JPS5926026B2 - Correctness judgment circuit in group reaction analyzer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a correctness determination circuit for a collective reaction analyzer consisting of one master unit and a large number of slave units.
It is particularly suitable as a correctness determination circuit in a two-wire analyzer in which the master unit and each slave unit are connected by two wires.

The correct/incorrect judgment circuit of the present invention uses an exclusive OR function to output a logic "1" signal only in the case of a correct answer, and outputs "o" in all cases of incorrect answers. A diode is connected between both terminals of the logic OR circuit (or element) to generate a potential difference (voltage width) equal to the forward voltage drop of the diode between both input terminals, and this potential difference is maintained to operate the logic circuit. The input voltage is varied up and down around the threshold voltage to obtain correct and incorrect outputs.

According to the present invention, only one exclusive OR circuit is required as the determination circuit corresponding to each child device in the parent device, so the circuit configuration is simple and accurate operation can be achieved.

The configuration of the circuit of the present invention will be explained with reference to the drawings.

R(a-n) is a child device, and P is a parent device, and a reply signal processing circuit P(a-n) is provided in the parent device corresponding to each child device. The slave unit R is configured to include a resistance value switching circuit A, which is known per se, and has option response switches 51 to 55 for switching resistance values R, to R5.

The common terminal of the switching resistors R1 to R5 of each slave unit is connected to the ground wire Li.
The common contacts of the response switches 51 to 55 are connected to the base unit through a signal line L2.

VP is a voltage setting circuit that outputs a predetermined voltage stepwise by correct answer setting switches P1 to P5.

EX is an exclusive OR circuit (hereinafter abbreviated as EX-OR) composed of a MOS type IC, and the above-mentioned correct answer setting voltage is supplied to its input terminal a via a voltage dividing resistor 2. .

A diode D1 is connected between both input terminals ab of EX-OR with its anode side connected to terminal a.

Note that R2 is a resistor for protecting the diode D1, and has approximately the same value of S as r1, but is not essentially necessary.

z is a protective constant voltage diode of EX-0R.

In the present invention, the switching resistors R1 to R5 correspond to the correct answer voltages set by the correct answer setting switches P1 to P5 of the voltage setting circuit, and the answer switches S1 to S5 of the handset correspond to the correct answer setting switches P1 to P5 of the voltage setting circuit. ), the value is selected such that the input voltage is applied to both input terminals of EX-0R with the threshold voltage sandwiched therebetween. As a result, the a terminal voltage Va
is above the threshold voltage, and when the b terminal voltage Vb, which has a potential difference of the voltage drop d due to the diode D1, becomes below the threshold voltage, the logic output of EX-0R is "1".
judge the correct answer.

In the present invention, Va<
Since there is no human power relationship such as Vb, the input voltage relationship that produces a correct output is limited to the above case, and when the voltage across Ab is simultaneously above the threshold or below the threshold, both are logical
0'', that is, an incorrect answer is output.

Next, the operation of the circuit of the present invention will be specifically explained.

The voltage between the EX-0Rf)Ab input terminals is always constant (for example, 0.6 V) due to the diode D, and Va>Vb. The response voltage Vb appearing at the b terminal is essentially a voltage divided by the resistor r1 and one of the resistors R1 to R5 of the slave unit. Now, assuming that the power supply voltage of EX-0R is 5 and the threshold voltage is 2.5V, EX-0R
The logic output of 0R becomes "1" only when a is 2.5V or more (logic "1") and b is below 2.5V (logic "O"), and the output of the slave unit is Pressure switching resistance R1 to R5
is selected so that the above conditions are satisfied when the answer is correct with respect to the set voltage of the base unit, and a voltage of 2.5 V or more or 2.5 V or less is applied when the answer is wrong. For example, if the correct answer to a certain question is black 3, the setting switch P on the base unit
3 is set to 0N, and the voltage setting circuit VP outputs a set voltage based on it.

At this time, if the answer switch S3 of the slave unit is turned on, E
With a potential difference of 0.6 V between the voltages at both terminals Ab of X-0R, a is 2.5 V or more and b is 2.5 V or less, and a logic "1" is output. In this case, if a switch other than switch S3 is turned on, the logic input will be "0""0" or "1""
1, so the logic output of EX is (・Even in the case of deviation, it is 0
” In other words, it is a wrong answer. The output voltage of the logic output "1" of EX-0R charges the memory capacitor C through the reverse current prevention diode D2, and also lights up the correct answer display lamp Y through the buffer circuit B, or is used as an input to other display or recording equipment. Signal.

Also, when the student has not answered, the EX-0R input is [
0” [0], which is the same as an incorrect answer output.

In addition, in the figure, an incorrect answer display circuit and the like are not shown because they are not directly related to the present invention. In the example circuit shown in the figure, if the student who selected the correct answer presses the wrong answer switch during the question, that is, the output of EX-0R changes from "1" to
When it becomes "0", the voltage of the voltage memory capacitor C is discharged through the diode D3, so it does not affect the output of incorrect answers.Therefore, no matter how many times you answer one question, the final answer is always the same. The correctness or wrongness of this is determined.

[Brief explanation of the drawing]

The figure is a wiring diagram of a collective reaction analyzer equipped with the circuit of the present invention.

Claims (1)

[Claims] 1. In a collective reaction analyzer consisting of a large number of slave units and a master unit, each slave unit is equipped with a resistance value switching circuit in which the resistance value is switched by a multiple-choice answer switch, and the common terminal on the resistor side and the common contact of the switch are connected. The main unit is connected to the main unit by a ground wire and a signal line, and the main unit has a voltage setting circuit that generates a predetermined voltage using a correct answer setting switch, and an exclusive OR circuit that has a diode connected between the input terminals. the correct answer setting voltage is supplied to the anode side of the diode, and the signal line is connected to the cathode side of the diode, and only when the slave unit selects the correct answer. When each input terminal voltage of the exclusive OR circuit becomes higher than or equal to the threshold voltage of the exclusive OR circuit, a logic "1" is output as a valid output, and "0" is output in the case of an incorrect answer. What is claimed is: 1. A correctness/incorrect determination circuit in a group reaction analyzer, characterized in that the circuit outputs the following.