A Computer Controlled Data Acquisition System for Combustion Calorimetric Experiments

At NBS a data acquisition system for a flow calorimeter which accommodates large samples has been developed. The system is based on an instrument controller, scanners, and voltmeters, all available commercially. Detectors for temperature, gas flow rate, pressure, and gas chemical composition provide data on key operating parameters of the calorimeter. A real-time, multi-tasking, general-purpose, data acquisition program is described. Computer science concepts important to the design of the program are explained. The software is driven by tables of data loaded at the start of the experiment. Thus, program execution is changed by providing different tables of information for the data channels desired, data display, and data storage. Tasks for data acquisition, instrument control, data storage, calculations, data display, and run-time-parameter entry are activated or deactivated during the experiment by the operator. Sample results are presented to illustrate the use of the data acquisition system. The software developed for this system is well suited for the changing experiments commonly encountered in the research laboratory.