SU1173385A1 - Converter of optical density of substances into time interval - Google Patents

Abstract

OPTICAL DENSITY CONVERTER OF SUBSTANCES IN THE INTERVAL TIME, containing two cuvettes and a source of radiant energy, between which is installed a radiant energy modulator, a photodetector with an amplifier, an electronic key, PS-trig-. a hero different in that. that, in order to improve the control accuracy, a comparator, a pulse shaper, a logic element I, a pulse generator of the reference frequency, a counting trigger and a reversible pulse counter with a buffer memory are entered into it, the input of the comparator and the pulse shaper input are connected to the output of the photodetector amplifier, and their outputs with the inputs of the RS-flip-flop, the output of which is connected to one input of the logic element And, the other input of which is connected to the output of the generator of the reference frequency pulses, 9 and the output - through the electronic key with (L input of the reversible pulse counter, the electronic key c is connected to the output of the counting trigger, the input of which is connected to the output of the pulse former, the radiant energy modulator is designed as a disk rotating with a constant speed d with an opening widened direction of disk rotation exponentially. 00 O1

Description

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The invention relates to measuring technology and can be used for automatic control of technological processes.

The purpose of the invention is to improve the accuracy of control.

The drawing shows a block diagram of the Converter.

The optical density converter of the substances in the time interval contains a source of radiant energy 1 with an optical system, including a prism 2, mirrors 3 and 4, an opaque screen 5 with two narrow transparent windows 6 and 7 Modulator 8, installed between the source of radiant energy 1 and the cuvettes 9 and 10, is made in the form of an opaque disc rotating from a synchronous motor 11 at a constant speed. The disk has a transparent window that increases in the Direction of rotation exponentially. This ensures alternate passage through the cuvette 9 with the test substance and the cuvette 10 with the comparative substance of the radiant energy from the source 1, the intensity of which decreases in time according to an exponential law. The light fluxes that pass through the aforementioned cuvettes are focused by an optical system consisting of, for example, prism 12 and two mirrors 3 and 14, onto the photodetector 15, where they are converted into an electrical signal that is amplified in amplifier 16. The signal amplified in amplifier 16 is fed to a comparator 17 and the driver 18 pulses, the outputs of which are connected to the inputs of the RS flip-flop 19. The output of the trigger 19 is connected to one input of the logic element And 20, the second input of which is connected to the output of the generator 21 pulses of the reference frequency, and the output through the electron key 22 with reversible counter inputs 23 pulses. The electronic key 22 is controlled by the output of the counting trigger 24, the input of which is connected to the output of the pulse shaper 18. The electronic key 22 can be in two stable positions by commands from the counting trigger 24, and in one case it also provides the transmission of pulses from the generator.

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21 to the summing input of the reversible counter 23, and in the other to its subtracting input.

Converter optical density of substances in the interval-time works as follows.

The cuvette 9 is filled with the test substance. Radiation from source 1 of radiant energy is divided into two

o beam - comparative and measuring, which pass alternately through the modulator 8 of the radiation intensity and, accordingly, through the cell 9 with the test substance in

5 cuvette 10 with comparative substance. The modulator 8, through its transparent window, alternately transmits the rays through the aforementioned cells. In this case, the intensity of the radiation entering the cells is exponentially. Upon exit from cuvette 9 and 10, the rays are focused on the photodetector 15, where they are converted into a proportional electrical signal amplified in the amplifier 16. At the moment the beam passes through the cells in the photodetector 15, a voltage pulse is generated,

0 which is amplified by amplifier 16 and supplied to pulse generator 18.

The voltage pulse received from the pulse driver 18, at the moment of the beginning of the passage of radiation through the cuvette 10, switches the RS-trigger 19 and the counter trigger 24 with the comparative substance. At their outputs, respectively, connected to one input of the logic element 20 and the control input The electronic key 22, appears logical 1. Therefore, the voltage pulses from the generator 21, the output of which is connected to another input of the logic element And 20, begin to flow through this logical. the element and the electronic switch 22 to the summing input of the reversible counter 23. The voltage pulses from the generator 21 are counted (summed) by the counter 23 until the magnitude of the signal input to the input of the comparator 17 reaches a predetermined level equal to the reference signal. At this point in time, the comparator I7 changes its state, and at its output a signal corresponding to logical 1 appears. This signal switches the P5 flip-flop 19, while O appears at its output. Therefore, the voltage pulses from the generator 21 cease to pass to the summing input of the reversing counter 23. The counter 23 for the considered time interval counts the number of pulses proportional to the optical density of the comparative substance, which is filled with the cuvette 10.

Thereafter, a beam of light begins to pass through the cuvette 9 with the test substance. At the moment when the beam starts to pass through the cuvette 9, a voltage pulse is generated on the photoreceiver 15, which is amplified by the amplifier 16 and fed to the pulse former 18. The voltage pulse received from the pulse driver 18 switches the p5-flip-flop 19 and the counting flip-flop 24. At the output of the RS flip-flop a connected to one input of the logic element 20, appears 1, and at the output of the counting flip-flop 24 is O. Changing the state of the counting trigger 24 leads to the switching of the electronic key 22. Therefore, the voltage pulses from the generator 21 through the element I 20 and the electronic key start 173385.44

They proceed to the subtractive input of the reversible counter 23. This happens until the magnitude of the signal input to the comparator 17 reaches a predetermined level equal to the reference signal. At this point in time, the comparator 17 changes its state, and a signal appears at its output. This

10 signal switches the RS-flip-flop 19,

at the output O appears. Therefore, the voltage pulses from the generator 21 cease to pass to the subtracting input of the reversing counter 23. From

The fS of the counter 23 subtracts in the interval in question a number of pulses, which is proportional to the optical density of the test substance. So in the counter

20–23, the number of pulses is recorded at this time. proportional to the difference in time intervals formed, respectively, during the passage of radiation through the cell

25 10 and cuvette 9. This result goes to the display unit and characterizes the difference between the optical densities of the comparative and the test substance.

In this case, fluctuations in the intensity of the radiation from the source I, the sensitivity of the photodetector 15 and the amplifier 16 do not affect the accuracy of the conversion.

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Claims (1)

OPTICAL DENSITY CONVERTER OF SUBSTANCES IN THE INTERVAL TIME, containing two cuvettes and a source of radiant energy, between which a radiant energy modulator, a photodetector with an amplifier, an electronic key, a PS trigger, characterized in that, in order to increase the accuracy of control, a comparator is introduced into it , a pulse shaper, a logical element AND, a pulse generator of a reference frequency, a counting trigger and a reversible pulse counter with buffer memory, while the input of the comparator and the input of the pulse shaper are connected to the output ohm of the photodetector amplifier, and their outputs with the inputs of the RS-flip-flop, the output of which is connected to one input of the AND logic element, the other input of which is connected to the output of the pulse frequency generator of the reference frequency, and the output is through an electronic key with the input of a reversible pulse counter, and the electronic key connected to the output of the counting trigger, the input of which is connected to the output of the pulse shaper, while the radiant energy modulator is made in the form of a hole rotating at a constant speed of the disk d, made expanding in full exponential rotation of the disk. SU .. „1173385