KR100930110B1 - RFID tag with wired communication function - Google Patents

Abstract

The present invention has a wired communication function to establish a desired sensor network in any space including an electromagnetic shielding space by providing a wired communication function to be connected to another RFID tag or reader and a cable to transmit and receive necessary data. It's about tags.

RFID tag having a wired communication function of the present invention comprises an antenna for emitting and capturing RF signals; A sensor unit converting and detecting various physical quantities into electrical signals; A processor unit having a memory for storing tag ID and sensing data from the sensor unit, a controller for controlling the overall operation of the tag, and a serial communication interface for performing serial communication with a reader or another tag; An RF communication unit which receives the RF signal captured by the antenna, transmits the RF signal to the processor unit, modulates the tag ID and the sensing data received from the processor unit, and radiates the RF signal as an RF signal through the antenna; It includes a connector for connecting the serial communication interface and the reader or another tag via a cable and a battery for supplying operating power to each part of the tag.

In the above configuration, the serial communication interface is preferably a CAN interface.

 RFID, Wired, Wireless, Airtight, Space, Tag, CAN, Semi-Active, Battery

Description

RFID tag with wired communication function {RFID tag with wire communication function}

The present invention relates to an RFID tag having a wired communication function, and more particularly, to an RFID tag having a wired communication function connected to another RFID tag or a reader and a cable to transmit and receive necessary data.

Generally recognized radio frequency (RFID: R adio F requency Id entification) recognizes the tag is attached to goods, animals, people, and by the non-contact type read information from or writes from a tag with a unique identification information by using a radio frequency , Technology that enables tracking and management. Such an RFID system has a plurality of tags (Electronic Tag or Transponder; hereinafter simply referred to as 'tag') attached to an object or animal with unique identification information and an RFID reader (Reader or Interrogator) for reading or writing the information of the tag. (Hereinafter referred to simply as 'leader'). The RFID system is also classified into mutual induction and electromagnetic waves according to the intercommunication method between the reader and the tag, and semi-active (active, passive, and a mixture of both depending on whether the tag operates on its own power) Active) type, and it is divided into long wave, medium wave, short wave, microwave and microwave according to the frequency used. In accordance with the above classification, various kinds of standards are enacted or in preparation for enactment. On the other hand, such an RFID system is being actively used in logistics and factory automation.

On the other hand, Ubiquitous Sensor Network (USN) attaches RFID tag to all necessary places and detects recognition information of objects and surrounding environment information and connects it to network in real time to manage information. I mean. Ultimately, it is to give computing and communication functions to all things to realize an environment that can communicate anytime, anywhere, network, device, and service.

However, it is also necessary to place a tag in a space where electromagnetic waves cannot be transmitted, for example, a space enclosed with a metal material, that is, an electromagnetic shielding space. The conventional tag has a function capable of communicating with another tag or a reader by wire. There is a problem that does not meet this need because it is not equipped at all. For example, if you want to use the tag as a sensor node that detects and reports the temperature of the refrigerator's refrigerator and freezer compartments, the tag or reader functions as another sensor node or sink node because the conventional tag does not have a wired communication function. There is no way to communicate with the device, and thus there is a problem in that a desired sensor network cannot be established.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and is provided with a wired communication function to transmit and receive necessary data connected to another RFID tag or reader by a cable, thereby providing a desired sensor network in any space including an electromagnetic shielding space. An object of the present invention is to provide an RFID tag having a wired communication function that can be constructed.

RFID tag having a wired communication function of the present invention for achieving the above object is an antenna for emitting and capturing an RF signal; A sensor unit converting and detecting various physical quantities into electrical signals; A processor unit having a memory for storing tag ID and sensing data from the sensor unit, a controller for controlling the overall operation of the tag, and a serial communication interface for performing serial communication with a reader or another tag; An RF communication unit which receives the RF signal captured by the antenna, transmits the RF signal to the processor unit, modulates the tag ID and the sensing data received from the processor unit, and radiates the RF signal as an RF signal through the antenna; It includes a connector for connecting the serial communication interface and the reader or another tag via a cable and a battery for supplying operating power to each part of the tag.

In the above configuration, the serial communication interface is preferably a CAN interface.

The apparatus may further include a voltage detector for detecting a voltage of the battery and a switching unit for selectively connecting the respective parts of the tag with an external power line of the battery or the CAN interface. The controller may further include a voltage of the battery detected by the voltage detector. If it is less than the reference voltage it is preferable to control the switching unit to connect each part of the tag to an external power line of the CAN interface.

According to the RFID tag having a wired communication function according to the present invention, if necessary, such as when installed in a space including an electromagnetic shielding space, data is transmitted by a reader or other tag and wired communication, so that a desired sensor network can be constructed in any space. It is possible.

Hereinafter, an RFID tag having a wired communication function according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of an RFID tag having a wired communication function according to the present invention. As shown in FIG. 1, an RFID tag having a wired communication function according to the present invention may be implemented as an active or semi-active tag having a battery and operating only on its own battery. Specifically, the RFID tag 400 having a wired communication function according to the present invention receives a continuous electromagnetic wave having a specific frequency and a modulated RF signal which is a command of a reader from another reader or tag, and transmits the modulated RF signal to an RF communication unit described later. An antenna 440 for receiving and transmitting data from the RF communication unit to transmit information stored in the tag internal memory to a reader or another tag; Using the continuous electromagnetic signal received from the antenna 440 generates the operating power of the tag and transmits the modulated RF signal to the processor to be described later to modulate the data stored in the receiver 432 and the processor to perform the command of the reader An RF communication unit 430 including a transmission unit 434 for wireless transmission through the antenna 440; A sensor unit 480 for converting and detecting various physical quantities such as physical, chemical, or bioinformation data into electrical signals having a corresponding size; The memory 424, which stores the ID (unique identifier) or sensor detection data of the tag 400, and the reader's command received from the receiving unit 432 of the RF communication unit 430, are interpreted / processed and detected by the sensor. The processor 420 and the tag 400 each include a controller 422 which processes and stores data in the memory 424 and transmits the data to the reader through the transmitter 434 of the RF communication unit 430. It may include a battery 450 that provides the required operating power.

In the above-described configuration, the power from the battery 450 may be supplied only when sufficient power is not supplied from the RF communication unit 430 to the processor unit 420. When the power is supplied from the RF communication unit 430, That is, when the tag 400 operates in a passive manner, a method of scattering electromagnetic waves received from a reader and returning the tags to the reader is generally used.

The control unit 422 decodes / implements all instructions of the reader that occur in the communication process between the reader and the tag, and includes all additional reader instructions necessary to obtain sensor data. The sensor unit 480 is provided in a form embedded in the tag 400, and senses and transmits surrounding environment information to the controller 422, and all operation control of the sensor may be made by a command of the controller 422.

On the other hand, in the RFID tag having a wired communication function of the present invention, the processor unit 420 may be further provided with a serial communication interface, preferably a CAN (Controller Area Network) interface for wired communication with another reader or tag. The CAN interface 420 is responsible for data communication between the connector 410 and the controller 422 connected to an external CAN bus.

More specifically about CAN, CAN was developed by Bosch in the early 1980s as a serial bus system for automotive applications, and this CAN protocol is currently used in a wide variety of automotive, marine, medical, manufacturing and aerospace / aviation applications. Widely used in industry. The CAN bus consists of a balanced (differential) 2-wire interface using either a shielded twisted pair (STP), an unshielded twisted pair (UTP), or a ribbon cable and each node Uses a male 9-pin D connector. The specific names and functions of each pin are shown in Table 1 below.

PIN number Signal name Signal description One Reserved Upgrade Path 2 CAN_L Dominant low 3 CAN_GND Ground 4 Reserved Upgrade Path 5 CAN_SHLD Shield, Optional 6 GND Ground, Optional 7 CAN_H Dominant High 8 Reserved Upgrade Path 9 CAN_V + Power, Optional

CAN, on the other hand, is a peer-to-peer network, that is, a network without a master that controls when individual nodes access it to read or write data on the CAN bus. In this architecture, when any CAN node is ready for data transmission, it checks whether the CAN bus is ready and then writes a CAN frame to the network. The transmitted CAN frame does not contain the address of either the transmitting node or the receiving node, but a unique arbitration ID classifies the frame in the network. Accordingly, all nodes on the CAN network receive the CAN frame, and each CAN node on the network determines whether to accept the frame according to the arbitration ID of the transmitted frame.

2 is a view for explaining the structure of the CAN protocol and its implementation element defined in ISO 11898.

As shown in FIG. 2, the CAN protocol is composed of three layers, a lowermost physical layer, a data-link layer existing above it, and an application layer existing at the highest level. Can be. In the above configuration, the physical layer is responsible for physical signaling, physical medium attachment, and medium dependent interface, and the data link layer is a logical link control and a logical link control. Responsible for Medium Access Control.

Meanwhile, the application layer may be implemented by a digital signal processor (DSP) or a similar controller, and the physical signaling of the data link layer and the physical layer may be implemented by an embedded CAN controller, and the other physical layer may include a transceiver, a connector, and a cable. It can be implemented with a CAN transceiver.

Table 2 below shows the structure of a CAN frame.

S O F 11-BIT ARBITRATION ID S L R I D E 18-BIT ARBITRATION ID R T R r 0  DLC 0… 8 BYTES DATA  CRC A C K E O F

As shown in Table 2 above, a CAN device transmits data in a packet called a frame on a CAN network, which can be organized into the following sections:

SOF (Start-of-frame): A specific bit (logic 0) that marks the beginning of a message.

Arbitration ID: Used to identify and prioritize messages. There are two formats for CAN frames: Standard using 11-bit Arbitration ID and Extension using 29-bit Arbitration ID.

IDE (Identifier Extension) bit: distinguishes between standard and extension frames.

Remote Transmission Request (RTR): It is used to distinguish a remote frame from a data frame. A major RTR bit (logic 0) indicates a data frame, and a recessive RTR bit (logic 1) indicates a remote frame.

DLC (Data Length Code): This indicates the number of bytes of the data field.

Data field: consists of 0 to 8 bytes of data.

Cyclic Redundancy Check (CRC): Used for error detection.

ACK (ACKnowledgement) slot: Any CAN controller that correctly receives a message sends an ACK bit at the end of the message. The transmitting node checks for the presence of an ACK bit on the bus and retries the transmission if no ACK is found.

End-of-frame (EOF): A specific bit indicates the end of a frame.

1 again, the RFID tag according to the present invention detects the voltage of the battery 450 and transmits the respective parts inside the tag under the control of the voltage detector 470 and the controller 422 to transmit the built-in battery ( 450 or a switching unit 460 for alternatively connecting to an external CAN bus power line through the CAN interface 426. The control unit 422 may have a voltage lower than or equal to a reference voltage. In this case, the tag 400 may be operated by power supplied through the CAN interface 426, that is, power supplied through pin 9 (see Table 1) of the connector 410. For this purpose, the controller 422 may refer to power monitoring information provided from another tag as described below.

Figure 3 is an application example of an RFID tag having a wired communication function of the present invention, Figure 4 is another application example of an RFID tag having a wired communication function of the present invention. First, as shown in FIG. 3, an application of an RFID tag having a wired communication function according to an embodiment of the present invention includes a tag installed in the electromagnetic shielding space 500 in the state where one tag is installed in the electromagnetic shielding space 500. In order to transmit data from an internal tag, for example, sensing data, to an RFID reader 200 or an upper sink node, the internal tag may be exposed to free space and serve as a transmission relay means. In the following description, it may be connected one-to-one by an external tag) and a CAN bus, that is, the cable 300 and the connector 410, where reference numeral 100 denotes middleware.

Meanwhile, as illustrated in FIG. 4, one external tag may transmit sensing data from a plurality of internal tags to the RFID reader 200 or an upper sink node, and these internal tags 400 may have different electromagnetic shielding spaces. 500, 510 can be installed, and further, two inner tags can be installed together in the same shielded space 510. In this case, the external tag and each internal tag may be interconnected through separate CAN bus 600 and connectors 320 and 410, and reference numeral 610 denotes a termination resistance of the CAN bus 600.

5 is a diagram illustrating a wireless communication data format between an RFID tag and an RFID reader having a wired communication function according to the present invention. The external tag may transmit sensing data received from the internal tag via the CAN bus to the RFID reader or the upper sink node by the frame structure as shown in FIG. 5. Such a frame may include, for example, a header and a plurality of tag information. It may be made, including. Here, each tag information basically includes a tag ID and sensing data, and may further include power monitoring information.

The RFID tag having the wired communication function of the present invention is not limited to the above-described embodiment and can be modified in various ways within the scope of the technical idea of the present invention. That is, in the above-described embodiment, a CAN bus is used as the serial communication interface, but a serial communication interface such as RS-485 may be used.

1 is a block diagram of an RFID tag having a wired communication function according to the present invention;

2 is a view for explaining the structure of the CAN protocol and its implementation element defined in ISO 11898,

Figure 3 is an application example of the RFID tag having a wired communication function of the present invention,

Figure 4 is another application example of the RFID tag having a wired communication function of the present invention,

5 is a diagram illustrating a wireless communication data format between an RFID tag and an RFID reader having a wired communication function according to the present invention.

*** Explanation of symbols for the main parts of the drawing ***

100: middleware, 200: RFID reader,

300: communication cable, 320: connector,

400: RFID tag, 410: connector,

420: processor unit, 422: control unit,

424: memory, 426: CAN interface,

430: an RF communication unit, 432: a receiving unit,

434: transmitter, 440: antenna,

450: battery, 460: switching unit,

470: voltage detection unit, 480: sensor unit,

500, 510: confined space, 600: CAN bus,

610: termination resistor

Claims (3)

An antenna for emitting and capturing an RF signal; A sensor unit converting and detecting various physical quantities into electrical signals; A processor unit having a memory for storing tag ID and sensing data from the sensor unit, a controller for controlling the overall operation of the tag, and a serial communication interface for performing serial communication with a reader or another tag; An RF communication unit which receives the RF signal captured by the antenna, transmits the RF signal to the processor unit, modulates the tag ID and the sensing data received from the processor unit, and radiates the RF signal as an RF signal through the antenna; A connector for connecting the serial communication interface with a reader or another tag through a cable; and RFID tag having a wired communication function comprising a battery for supplying operation power to each part of the tag. The method of claim 1, The serial communication interface is a RFID tag having a wired communication function, characterized in that the CAN interface. The method according to claim 1 or 2, A voltage detector detecting a voltage of the battery; It further includes a switching unit for selectively connecting each part of the tag with the external power line of the battery or CAN interface, When the voltage of the battery detected by the voltage detector is less than the reference voltage, the controller controls the switching unit to connect each part of the tag to an external power line of the CAN interface. .

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