An Automatic Data-Logging System for Meteorological Studies in Reactor Environments

An automatic data-logging system has been designed for meteorological studies for the Tarapur power reactor. The system is designed to log data from 256 sensors divided into two groups of 128 each. The outputs from the sensors in analog form, varying from 0 to 100 mV can be scanned sequentially. The scanning unit, used for time multiplexing, consists of a bank of 256 pairs of reed relays. It connects sequentially the outputs from the two groups of sensors to two chopper-modulated d.c. amplifiers. The output from the chopper-modulated d.c. amplifier varies from -4 to -10 V. A linear and highly stable A-D converter connected alternately to the chopper-modulated d. c. amplifiers digitizes the amplified outputs. The digitized data are stored in a ferrite core memory with a capacity of 256 5-digit words. The data are handled in the binary-coded decimal form. Each memory location corresponds to a particular input sensor. When sensor Mi is selected by the scanning unit, its digitized output is added to the previously stored data in the Mith memory location and the result is stored back in the same location. The Mi + 1 sensor is next selected. The scanning unit selects all the sensors every second. At the end of 10 min the memory locations contain the averages of outputs of all the sensors. This data' is punched on a paper tape in the next 2 min. The sensors are scanned again after clearing the memory. The logical operations are controlled with a 100-kc/s crystal controlled time clock. The data are fed to a digital computer for analysis. (author)