JPH0537334Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention is a material sorting circuit for sorting whether the material of coins inserted into telephones, vending machines, etc. has a predetermined material. Regarding.

[Conventional technology]

When sorting out whether coins inserted into telephones, vending machines, etc. are genuine or fake, it is necessary to determine whether the material of the coins, etc. has a predetermined material, and to determine whether the coins, etc. If it is not, a method is used to easily identify it as a fake coin.

To electrically determine the material, it is sufficient to interpose the object to be determined between the input coil and the output coil, and to detect changes in mutual inductance occurring between the input coil and the output coil.

The structure of a conventional material selection circuit based on this principle will be explained with reference to FIG.

In Fig. 2, the detection coil 1 is the input coil 1.
1 and an output coil 12, and a coin 13 is interposed between the input coil 11 and the output coil 12.

An oscillation signal from the oscillator 2 is input to this input coil 11 .

This oscillator 2 is provided with a variable resistor VR, so that the magnitude of the voltage of the oscillation signal output from the oscillator 2 can be changed.

Further, the output voltage output from the output coil is amplified via an amplifier 3 and input to a rectifier circuit 4.

The DC voltage rectified by the rectifier circuit 4 is input to the positive input terminal 51a of the first comparator 51 and the positive input terminal 52a of the second comparator 52.

On the other hand, between the power supply 8 and the ground, there are
A series circuit in which voltage dividing resistors R ₁ , R ₂ and R ₃ are connected in series is connected, and the connection point of the first and second voltage dividing resistors R ₁ and R ₂ is connected to the first comparator. The connection point between the second and third voltage dividing resistors R ₂ and R ₃ is connected to the negative input terminal 52 b of the second comparator 52 .

Also, the output terminals 5 of the first and second comparators 51 and 52
The signals outputted from 1c and 52c are input to a discriminating means 7 composed of a microcomputer or the like.

Here, if the voltage of the power supply 8 is V, the negative input terminal of the first comparator 51 has (R ₂ +R ₃ )V/
This means that the upper limit setting voltage V _H of (R ₁ + R ₂ + R ₃ ) is input.

Further, the lower limit setting voltage V _L of R ₃ V/(R ₁ +R ₂ +R ₃ ) is input to the negative input terminal of the second comparator 52.

In this case, each of the first and second comparators 51 and 52 operates when the voltage input to the positive input terminals of the comparators 51 and 52 is higher than the voltage input to the negative input terminals of the comparators. It outputs an H level signal, and otherwise outputs an L level signal.

In the material selection circuit configured in this way,
When adjusting the circuit, first a reference object to be measured, such as a real coin, is interposed in the detection coil 1, or a detection coil having the same characteristics as when the reference object to be measured is interposed is set.

At this time, the rectified voltage output from the rectifier circuit 4 is measured with a voltmeter 6, and the variable resistor VR provided in the oscillator 2 is adjusted so that this voltage becomes the adjusted voltage _V1 to be adjusted.

At this time, the upper limit set voltage V _H input to the negative input terminal 52b of the first comparator 51 is set so that the set voltage V _H =adjusted voltage V ₁ + allowable voltage V _A , and the second comparator The lower limit setting voltage V _L input to the negative input terminal 52b of 52 is determined by adjusting the values of the first, second, and third voltage dividing resistors so that the setting voltage V _L =adjusted voltage V ₁ - allowable voltage V _A. is predetermined. Thereby, the adjusted voltage V ₁ is set to a voltage value intermediate between the upper limit set voltage V _H and the lower limit set voltage V _L , and the relationship of V _H > V ₁ > V _L is obtained.

Therefore, the coil 1 detects a coin, etc. that serves as a reference.
If the rectified voltage output from the rectifier circuit 4 is adjusted to a predetermined adjustment voltage V ₁ when the voltage is interposed between the input coil 11 and the output coil 12 of the detection coil 1, it is possible to When an object to be measured is present, if the object to be measured, such as a coin, is genuine, the output of the first comparator 51 will be an L level signal, and the output of the second comparator 52 will be an H level signal. .

Therefore, if the first and second comparators 51 and 52 output signals other than this combination, it can be determined that the signals are fake, that is, they do not have the specified material, and the material can be selected. Become.

Note that this selection is processed by the discriminating means 7.

[Problem that the invention attempts to solve]

Since the conventional material selection circuit was constructed as described above, the following problems occurred.

When adjusting the circuit, the rectified voltage output from the rectifier circuit is measured with a voltmeter, and when the variable resistor of the oscillation circuit 2 is adjusted, the output voltage of the rectifier circuit decreases due to the input impedance of the voltmeter. 1. Since the voltage input to the second comparator decreases, the variable resistor cannot be adjusted accurately so that the rectified voltage output from the rectifier circuit becomes the predetermined adjusted voltage _V1 . Furthermore, since a voltmeter is used during adjustment, for example, when it is necessary to adjust the output voltage of an oscillator on site, the voltmeter must be carried, which is inconvenient.

This idea was made to solve the above problems, and in order to be able to accurately adjust the rectified voltage and eliminate the inconvenience of carrying a voltmeter, we created a material selection circuit that does not require a voltmeter. The purpose is to obtain.

[Means for solving problems]

In order to achieve the above object, the present invention includes a detection coil 1 having an input coil 11 and an output coil 12; The output signal output from the output coil 12 is input to one input terminal 51a of the comparator 51,
1, the voltage of the output signal and a predetermined set voltage inputted to the other input terminal 51b of the comparator 51.
In the material selection circuit that selects the material of the object to be measured 13 by comparing V _H with: an oscillator 2 that outputs an oscillation signal to the input coil 11; a variable resistor that varies the voltage value of the output signal of the oscillator 2; VR; an adjustment resistor R for adjusting the voltage of the output signal output from the output coil 12 to the adjustment voltage _V1 ; and inputting the predetermined set voltage _VH to the comparator 51. It has a normal side contact S, and an adjustment side contact M that inputs the output signal of the adjustment voltage V ₁ adjusted by the adjustment resistor R to the comparator 51, and by switching the contact, either output is set to the comparison a switch SW input to the other input end 51b of the device 51; when the switch SW is switched to the adjustment side contact M, it is determined that the output signal from the output coil 12 is equal to the adjustment voltage _V1 ; In addition, when the switch SW is switched to the normal side contact S, a discrimination means 7 is provided for discriminating the material of the object to be measured 13 based on the output voltage of the comparator 51, and the switch SW is switched to the adjustment side contact M. By stopping the variation of the variable resistor VR at the point where the output voltage of the output coil 12 becomes equal to the adjustment voltage V ₁ as determined by the discrimination means 7 when the switch is switched, the output of the output terminal 51c of the comparator 51 is The present invention is characterized in that the voltage of the output signal is adjusted to the predetermined adjustment voltage _V1 by obtaining the change point of the signal level.

[Effect]

During adjustment, the switch SW is switched to the adjustment side contact M, and the oscillator 2 is connected to the input terminal 51a of the comparator 51.
In addition, the voltage applied to the adjustment resistor R is input to the input terminal 51b.

The adjustment resistor R holds the adjustment voltage V ₁ to be adjusted, and the output coil 12 is controlled by the variable resistor VR.
The comparator 51 outputs an output only when the voltage of the output signal output from the adjusting resistor R is the same as the voltage point, and the determining means 7 determines the adjustment point. When the variable resistance VR stops changing at this adjustment point, the output voltage of the output coil 12 becomes the adjustment voltage _V1 .

After completing this adjustment, switch switch SW to normal side contact M.
Material selection is performed with the adjustment resistor R removed.

〔Example〕

Embodiments of the present invention will be described below based on the drawings. Note that parts having the same configuration as the conventional one are given the same numbers and the explanation thereof will be omitted.

FIG. 1 shows a material selection circuit according to the present invention.

In FIG. 1, the negative input terminal 51b of the first comparator 51, that is, the first and second voltage dividing resistors
One end of the adjustment resistor R is connected to the connection point of R ₁ and R ₂ , and the other end of this adjustment resistor R is connected to the switch.
It is connected to the first movable contact M of the SW.

The stationary contact O of this switch SW is connected to ground, and the second movable contact S is connected to the discriminating means 7 and the resistor R ₄
It is connected to the power supply 9 via.

Here, the switch SW is a two-contact type switch having first and second movable contacts M and S. In order to adjust the circuit, the switch SW is connected to the first movable contact M.
When tilted to the side, the first voltage dividing resistor R ₁ is connected from the power supply 8,
A current flows through the adjustment resistor R and the switch SW, and the voltage applied to the adjustment resistor R is the negative input terminal 51b of the first comparator 51.
It is now entered into .

Also, the switch is turned on for normal material selection operation.
The information that the SW is turned to the first movable contact M side is input to the discrimination means 7,
The determining means 7 can determine whether the output voltage of the first comparator 51 is an H level signal or an L level signal.

Here, the resistance value of the adjustment resistor R is determined by the switch.
It is determined that when the SW is turned toward the first movable contact M, the voltage applied to both ends of the adjustment resistor R becomes the adjustment voltage _V1 .

The value of this adjustment resistor R can be determined by calculation since the voltage V of the power supply 8 and the values of the first, second, and third voltage dividing resistors R ₁ , R ₂ , and R ₃ are known.

However, in such a configuration, the switch SW
When the is moved toward the first movable contact M, the first comparator 5
The voltage at the input terminal 51b of 1 becomes _V1 .

Then, by adjusting the variable resistor VR provided in the oscillator 2 and changing the voltage output from the rectifier circuit 4, as shown in FIG. 3, when the output voltage of the rectifier circuit 4 is _V1 , the output of the first comparator 51 becomes The output signal at the end 51c changes from H level to L level or from L level to H level. The point of change in this level is determined by the determining means 7, and at this point of change, the variable resistor VR
Stop adjusting. This point of change is the point where the voltage output from the rectifier circuit 4 matches V ₁ , so the rectified voltage output from the rectifier circuit 4 is adjusted to the predetermined adjustment voltage V ₁ .

This adjustment voltage V ₁ is set to an intermediate voltage value between the upper limit setting voltage V _H and the lower limit setting voltage V _L , and V _H > V ₁ >
It is a _VL relationship. Then, the first comparator 51 is
The adjustment voltage V ₁ is set to a voltage value different from the upper limit setting voltage V _H.

After this adjustment is completed, by switching the switch SW to the second movable contact side S, the adjustment resistor R is disconnected from the input terminal 51b of the first comparator 51, and the first comparator 51 is set to the upper limit setting voltage. An output of "H" or "L" level can be obtained by using _VH as a comparison level.

Therefore, when an object to be measured such as a coin is interposed, if the object to be measured such as a coin is genuine, the output of the first comparator 51 becomes an L level signal, and the second
The output of the comparator 52 becomes an H level signal, and the determining means 7 determines that the object to be measured is genuine only in this combination.

Therefore, when the first and second comparators 51 and 52 output signals other than this combination, the discriminating means 7 determines that the signal is fake, that is, does not have the predetermined material, and selects the material.

In this embodiment, the adjustment resistor R is connected to the input end 51b of the first comparator 51, but the adjustment resistor R is connected to the input end 51b of the second comparator 52.
2b, a second comparator 52 may compare the voltage applied to the adjustment resistor R with the rectified voltage output from the rectifier circuit 4.

[Effect of idea]

As explained above, the material selection circuit according to the present invention includes an adjustment resistor for adjusting the voltage of the output signal output from the output coil, and a voltage applied to this adjustment resistor by switching at the time of adjustment to the set voltage. A switch is provided at the input end of the comparator where the voltage is input, and the point at which the voltage applied to this adjustment resistor matches the rectified voltage output from the rectifier circuit is the point at which the output signal of the comparator changes. This has the effect of allowing accurate adjustment of the rectified voltage without being affected by the input impedance of the voltmeter when measuring the rectified voltage with a voltmeter.

It is also convenient for on-site adjustments since there is no need to carry a voltmeter.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a material sorting circuit according to the present invention, Fig. 2 is a block diagram of a conventional material sorting circuit, and Fig. 3 is a block diagram of a conventional material sorting circuit.
The figure shows a change in the level of the comparator due to the variable output of the rectifier circuit during adjustment. 1...Detection coil, 7...Discrimination means, 11...
Input coil, 12...Output coil, 13...Device under test, 51...First comparator, 52...Second comparator, R...Adjustment resistor, SW...Switch, V ₁
...Adjustment voltage, VR...variable resistance.

Claims (1)

[Claims for Utility Model Registration] A detection coil 1 having an input coil 11 and an output coil 12; When an input signal is input to the input coil and an object to be measured 13 is brought close to the detection coil, an output is output from the output coil. The output signal is input to one input terminal 51a of the comparator 51, and the comparator compares the voltage of the output signal with a predetermined set voltage _VH input to the other input terminal 51b of the comparator. In a material selection circuit that compares and selects the material of a measured object: an oscillator 2 that outputs an oscillation signal to the input coil;
and; a variable resistor VR that varies the voltage value of the output signal of the oscillator; and an adjustment resistor R that adjusts the voltage of the output signal output from the output coil to the adjustment voltage _V1 .
and; a normal side contact S that inputs the predetermined set voltage V _H set in advance to the comparator, and an adjustment side that inputs the output signal of the adjustment voltage V ₁ adjusted by the adjustment resistor to the comparator. a switch SW having a contact M, and by switching the contact, one of the outputs is inputted to the other input terminal of the comparator; when the switch is switched to the adjustment side contact, the output from the output coil Determining the point where the signal is equal to the regulated voltage V ₁ and when the switch is switched to the normal contact;
and a determination means 7 for determining the material of the object to be measured based on the output voltage of the comparator, and when the switch is switched to the adjustment side contact, the output voltage of the output coil 12 is determined by the determination of the adjustment side contact. By stopping the variation of the variable resistor at a point equal to the voltage _V1 , a point of change in the level of the output signal at the output end of the comparator is obtained, and the voltage of the output signal is adjusted to the predetermined adjustment voltage. A material selection circuit characterized by: