Automatic radiant energy analyzer with programmed sample selection and analysis

Claim 1

An analytical system for automatically analyzing a plurality of samples according to selected programs, comprising: radiant energy analyzer means having a sample path traversed by a radiant energy beam of selected intervals of wavelength thereby analyzing samples positioned in said path, said analyzer means being a spectrophotometer having a wavelength determining mechanism and a mechanism driving motor whereby the radiant energy beam wavelength is scanned; sample changer means adjacent said analyzer means for selecting and positioning samples in said path, said changer means having a sample changer programmer and a plurality of sample storage locations from which samples are selected according to said sample changer programmer; wavelength programmer means connected to said analyzer and said sample changer means for determining a sequence of said selected intervals of wavelength, said programmer means having a multiplicity of wavelength interval determining programs and a program selection logic circuit responsive to control signals applied to said programmer for selecting said wavelength interval programs, said wavelength programmer means comprising a wavelength potentiometer having the variable tap thereof mechanically coupled to said wavelength determining mechanism and having a voltage potential at said variable tap which is a function of wavelength, a multiplicity of potentiometers arranged in a plurality of groups, each group forming a wavelength interval program, each potentiometer having an adjustable voltage potential equivalent to one boundary wavelength of one wavelength interval, and a voltage comparator circuit connected between said wavelength potentiometer and said multiplicity of potentiometers for comparing each adjustable voltage potential of said group with the voltage potential of said wavelength potentiometer and having an output connected to said program selection logic circuits for indicating when the potentials are equal; and a motor speed control logic circuit connected between said program selection logic circuit and said wavelength mechanism driving motor to change the motor speed when the wavelength passes through each selected boundary wavelength thereby changing the wavelength scanning speed.