Application of a digital computer to data acquisition and shield temperature control of a high-temperature, adiabatic calorimeter

Abstract

The use of a digital computer, operating under real-time, time-sharing mode, for the operation of a high-temperature (300–1300 K), adiabatic calorimeter is described. The specimen temperature and power to the specimen heater are logged continuously, from which the heat capacity is calculated for specified temperature intervals (e.g., 20 K). The determinate error in the calculated heat capacity is about ±0.6%. The temperature control of the adiabatic shields is quite comparable with that obtained previously with analog controllers. The temperature difference between the specimen and a shield can be maintained to about ±0.1 K. The heat capacity of a pure titanium specimen has been measured from 320 to 1020 K using the computer and also using the analog control. No discernible difference in results can be seen. The heat capacity data scatter about ±1% from a smooth curve fitted through the 325 data points.