Single-Wire Thermocouple-to-Digital Converters Simplify Multi-Sensor Designs
Thermocouple-to-digital converters developed by Maxim integrate a discrete analog-to-digital converter (ADC), a highly accurate reference, a temperature sensor for cold-junction compensation, and a single-wire bus interface. The single-wire interface allows multiple sensor locations to communicate and draw power over a single data line, greatly simplifying wiring requirements. The MAX31850 and 31851 converters achieve ±2.0°C accuracy (not including sensor nonlinearity) and operate with several types of thermocouples (the MAX31850 handles K, J, N, T, and E thermocouple types, and the MAX31851 is for R and S types). Both chips also identify open or shorted thermocouples that could result in erroneous temperature readings or system faults. A microcontroller can read the fault status at any time to help ensure uptime and prevent costly repairs.