JP3676175B2 - Capacitance type detection device and self-diagnosis device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a capacitance type detection device provided with a capacitance type sensor and a self-diagnosis device for the capacitance type detection device.
[0002]
[Prior art]
Various detection devices using sensors are known. For example, an optical sensor is used as a safety device that detects whether a human hand has approached a production machine or the like. The optical sensor has an advantage that non-contact detection is possible.
[0003]
[Problems to be solved by the invention]
However, since the detection area of the optical sensor is narrow, when trying to expand the detection area, a large number of optical sensors are required and there is a problem in cost.
The present invention has been made in view of the above circumstances, and its object is to provide a detection device using a non-contact sensor capable of sufficiently securing a detection area and a self-diagnosis device for the detection device. It is.
[0004]
[Means for Solving the Problems]
In order to solve the above problems, a capacitance type detection device according to the present invention includes:
An electrode disposed opposite to the grounding portion;
A detection circuit that detects a change in electrostatic capacitance between the electrode and the ground portion is provided.
[0005]
The sensor used in this detection device detects a change in capacitance between the electrode and the grounding portion. When a person or an object enters between the electrode and the grounding part, the capacitance changes. By detecting this, the detection circuit can detect the entry of the person or the object. That is, it is a non-contact type sensor. In addition, the detection area can be easily expanded by sufficiently taking the size of the electrode and the grounding portion. As a result, it is possible to provide a detection device using a non-contact sensor that can secure a sufficient detection area.
[0006]
As a first preferred embodiment of the present invention, comprising a transport means that is transported along a transport path in a state where a metal object and a non-metal object are mixed,
The electrode is arranged to face the grounding part so as to sandwich the object group to be conveyed, and the detection circuit is configured to be able to select a metal object from the mixed object group. It is done.
[0007]
For example, by transporting aluminum cans (metal objects), bottles, PET bottles (non-metal objects) in a mixed manner on a transport means such as a transport conveyor, and passing these between the electrode and the grounding part It is possible to sort only aluminum cans. This is based on the property that the relative permittivity of an aluminum can is different from other non-metallic objects. Thereby, separation of garbage can be performed reliably.
[0008]
As a second embodiment of the present invention, it comprises a transport means that is transported along a transport path in a state where a plurality of objects having different relative dielectric constants are mixed,
The electrode is arranged to face the ground portion so as to sandwich the object group to be conveyed, and the detection circuit is configured to be able to select an object having a specific dielectric constant from the mixed object group What is being done.
[0009]
Although this is a modification of the first embodiment, it pays attention to the property that the dielectric constant is different when the material is different. This makes it possible not only to separate metals but also to separate only specific resin materials from a mixture of many types of resin materials. Thereby, it can be set as the electrostatic capacitance type detection apparatus which can be applied not only to waste separation but also to other various uses, for example.
[0010]
As a third embodiment of the present invention, the electrode is arranged on the front side or the rear side of a vehicle, and the detection circuit is configured to detect the presence of a person or an object between the electrode and the grounding unit. I can give you.
[0011]
According to this configuration, it is possible to detect that a person or an object (such as a small animal) crosses the front or rear side of a vehicle (such as an automobile, a truck, a bus, or a train), and an accident can be prevented. In particular, it is effective when detecting a person or an object that does not enter the field of view of the driver of the vehicle. Further, when a vehicle is put in a parking lot or a garage, a wall surface or the like can be detected to prevent a collision between the vehicle body and the wall surface of the vehicle.
[0012]
As a fourth embodiment of the present invention, a probe main body is provided, the electrode is arranged at the tip of the probe main body, and the detection circuit is configured to detect a specific object existing in the soil or the like. Things can be raised.
According to this configuration, for example, landmines existing in the soil can be detected.
[0013]
As a fifth embodiment of the present invention, an openable / closable shutter is provided, and the electrode is disposed at an end of the shutter, and the detection circuit includes a person or an object between the electrode and the grounding portion. Can be detected.
[0014]
According to this configuration, the electrodes are arranged at the end of the shutter (provided at the entrance of the parking lot, the entrance of the building, etc.), and when the shutter is closed, the end of the shutter and the floor surface It is possible to detect the presence of a person or an object existing between the ground or the road surface. Thereby, it is possible to prevent an accident that a person or an object is caught between the shutters.
[0015]
As a sixth embodiment of the present invention, the electrode is arranged in a room in a building, and the detection circuit is configured to detect the presence of a person in the room.
[0016]
For example, an electrode is arranged on the floor surface in each room of a residence, and the floor surface around the electrode is used as a grounding portion. This makes it possible to detect in which room a person is present in each room. When an elderly person living alone lives in a residence, the surveillance center monitors who is currently in the room, for example, a situation where the person stays in the same room for a long time. If it is detected, it is possible to take immediate measures as if some abnormality has occurred.
[0017]
As a seventh embodiment of the present invention, the detection circuit is configured to be able to detect the amount of an object that has entered between the electrode and the grounding portion.
[0018]
In this configuration, the amount of entry of an object such as a conductor that has entered between the electrode and the grounding part is detected, and the amount of change in capacitance varies depending on the amount of entry of the object. Can be sought. This capacitance type detection device can be used as a position sensor and can be used for various applications.
[0019]
As an eighth embodiment of the present invention, an electrode is arranged at the entrance / exit of a building, and the detection circuit is configured to be able to detect intrusion of a person or an object from the entrance / exit. .
[0020]
According to this configuration, it is possible to reliably detect the intrusion of a thief or a burglar that enters from the entrance / exit of a building veranda, door, window or the like. Since the relative permittivity of a person is larger than the relative permittivity of air, it can be easily detected. Moreover, it is applicable not only to the entrance / exit part with the exterior of a building but also to the entrance / exit part such as an indoor door.
[0021]
As a ninth embodiment of the present invention, the electrode is arranged in the vicinity of a toilet in the toilet, and the detection circuit is configured to detect the presence of a person in front of the toilet.
[0022]
According to this configuration, when a person enters the toilet and stands in front of the toilet, the person is detected by a change in capacitance. As an application in this case, for example, when there is an elderly person living alone, it is possible to detect that a person has entered the toilet at the monitoring center and also monitor the time in which the person has been in the toilet. If it is determined that the time in the toilet is longer than usual, it is possible to quickly take a countermeasure as something abnormal has occurred. Alternatively, it is possible to adopt a configuration in which water is automatically flowed by detecting that a person has entered in front of the toilet or that the person has left.
[0023]
As a tenth embodiment of the present invention, the electrode is arranged in the vicinity of a track in a station platform, and the detection circuit is configured to detect the presence of a person on or near the track. Can be given.
According to this configuration, since it is possible to detect that a person has fallen from the platform of the station, it is possible to prevent personal injury.
[0024]
A self-diagnosis device according to the present invention is a self-diagnosis device for performing a self-diagnosis of any of the capacitance type detection devices described above,
A capacitance sensor having an electrode disposed opposite to the grounding portion;
In order to perform self-diagnosis, a simulation signal supply unit that supplies a simulation signal for operating the capacitance sensor;
A comparison signal output unit for outputting a comparison signal having a preset width;
A comparison determination unit that compares the width of the sensor output signal output from the capacitance sensor with the simulated signal and the width of the comparison signal;
When the width of the sensor output signal is shorter than the width of the comparison signal as a result of the comparison, an error signal output unit that outputs an error signal is provided.
[0025]
The operations and effects of the above configuration are as follows.
(1) A simulation signal for operating the capacitance sensor is supplied. For example, an auxiliary electrode is provided between the electrode and the grounding part, and this auxiliary electrode is operated by a simulated signal, so that an object or a human body is inserted between the electrode and the grounding part. Can be created. Or you may make it the structure which inserts a simulated object between an electrode and a grounding part.
(2) A sensor output signal having a certain width is output from the capacitance sensor by the simulation signal.
(3) On the other hand, a comparison signal having a width set in connection with the supply of the simulation signal is output.
(4) The width of the comparison signal is compared with the width of the sensor output signal.
(5) When the width of the sensor output signal is shorter than the width of the comparison signal, an error signal is output.
[0026]
This is based on the technical idea that if a capacitance sensor or the like is normal, a sensor output signal having a width equal to or larger than a predetermined width should be output. The case where the width is shorter than the width of the comparison signal includes, of course, the case where the sensor output signal is not output at all. Whether or not an error has occurred can be determined based on the width of the sensor output signal as described above.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram for explaining a detection principle of a capacitance type detection device using a capacitance sensor. In Fig.1 (a), it arrange | positions so that the electrode 10 and the rolling roll 13 of a rolling mill may face each other. The rolling roll 13 is grounded. An area between the electrode 10 and the rolling roll 13 is a detection area, and detects an intrusion of a human hand. On the back side of the electrode 10, that is, the side opposite to the detection region, a guard plate 11 is arranged in parallel to the electrode 10 with a relatively small interval. The guard plate 11 is made of a good conductor such as stainless steel, copper, or aluminum, and has a dimensional shape that can completely cover the entire surface of the electrode 10. Capacitance coupling occurs between the electrode 10 configured as described above and the grounded roll 13, and a part of the human body enters the gap, thereby changing the capacitance.
[0028]
The capacitance sensor configured as described above is connected to a detection circuit 42 in order to detect a change in capacitance. That is, the electrode 10 is connected to the input terminal P1 of the detection circuit 42 by the center conductor of the coaxial cable 12, and the guard plate 11 is connected to the input terminal P2 of the detection circuit 42 by the shield of the coaxial cable 12. The detection circuit 42 uses a so-called impedance bridge (see the principle diagram of FIG. 1B), and measurement power sources e1 and e2 are connected to two sides of the four-side bridge. In addition, one side of the four-side bridge has a capacitance constituted by the electrode 10 and the rolling roll 13, and the remaining one side is provided with an equilibrium capacitance CB. An output amplifier 14 is provided between the terminal P2 between the measurement power sources e1 and e2 and the ground portion. Further, an auxiliary electrode 40 for performing a self-diagnosis is provided, and the switch 41 is for causing the auxiliary electrode 40 to function. This will be described later.
[0029]
The guard plate 11 is provided for the following reason. That is, the area between the electrode 10 and the rolling roll 13 is the original detection area, but in practice, the lines of electric force extend from the back side of the electrode 10 (the side opposite to the detection area) to the rolling roll 13 (grounding portion). Therefore, an electric field is also formed outside the original detection region. As a result, the capacitance changes even when a person or an object passes through the back side of the electrode 10, which causes false detection. Therefore, by providing the guard plate 11 as described above, an electric field is not formed on the back side of the electrode 10, and erroneous detection can be prevented.
[0030]
<Equivalent circuit>
The circuit shown in FIG. 2 is an equivalent circuit in which the detection circuit 42 shown in FIG. 1 is shown in a form including the capacitance formed by the electrode 10 and the rolling roll 13 and the capacitance at other portions. In this figure, Co represents a capacitance defined by the electrode 10 and the rolling roll 13, and C1 represents a capacitance between the central conductor of the coaxial cable 12 and the shield. Symbols Ze1 and Ze2 are internal impedances of the measurement power sources e1 and e2, respectively. Symbol Zi is an internal impedance of the output amplifier 14.
[0031]
Here, the operation of the circuit shown in FIG. 2 will be described. When the measurement power sources e1 and e2 are turned on in the state where only air exists between the electrode 10 and the rolling roll 13, the current flowing from the power source e1 through the capacitance C1 is higher than the voltage of the measurement power source e1 than Ze1 × i1. If it is sufficiently large, it hardly flows through the impedance Zi and can be ignored. The current flowing through the capacitance Co is divided into the capacitance C1 and the impedance Zi. At this time, when 1 / (ωC1) is sufficiently larger than Zi, most of the current i1 flows through the impedance Zi. When the voltages e1 and e2 are the same voltage and the current i2 flowing from the measurement power source e2 through the capacitance CB is equal to the current i1 and the phase difference is 180 °, the current of the impedance Zi is zero. Now, when a dielectric grounded enters between the electrode 10 and the rolling roll 13, Co increases by an amount corresponding to the dielectric constant of the dielectric. If this increase is ΔC, the current i1 is increased by e1ωΔC, the current flows through the impedance Zi, and is output as a signal. Further, even when the dielectric is not grounded and so-called floating, the capacitance Co increases, and a current flows through Zi similarly.
[0032]
As described above, in the circuit shown in FIG. 2, the capacitance formed between the electrode 10 and the guard plate 11, the capacitance of the coaxial cable, and other disturbances are not easily affected. It is possible to accurately detect a change in capacitance between the two. Note that ΔC ′ in the figure indicates a change in capacitance when the auxiliary electrode 40 is operated as described later.
[0033]
<Application example 1>
Examples in which the capacitance type detection device according to the present invention is applied to various industrial fields will be described. In each application example described below, only the arrangement of the electrodes 10 is basically shown.
[0034]
FIG. 3 shows an apparatus for separating aluminum cans (or steel cans) K conveyed from the belt conveyor 20 from the bottles / pet bottles B. This is based on the principle that the relative dielectric constant of aluminum is different from that of bottles and PET bottles. An electrode 10 is disposed above an object such as an aluminum can to be conveyed. The belt conveyor 20 is grounded. When it is detected that the aluminum can K has come between the electrode 10 and the grounding portion, the cylinder 21 is operated and the aluminum can K is recovered in the recovery device 22. In the example of FIG. 3, the electrode 10 is disposed above the transport path. However, the electrode 10 may be disposed on the left or right side of the transport path. The floor surface may be a grounding part.
[0035]
As another modification, on the contrary, only bottles and PET bottles may be separated and collected. When various types of materials are mixed, the detection device can sort only specific materials when the materials are loaded on a belt conveyor and conveyed. In the example of FIG. 3, the metal and the nonmetal are separated, but it is also possible to configure so that only a specific nonmetal material can be separated among the nonmetals. For example, Teflon has a dielectric constant of 2.0, PET has a dielectric constant of 3.1 to 3.2, and soft vinyl chloride has a dielectric constant of 5.0 to 9.0. Focusing on the difference in rate, it is also possible to configure a detection device that can separate only a specific resin.
[0036]
<Application example 2>
FIG. 4 shows an example in which the electrodes 10 are arranged on the front and rear bumpers of an automobile. The road surface becomes the grounding part. Thereby, when there is a small child in the vicinity of the electrode 10, this can be detected. In particular, it is effective for detecting a person or an object in an area that cannot be seen from the view from the driver's seat. In addition, even when an automobile is put in the back of a parking lot or garage, it is possible to detect the approach of obstacles and wall surfaces that are difficult to see from the driver's seat view. Can be prevented in advance.
The vehicle is not limited to automobiles, but can be applied to trucks, buses, trains, and the like.
[0037]
<Application example 3>
FIG. 5 is an example applied to a landmine detector, in which the electrode 10 is disposed at the tip of the probe body 23. If the landmine 24 (corresponding to a specific object) is present in the soil, the capacitance formed by the electrode 10 and the grounding portion (ground) changes, so that the presence of the landmine can be searched and detected.
[0038]
As another modified example, the present invention can also be applied to a case where a specific type of metal or resin is searched from a garbage disposal site in which various types of garbage are mixed. It can also be applied to search for specific objects in concrete or under water, not in the soil.
[0039]
<Application Example 4>
FIG. 6 is an example applied to a parking lot, an entrance / exit of a building, or a shutter of a warehouse, and the electrode 10 is disposed at the lower end of the shutter 25. The road surface, floor surface, etc. with which the lower end of the shutter 25 abuts when the shutter 25 is closed constitute the grounding portion. Thereby, the presence of a person or an object between the lower end portion of the shutter 25 and the road surface / floor surface can be detected, and an accident caused by the person or object being sandwiched between the shutter 25 and the road surface or the like can be prevented. Can do.
[0040]
<Application Example 5>
FIG. 7 is an example in which the electrodes 10A, 10B, 10C, and 10D are arranged on the floor surface in each room in a building (a residence, a building, etc.). The ceiling surface or wall surface is configured as a grounding part. This makes it possible to detect in which room a person is present in each room. When an elderly person living alone lives in a residence, the surveillance center monitors who is currently in the room, for example, a situation where the person stays in the same room for a long time. If it is detected, it is possible to take immediate measures as if some abnormality has occurred.
[0041]
In addition, when the building is an art museum or a museum, the intrusion of a thief or the like at night can be detected, thereby preventing the theft of the exhibit. In addition, theft of valuables can be prevented by installing electrodes in a room where a safe is stored.
[0042]
<Application Example 6>
FIG. 8 shows an apparatus for detecting that an object such as a conductor 29 has entered between the electrode 10 and the wall surface 28 as a grounding portion. The amount of change in capacitance varies depending on the amount of the conductor 29 entering. Therefore, since the position of the conductor 29 can be detected by detecting this change, the apparatus of FIG. 8 can be applied to various industrial fields as a position sensor.
[0043]
<Application example 7>
FIG. 9 is an example in which the electrode 10 is arranged on the upper side of the handrail portion 30 of the veranda corresponding to the entrance of the building. The floor of the veranda is configured as a grounding part. The electrode 10 may be arranged on the ceiling surface of the veranda or the side surface of the handrail. Thereby, the intrusion of the thief can be detected. When there is a resident in the room, the detection circuit is deactivated, and the detection circuit is activated when the resident goes to bed or goes out. It is also possible to connect the detection circuit to a monitoring center and monitor it constantly. The electrode is preferably not protected but protected by a cover member or the like.
[0044]
In addition to the veranda, it may be provided at entrances such as entrances, windows, gates and chimneys. Moreover, you may provide in the door (equivalent to an entrance / exit part) of an elevator. You may provide in the entrance (door etc.) of a specific room in a house. FIG. 10 is an example provided at the entrance 31. By providing the electrode 10 outside the door of the entrance 31, it can be detected that a person is present in front of the entrance 31. Thereby, even if the doorbell is not pushed, the resident in the room can know that the visitor has come. Further, by providing the electrode 10 inside the entrance 31, it is possible to detect that a person has entered from the outside, and it is possible to automatically turn on indoor lighting or sound an alarm. In the case of FIG. 10, the electrode 10 is elongated along the width direction of the entrance 31, and the floor surface around the electrode 10 is a grounding portion. When a person straddles the electrode 10, the capacitance changes.
[0045]
<Application Example 8>
FIG. 11 is an example in which the electrode 10 is disposed above the toilet bowl 32 of the toilet. As a grounding part, it can comprise on a floor surface. It is possible to detect the fact that a person has stood in front of the toilet bowl 32 or to have left the toilet bowl 32 and to flow water. The toilet is not particularly limited, such as the station premises, the building interior, and the residence. As another application, for example, when there is an elderly person living alone, the monitoring center detects that a person has entered the toilet and also monitors the time spent in the toilet. Then, if it is determined that the time in the toilet is longer than usual, it is possible to take countermeasures as if some abnormality has occurred. This is particularly necessary for toilets in hospitals and facilities. It is preferable to embed the electrode 10 in the wall because it does not impair the beauty.
[0046]
<Application example 9>
FIG. 12 is an example in which the electrode 10 is arranged on a wall surface portion (corresponding to the vicinity of the track) facing the track of the platform 33 of the station. The presence of a person on or near the track can be detected by the detection circuit. Thereby, it is possible to prevent personal injury.
[0047]
<Self-diagnosis device>
Next, a self-diagnosis device for a detection device using the capacitance sensor according to the present invention will be described. FIG. 13 is a sequence diagram showing a self-diagnosis circuit for performing self-diagnosis of the capacitance type detection device, and this sequence is composed of components and devices that can be electrically controlled, such as a microprocessor / programmable controller and a personal computer. it can. FIG. 14 is a diagram showing a time chart and an auxiliary electrode driving unit corresponding to the sequence diagram of FIG. In this self-diagnosis device, an auxiliary electrode 40 is installed so as to face the electrode 10, and this is periodically switched by a simulation signal generating relay R2 (corresponding to the switch 41 in FIG. 1) described later, This is to check whether the desired detection can be performed.
[0048]
In FIG. 13, a cycle timer T1 for setting a cycle for performing self-diagnosis and a B contact of the cycle timer T1 are connected in series, and a simulation signal timer T2 for outputting a simulation signal connected in parallel with the cycle timer T1. Similarly, a self-diagnosis timer T3 for setting a time for performing self-diagnosis, which is connected in parallel with the periodic timer T1, is provided.
[0049]
A sensor output relay R1 is connected in series with the SW that is turned on by the operation of the capacitance sensor. That is, the sensor output relay R1 is excited (turned on) when the SW is turned on. The time for which the sensor output relay R1 is turned on corresponds to the width of the sensor output signal (see r1, r2, and r3 in FIG. 14).
The B contact of the simulation signal timer T2 and the simulation signal generating relay R2 are connected in series. That is, a simulation signal for operating the sensor is generated for the time t2 set by the simulation signal timer T2 (see FIG. 14).
The B contact of the self-diagnosis timer T3 and the self-diagnosis signal output relay R3 are connected in series. Thereby, the time t3 set by the self-diagnosis timer T3 is set as a time for performing the self-diagnosis. The time t3 is set so that it can be covered in consideration of the width of the sensor output signal.
[0050]
The A contact of the sensor output relay R1 and the width determination timer T4 are connected in series. The width determination timer T4 is provided to output a comparison signal having a preset width, and an error occurs in the capacitance sensor or the like by comparing the width of the comparison signal with the width of the sensor output signal. It is determined whether or not.
[0051]
The A contact of the width determination timer T4 and the width determination relay R4 are connected in series. Then, a comparison signal is output by the width determination relay R4 for a time t4 set by the width determination timer T4 (see FIG. 14).
The A contact of the width judging relay R4, the A contact of the sensor output relay R1, the B contact of the simulated signal generating relay R2, and the normal signal generating relay R5 are connected in series, and the width judging relay R4 The A contact and the A contact of the sensor output relay R1 and the A contact of the normal signal generating relay R5 are connected in parallel. That is, the relay R5 is turned on by turning on the relays R1 and R4 and turning off the relay R2.
[0052]
A contact of self-diagnosis signal output relay R3 and error signal generation relay R6 are connected in series. The relay R3 and the contact A of the normal signal generating relay R5 are connected in parallel.
A normal detection signal generating relay R7, a B contact of the self diagnostic signal output relay R3, and an A contact of the sensor output relay R1 are connected in series. The A contact of the relay R3 is also connected in series with the relay R7.
[0053]
<Time chart of self-diagnosis circuit>
FIG. 14B is a schematic diagram of a self-diagnosis device using a capacitance sensor including the electrode 10. The auxiliary electrode 40 functioning as a simulated human body (or simulated object) is connected to the detection circuit via the contact of the simulated signal generating relay R2. The self-diagnosis circuit 5 is configured based on the sequence diagram shown in FIG. The electrostatic capacity sensor detects that the electrostatic capacity between the electrode 10 and the grounding part changes due to the entry of an object or a person, thereby outputting an alarm signal or performing a predetermined operation. That is, the self-diagnosis of the capacitance sensor can be performed by operating the auxiliary electrode 40 and forcibly creating the same state that an object or person has entered between the electrode 10 and the grounding portion.
[0054]
Therefore, a simulation signal (R2) as shown in FIG. 14A is periodically generated from the self-diagnosis circuit 5 by the simulation signal generating relay R2. The period is indicated by t1, which is set by the period timer T1. The width of the simulation signal (R2) is indicated by t2, and this is set by the simulation signal generating relay R2. In FIG. 14 (a), three periods are shown for convenience of explanation. When the output from the sensor is normal in the first period, the output from the sensor is abnormal in the second period (the output signal width is small). , The third period shows the case where the output from the sensor is abnormal (no output signal).
[0055]
<When normal>
Due to the simulation signal (R2), the auxiliary electrode 40 is brought into a floating state, and the capacitance changes between the electrode 10 and the ground portion (corresponding to ΔC ′ in FIG. 2). This is detected by the detection circuit, and an output signal (R1) is output by the sensor output relay R1. As shown in FIG. 14, the simulation signal (R2) and the output signal (R1) have a time difference of Δt, which is caused by a conversion delay by the A / D converter, and is actually several tens of msec. A small amount of degree. (FIG. 14 is exaggerated.) If the sensor or the like is normal, the output signal (R1) is a pulse signal having a width tr1.
[0056]
Simultaneously with the output signal (R2), the comparison signal (R4) from the width determination relay R4 is output. The width of the comparison signal (R4) is set to t4 by the width determination timer T4. The comparison signal (R4) is normally at the H level (ON), and the L level (OFF) is active. If the output signal (R2) is at the L level, the comparison signal (R4) is at the H level, and the output signal (R1) is at the H level when the width determination time t4 elapses, a normal signal is generated. Relay R5 is turned on to generate an H level normal signal (R5). That is, if the width tr1 of the output signal (R1) is larger than the width t4 of the comparison signal (R4), it is determined that the sensor or the like is normal. The output signal (R1) changes to L level when the time corresponding to the width tr1 elapses, but the relay R5 is self-held by the A contact of the relay R5, so that the normal signal (R5) is held at the H level as it is. Is done. When the simulation signal (R2) rises in the next cycle, the self-holding is released (see FIG. 13).
[0057]
The error signal generating relay R6 is for outputting an L level error signal (R6) when an error occurs in the sensor or the like as a result of self diagnosis. The self diagnosis signal (R3) sets a period for performing the self diagnosis. ) Is not output, and no error signal (R6) is output if an H-level normal signal (R5) is output even after the self-diagnosis period has elapsed. (See FIG. 14).
[0058]
The normal detection signal generating relay R7 outputs an L level normal detection signal (R7) in a normal use state in which self-diagnosis is not performed. Since the relay R7 is connected in series with the contact A of the relay R3 for self-diagnosis signal output, the L level normal detection signal (R7) is not output during the self-diagnosis period. As shown in FIG. 14, when there is an output signal (R1) as indicated by r2, the normal detection signal (R7) becomes L level.
[0059]
Although not shown, when an error signal (R6) is output, an alarm is issued to notify the operator. An alarm is also issued when a normal detection signal (R7) is output.
[0060]
<If abnormal>
Next, it is assumed that there is an abnormality in the capacitance sensor or the like, and the width of the output signal (R1) is as small as tr3. The width tr3 is smaller than the set width of the comparison signal t4. Therefore, when the self-diagnosis period t4 has elapsed, the relay R1 is already OFF, and as a result, the normal signal generating relay R5 is not turned ON. Therefore, the normal signal (R5) is not output. Further, when the self-diagnosis period t3 has elapsed since the relay R5 is not turned ON, the error signal generating relay R6 is turned OFF. That is, an L level error signal (R6) is generated.
Even when the capacitance sensor is abnormal and the output signal R1 is not output at all, the result is the same as when the width is small.
[0061]
As described above, the relay R2 and the timer T2 function as a simulation signal supply unit,
Relay R4 and timer T4 function as a comparison signal output unit,
Relays R1, R2, R4, and R5 function as a comparison / determination unit.
Relays R3, R5, R6 function as error signal output units,
The timer T3 and the relay R3 function as a self-diagnosis signal output unit.
[0062]
As described above, the capacitance type detection device according to the present invention can be used in various industrial fields, and can be a device with high added value by providing a self-diagnosis function.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining the detection principle of a capacitance type detection device using a capacitance sensor. FIG. 2 is a diagram showing details (equivalent circuit) of the detection circuit in FIG. 1. FIG. Application example using can separation [Fig. 4] Application example using the present invention for a bumper of an automobile [Fig. 5] Application example using the present invention for a landmine detector [Fig. 6] Application using the present invention for a shutter Example [Fig. 7] Application example using the present invention on an indoor floor surface [Fig. 8] Application example using the present invention as a position sensor [Fig. 9] Application example using the present invention in a building veranda [Fig. Application example using the present invention for the entrance. FIG. 11 Application example using the present invention in a toilet bowl. FIG. 12 Application example using the present invention in a station platform. FIG. 14 is a sequence diagram showing a self-diagnosis circuit for performing self-diagnosis of the robot. Shows a Muchato and auxiliary electrode driver [Description of symbols]
10 Electrode Co Capacitance ΔC Capacitance change e1 Measurement power supply e2 Measurement power supply

Claims (11)

A self-diagnosis device for performing self-diagnosis of a capacitance type detection device comprising an electrode disposed opposite to a grounding portion, and a detection circuit for detecting a change in capacitance between the electrode and the grounding portion. There,
An auxiliary electrode provided between the electrode disposed opposite to the ground portion and the ground portion;
A simulation signal supply unit that connects the auxiliary electrode to the detection circuit and supplies a simulation signal for operating the auxiliary electrode as a simulated intruder;
A comparison signal output unit for outputting a comparison signal having a preset width;
A comparison determination unit that compares the width of the output signal output from the detection circuit with the simulation signal and the width of the comparison signal;
As a result of the comparison, an error signal that outputs an error signal when the width of the output signal is shorter than the width of the comparison signal or when the output signal output from the detection circuit is not output by the simulation signal A self-diagnosis device comprising an output unit. A capacitance type detection device self-diagnosed by the self-diagnosis device of claim 1,
It has a transport means that is transported along a transport path in a state where a metal object and a non-metal object are mixed,
An electrode is disposed opposite the grounding part so as to sandwich the object group to be conveyed, and a detection circuit for detecting a change in electrostatic capacitance between the electrode and the grounding part includes the electrode and the grounding part. An electrostatic capacitance type detection device , which is connected to an auxiliary electrode for self-diagnosis arranged between the metal objects and is capable of selecting a metal object from a mixed object group. A capacitance type detection device self-diagnosed by the self-diagnosis device of claim 1,
A transport unit transported along a transport path in a state where a plurality of objects having different relative dielectric constants are mixed;
An electrode is disposed opposite the grounding part so as to sandwich the object group to be conveyed, and a detection circuit for detecting a change in electrostatic capacitance between the electrode and the grounding part includes the electrode and the grounding part. Capacitance characterized in that it is connected to an auxiliary electrode for self-diagnosis arranged between the two and the object having a specific dielectric constant can be selected from a mixed object group Type detection device. A capacitance type detection device self-diagnosed by the self-diagnosis device of claim 1,
Electrodes are arranged on the front or rear side of the vehicle,
A detection circuit for detecting a change in capacitance between the electrode and the grounding unit is connected to an auxiliary electrode for self-diagnosis arranged between the electrode and the grounding unit, and the electrode and the grounding are connected. An electrostatic capacitance type detection device configured to be able to detect the presence of a person or an object between parts. A capacitance type detection device self-diagnosed by the self-diagnosis device of claim 1,
With a probe body,
An electrode is placed at the tip of this probe body,
A detection circuit for detecting a change in capacitance between the electrode and the grounding unit is connected to an auxiliary electrode for self-diagnosis arranged between the electrode and the grounding unit, and exists in the soil or the like. A capacitance type detection device configured to be able to detect a specific object. A capacitance type detection device self-diagnosed by the self-diagnosis device of claim 1,
It has a shutter that can be opened and closed,
An electrode is placed at the end of this shutter,
A detection circuit for detecting a change in capacitance between the electrode and the grounding unit is connected to an auxiliary electrode for self-diagnosis arranged between the electrode and the grounding unit, and the electrode and the grounding are connected. An electrostatic capacitance type detection device configured to be able to detect the presence of a person or an object between parts. A capacitance type detection device self-diagnosed by the self-diagnosis device of claim 1,
The electrode is placed in the room in the building,
A detection circuit for detecting a change in capacitance between the electrode and the grounding unit is connected to an auxiliary electrode for self-diagnosis disposed between the electrode and the grounding unit, and A capacitance-type detection device configured to detect presence. A capacitance type detection device self-diagnosed by the self-diagnosis device of claim 1,
An electrode disposed opposite to the ground part, and a detection circuit for detecting a change in capacitance between the electrode and the ground part
The detection circuit is connected to an auxiliary electrode for self-diagnosis arranged between the electrode and the ground part, and can detect the amount of an object entering between the electrode and the ground part. A capacitance type detection device characterized by comprising. A capacitance type detection device self-diagnosed by the self-diagnosis device of claim 1,
Electrodes are arranged at the entrance and exit of the building,
A detection circuit for detecting a change in capacitance between the electrode and the grounding unit is connected to an auxiliary electrode for self-diagnosis disposed between the electrode and the grounding unit, and from the entrance / exit part. A capacitance type detection device configured to be able to detect intrusion of a person or an object. A capacitance type detection device self-diagnosed by the self-diagnosis device of claim 1,
An electrode is placed near the toilet in the toilet,
A detection circuit for detecting a change in capacitance between the electrode and the grounding unit is connected to an auxiliary electrode for self-diagnosis disposed between the electrode and the grounding unit, and is connected to the front of the toilet. A capacitance type detection device configured to be able to detect the presence of a person. A capacitance type detection device self-diagnosed by the self-diagnosis device of claim 1,
The electrode is arranged in the vicinity of the track on the platform of the station,
A detection circuit for detecting a change in capacitance between the electrode and the grounding unit is connected to an auxiliary electrode for self-diagnosis arranged between the electrode and the grounding unit, and is on the line or the line A capacitance type detection device configured to be able to detect the presence of a person in the vicinity.

Images