Calibration is needed for high accuracy or for verification to third party.
Calibration of RTD sensors 1. The sensors are compared at -195 °C, -75 °C, 0 °C and 100 °C with traceable references. 2. A certificate with measurements, calculated Calendar Van-Dusen coefficients, uncertainty and traceability is issued.
Unique calibration Senmatic offer a unique calibrated 4-20 mA transmitter – RTD sensor set.
What does unique calibration mean? 1. The RTD sensor is calibrated 2. The transmitter is programmed with the Callendar Van-Dusen coefficients 3. The transmitter is calibrated by simulating the RTD resistance at 3 points (4 mA, 12 mA and 20 mA) 4. Certificates for both calibrations are supplied together with the paired transmitter-sensor set
Callendar Van-Dusen coefficients? The resistance at temperature t can be described this way R(t) = Ro*( 1 + A*t + B*t2 + C*(t-100)*t3) where Ro is the resistance at 0 °C and A, B and C the Calendar Van-Dusen coefficients. Above 0 °C C=0. By active use of the coefficients the sensors uncertainty is less than ±0.024 °C in the calibrated range.
