JP2020181445A - RF communication system - Google Patents

Abstract

To allow a RF communication system to extend a communication distance with a simple means and to enhance degree of freedom in arrangement of a reader-side device.SOLUTION: A RF communication system according to an embodiment of the present invention has a reader, a first coil provided within a communication range of the reader, and a second coil connected to the first coil. The reader and the first coil are disposed so as to be disposed on an opposite side of the second coil with respect to a partition wall. The reader is arranged so that it can detect change of a magnetic field around the second coil caused by intrusion of a RF tag into the communication range of the second coil.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to RF communication systems.

When freezing food in the freezer, there is a method of continuously freezing the food while transporting it on a conveyor in the freezer. The conveyor belt of this conveyor may derail from the track, and as a method of detecting this, there is a method of arranging a proximity sensor near the conveyor belt and detecting the presence or absence of derailment with the proximity sensor. However, the inside of the freezer is usually kept at an extremely low temperature of −30 ° C. or lower, is exposed to a large temperature change that rises to room temperature or higher during defrost operation, and is exposed to a high humidity environment when cleaning the inside of the freezer. Therefore, there are cases where moisture invades from the connection portion of the power supply line and the signal line connected to the proximity sensor and the proximity sensor fails. If the proximity sensor fails, even if the conveyor derails, it cannot be detected. Therefore, the derailment spreads, and finally, an abnormal stop occurs due to an overload of the conveyor drive device. It takes a lot of labor and time to recover from this spillover derailment, and there is a problem that the productivity of the freezer is lowered.

Therefore, without using a proximity sensor, as disclosed in Patent Documents 1 to 3, the information of the RF tag provided on the detected object side is non-contacted by an induced electromagnetic field or an electromagnetic wave and is located at a remote position. It is conceivable to adopt an RFID system that can be supplied to.

Japanese Unexamined Patent Publication No. 07-168985 Japanese Unexamined Patent Publication No. 2013-142675 Japanese Unexamined Patent Publication No. 2016-71462

However, in the RF communication system, when the RF tag is a passive type RF tag without a battery, the communication area is limited even if an electromagnetic wave in the ultra high frequency (UHF) band having a relatively long communication range is used. There is. This causes various restrictions on the arrangement of the reader / writer side device. On the contrary, in the case of an active type RF tag equipped with a battery, there is a problem that the workability is lowered because the cost is high and the shape is large and the battery needs to be replaced.
In addition, when the RF tag is placed in a harsh environment where the temperature, pressure, etc. such as freezing temperature are significantly different from normal temperature and pressure, or in an environment where the human body cannot survive, the RF tag is a reader-side device that is not as durable as the RF tag. There is a problem that it cannot be placed near.

One embodiment of the present disclosure aims to extend the communication distance by simple means in an RF communication system and increase the degree of freedom in arranging reader-side devices.

(1) The RF communication system according to the embodiment is
With the leader
The first coil provided within the communication range of the reader and
A second coil connected to the first coil is provided.
The reader and the first coil are arranged with respect to the second coil with a partition wall.
The reader is configured to read the change in the magnetic field around the second coil due to the intrusion of the RF tag into the communication range of the second coil via the first coil.
In the present specification, the term "reader" refers to a reader having only a function of reading information held by an RF tag, but a plurality of RF tags are used to identify each RF tag in order to identify each RF tag. When applied to a communication system in which a number needs to be written, it shall include one having a function as a reader / writer capable of writing information to an RF tag as well as reading.

According to the configuration of (1) above, by adopting the RFID system, the proximity sensor becomes unnecessary, so that it is possible to eliminate the undetectability and false detection due to the failure of the proximity sensor. Further, by lengthening the lead wire connecting the first coil and the second coil and increasing the distance between the first coil and the second coil, the communication distance of the tag information can be extended, so that the reader side device can be used. The restrictions on the placement location can be relaxed. Further, by arranging the first coil and the second coil with the partition wall separated, even if the RF tag is surrounded by the partition wall and is arranged in a place where it is difficult for workers to enter, the reader side device is placed outside the partition wall. It can be placed in a place suitable for operation. This makes it possible to expand the applications of RF communication systems.

(2) In one embodiment, in the configuration of (1) above,
The space inside the wall surrounded by the bulkhead is in an environment where the temperature, pressure or atmosphere is different from the outside of the bulkhead.
The second coil and the RF tag are arranged in the space inside the partition wall, and the reader and the first coil are arranged outside the partition wall.
According to the configuration of (2) above, the space inside the partition wall is in a harsh environment where the temperature, pressure, etc. are significantly different from normal temperature and pressure, or in an environment harmful to the human body, and the RF tag and the second coil are Even if it is placed in such an environment, the distance between the first coil and the second coil can be extended, so that the leader and the first coil can be placed in an environment suitable for operation outside the partition wall.

(3) In one embodiment, in the configuration of (1) or (2) above,
A plurality of the RF tags are provided at different parts of the different object to be detected or the same object to be detected, which is the object to be detected to which the RF tag is installed.
A plurality of the second coils provided corresponding to each of the plurality of RF tags, and
A plurality of the first coils connected to each of the plurality of second coils,
To be equipped.
Here, "the RF tag is installed" means that the RF tag is directly attached to the object to be detected, and that the RF tag is not in contact with the object to be detected and corresponds to the operation of the object to be detected. It shall include the case where it is placed close to a position where the position can be changed.

According to the configuration of (3) above, a plurality of information can be obtained at the same time from a plurality of RF tags provided at different parts of different objects to be detected or the same object to be detected, and the first coil and the second coil can be obtained. Since a plurality of independent coil assemblies including coils are provided, the induced current generated in each first coil is distributed to the second coil of the other coil assembly, and the amount of current flowing through the second coil of the same coil assembly is reduced. It will not end up. Therefore, the reader can accurately read the information sent from each RF tag.

(4) In one embodiment, in the configuration of (1) or (2) above,
A plurality of the RF tags are provided at different parts of the different object to be detected or the same object to be detected, which is the object to be detected to which the RF tag is installed.
A plurality of the second coils provided corresponding to each of the plurality of RF tags, and
One said first coil connected to each of the plurality of second coils,
To be equipped.
According to the configuration of (4) above, since one first coil may be provided for each of the plurality of second coils, the cost of the coil assembly can be reduced.

(5) In one embodiment, in the configuration of (4) above,
A switch for connecting or disconnecting an antenna lead wire connected to each of the plurality of second coils is provided.
According to the configuration of (5) above, since the switch is provided, only the RF tag for which tag information is desired can be connected to the reader side, and the other antenna conductors can be disconnected from the reader side. As a result, the induced current generated in the first coil flows only in the second coil for which tag information is desired, and does not flow in other antenna conductors, so that the distance between the second coil and the first coil can be extended. By switching the switch, the tag information sent from a plurality of RF tags can be read by the reader.

(6) In one embodiment, in any of the configurations (1) to (5) above,
A storage unit that stores information obtained from the RF tag by the reader, and a storage unit.
A display unit that displays the information stored in the storage unit, and
To be equipped.
According to the configuration of (6) above, the tag information sent to the reader can be stored in the storage unit and displayed on the display unit as needed.

(7) In one embodiment, in any of the configurations (1) to (6) above,
A support member that movably supports the RF tag is provided.
The support member is configured so that the RF tag can be arranged within or outside the communication range of the second coil depending on the first state or the second state of the object to be detected.
According to the configuration of (7) above, by providing the support member, the RF tag is arranged within or outside the communication range of the second coil depending on the first state or the second state of the object to be detected. Therefore, the reader can read that the object to be detected is in the first state or the second state.

(8) In one embodiment, in the configuration of (7) above,
The support member is composed of a rod-shaped body rotatably supported around the axis.
The rod-shaped body is arranged so that one end is in contact with the object to be detected, and the RF tag is attached to the other end.
When the object to be detected is in the first position, the RF tag is arranged within the communication range of the second coil, and when the object to be detected is in the second position, the RF tag is in the second coil. It is configured to be placed outside the communication range of.
According to the configuration (8) above, the reader can read that the object to be detected exists in the first position or the second position by using the simple support member composed of the rod-shaped body.

(9) In one embodiment, in any of the configurations (1) to (8) above,
The object to be detected to which the RF tag is installed is composed of a conveyor.
The plurality of RF tags are arranged at different locations in the transport direction of the conveyor.
According to the configuration (9) above, since a plurality of RF tags are provided at different locations in the conveyor transport direction, it is possible to obtain conveyor operation information in a wide area in the conveyor transport direction.

(10) In one embodiment, in the configuration of (9) above,
When the conveyor belt of the conveyor is in the normal position, the RF tag is arranged within the communication range of the second coil, and when the conveyor belt is derailed, the RF tag is arranged outside the communication range of the second coil. It is configured to be.
According to the configuration (10) above, the presence or absence of derailment of the conveyor belt can be detected, and the same information is supplied to the reader when an abnormality such as a broken line of the antenna lead wire occurs. Therefore, the occurrence of the broken line of the antenna lead wire is also abnormal. It can be detected as an occurrence.

(11) In one embodiment, in the configuration of (9) or (10) above,
The reader includes a storage unit that stores information obtained from the RF tag.
A plurality of the RF tags are arranged at different locations in the transport direction of the conveyor.
Each of the plurality of RF tags retains a unique identification number and
The unique identification number and the placement location of each of the plurality of RF tags are stored in the storage unit.
According to the configuration of (11) above, the reader can read the location where the tag information supplied from the RF tag comes from the RF tag.

(12) In one embodiment, in any of the configurations (1) to (11) above,
The object to be detected to which the RF tag is installed is an object to be conveyed on a conveyor.
The RF tag is attached to the object to be transported.
According to the configuration of (12) above, it is possible to identify from which object the tag information supplied from the RF tag is supplied. Therefore, by collating with the tag information from the RF tag provided on the conveyor, for example, when the transported object is food, quality control such as traceability of the food becomes possible.

According to some embodiments, the RF communication system using electromagnetic waves can be used, and the communication distance can be extended by a simple means, so that the reader can be used even if the RF tag is separated from the reader side device by a partition wall. It is readable by. As a result, restrictions on the arrangement of reader-side devices can be relaxed, and the applications of RF communication systems can be expanded.

It is a schematic diagram of the RF communication system which concerns on one Embodiment. It is a schematic diagram of the RF communication system which concerns on one Embodiment. It is a schematic diagram of the RF communication system which concerns on one Embodiment. It is a schematic diagram of the RF communication system which concerns on one Embodiment. It is a schematic diagram of the support member of the RF tag which concerns on one Embodiment. It is a schematic diagram of the RF communication system which concerns on one Embodiment applied to a conveyor. It is a schematic diagram which shows the tension adjustment device of a conveyor belt. It is a schematic diagram of the RF communication system applied to the tension adjusting apparatus of FIG. It is a schematic diagram of the support member of the RF tag which concerns on one Embodiment. It is a schematic diagram of the support member of the RF tag which concerns on one Embodiment.

Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention to this, and are merely explanatory examples.
For example, expressions that represent relative or absolute arrangements such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" are exact. Not only does it represent such an arrangement, but it also represents a state of relative displacement with tolerances or angles and distances to the extent that the same function can be obtained.
For example, expressions such as "same", "equal", and "homogeneous" that indicate that things are in the same state not only represent exactly the same state, but also have tolerances or differences to the extent that the same function can be obtained. It shall also represent the state of existence.
For example, an expression representing a shape such as a quadrangular shape or a cylindrical shape not only represents a shape such as a quadrangular shape or a cylindrical shape in a geometrically strict sense, but also an uneven portion or chamfering within a range in which the same effect can be obtained. The shape including the part and the like shall also be represented.
On the other hand, the expressions "equipped", "equipped", "equipped", "included", or "have" one component are not exclusive expressions that exclude the existence of other components.

FIG. 1 shows an RF communication system 10 (10A) according to an embodiment. The RF communication system 10 (10A) includes a reader / writer 12 and a coil assembly 14. The coil assembly 14 includes a first coil 15 and a second coil 16 composed of conductive antenna conductors. The first coil 15 and the second coil 16 are connected by a conducting wire, and the first coil 15 is provided within the communication range of the reader / writer 12. The reader / writer 12 and the first coil 15 are arranged with the partition wall 17 separated from the second coil 16. The second coil 16 is arranged in the vicinity of the RF tag 20 so that the RF tag 20 can enter the communication range of the second coil 16. Due to the magnetic field generated by the reader / writer 12, an induced current is generated in the first coil 15 by the principle of electromagnetic induction. When this induced current flows through the second coil 16, a magnetic field is conversely generated in the second coil 16. When the RF tag 20 enters the communication range of the second coil 16, power is transmitted and the IC in the RF tag operates. By reading the change in the magnetic field around the second coil caused by this, the reader / writer 12 can identify the information about the object to be detected 18 included in the RF tag 20.

According to the above configuration, since the proximity sensor becomes unnecessary by using the RFID system, it is possible to eliminate the undetectable or false detection due to the failure of the proximity sensor. Further, by increasing the distance between the first coil 15 and the second coil 16, the communication distance of the tag information can be extended, so that the restriction on the arrangement location of the reader / writer side device can be relaxed. The induced current flowing between the first coil 15 and the second coil 16 is reduced by the resistance of the antenna lead wires constituting the first coil 15 and the second coil 16, so that the distance between the first coil 15 and the second coil 16 is increased. Is limited. However, as disclosed in Patent Documents 1 to 3, the communication distance can be extended as compared with the communication between the RF tag 20 and the reader / writer 12 by electromagnetic waves. Further, by arranging the first coil 15 and the second coil 16 so as to separate the partition wall 17, the object to be detected 18 and the RF tag 20 are surrounded by the partition wall 17, and even if they are arranged in a place where it is difficult for workers to enter. , The reader / writer side device can be arranged in a place suitable for operation outside the partition wall 17. This makes it possible to expand the applications of the RF communication system 10 (10A).

As the antenna lead wire used in the coil assembly 14, for example, a copper wire or an aluminum wire having a small resistance is used.

In one embodiment, the inner space Si of the partition wall 17 surrounded by the partition wall 17 is in an environment in which the temperature, pressure or atmosphere is different from the outside of the partition wall 17, and the second coil 16 and the RF tag 20 are provided in the inner space Si under such an environment. May be placed. Since the communication distance can be extended even in a harsh environment such as a freezer where the temperature and pressure of the inner space Si are significantly different from normal temperature and pressure, or in an environment harmful to the human body, the first coil 15 and the reader The writer-side device can be placed in an environment suitable for operation outside the partition wall 17.

In one embodiment, in the reader / writer side device, power is supplied to the reader / writer 12 from the power supply 22. In the above embodiment, the reader / writer 12 has a function of not only reading the information held by the RF tag 20 but also writing new information to the RF tag 20. However, when it is not necessary to write information to the RF tag 20, for example, since only one RF tag 20 is used, it is not necessary to write identification information such as an identification number to the RF tag 20, or a plurality of RFs are used. Even if the tag 20 is used, if the identification information is already written in each RF tag 20 and there is no need to write in the future, a reader having a read-only function is used instead of the reader / writer 12. May be good.

In one embodiment, the RF tag 20 uses a passive type without a battery. This has the advantage that battery replacement is not required at low cost and workability is not reduced.

In one embodiment, as shown in FIG. 1, the control unit 30 has a programmable logic controller (PLC) 24 and a programmable logic controller (PLC) 24 having a built-in memory for storing information obtained from the RF tag 20 by the reader / writer 12. A display 26 (display unit) for displaying the information stored in the memory is provided. As a result, the tag information sent to the reader / writer 12 can be stored in the memory, and the information stored in the memory can be displayed on the display 26 as needed.
In one embodiment, the control unit 30 incorporates an alarm 28. When the tag information stored in the memory built in the PLC 24 indicates an abnormality of the object to be detected 18, the alarm 28 is configured to issue an alarm.

In one embodiment, in the RF communication system 10 (10B) shown in FIG. 2, a plurality of RF tags 20 (20a, 20b, 20c) are provided. The plurality of RF tags 20 are provided on a plurality of different objects to be detected 18, or are provided at different sites of the same object to be detected 18 as shown in FIG. In this embodiment, the same number of second coils 16 (16a, 16b, 16c) are provided corresponding to the plurality of RF tags 20, and the same number of second coils 16 (16a, 16b, 16c) are provided with respect to the plurality of second coils 16 across the partition wall 17. The first coil 15 (15a, 15b, 15c) is connected. That is, a plurality of independent coil assemblies 14 (14a, 14b, 14c) are configured across the partition wall 17.

According to this embodiment, a plurality of information can be obtained at the same time from a plurality of RF tags 20 provided at different parts of the different object to be detected 18 or the same object to be detected 18, and the first coil 15 and the first coil 15 and the first coil 15 can be obtained. Since a plurality of independent coil assemblies 14 including two coils 16 are provided, the induced current generated in each first coil 15 is distributed to the second coil 16 of the other coil assembly 14, and the second coil of the same coil assembly 14 is provided. The amount of current flowing through 16 will not decrease. Therefore, the reader / writer 12 can accurately read the information sent from each RF tag 20.

The object to be detected 18 (18a) shown in FIG. 2 is a spiral conveyor in which a conveyor belt 19 (19a) is arranged in a spiral shape in the vertical direction. Three RF tags 20 (20a, 20b, 20c) are provided on the upper, middle and lower conveyor belts 19 (19a), respectively, and conveyors are provided at these three locations by information sent from the RF tags 20 (20a to 20c). The state of the belt 19 (19a) can be monitored.

3 and 4 show RF communication systems 10 (10C, 10D) according to different embodiments. In these embodiments, a plurality of RF tags 20 (20a, 20b, 20c) are provided on a plurality of different objects to be detected 18, or as shown in FIGS. 3 and 4, the same object to be detected 18 It is installed in different parts of. Further, a plurality of second coils 16 (16a, 16b, 16c) are provided for each of the plurality of RF tags 20, but the configuration different from that of the RF communication system 10 (10B) is that each coil assembly 14 (14A, 14B) is configured by connecting one first coil 15 to a plurality of second coils 16 (16a to 16c) with a partition wall 17 interposed therebetween.
According to this embodiment, since one first coil 15 may be provided for a plurality of second coils 16 (16a to 16c), the configuration of the coil assembly 14 (14A, 14B) is simple and low cost. Can be converted.

In the embodiment shown in FIG. 3, similarly to the embodiment shown in FIG. 2, the object to be detected 18 (18a) is composed of a spiral conveyor having a spiral conveyor belt 19 (19a). Three RF tags 20 (20a to 20c) are provided on the upper, middle and lower conveyor belts 19 (19a), respectively, and the state of the conveyor belts 19 (19a) can be monitored at these three locations.

In the embodiment shown in FIG. 4, the object to be detected 18 (18a) is composed of a conveyor having a conveyor belt 19 (19b) forming a transport surface along the horizontal direction. The conveyor belt 19 (19b) moves in the direction of the arrow, and three RF tags 20 (20a to 20c) are provided at three locations on the upstream side, midstream side, and downstream side of the conveyor belt 19 (19b) in the transport direction, respectively. ing. Therefore, the state of the conveyor belt 19 (19a) can be monitored at these three locations.

In one embodiment, as shown in FIGS. 3 and 4, a plurality of second coils 16 (16a, 16b, 16c) are provided for each of the plurality of RF tags 20 (20a, 20b, 20c). A switch 32 for connecting or disconnecting the antenna lead wire connected to the second coil 16 is provided. According to this embodiment, since the switch 32 is provided, only the RF tag 20 for which tag information is desired can be connected to the first coil 15, and the other antenna conductors can be disconnected from the first coil 15. As a result, the induced current generated in the first coil 15 flows only to the second coil 16 for which tag information is desired, and does not flow to other antenna conductors. Therefore, the distance between the second coil 16 and the first coil 15 should be extended. The tag information sent from the plurality of RF tags 20 can be read by the reader / writer 12 by switching the switch.

In one embodiment, as shown in FIG. 5, a support member 34 provided corresponding to the object to be detected 18 and movably supporting the RF tag 20 is provided. The support member 34 is configured so that the RF tag 20 can be arranged within the communication range R or outside the communication range R of the second coil 16 according to the first state A or the second state B of the object to be detected 18. According to this embodiment, the RF tag 20 is arranged by the support member 34 in or out of the communication range R of the second coil 16 according to the first state A or the second state B of the object to be detected 18. Therefore, the reader / writer 12 can read that the object to be detected 18 is in the first state A or the second state B.

In one embodiment, as shown in FIG. 5, the support member 34 is composed of a rod-shaped body 36 rotatably supported around the axis. The rod-shaped body 36 is arranged so that one end is in contact with the object to be detected 18, and the RF tag 20 is attached to the other end. When the object to be detected 18 is in the first position A, the RF tag 20 is arranged within the communication range R of the second coil 16, and when the object to be detected 18 is in the second position B, the RF tag 20 is in the second position. It is configured to be arranged outside the communication range R of the two coils 16.
According to this embodiment, the reader / writer 12 reads the tag information in which the object to be detected 18 exists in the first position A or the second position B by using the simple support member 34 composed of the rod-shaped body 36. Can be done.

In one embodiment, as shown in FIGS. 2 to 4, the object to be detected 18 to be detected by the RF tag 20 is composed of a conveyor, and a plurality of RF tags 20 are arranged at different places in the transport direction of the conveyor. .. According to this embodiment, since the plurality of RF tags 20 are provided at different locations in the conveyor transport direction, the conveyor information can be obtained in a wide area in the conveyor transport direction.

In one embodiment, when the conveyor belt of the conveyor, which is the object to be detected 18, is in the normal position, for example, when it is in the first position A shown in FIG. 5, the RF tag 20 is within the communication range R of the second coil 16. The RF tag 20 is configured to be located outside the communication range R of the second coil 16 when the conveyor belt is derailed. According to this embodiment, it is possible to detect the presence or absence of derailment of the conveyor belt, and even when an abnormality such as a broken line of the antenna lead wire occurs, the same information as when the RF tag 20 is arranged outside the communication range R of the second coil 16. Is supplied to the reader / writer 12, so that the leader / writer 12 can read the occurrence of the broken line of the antenna lead wire as the occurrence of an abnormality.

In one embodiment, as shown in FIGS. 2 to 4, a plurality of RF tags 20 are arranged at different locations on the conveyor belt 19 (19a, 19b) in the transport direction of the conveyor which is the object to be detected 18, and the plurality of RF tags are arranged. Each tag 20 holds a unique identification number. Then, the unique identification number and the arrangement location of each of the plurality of RF tags 20 are stored in the memory built in the PLC 24. According to this embodiment, the reader / writer 12 can read the location of the conveyor where the tag information supplied from the RF tag 20 is from the RF tag 20.

In one embodiment, the object to be detected 18 to which the RF tag 20 is installed is the object to be transported 40 to be conveyed by a conveyor, and the plurality of RF tags 20 are attached to the plurality of objects to be transported 40, which are different from each other. To. According to this embodiment, since each RF tag 20 has a unique identification number, it is possible to identify from which object 40 the tag information supplied to the reader / writer 12 is supplied. As a result, it is possible to detect where the specific object to be transported 40 is located in the transport direction of the conveyor, and it is possible to detect that the objects to be transported 40 are piled up. Further, by collating the tag information of the RF tag 20 provided on the transported object 40 with the tag information from the RF tag 20 provided on the conveyor, for example, the transported object 40 is provided in the freezer. When food is transported by a conveyor and frozen during transportation, quality control such as traceability of the food becomes possible.

Conventionally, as an emergency stop means when an abnormality occurs in the spiral type conveyor installed in the freezer, mechanical rope switches are stretched around the conveyor, and the worker who discovers the abnormality pulls the rope when the abnormality occurs. Means for urgently stopping the conveyor are used. In one embodiment, instead of the above means, RF tags 20 are arranged in various places in the refrigerator as shown in FIG. When an abnormality occurs on the conveyor, the RF tag 20 is separated from the second coil 16 by the worker pulling the rope 42, and the reader / writer 12 provided outside the refrigerator 17 across the partition wall 17 reads this off signal. It is configured to stop the conveyor and issue an alarm. A spring member 44 is provided between the RF tag 20 and the rope 42, and the spring member 44 returns the RF tag 20 and the rope 42 to their original positions.

As shown in FIG. 7, the conveyor is provided with a device 50 for adjusting the tension of the conveyor belt 19. The tension adjusting device 50 is provided, for example, in the vicinity of the driving roller 46 for driving the conveyor belt 19, and the adjusting roller 54 can reciprocate so that the distance between the pair of guide rollers 52 and the guide rollers 52 is variable. And have. The tension of the conveyor belt 19 can be adjusted by adjusting the distance between the adjusting roller 54 and the guide roller 52.
In one embodiment, as shown in FIG. 8, the adjusting roller 54 is provided with the RF tag 20, and the second coil 16 (16d, 16e) is located at a position facing the RF tag 20 at both ends of the reciprocating movement of the adjusting roller 54. ) Is placed. When the adjusting roller 54 comes to both end positions, the reader / writer 12 reads the change in the magnetic field around the second coil 16 due to the intrusion of the RF tag 20, and determines that an abnormality has occurred in the conveyor belt 19.

In one embodiment, the RF tag 20 is attached to the tools used in the freezer, and the tag information is read by the reader / writer 12 provided outside the freezer. As a result, it is possible to prevent the tool from being misplaced.

In one embodiment, as shown in FIG. 9, a non-conductive liquid such as pure water is stored in the tank 60, the second coil 16 and the RF tag 20 are arranged in the non-conductive liquid, and the first coil 15 and The leader / writer 12 is arranged outside the partition wall 60a of the tank 60. The reader / writer 12 can read the tag information while the non-conductive liquid retains the non-conductive property. On the other hand, when the non-conductive liquid becomes conductive due to contamination of the non-conductive liquid or the like, an overcurrent is generated in the non-conductive liquid, and the reader / writer 12 cannot read the information of the RF tag 20. Thereby, dirt and the like of the non-conductive liquid can be detected. If the combination of the second coil 16 and the RF tag 20 is arranged at a plurality of locations in the tank 60, it is possible to monitor dirt and the like at the plurality of locations.

FIG. 10 shows an embodiment for detecting the liquid level of the conductive liquid stored in the tank 60. In FIG. 10, the second coil 16 (16f) and the RF tag 20 (20d) and the second coil 16 (16g) and the RF tag 20 (20e) are arranged in the tank 60, and the second coil 16 (16f) is arranged. , 16g), the first coil 15 and the reader / writer 12 are arranged outside the partition wall 60a of the tank 60. The second coil 16 (16f) and the RF tag 20 (20d) is provided for detecting the lower limit liquid level _{h 1,} the second coil 16 (16f) and the RF tag 20 (20d) and a lower limit liquid level It is provided so as to sandwich h ₁ . The second coil 16 (16g) and the RF tag 20 (20e) is provided for detecting the maximum fluid level _{h 2,} the second coil 16 (16g) and RF tag 20 (20e) and an upper limit liquid level It is provided so as to sandwich h ₂ .

Since the reader / writer 12 can read the tag information when the liquid level is below the RF tag 20 (20d), it is therefore detected that the liquid level is below the RF tag 20 (20d). it can. When the liquid level is between the second coil 16 and the RF tag 20, the reader / writer 12 cannot read the tag information. That is, when the liquid level is at the lower limit liquid level _{h 1,} the reader writer 12 is not be read the information of the RF tag 20 (20d), it reads the information of the RF tag 20 (20e). When the liquid level is at the upper limit liquid level _{h 2,} the reader-writer 12 is not be read the information of the RF tag 20 (20d) and the RF tag 20 (20e). In this way, the liquid level can be grasped. If only one liquid level is to be detected, a set of the second coil 16 and the RF tag 20 may be provided in the tank 60.

In one embodiment, it can be applied to the case of monitoring the open / closed state of the open / close door of a refrigerator or a freezer, the open / close door in a vacuum environment where workers cannot approach, and the open / close state of an open / close door in a radiation environment, or when managing inventory. In this example, the RF tag 20 is provided on the door side, and the second coil 16 is provided on the door frame. By reading the change in the magnetic field due to the penetration of the RF tag 20, the second coil 16 reads that it is in the closed state, and reads that it is in the open state when there is no change in the magnetic field.

According to some embodiments, in the RF communication system, the communication distance can be extended by a simple means, and the degree of freedom in arranging the reader side device can be increased, thereby expanding the use of the RF communication system. it can.

10 (10A, 10B, 10C, 10D) RF communication system 12 Reader / writer 14 (14A, 14B, 14a, 14b, 14c) Coil assembly 15 (15a, 15b, 15c) First coil 16 (16a, 16b, 16c, 16d) , 16e, 16f, 16g) 2nd coil 17 partition wall 18 (18a, 18b) object to be detected 19 (19a, 19b) conveyor belt 20 (20a, 20b, 20c, 20d, 20e) RF tag 22 power supply 24 PLC
26 Display 28 Alarm 30 Control unit 32 Switch 34 Support member 36 Rod-shaped body 40 Object to be transported 42 Rope 44 Spring member 46 Drive roller 50 Tension adjustment device 52 Guide roller 54 Adjustment roller 60 Tank 60a Partition A 1st position (1st state) )
B 2nd position (2nd state)
Si internal space h ₁ Lower limit liquid level level h ₂ Upper limit liquid level level R Communication range

Claims (12)

With the leader
The first coil provided within the communication range of the reader and
A second coil connected to the first coil is provided.
The reader and the first coil are arranged with respect to the second coil with a partition wall.
The RF communication system is characterized in that the reader is configured to read a change in the magnetic field around the second coil due to the intrusion of the RF tag into the communication range of the second coil via the first coil. .. The space inside the partition wall surrounded by the partition wall is in an environment in which the temperature, pressure or atmosphere is different from the outside of the partition wall.
The RF communication system according to claim 1, wherein the second coil and the RF tag are arranged in the inner space of the partition wall, and the reader and the first coil are arranged outside the partition wall. .. A plurality of the RF tags are provided at different parts of the different object to be detected or the same object to be detected, which is the object to be detected to which the RF tag is installed.
A plurality of the second coils provided corresponding to each of the plurality of RF tags, and
A plurality of the first coils connected to each of the plurality of second coils,
The RF communication system according to claim 1 or 2, wherein the RF communication system comprises. A plurality of the RF tags are provided at different parts of the different object to be detected or the same object to be detected, which is the object to be detected to which the RF tag is installed.
A plurality of the second coils provided corresponding to each of the plurality of RF tags, and
One said first coil connected to each of the plurality of second coils,
The RF communication system according to claim 1 or 2, wherein the RF communication system comprises. The RF communication system according to claim 4, further comprising a switch for connecting or disconnecting an antenna lead wire connected to each of the plurality of second coils. A storage unit that stores information obtained from the RF tag by the reader, and a storage unit.
A display unit that displays the information stored in the storage unit, and
The RF communication system according to any one of claims 1 to 5, wherein the RF communication system comprises. A support member that movably supports the RF tag is provided.
The support member can arrange the RF tag within or outside the communication range of the second coil according to the first state or the second state of the object to be detected to which the RF tag is installed. The RF communication system according to any one of claims 1 to 6, wherein the RF communication system is configured. The support member is composed of a rod-shaped body rotatably supported around the axis.
The rod-shaped body is arranged so that one end is in contact with the object to be detected, and the RF tag is attached to the other end.
When the object to be detected is in the first position, the RF tag is arranged within the communication range of the second coil, and when the object to be detected is in the second position, the RF tag is in the second coil. The RF communication system according to claim 7, wherein the RF communication system is configured to be arranged outside the communication range of the above. The object to be detected to which the RF tag is installed is composed of a conveyor.
The RF communication system according to any one of claims 1 to 8, wherein a plurality of the RF tags are arranged at different locations in the transport direction of the conveyor. When the conveyor is in the normal position, the RF tag is arranged within the communication range of the second coil, and when the conveyor derails, the RF tag is arranged outside the communication range of the second coil. The RF communication system according to claim 9, wherein the RF communication system is configured. The reader includes a storage unit that stores information obtained from the RF tag.
A plurality of the RF tags are arranged at different locations in the transport direction of the conveyor.
Each of the plurality of RF tags retains a unique identification number and
The RF communication system according to claim 9 or 10, wherein at least the unique identification number and the arrangement location of each of the plurality of RF tags are stored in the storage unit. The object to be detected to which the RF tag is installed is an object to be conveyed on a conveyor.
The RF communication system according to any one of claims 1 to 11, wherein the RF tag is attached to the object to be transported.

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