A data system was designed to measure 30 temperatures to an overall accuracy of + or - 0.1 C. The temperature measurements were part of a dimensional ability study being done on a diagnostic canister used at the Nevada Test Site by the Lawrence Livermore National Laboratory. The system consisted of thermistors as the temperature-sensing element and a data logger which provided the following functions: current source, scanning system, voltmeter, and clock. A microprocessor, in turn, provided control to the data logger, a storage medium for the data, and the means for on-line conversion and display of the data. The performance of the system was optimized by calibrating each thermistor channel using the data system as readout and creating a unique calibration equation for each thermistor. Thus the system was calibrated as a whole to eliminate as many variables as possible. Four separate calibration runs were made. The data from one of these runs were used to calculate the constants for the temperature versus resistance equation for each thermistor channel. The data from the remaining three runs were then compared to resistance points calculated using this equation. The maximum deviation for any thermistor channel was 0.03 C. The system performed very well, recording data every hour for approximately three weeks.
Range Commanders Council Twelfth Transducer Workshop
- Pub Date:
- Temperature Measuring Instruments;
- Data Processing;
- Error Analysis;
- Instrumentation and Photography