JPH02310449A - Instrument for measuring coexistence rate - Google Patents

Abstract

PURPOSE:To make stable measurement of a coexistence rate even if a detecting level is changed by aging and staining by detecting the characteristics of two kinds of coexisting materials by each grain by means of a sensor and connecting a detection signal to an amplifier. CONSTITUTION:Plastic pieces 3 to be subjected to the measurement of the coexistence rate pass between a light emitting diode 1 and a phototransistor (TR) 2. The coexistence rate is determined by the following operation if two kinds of the plastic pieces which are different in the transmittance of light coexist in the plastic pieces 3. The output of the detecting part of the Tr 2 is amplified by the amplifying section of an operational amplifier 4 and the rising detection consisting of a gate circuit is executed by a rising detecting circuit 5, by which an A/D conversion start signal is generated and is transmitted to a peak hold circuit 6 which stores voltage levels. The peak voltage amplified in the amplifier part is held by the circuit 6 and is subjected to A/D conversion by a microcomputer 7 with an A/D converter; thereafter, the voltage is subjected to a signal processing in a comparing and deciding circuit which internally executes comparison and decision and an arithmetic processing circuit which executes arithmetic processing. The result of the processing is displayed 8.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a device for measuring the mixing ratio of two types of substances mixed together.

Conventional technology When determining the mixing ratio of two types of substances, a sensor measures a certain characteristic of the mixed substance one by one, and then determines a certain threshold based on that characteristic as an absolute value. When there are n items larger than the hold value and m items smaller than the hold value, the mixing ratio is expressed as n/(n+m) or m/(n+m).

However, since the threshold value is an absolute value, a judgment error often occurs when an error occurs in the detection level.

Specifically, for example, when detecting a substance using an optical sensor, there is a concern that the detection level may decrease due to changes in the sensitivity of the optical sensor over time, dirt, etc., making it impossible to accurately measure the mixture rate.

Problems to be Solved by the Invention The present invention aims to make it possible to measure a stable mixture rate even if the detection level changes due to aging, dirt, etc.

Means for solving the problem The signal detected by a sensor for each grain is usually minute, and the moment the substance passes over the sensor, the signal shows a maximum value (or minimum value). Therefore, the present invention provides an amplifier that amplifies the signal from the sensor, a detector that detects the rising edge of this signal waveform, and a peak hold circuit that uses this detection signal as a trigger signal to open the switch gate and stores the voltage level. A converter that converts this voltage level into a digital signal, a determination circuit that determines the magnitude of this digital signal and an output signal that has been shifted back from a subsequent arithmetic processing unit, and an arithmetic processing unit that calculates a relative value from the digital signal. It consists of a circuit.

In other words, the judgment/arithmetic processing circuit does not set the threshold value for determining the mixing ratio of two types of substances as an absolute value, but uses a method of relatively changing the threshold value to detect changes in the detection level due to aging, dirt, etc. This allows for stable mixing ratios to be measured.

A sensor detects the characteristics of the substance containing the active species and B species one by one, and the detection signal is connected to an amplifier. As time passes, this amplified detection signal successively generates peak voltage signals of V for type A, V□ for type B, etc. These peak voltage rising signals are detected by a rising detection circuit,
A peak hold circuit instantly holds the peak voltage. These are processes to ensure the next stage analog/digital conversion time.

All analog/digital conversion is performed for each peak waveform. The digital signals are transferred to a comparator circuit, and compared at a threshold level V, the largest digital signal of a certain amount or period of time is selected (
vM□X) and the smallest one (V□, 1) 1-extract;
It is transmitted to the arithmetic processing circuit.

Preliminary experiments etc. required meta v,, > V, B(V,, <
V, B) (7) Relationship, maximum vPi = vWAX,
min'/,B=V,,.

(f&dogV,, = VMAx, minimum V,, = V,
XN) +7) Since the equivalence formula holds, vPA and V, B
The threshold level for determining f is calculated as shown below.

V, = a ・V, A, tenβ・vM! N (α+
β=1) In the above formula, α and β are experimental values v, and vM &! "" represents the ratio between 7101.

The VTf obtained by the above calculation is fed back to the comparison circuit.

As a result, by updating v by a certain amount or at regular intervals, even if the sensor output decreases overall due to dirt, etc., V also decreases at the same rate and changes relatively, so it can be detected. Even if the level changes due to aging or dirt, a stable mixture rate can be measured.

Embodiment FIG. 1 shows a circuit according to an embodiment of the present invention, and its operation is to maintain the mixing ratio of two types of plastic pieces at 80% and to display the mixing ratio.

A plastic piece 3 is passed between the light emitting diode 1 and the phototransistor 2 for measuring the mixing ratio.

When two types of plastic pieces 3 having different light transmittances are present in this plastic piece 3, the mixing ratio is determined by the following operation.

e)) The output of the detection section such as the run raster 2 is amplified by an amplifier section such as an operational amplifier 4, and is carried out by a rise detection full rise detection circuit 6, which is a gate circuit, to generate a MU/D conversion start signal. It is transmitted to a peak hold circuit 6 which stores all voltage levels.

The peak voltage amplified by the amplifier section is held by this peak hold circuit 6, and after being subjected to Mu/D conversion by a microcomputer 7 equipped with a Mu/D converter (-), it is internally converted.

Signals are processed by a comparison/determination circuit that performs comparison and determination, and an arithmetic processing circuit that performs arithmetic processing.

Calculations and processing are performed as follows.

Maximum peak voltage V from the data for every 1000 grains stored in the memory section of the microcomputer T. Read out X and the minimum peak voltage vMIN. According to preliminary research, the above two types of plastic pieces have light transmittance characteristics of υ, threshold level V, eVM, and vM.
l) Since it is known that it should be set in the middle of l, v
The calculation of , is v=o, 6xv +o, sxv □.

I will use this V to judge the size of 1000 grains of data without hitting it with Tesamu X.

Thereafter, V is updated one after another every 1000 grains and changes relatively.

The mixing ratio is determined by the number of data with a value larger than vT and the number of data with a value smaller than vT.

The microcomputer 7 that calculated the mixing ratio is.

A signal is sent to a display unit 8 that informs the person of the mixing ratio and to a control circuit 9 that maintains the mixing ratio of the two types of plastic pieces at '6so%.

Effects of the Invention As described above, according to the present invention, by relatively detecting two mixed substances, it is possible to obtain a stable mixing ratio against aging and dirt.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a mixture ratio measuring device according to an embodiment of the present invention. 1...Light emitting diode, 2...Phototransistor, 3...Plastic piece to be measured,
4... operational amplifier, 6... rise detection circuit, 6... peak hold circuit, T...
...Microcomputer, 8...Display section, 9
...control circuit. Name of agent: Patent attorney Shigetaka Awano and one other person
(Procedural amendment 1. Indication of the case 2. Name of the invention Mixed rate measuring device 3. Person making the amendment Relationship with the case Patent applicant address 1006 Kadoma, Kadoma City, Osaka Prefecture Name
(582) Matsushita Electric Industrial Co., Ltd. Representative Tani
Akio I 4 Agent 571 Address 1006 Oaza Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. Column for detailed description of the invention in the specification subject to the 6th amendment

Claims (1)

[Claims] An amplifier that amplifies the signal from the sensor, a detector that detects the rising edge of this signal waveform, a peak hold circuit that uses this detection signal as a trigger signal to open the gate and stores the voltage level, and converts this voltage level into a digital signal. A mixture ratio measurement system consisting of a converter to convert, a judgment circuit that judges the magnitude of this digital signal and an output signal fed back from a subsequent arithmetic processing section, and an arithmetic processing circuit that calculates a relative value from the digital signal. Device.