Sensors calibration set point

why there is need to calibrate on high point and low point calibration? what is the criteria to set low and high point value during eg we are calibrating pt 100 sensors which we are using for autoclave validation for that we kept pre/post calibration set point as 130oC, 90oC and 121oC what is the logic to keep high and low point values any guideline which gives calculation for such determination

Thanks in advance

Dear Bhagyesh
Two point calibration is used for bracketing the sterilization temperature for the sterilization process under validation for eg 100 degree and 130 degree and a calibration check point of 121 degree to verify the calibration accuracy of the sensors. For More details you can refer PDA technical report.

Dear arun
Cal u plz tell which technical report should i refer for the same becoz my question remains the same for selection of high and low point for calibration