SBAS894A April 2018 – October 2018 ADS112C04
Figure 72 and Figure 73 show the measurement results. The measurements are taken at TA = T(CJ) = 25°C. A system offset calibration is performed at T(TC) = 25°C, which translates to a V(TC) = 0 V when T(CJ) = 25°C. No gain calibration is implemented. The data in Figure 72 are taken using a precision voltage source as the input signal instead of a thermocouple. The respective temperature measurement error in Figure 73 is calculated from the data in Figure 72 using the NIST tables.
The design meets the required temperature measurement accuracy given in Table 24. The measurement error shown in Figure 73 does not include the error of the thermocouple itself nor the measurement error of the cold-junction temperature. Those two error sources are in general larger than 0.2°C and therefore, in many cases, dominate the overall system measurement accuracy.