New Design Concepts for Direct Reader Measurement Electronics

Abstract

A dual-processor, distributed-intelligence approach toward the computerization of a direct-reading polychromator for atomic emission spectrometry is described. Emphasis is placed on a “zero based design” of the PMT current integration electronics of a direct-reader channel using microprocessor bus architectures, programmable support chips, data domain conversion integrated circuits, and inexpensive single-board microcomputers. Traditional analog integration of the current signal is replaced by domain conversion of the current to a frequency, and integration/digitization is achieved with the use of single chip software programmable counters. Each channel can be independently addressed, configured, cleared, preset, and read, as the channels are autonomous units on the bus of the data acquisition and control microcomputer.