JPH1093485A - Discriminating system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform data communication without causing faults to other parts by providing a data receiving means, plural data carrier discriminating means, response command transmitting means, a transmitting means, data transmitting means, memory and a successive shunt output means. SOLUTION: An output of a discriminating circuit 26 of a read/write head 20A is supplied to a plural DCs detecting circuit 27 which is a plural data carriers discriminating means and the circuit 27 detects the plural data carriers. The detected output is given to a communication control part 28 which is a responding command transmitting means, specifies the data carrier and performs communication. Memory 17 of the data carrier 10A is provided with an area to store an ID code proper to each data carrier and a communication control part 16 performs data communication as it is when a simple responding command is received. When the plural responding commands are received, the communication control part 16 successively outputs a shunt signal until the response time proper to each data carrier or specified by a random number and performs data communication after the completion of output of the successive shunt signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an identification system used for a distribution system, an electronic coupon system, and the like.

[0002]

2. Description of the Related Art In a component identification system, an electronic coupon system, and the like used in a conventional assembly conveyance line, a system for identifying and managing articles is required. Therefore, a data carrier (ID card) having a memory as an object to be identified is provided as in JP-A-1-163991, and necessary information is written to the data carrier by external data transmission.
An identification system has been proposed in which the information is read as needed. Such a data carrier is attached to a pallet or the like, or is carried by a user, and is provided with a writing / writing device arranged on a pallet transport path or a side of an entrance / exit gate.
The read control unit is configured to write or read necessary data to the data carrier.

FIG. 7 is a block diagram showing a configuration of a read / write head which is a write / read control unit of a conventional identification system, and a data carrier for holding data.
In FIG. 7, the data carrier 10 has a demodulation unit 12 and a memory control unit 13 connected to a resonance circuit 11 including a coil L1 and a capacitor C1. The memory control unit 13 writes or reads data to or from the nonvolatile memory 14 in accordance with the demodulated command, and the read data is temporarily converted to a biphase code. The shunt circuit 15 short-circuits both ends of the resonance circuit 11 using a biphase code. On the other hand, the read / write head 20 has a modulation circuit 21 and a transmission circuit 22 as transmission means. Transmission circuit 2
Reference numeral 2 denotes an oscillation circuit that oscillates at a constant carrier frequency, and interrupts the oscillation at a constant cycle. Then, the duty ratio of the intermittent oscillation is changed to first and second duty ratios, for example, 70% and 30% according to the given transmission data. Further, at the time of reception, the transmission circuit 22 drives the transmission coil L2 by interrupting the oscillation at a constant duty ratio (for example, 50%). The receiving circuit 23 is connected to the receiving coil L3 and receives reverberation. The output of the receiving circuit 23 is passed through an amplifier 24 and an envelope detection circuit 25 to the judgment circuit 2.
6 given. The judgment circuit 26 converts the received signal into a digital value by discriminating the output level with a predetermined threshold value.

In such a conventional identification system, when there is one data carrier in a communicable area, transmission and reception can be performed normally. FIG. 8A shows an intermittent carrier signal applied to the transmitting coil L2. In this case, the read / write head 20 is in a state of receiving data, and is driven at a duty ratio of 50%. The data carrier 10 extracts a clock signal from the intermittent carrier by the resonance circuit 11 and reads data from the memory 14, and the transmission data is converted into a biphase code. FIG. 8B
Indicates a biphase code, and at the L level, a shunt pulse is output when the carrier stops as shown in FIG. 8C. As shown in FIG. 8D, if there is no shunt pulse, the resonance waveform of the data carrier includes reverberation,
Reverberation is stopped if there is a shunt pulse. Therefore, FIG.
The reverberation is received by the coil L3 of the read / write head 10 as shown in (e) to (g). The data is demodulated by envelope detection and discrimination at a predetermined level.

[0005]

However, when a plurality of data carriers exist in a communication area, there is a problem that communication cannot be performed at all or a communication error occurs. FIGS. 8H to 8J show the operation of another data carrier when another data carrier is simultaneously present in the communication area. If there are a plurality of data carriers in the communication area as described above, the reverberation shown in FIGS. 8D and 8J will be overlapped, so that the read / write head has a disadvantage that normal reception cannot be performed.

SUMMARY OF THE INVENTION The present invention has been made in view of such a conventional problem, and has an object to enable data communication without interference even when a plurality of data carriers exist in a communication area. With the goal.

[0007]

According to the present invention, as shown in FIG. 1, a data carrier having a memory for holding data, a write / read control unit for performing data transmission between the data carrier, and The write / read control unit comprises: a data receiving unit for receiving data depending on the presence or absence of reverberation of a carrier which is intermittent when receiving data; A plurality of data carrier discriminating means 2 for detecting the presence of a plurality of data carriers in the communication area;
A response command transmitting means 3 for transmitting a simple response command at the start of communication and transmitting a plurality of response commands when a plurality of data carriers are determined by the plurality of data carrier determining means;
When the data and the response command are transmitted, the duty ratio is changed to first and second duty ratios, and when the data is received, the duty ratio is changed to the third duty ratio.
Transmitting means 4 for setting the duty ratio of the data carrier, wherein the data carrier includes a resonance circuit, and performs data transmission with the write / read control unit; A memory for holding a unique ID code, and a continuous shunt for outputting a continuous shunt signal when a carrier signal obtained by the resonance circuit is stopped until a response start time when a plurality of response commands are received by the data transmission means; Output means 7 and its own ID after the end of the continuous shunt by said continuous shunt output means.
And a communication control means 8 for transmitting a signal including a code and controlling data communication.

According to the present invention having such features,
The write / read control unit sends a simple response command at the start of communication. Then, at the time of data reception, it is determined whether or not a plurality of data carriers exist based on whether or not an interference state occurs. If there is no plurality of data carriers, data communication is performed with one data carrier. When a plurality of data carriers are determined, a plurality of response commands are transmitted. If a simple response command is received, the data carrier performs data communication as it is. If a plurality of response commands are received, data communication starts after a different response time for each data carrier. Until then, the mode is the no-response mode, and the shunt pulse for stopping reverberation is continuously output from the write / read control unit every time the carrier is interrupted. Thus, in the no-response mode, the data communication between the other data carrier and the write / read control unit is not interfered, and the data communication can be performed sequentially.

[0009]

FIG. 2 is a block diagram showing the overall configuration of an identification system according to an embodiment of the present invention. The same parts as those in the above-described conventional example are denoted by the same reference numerals, and detailed description is omitted. . In this figure, a read / write head 20A constituting a write / read control unit has a modulation circuit 21 and a transmission circuit 22, and these constitute a transmission means 4.
A receiving circuit is provided to the receiving coil L3 as the data receiving means 1,
An amplifier 24, an envelope detection circuit 25, and a determination circuit 26 for determining received data are provided. In this embodiment, a plurality of DC detection circuits 27, which are a plurality of data carrier determination means 2, are provided at the output of the determination circuit 26.
The multiple DC detection circuit 27 detects a plurality of data carriers. If the code used for communication is a bi-phase code, the H level does not continue three consecutive times. In such a case, the presence of a plurality of data carriers in the communication area is detected based on the fact that the HL level of the received output continues three or more times. When a plurality of data carriers are detected, the output is provided to the communication control unit 28.
The communication control unit 28 is a response command transmitting unit 3 that transmits one of a simple response command and a plurality of response commands and performs data communication by specifying a data carrier, as described later, and includes a microcomputer. I have.

Next, the data carrier 10A will be described. The data carrier 10A includes a resonance circuit 11, a demodulation circuit 12, a communication control unit 16, a memory 17, and a shunt circuit 15 which is continuous shunt output means 7.
The memory 17 according to the present embodiment has an area for storing an ID code unique to each data carrier. Communication control unit 1
Reference numeral 6 denotes a data communication as it is when a simple response command is received from the write / read control unit, and when a plurality of response commands are received, a continuous shunt signal until a response time unique to each data carrier or a response time determined by random numbers Is output, and data communication is performed after the completion of the processing, and is constituted by a microcomputer.

Next, the operation of this embodiment will be described with reference to a time chart and a flowchart. FIG. 3 shows a time chart when a plurality of data carriers exist in the communication area. FIG. 4 is a flowchart showing the operation of the read / write head, and FIG. 5 is a flowchart showing the operation of the data carrier. The read / write head 20A first sends a simple response command when the data carrier arrives in the communication area and starts communication (step S1). Then, it is determined whether there is a plurality of responses based on the presence or absence of interference (step S2). In the initial state, all data carriers have received the simple response command, and therefore transmit their own ID code (steps S21 and S22). If only one data carrier exists in the data communication area, no interference will occur. Accordingly, the read / write head moves 1: 1 with the data carrier obtained in step S3.
The data communication is performed to end the processing. Since the data carrier does not receive a plurality of commands in step S23, the process proceeds to step S24 to perform 1: 1 data communication and end the processing.

If there are a plurality of data carriers in this communication area, the IDs are respectively set as shown in the time chart of FIG.
Since the code is transmitted, an interference state occurs in the read / write head. On the read / write head side, the interference state is detected by a plurality of DC detection circuits 27. When a plurality of data carriers are detected, the process proceeds to the time chart and step S4 in FIG. 4 to transmit a plurality of response commands to each data carrier. Upon receiving this response command, the data carrier proceeds from step S23 to S25 to S27, determines the time until a response unique to each data carrier, and transmits the ID code of its own data carrier after the no-response mode. For example, the response time of the data carrier DC1 is set to t1, and the response time of the data carrier DC1 is t1.
2 (t1 <t2). The data carriers DC1 and DC2 wait for the elapse of the response times t1 and t2, respectively (steps S26 and S27). Step S2
Reference numeral 6 denotes a no-response mode, in which a carrier signal is intermittently transmitted at a constant duty ratio when transmitting a data carrier.
Immediately after each carrier is interrupted, the resonance circuit 1
A shunt pulse is output to 1 to stop reverberation.
When the response time t1 has elapsed, the data carrier DC1 immediately proceeds from step S27 to S28 to transmit the ID code. On the other hand, since the time when the data carrier DC2 enters the non-response mode is defined as t2 (> t1),
In this case, a continuous shunt pulse is output during that time.

FIG. 6 is a waveform diagram showing a state where the data carrier DC1 transmits an ID code and transmits it to the read / write head side. At this time, since the transmission circuit 22 of the read / write head is in the receiving state, the carrier is intermittently switched on at a duty ratio of 50% as shown in FIG. On the other hand, FIG. 6B shows transmission data of the data carrier DC1, and when the transmission data is at the L level, a shunt pulse is output from the shunt circuit 15 based on the data read from the communication control unit. When the shunt pulse is output, the data carrier DC1 is output as shown in FIG.
The reverberation of the resonance circuit 11 stops, and if there is no shunt pulse, the reverberation remains. At this time, the other data carrier DC2 continuously outputs a shunt pulse as shown in FIG. 6E every time the carrier of the coil L2 of the read / write head is intermittent. Therefore, data carrier D
The resonance circuit 11 of C2 always operates without reverberation. Therefore, the receiving coil L3 on the read / write head side receives the reverberation component shown in FIG. 6D, and can perform data communication without interference.

Now, the data carrier DC1 determines in step S2
8, the flow advances to step S29 to check again whether or not a plurality of response commands have been received. If not, the own ID code is confirmed and the communication state with the read / write head is entered (step S29). Then, when the data communication is completed, a no-response mode is set. On the other hand, the read / write head proceeds from step S4 to step S5, determines again whether or not there are multiple responses, and if there are multiple responses, returns to step S4 and repeats the same processing. If there are no multiple responses, the process proceeds to step S6, and the ID code of any of the data carriers is received. When this ID code is received, communication with the data carrier is performed. At the start of the communication, the confirmed ID code is transmitted to the data carrier side as shown in the time chart (step S7), and the data carrier confirms the ID and enters the communication mode.
When the communication is completed, the process enters the standby mode in step S9, and waits for the next data carrier DC2 to switch from the no-response mode to the communication mode.

After receiving the command, the data carrier DC2 waits for the elapse of the response time t2, during which it continuously outputs the shunt pulse in the no-response mode (steps S26 and S27). When the time is over, the process proceeds from step S27 to step S28 to transmit the ID code in the same manner as the data carrier DC1. The read / write head similarly transmits the ID code confirmed, and if the ID code is its own ID code, the data carrier DC2 enters the communication mode and performs communication. On the other hand, when the data carrier DC1 ends the communication, the process proceeds to step S31, and the data carrier DC1 enters the no-response mode again. In the non-response mode, each data carrier outputs a shunt pulse continuously after the start of reverberation. Then, reverberation does not occur from the data carrier, so that communication can be performed normally without interfering with communication of another data carrier during data communication.

In this embodiment, when a plurality of response commands are received for each data carrier, the response time is determined. However, each response time may be determined in advance for each data carrier. To make the communication opportunity with the write head fair, the response time may be set by a random number.

[0017]

As described above in detail, according to the present invention, even when a plurality of data carriers arrive in the communication area, communication with the read / write head is performed after each response time. Communication becomes possible. Since the data carrier generates continuous shunt pulses during standby, it does not hinder other communications.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a functional configuration of the present invention.

FIG. 2 is a block diagram showing an overall configuration of an identification system according to the embodiment.

FIG. 3 is a time chart showing an operation when a plurality of data carriers exist according to the embodiment.

FIG. 4 is a flowchart showing an operation of the read / write head according to the embodiment.

FIG. 5 is a flowchart showing the operation of the data carrier according to the embodiment.

FIG. 6 shows one data carrier D according to this embodiment.
FIG. 4 is a waveform diagram showing waveforms of various units during communication by C1.

FIG. 7 is a block diagram showing the overall configuration of a conventional identification system.

FIG. 8 is a waveform chart showing waveforms at various parts of the conventional identification system.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 data receiving means 2 plural DC discriminating means 3 response command sending means 4 transmitting means 5 data transmitting means 6 memory 7 continuous shunt output means 8 communication control means 10, 10A, DC1, DC2 data carrier 11 resonance circuit 12 demodulation unit 13 memory control Unit 14, 17 Memory 15 Shunt circuit 16 Communication control unit 21 Modulation circuit 22 Transmission circuit 23 Receiving circuit 24 Amplifier 25 Envelope detection circuit 26 Judgment circuit 27 Multiple data carrier detection circuit 28 Communication control unit

Claims (1)

[Claims] 1. An identification system comprising: a data carrier having a memory for holding data; and a write / read control unit for performing data transmission between the data carrier and the data carrier. The unit consists of a data receiving means for receiving data depending on the presence or absence of intermittent reverberation of the carrier when receiving data, and a plurality of data for detecting the presence of a plurality of data carriers in a communication area due to interference when receiving data. Carrier determination means; response command transmission means for transmitting a simple response command at the start of communication, and transmitting a plurality of response commands when the plurality of data carriers are determined by the plurality of data carrier determination means; At the time of transmission of data and the response command, the duty ratio of the first and the second. Transmitting means for changing the duty ratio to a second duty ratio, and at the time of data reception, setting the duty ratio to a third duty ratio, wherein the data carrier includes a resonance circuit; A data transmission unit for performing data transmission with the read / write control unit, a memory for holding data and a unique ID code, and a response start time when a plurality of response commands are received by the data transmission unit. A continuous shunt output means for outputting a continuous shunt signal when the carrier signal obtained in the resonance circuit is stopped, and transmitting a signal including its own ID code after the continuous shunt by the continuous shunt output means to control data communication. An identification system comprising: