to calculate Chebychev coefficients from experimental values. So,
Do you know how determine Chebychev coefficients from experimental values ?
Hi, Julien- You are responding to a thread that is several years old!
Although I am not familiar with the temperature sensors you are using or the model to calculate temperature from the resistance, I do have a couple suggestions for you to convert resistance to temperature.
First, There are shipping examples for RTD and thermistor resistance to temperature conversion that use a parabolic model. Each has a pull-down of standard device types (and the VI uses a lookup of the polynomial coefficients) and also has a "custom" option, which allows you to enter the three coefficients for a parabolic model.
Second, as it appears that your calibration report provides you with fifth-order coefficients, you can use a formula node to convert a resistance to a temperature based on whatever calculation you would like. You can even work it out to use 2D arrays or arrays of clusters or similar to store the specific coefficients that a calibration service provides you for each sensor you use.
It sounds like you want to use one supplier-calibrated sensor to be a standard for you to calibrate additional units. Assuming you have sufficient data for each device along an appropriate temperature range, you can calculate the model coefficients mathematically. I suggest you familiarize yourself with your sensors and with the examples that ship with LabVIEW. A good place to start studying these temperature devices is: http://www.lakeshore.com/Documents/F010-00-00.pdf.
If you need help with components of a LabVIEW program for your conversion, data collection, or coefficient derivation, you should post specific questions in a new thread and show the forum what you have done and where you need help.