JP2005086415A - Sensor switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a more convenient sensor switch.
In a sensor switch in which an opening / closing element 3 opens and closes according to a sensing state, an antenna coil 4 connected to the opening / closing element 3 and an IC module 5 that operates with electric power from the antenna coil 4 and wirelessly communicates with the outside. Prepared. Electric power can be supplied to the switching element 3 via the antenna coil 4.
[Selection] Figure 1

Description

  The present invention relates to a sensor switch that opens and closes depending on a sensing state, and relates to a sensor switch including an RFID tag that wirelessly communicates the opening and closing state of the opening and closing element.

  The sensor switch utilizes the fact that the opening / closing element opens and closes depending on a sensing state such as a temperature higher than a predetermined temperature. By adopting limit switches, temperature sensors, pressure sensors, etc. for the open / close elements, there are various quantities and phenomena that are to be sensed by the sensor switches. Sensor switches are used in various applications from the FA (factory automation) field to the security field.

  On the other hand, RFID tags (also called IC tags, non-contact IC tags, ID tags, etc.) are known as techniques for recognizing information without contact. There are various uses of RFID tags. An RFID tag is used by a person or by being fixed to an object. The RFID tag includes an antenna coil and an IC module that receives power from outside through the antenna coil and wirelessly communicates information with the outside. An LC circuit is constituted by the inductance L of the antenna coil and the capacitance C of the IC module, and the resonance frequency of the LC circuit is set to a frequency used for communication. The RFID tag performs non-contact communication with an external counterpart device (reader / writer) while obtaining power by electromagnetic induction using an LC circuit.

  Patent Document 1 describes a detection device that stores an open / close state of an open / close element of a sensor switch and wirelessly communicates using an RFID tag.

  Patent Document 2 describes a sensor switch that includes a battery for supplying power to an open / close element and can wirelessly communicate the open / closed state of the open / close element.

Japanese Patent Laid-Open No. 2002-188754 JP 05-328661 A

  Since the sensor switch uses the fact that the opening / closing element opens and closes depending on the sensing state, the sensor switch and a monitor device that monitors the sensing state of the sensor switch need to be electrically connected by wire. When using a plurality of sensor switches, it is necessary to route a lot of wiring, and it is necessary to secure a wiring space from the sensor switch to the monitor device and to examine a wiring layout. Furthermore, since wiring is connected to the sensor switch, it is difficult to attach the sensor switch to a movable part such as a rotating body. If the wiring can be eliminated, it is not necessary to consider the wiring space and the wiring layout, and the attachment to the movable part is facilitated.

  In that respect, since the detection device of Patent Document 1 wirelessly communicates the open / closed state of the open / close element to the monitor device, the wiring for communication can be eliminated. However, it is necessary to connect to an external power source in order to supply power to the switching element.

  The sensor switch of Patent Document 2 does not need to be connected to an external power source because there is a battery that supplies power to the switching element. However, if the charge amount of the battery is exhausted, the sensing function is lost, and thus means for constantly monitoring the charge amount of the battery is required.

  As described above, in the prior art, since the means for supplying power to the switching element is a wired or battery, connection or charge amount monitoring is indispensable, and it cannot be said that convenience is sufficient.

  Further, what is important in the service life of the sensor switch is the number of times the switching element is opened and closed. In the conventional sensor switch, in order to grasp the service life, it is necessary to count the number of opening and closing of the opening / closing element in the monitor device.

  Accordingly, an object of the present invention is to solve the above-described problems and provide a more convenient sensor switch.

  In order to achieve the above object, the present invention provides an antenna coil that opens and closes depending on a sensing state, an antenna coil connected to the switch element, and an IC that operates with power from the antenna coil and wirelessly communicates with the outside. Module.

  The switching element may be provided in series between the antenna coil and the IC module.

  The switching element may be provided in parallel with the antenna coil or the IC module.

  The open / close element may be a switch that is mechanically opened and closed by interfering with a sensing object.

  A temperature sensor that opens and closes according to the temperature may be used.

  The opening / closing element may be a pressure sensor that is opened and closed according to pressure.

  The IC module may have a readable storage area.

  The IC module may have a writable storage area.

  The IC module may have a function of distinguishing from other sensor switches.

  The present invention exhibits the following excellent effects.

  (1) Since the antenna coil connected to the switching element is provided, power can be supplied to the switching element via the antenna coil, and wiring and charge amount monitoring are not required.

  In the present invention, an antenna coil of an RFID tag and an IC module are incorporated in a sensor switch having an opening / closing element. Of course, the IC module receives electric power from the outside via the antenna coil and wirelessly communicates with the outside via the antenna coil, but the electric power of the switching element is also supplied to the outside via the antenna coil. As a result, not only non-contact communication can be performed with an external counterpart device (tag reader, reader / writer, etc.), but the power of the switching element can be provided from the counterpart device in a non-contact manner, and no wiring is required. Therefore, it is not necessary to consider the wiring space and the wiring layout, and the mounting to the movable part is facilitated, and the charge amount monitoring is not required.

  By providing the switching element in series between the antenna coil and the IC module, electric power is supplied to the IC module only when the switching element is closed.

  By providing the switching element in parallel with the antenna coil or the IC module, power is supplied to the IC module only when the switching element is open.

  If the open / close element is a switch that is mechanically opened and closed by interfering with the sensing object, the sensing state of whether or not the sensing object is interfering can be detected.

  If the open / close element is a temperature sensor that opens and closes according to temperature, a sensing state in which the temperature is higher or lower than a predetermined temperature can be detected.

  If the open / close element is a pressure sensor that opens and closes according to pressure, a sensing state in which the pressure is higher or lower than a predetermined pressure can be detected.

  If the IC module has a readable storage area, the read information can be communicated to the counterpart device.

  If the IC module has a writable storage area, an information writing function (write function) is realized. For example, it becomes possible to store the operation status of the sensor switch (such as the number of times of opening / closing of the switching element) in the IC module, and there is no need to have a database for storing the number of times of opening / closing in the counterpart device.

  If the IC module has an identification function (such as an anti-collision function) with other sensor switches, a single counterpart device can communicate with a plurality of sensor switches, which facilitates monitoring.

1) First Embodiment As shown in FIG. 1, a sensor switch (sensor switch with an RFID tag) according to the present invention is deformed according to temperature (sensing state), and deformation of the thermobimetal 1. An opening / closing element 3 as a temperature sensor comprising a contact 2 that is mechanically opened and closed is provided, and an RFID tag 6 comprising an antenna coil 4 and an IC module 5 is provided.

  As shown in FIG. 2, the sensor switch of FIG. 1 is one in which an opening / closing element 3, an antenna coil 4, and an IC module 5 are connected in parallel. The switching element 3 that is a temperature sensor is in a state in which the contact 2 comes into contact with the switching element 3 in a normal state (temperature is higher or lower than a predetermined temperature), and the switching element 3 is closed. When the temperature is lower than or higher than a predetermined temperature), the thermo-bimetal 1 is deformed so that the contact 2 is separated and the switching element 3 is opened.

  FIG. 3A shows a circuit state in a normal state. Since the switching element 3 connected in parallel with the IC module 5 is closed in normal times, the LC circuit composed of the inductance L of the antenna coil 4 and the capacitance C of the IC module 5 is reduced by the switching element 3. Both ends of the are short-circuited. Even if the counterpart device 7 such as a tag reader exists in the communication area where it can communicate with the IC module 5 and emits radio waves, the LC circuit does not enter a resonance state, so communication is impossible.

  FIG. 3B shows a non-normal circuit state. In non-normal times, the switching circuit 3 which is a temperature sensor opens because the temperature exceeds a predetermined temperature, so that the LC circuit can resonate. If the counterpart device 7 exists in a communication area where it can communicate with the IC module 5 and emits radio waves, the IC module 5 can communicate with the power from the LC circuit. By enabling communication, the counterpart device 7 recognizes that the sensor switch is on (opening / closing element 3 is open; non-normal). Since the open / close state of the open / close element corresponds to the sensing state, the counterpart device 7 can monitor that the temperature detected by the sensor switch (sensing state) exceeds a predetermined temperature (higher or lower). .

  The opening / closing element 3 may be a normally-off type that is normally open and closed in a non-normal state. In this case, communication is possible in a normal state and communication in a non-normal state is impossible.

  The switching element 3, the antenna coil 4, and the IC module 5 may be connected in series. In this case, if the opening / closing element 3 is a normal-on type, communication is possible during normal times and communication is not possible during non-normal times.

  In the first embodiment, the open / close element 3 is a thermo-bimetallic temperature sensor. However, the open / close element 3 may be a switch such as a limit switch that is mechanically opened and closed by interfering with a sensing object. The pressure sensor may be opened or closed according to the pressure.

2) Second Embodiment As shown in FIG. 4, the sensor switch 42 of the present invention is attached to the sensing object 41, and the host (monitor device) 43, which is a communication counterpart device, connects the antenna 44 to the sensor switch. 42. Although not shown, the IC module in the sensor switch 42 is provided with a read / write type storage area in which at least one memory write can be performed. Basic information of the sensor switch 42 can be written in this storage area. The basic information includes an identification number (tag ID), an installation location (sensing object 41), a sensor type (temperature, limit, pressure), and the like. In addition, the operation status of the sensor switch 42 (such as the number of times of opening / closing the switching element) can be written in the storage area.

  Thereby, the host 43 can access the sensor switch 42 and read the basic information and the operation status from the storage area. Therefore, even if the host 43 does not know the relationship between the tag ID and the installation location or the sensor type or the operation status in advance, the host 43 reads the basic information or the operation status from the sensor switch 42 and installs the sensor switch 42. The sensor type can be confirmed and the operating status of the switching element can be grasped.

  In FIG. 4, information read by the host 43 from the sensor switch 42 is illustrated in the host 43. As shown in the figure, the host 43 can grasp the installation location and the number of times of monitoring (number of times of opening and closing) corresponding to the tag ID.

  The sensor switch 42 can be configured using various types of switching elements (temperature sensor, limit switch, pressure sensor, etc.). The host 43 can recognize the sensing state of on or off regardless of the type of the open / close element.

3) Third Embodiment As shown in FIG. 5, a plurality of sensor switches 52 (A, B, C, D) of the present invention are attached to a sensing object 51, and a host which is a communication counterpart device (Monitor device) 53 has an antenna 54 facing a plurality of sensor switches 52. Although not shown, the IC module in each sensor switch 52 is provided with an identification function (a known anti-collision function or the like) for identifying the other sensor switch 52 from each other.

  When radio waves are radiated from the antenna 54 of the host 53, the sensor switches 52 communicate wirelessly with the open / close states of the open / close elements. Even when the plurality of sensor switches 52 communicate with the host 53 at the same time, the host 53 can simultaneously monitor the plurality of sensor switches 52 because the identification source can identify the communication source.

  In FIG. 5, information read from each sensor switch 52 by the host 53 is illustrated in the host 53. As shown in the figure, the host 53 recognizes that the opening / closing state of the tag A (A of the sensor switch 52) is ON, the opening / closing state of the tag B is OFF, and the opening / closing state of the tag C is ON. The open / close state of each is distinguished and grasped.

  The sensor switch according to the present invention can be used for various applications from the FA field to the security field. By adopting a limit switch, temperature sensor, pressure sensor, or the like as the open / close element, various events are sensed by the sensor switch.

1 is a schematic structural diagram of a sensor switch showing one embodiment of the present invention. It is a circuit diagram of the sensor switch of FIG. FIGS. 2A and 2B are operation explanatory diagrams of the sensor switch of FIG. 1, in which FIG. 1A shows a normal circuit state, and FIG. 1B shows a non-normal circuit state; It is a figure of the utilization form of the sensor switch which shows one Example of this invention. It is a figure of the utilization form of the sensor switch which shows one Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thermo bimetal 2 Contact 3 Opening / closing element 4 Antenna coil 5 IC module 6 RFID tag 7 Counterpart device

Claims (9)

  A sensor switch that opens and closes depending on a sensing state, comprising: an antenna coil connected to the opening and closing element; and an IC module that operates with electric power from the antenna coil and wirelessly communicates with the outside. switch.   2. The sensor switch according to claim 1, wherein the switching element is provided in series between the antenna coil and the IC module.   2. The sensor switch according to claim 1, wherein the switching element is provided in parallel with the antenna coil or the IC module.   4. The sensor switch according to claim 1, wherein the open / close element is a switch that is mechanically opened and closed by interfering with a sensing object.   The sensor switch according to any one of claims 1 to 3, wherein the open / close element is a temperature sensor that is opened and closed according to temperature.   4. The sensor switch according to claim 1, wherein the opening / closing element is a pressure sensor that is opened / closed in accordance with pressure.   The sensor switch according to claim 1, wherein the IC module has a readable storage area.   The sensor switch according to claim 1, wherein the IC module has a writable storage area. 9. The sensor switch according to claim 1, wherein the IC module has a function of distinguishing from other sensor switches.

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