JP2602135Y2 - Sensor output circuit - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor output circuit for displaying not only a sensor output but also a connection state of a sensor circuit.

[0002]

2. Description of the Related Art Circuits shown in FIGS. 6, 7 and 8 are known as conventional sensor output circuits for binarizing and outputting this kind of sensor output.

FIGS. 6 and 7 show a photo-interrupter 1.
2 is binarized by the interface circuit 2 and output from the output terminal 10. The difference between the circuits shown in FIGS. 6 and 7 is that the circuit shown in FIG. 6 uses an NPN transistor for the interface circuit 2, and the circuit shown in FIG. 7 uses a PNP transistor for the interface circuit 2. Only points. LED (Ligh) at the collector output of the transistor of interface circuit 2
t Emitting Diode) to display the binarized output.

FIG. 8 shows a configuration in which a plurality (N) of sensors 16 and interface circuits 2 are provided, and the output of each sensor 16 is binarized by the interface circuit 2 and output from the output terminal 10. . In the circuit shown in FIG. 8 as well, the LED is driven by the collector output of the transistor of the interface circuit 2 to display a binarized output. In addition, the display circuit 25 and a plurality (N) of zeners are displayed. A diode is provided to detect and display that the signal line is in a short state.

[0005]

However, in the above-described conventional sensor output circuit, the LED is driven to
Since only the digitized output is displayed, the connection state of the circuit such as the short-circuit state of each signal line cannot be displayed unless the detection target is detected. Further, in the circuit shown in FIG. 8, it cannot be determined which signal line is in the short state. For this reason, when performing maintenance and the like, labor and labor are required, and there is also a problem that work cannot be performed efficiently.

Further, as disclosed in Japanese Utility Model Laid-Open No. 59-41837, a circuit is known in which a display means (LED) is inserted into a signal line connecting a sensor and an interface circuit. The disconnection state, short-circuit state, or normal state of the signal line cannot be displayed with the three gradations of the display means.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems. In a sensor output circuit which displays not only the sensor output but also the connection state of the sensor circuit, the object to be detected is not sensed. It also displays the connection state of the sensor circuit, and if there are multiple sensor circuits, it is possible to display the connection state of each circuit individually, with the purpose of easily and reliably grasping the connection state of the sensor circuit .

[0008]

In order to achieve this object, a sensor output circuit according to the present invention has a sensor circuit whose output impedance changes according to a detection state, and binarizes the output of the sensor circuit and outputs it to the outside. An interface circuit, a display unit inserted into a signal line connecting the sensor circuit and the interface circuit, and a resistance circuit connected to a signal line between the sensor circuit and the display unit, and a disconnection state of the signal line; It is configured to display the short state or the normal state with three gradations of the display means.

[0009]

In the sensor output circuit having the above-mentioned structure, display means is inserted into a signal line connecting a sensor circuit whose output impedance changes according to a detection state and an interface circuit which binarizes the output of the sensor circuit and outputs the binary signal to the outside. Since the resistance circuit is connected to the signal line between the sensor circuit and the display means, the display of the display means changes to three gradations depending on the connection state of the signal line. The connection state of the sensor circuit can be displayed.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a first embodiment of a sensor output circuit according to the present invention. In the figure, 1 is a sensor circuit, and 12 is a photo interrupter as a sensor of the sensor circuit 1. The sensor circuit 1 has a configuration in which the output impedance changes according to the detection state (on / off operation) of the photo interrupter 12. The resistor 6 of the sensor circuit 1 generates a potential difference between both ends, and the resistor 6 has a function of suppressing power supply to the light emitting diode 3 when the photo interrupter 12 is in an ON state.

A power supply voltage is applied to the light emitting diode 12a of the sensor circuit 1 from the power supply 4 via the power supply line 5c and the resistor 17, and the light emitting diode 12a emits light toward the phototransistor 12b. The power supply voltage of the power supply 4 is applied to the phototransistor 12b via the resistors 6 and 8. The connection point between the resistor 6 and the resistor 8 is
Transistor 2 through a series circuit of
a. A bias voltage is applied to the base of the transistor 2a from the power supply voltage of the power supply 4 via the resistor 2b, and the collector voltage of the transistor 2a is output from the output terminal 10
Output to the outside.

When an object to be detected (not shown) is not close between the light emitting diode 12a and the phototransistor 12b, the phototransistor 12b is turned on,
The output impedance of the sensor circuit 1 becomes low. At this time, the output voltage of the sensor circuit 1 becomes substantially equal to the value obtained by dividing the power supply voltage by the ratio of the resistor 6 and the resistor 8. The output voltage of the sensor circuit 1 is applied to the base of the transistor 2a of the interface circuit 2 through the series circuit of the resistor 7 and the light emitting diode 3, and the transistor 2a
Is turned on and the light emitting diode 3 is turned on.

When an object to be detected comes close to between the light emitting diode 12a and the phototransistor 12b, the phototransistor 12b is turned off and the sensor circuit 1 is turned off.
Output impedance is high. When the phototransistor 12b is turned off, the output voltage of the sensor circuit 1 becomes substantially equal to the power supply voltage, and the transistor 2a
Is turned off and the light emitting diode 3 is turned off.

If the sensor line 5a and the earth line 5b are short-circuited due to an accident, the resistance 6 and the resistance 8
Is connected to the ground, and the transistor 2
The light emitting diode 3 is turned on at the same time as a is turned on. At this time, the voltage at the connection point between the resistor 6 and the resistor 8 is the same as the voltage between the resistor 6 and the resistor 8 when the object to be detected is not close between the light emitting diode 12a and the phototransistor 12b.
Is lower than the voltage at the connection point with the light emitting diode 3
Lights up brighter.

If any one or more of the sensor line 5a, the ground line 5b, and the power supply line 5c is disconnected due to an accident, the connection point between the resistors 6 and 8 becomes substantially equal to the power supply voltage. Is turned off and the light emitting diode 3 is turned off.

FIG. 2 is a block diagram showing a second embodiment of the sensor output circuit according to the present invention. The second embodiment is characterized in that the output impedance is high when the contact switch 14 as a sensor of the sensor circuit 1 is turned on, and the output impedance is low when the contact switch 14 is turned off. Unlike the first embodiment, the resistor 6 serves to suppress the power supply to the light emitting diode 3 when the contact switch 14 is in the off state.

The contact switch 14 of the sensor circuit 1 includes:
A power supply voltage is applied from the power supply 4 via the resistors 8 and 27. The contact switch 14 is turned on only when an object to be detected is in proximity, and maintains the off state for the rest. The contact switch 14 is connected between the base and the emitter of the transistor 22, and the collector of the transistor 22 has a resistor 6
Are connected at one end. The other end of the resistor 6 is connected to the resistor 8 via the sensor line 5a. The other end of the resistor 8 is connected to the power supply 4 and a power supply voltage is applied.

The connection point between the resistors 6 and 8 is connected to the light emitting diode 13a of the photocoupler 13 via a series circuit of the resistor 7 and the light emitting diode 3. Therefore, the light emitting diode 3 and the light emitting diode 13
a turns on and off simultaneously. Power is supplied from the power supply 4 a to the phototransistor 13 b of the photocoupler 13, and the emitter output of the phototransistor 13 b is output from the output terminal 10 as the output of the interface circuit 2.
Output to the outside.

When the object to be detected is not close to the contact switch 14, the contact switch 14 is kept off and the transistor 22 is turned on. When the transistor 22 is turned on, the output impedance of the sensor circuit 1 becomes low. At this time, the sensor circuit 1
Is substantially equal to a value obtained by dividing the power supply voltage by the ratio of the resistor 6 and the resistor 8. Since the output voltage of the sensor circuit 1 is applied to the cathode of the light emitting diode 13a via the series circuit of the resistor 7 and the light emitting diode 3, the light emitting diode 13a is turned on and the light emitting diode 3 is also turned on.

When the object to be detected approaches the contact switch 14, the contact switch 14 is turned on and the transistor 22 is turned off. When the transistor 22 is turned off, the output impedance of the sensor circuit 1 becomes high. At this time, since the output voltage of the sensor circuit 1 becomes substantially equal to the power supply voltage, the light emitting diode 13
a is turned off, and the light emitting diode 3 is also turned off.

If the sensor line 5a and the ground line 5b are short-circuited due to an accident, the resistance 6 and the resistance 8
Is connected to ground, so that the light emitting diode 13a is turned on. At this time, the light emitting diode 3 is also turned on. Since the voltage at the connection point between the resistor 6 and the resistor 8 at the time of the short circuit is lower than the voltage at the connection point between the resistor 6 and the resistor 8 when the detection target approaches the contact switch 14, the light is lit brighter.

If the sensor line 5a or the ground line 5b is broken due to an accident, the resistance 6 and the resistance 8
Is almost equal to the power supply voltage, the light emitting diode 13a is turned off, and the light emitting diode 3 is also turned off.

FIG. 3 is a block diagram showing a third embodiment of the sensor output circuit according to the present invention. The third embodiment is characterized in that the output impedance becomes substantially zero Ω when the contact switch 14 is turned on, and the output impedance becomes high when the contact switch 14 is turned off. Unlike this, the contact switch 14 and the resistor 9 of the sensor circuit 1 are connected in parallel. Resistance 9
Plays a role in conservatively supplying power to the light emitting diode 3 when the contact switch 14 is in the off state.

The contact switch 14 is turned on only when an object to be detected (not shown) approaches, and is kept off for the rest. The power supply voltage of the power supply 4 is applied to the resistor 9 via the resistor 8 by the sensor line 5a. Resistance 9
The connection point of the resistor 8 and the resistor 8 is connected to the base of the transistor 2a via a series circuit of the resistor 7 and the light emitting diode 3. The base of the transistor 2a is connected to the ground potential via the resistor 2b. The collector voltage of the transistor 2a is output from the output terminal 10 to the outside as an output of the interface circuit 2.

When the object to be detected is not close to the contact switch 14, the contact switch 14 is kept off and the output impedance of the sensor circuit 1 is high. At this time, the output voltage of the sensor circuit 1 is
It is a value obtained by dividing the power supply voltage by the ratio of the power supply voltage and the resistance 8. This voltage is applied to the base of the transistor 2a of the interface circuit 2 via the series circuit of the resistor 7 and the light emitting diode 3, and the light emitting diode 3 is turned on and the transistor 2a is turned on.

When the object to be detected comes close to the contact switch 14, the contact switch 14 is turned on, and the output impedance of the sensor circuit 1 becomes low. At this time, since the output voltage of the sensor circuit 1 becomes substantially equal to the ground potential, the light emitting diode 3 is turned off and the transistor 2a is turned off.

If the sensor line 5a and the ground line 5b are short-circuited due to an accident, the resistance 9 and the resistance 8
Is grounded, the light emitting diode 3 is turned off, and the transistor 2a is turned off.

If the sensor line 5a or the ground line 5b is broken due to an accident, the resistance 9 and the resistance 8
Is substantially equal to the voltage value obtained by subtracting the voltage drop due to the resistor 8 from the power supply voltage, so that the light emitting diode 3 is turned on and the transistor 2a is turned on. At this time, the voltage at the connection point between the resistance 9 and the resistance 8 is higher than the voltage at the connection point between the resistance 9 and the resistance 8 when the object to be detected is not close to the contact switch 14. .

FIG. 4 is a block diagram showing a fourth embodiment of the sensor output circuit according to the present invention. The fourth embodiment differs from the first to third embodiments in that the light emitting diode 3 is connected to the signal line in the sensor circuit 1.
The disconnection detection circuit 24 is connected to the power supply line 5c and the earth line 5b in the sensor circuit 1.

The magnetic detection switch 15 as a sensor of the sensor circuit 1 is turned on only when an object to be detected (not shown) is in proximity, and maintains the off state for the rest. The collector of the output transistor 15a of the magnetic detection switch 15 is connected to the power supply 4 via the resistor 7 and the disconnection detection circuit 24.
Is applied. In the disconnection detection circuit 24, the emitter of the transistor 24a is connected to the power supply line 5c,
The base is connected to the ground line 5b via the resistor 24c. The emitter and the base of the transistor 24a are connected via a resistor 24b. Therefore, when the emitter of the transistor 24a is connected to the power supply line 5c and the base is connected to the ground line 5b, a bias voltage is applied between the base and the emitter, and the transistor 24a is turned on. At this time, a current flows through the collector of the transistor 24a, and the light emitting diode 3 is turned on. When the ground line 5b is disconnected, the bias voltage between the base and the emitter disappears, and the transistor 24a is turned off. At this time, the transistor 24a
Does not flow, and the light emitting diode 3 is turned off.

The resistors 7 and 8 are connected via the light emitting diode 3, and the light emitting diode 3 is connected via the resistor 2d to the base of the transistor 2a. The base of the transistor 2a is connected to the ground potential via the resistor 2b. The collector voltage of the transistor 2a is output from the output terminal 10 to the outside as an output of the interface circuit 2.

When the object to be detected is not in proximity to the magnetic detection switch 15, the magnetic detection switch 15 is kept off, and the output impedance of the magnetic detection switch 15 is high. At this time, the output voltage of the sensor circuit 1 becomes a value close to a value obtained by dividing the power supply voltage by the ratio of the resistors 7 and 8. This voltage is applied to the base of the transistor 2a of the interface circuit 2 via the light emitting diode 3 and the resistor 2d, turning on the light emitting diode 3 and turning on the transistor 2a.

When the detection target approaches the magnetic detection switch 15, the magnetic detection switch 15 is turned on. At this time, since the output impedance of the magnetic detection switch 15 is in a low state, a voltage substantially close to the ground potential is applied to the light emitting diode 3, turning off the light emitting diode 3 and turning off the transistor 2a.

When the sensor line 5a and the earth line 5b are short-circuited due to an accident, the connection point between the light emitting diode 3 and the resistor 8 is grounded, and the light emitting diode 3 is turned on. Light emitting diode 3 at this time
Is at the ground potential, so that the light emitting diode 3 lights up brighter than when the detection target is not close to the magnetic detection switch 15.

When one or more of the sensor line 5a, the ground line 5b, and the power supply line 5c is disconnected due to an accident, the voltage difference applied to both ends of the light emitting diode 3 becomes almost zero. 3 goes out.

FIG. 5 is a block diagram showing a fifth embodiment of the sensor output circuit according to the present invention. This fifth embodiment is similar to the first embodiment, the second embodiment, and the third embodiment.
The on / off operation of the sensor 16 is output as a change in impedance without using the resistors 6 and 9 described in the embodiment.

The output impedance of the sensor 16 of the sensor circuit 1 is increased only when an object to be detected (not shown) is close to the sensor 16; The sensor circuit 1 is connected in series with the resistor 8, and a value obtained by dividing the power supply voltage between the two is applied to the light emitting diode 3 via the resistor 7. This voltage is supplied to the base of the transistor 2a. The base of the transistor 2a is connected to the ground potential via the resistor 2b. The collector voltage of the transistor 2a is output from the output terminal 10 as the output of the interface circuit 2.
Output to the outside.

When the object to be detected is not close to the sensor 16, the output impedance of the sensor 16 becomes small. At this time, a voltage obtained by dividing the power supply voltage by the ratio between the output impedance of the sensor 16 and the resistor 8 is applied to the light emitting diode 3 via the resistor 7,
Lights up. This voltage is applied to the base of the transistor 2a, turning on the transistor 2a.

When an object to be detected comes close to the sensor 16, the output impedance of the sensor 16 increases, and a voltage substantially equal to the ground potential is applied to the light emitting diode 3 via the resistor 7, and the light emitting diode 3 is turned off. This voltage is applied to the base of the transistor 2a, turning off the transistor 2a.

When the power supply line 5c and the sensor line 5a are short-circuited due to an accident, the power supply voltage is applied to the series circuit of the resistor 7 and the light emitting diode 3, so that the light emitting diode 3 is turned on and the transistor 2a is turned on. State. At this time, since a voltage higher than the voltage when the detection target is not close to the sensor 16 is applied to the anode of the light emitting diode 3, the light emitting diode 3 does not have the detection target close to the sensor 16. Lights up brighter than when.

If the power supply line 5c or the sensor line 5a is disconnected due to an accident, the light emitting diode 3
Since the voltage applied to the anode of the transistor becomes almost the ground potential, the light emitting diode 3 is turned off and the transistor 2 is turned off.
a is turned off.

As can be understood from the above-described five embodiments, when the object to be detected does not approach, pass through, or separate from the sensor (state in which the object to be detected is not sensed), the display of the light emitting diode 3 is turned off, turned on, and further turned on. It will be in one of the three brightly lit states. The three states correspond to disconnection, normal, and short in the first, second, fourth, and fifth embodiments, respectively. Further, in the third embodiment,
Corresponds to normal and disconnection. Therefore, by displaying these three states, the sensor circuit 1 and the interface circuit 2 are displayed.
Can be determined.

When an object to be detected approaches, passes, or separates from the sensor, the display of the light emitting diode 3 is kept off and blinks (lights up in accordance with approaching, passing, and separating).
(The state of turning off and lighting) and one of the three states in which the light remains brighter than when blinking. The three states correspond to disconnection, normal, and short in the first, second, fourth, and fifth embodiments, respectively. Further, the third embodiment corresponds to short, normal and disconnection. Therefore,
By displaying these three states, the connection state between the sensor circuit 1 and the interface circuit 2 can be determined.

When the detection target stays at the sensor,
The display of the light-emitting diode 3 is in one of two states: off or brightly lit, and the connection state between the sensor circuit 1 and the interface circuit 2 (disconnection, normal, and short) cannot be determined. Therefore, the sensor output circuit according to the present invention is not suitable for use in which the detection target stays at the sensor, but is not suitable for use in which the detection target does not stay at the sensor (for example, a circuit for detecting the passage of a pachinko ball). Optimal.

In the first to third embodiments, the resistor 6 or the resistor 9 is provided in the sensor circuit 1, but a Zener diode or the like may be provided instead of the resistor 6 or the resistor 9.

According to the above-described embodiment, the connection state of the sensor circuit is not limited to the state in which the detection target approaches, passes, and separates from the sensor, but also the state in which the detection target does not approach, pass, and separate from the sensor. Can be displayed. That is, the connection state of the sensor circuit can be checked without causing the sensor to detect the detection target. Further, even if a large number of sensor circuits are mounted on a single machine such as a pachinko machine, the connection states of all the sensor circuits can be individually displayed without increasing the cost.

Further, since the connection state of each sensor circuit can be easily determined, maintenance work of each sensor circuit can be performed efficiently.

[0049]

As described above, according to the sensor output circuit of the present invention, the sensor circuit whose output impedance changes according to the detection state, and the interface circuit that binarizes the output of this sensor circuit and outputs it to the outside. By inserting the display means into the connected signal line and connecting the resistance circuit to the signal line between the sensor circuit and the display means, the display on the display means changes to three gradations depending on the connection state of the signal line. It is possible to display the connection state of the sensor circuit by displaying three gradations. As a result, the connection state of the sensor circuit can be displayed without sensing the object to be detected, and if there are multiple sensor circuits, the connection state of each circuit can be displayed individually, making it easier to connect the sensor circuits. And it becomes possible to grasp it reliably.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of a sensor output circuit according to the present invention;

FIG. 2 is a block diagram showing a second embodiment of the sensor output circuit according to the present invention;

FIG. 3 is a block diagram showing a third embodiment of the sensor output circuit according to the present invention;

FIG. 4 is a block diagram showing a fourth embodiment of the sensor output circuit according to the present invention;

FIG. 5 is a block diagram showing a fifth embodiment of the sensor output circuit according to the present invention;

FIG. 6 is a block connection diagram showing an example of a conventional sensor output circuit.

FIG. 7 is a block diagram showing an example of a conventional sensor output circuit.

FIG. 8 is a block connection diagram showing an example of a conventional sensor output circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sensor circuit 2 Interface circuit 2a Transistor 2b Resistance 2c Resistance 2d Resistance 3 Light emitting diode 4 Power supply 5a Sensor line 5b Earth line 5c Power supply line 6 Resistance 7 Resistance 8 Resistance 9 Resistance 10 Output terminal 12 Photo interrupter 12a Light emitting diode 12b Phototransistor 13 Photo Coupler 13a Light emitting diode 13b Phototransistor 14 Contact switch 15 Magnetic detection switch 16 Sensor 17 Resistance 23 Detection circuit 23a Transistor 23b Resistance 23c Resistance 24 Disconnection detection circuit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H03K 17/945 H03K 17/18 H03K 17/78

Claims (1)

(57) [Scope of request for utility model registration] 1. A sensor circuit whose output impedance changes according to a detection state, an interface circuit that binarizes an output of the sensor circuit and outputs the binarized output, and a signal line connected to the sensor circuit and the interface circuit. Display means, and a resistance circuit connected to the signal line between the sensor circuit and the display means, wherein a broken state, a short-circuit state, or a normal state of the signal line is displayed on three levels of the display means. A sensor output circuit characterized by displaying in tone.