Precision Thermocouple Amplifier (Thermocouple to Digital Converter with Linearization – SPI Interface)

This precision thermocouple sensor module performs cold-junction compensation and digitizes the signal from any type of thermocouple. The output data is formatted in degrees Celsius. The converter resolves temperatures to 0.0078125°C, allows readings as high as +1800°C and as low as -210°C (depending on thermocouple type), and exhibits thermocouple voltage measurement accuracy of ±0.15%. The thermocouple inputs are protected against overvoltage conditions up to ±45V. A lookup table (LUT) stores linearity correction data for several types of thermocouples (K, J, N, R, S, T, E, and B). Line frequency filtering of 50Hz and 60Hz is included, as well as thermocouple fault detection. An SPI-compatible interface allows the selection of thermocouple type and setup of the conversion and fault detection processes. The operating supply of the project is 5V and it consumes a very low current. The module communicates over the SPI interface.