A smart thermal environment monitor based on IEEE 1451.2 standard for global networking

A temperature and relative humidity (RH) monitor using a thermistor and a polyimide-film RH sensor is developed for global assessment of thermal environments. The smart transducer interface module includes the relaxation oscillators for signal conditioning and a one-chip 16-bit microcomputer for networking. The microcomputer accommodates the calibration tables as well as the mandatory transducer electronic data sheets specified by the IEEE 1451.2 standard. The online calibration using the calibration table and the ratiometric signal conditioning allow ±0.14°C accuracy over the temperature range from -20°C to 50°C and ±2.5RH accuracy over the RH range from 20%RH to 90%RH. Beside these high-accuracy measurements using low-cost sensors, the monitor features an adaptive architecture for global networking.