Automated Calibration of Temperature Transducers

An automated system of laboratory equipment and computer hardware and software reduces the time that technicians must spend in calibrating temperature transducers. The laboratory equipment includes a controlled-temperature bath, two digital multimeters for processing the outputs of two temperature transducers at a time, and standard interface bus circuitry for controlling and monitoring the bath and the multimeters. The operation of the laboratory equipment is controlled by equipment-specific software on a computer that runs Windows 95 and is equipped with a standard general-purpose interface bus circuit card. A technician specifies data points for calibration, and thereafter the software controls the calibration process. The process includes timed advances to subsequent temperatures and holding periods for stabilization at calibration temperatures, with a sampling period of 1 second. The technician can leave the system unattended during the calibration process. Using manual techniques, it usually takes about half a day to calibrate two temperature transducers at three data points; using this system, it takes about two hours.