JP2653269B2 - Multi-access communication device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication apparatus capable of communicating with one master station and a plurality of slave stations, and more particularly to a weak radio wave transmitting / receiving apparatus for monitoring the passage of a gate by the master station. Is a device that is mounted on a so-called non-contact type card carried by a passer of the gate and transmits / receives the passer's qualification information and the like to / from the master station. The present invention relates to a multi-access communication device capable of communicating with a plurality of slave stations when the number of slave stations is not constant.

[0002]

2. Description of the Related Art FIG. 2 is a diagram for explaining an example of a communication apparatus comprising a master station and a slave station as described above. The slave station 2 approaching within a certain distance from the master station 1 can communicate with the master station by, for example, weak radio waves. However, the slave station 2 in an area where communication with the master station 1 can be performed as described above. For example, since a passer of the gate moves while carrying it, it is constantly replaced, and the number varies, and there may be no slave station at all.

Under such conditions, a communication procedure described below has been considered in order to enable a plurality of slave stations to communicate with the master station within a certain period. FIG. 3 is a diagram for explaining such a communication procedure. The example of the transmission information of the master station, the reception information of the master station, and the respective transmission information of the slave stations a to c are shown in order from left to right. Is displayed as passing.

The master station 1 performs a predetermined read command, the number of areas, and a read temporary ID (shown in FIG. 1) as shown in FIG.
Thus, for example, polling information having a column of as short as 1 byte) is transmitted.

Here, the number of areas is a number corresponding to the number of slave stations that can simultaneously receive a response in this system, and directly indicates the number of ID recording areas in the next read temporary ID column. Are shown as "4" for explanation.

In each ID recording area of the read temporary ID column,
As will be described later, the temporary ID is transmitted to the area where the temporary ID is registered, and information indicating the availability is transmitted to the area where the temporary ID is not registered.

Next, the fixed time T ₀ following the transmission of the polling information is defined as a period during which the master station receives the temporary IDs transmitted from the slave stations. Provide.

[0008] The slave station that has received the polling information has a temporary ID.
If the slave station is not registered, the empty area in the read temporary ID column is stored, and one of the empty areas is selected using, for example, a random number, and the temporary area is temporarily transmitted during the temporary ID transmission period corresponding to the area. The temporary ID is transmitted by transmitting the ID code as the ID.
Register As the identification code, for example, the number of the area is used.

In the example shown in the figure, it is assumed that the slave stations a and b receive the first polling information in the figure for the first time. In this case, the four areas are all empty, and the slave station a is the third station.
The area and the slave station b select the fourth area, and transmit the temporary IDs “3” and “4” in the corresponding transmission periods.

The slave station that has registered the temporary ID stores the temporary ID, and the slave station that has received the polling information again has the transmitted temporary ID in the corresponding area of the read temporary ID column. , The same temporary ID is transmitted again in the subsequent temporary ID transmission period (see the second transmission information of the slave station b in the figure). If there is no temporary ID transmitted in this case and the registration is found to be unsuccessful, for example, at an appropriate timing, the process is repeated from the selection of the free area.

When the master station normally receives the temporary ID transmitted for registration as described above, it transmits them in the read temporary ID column of the next polling information (refer to the second polling information in the figure). ) Selects one of the previously registered temporary IDs, transmits a PID command and the selected temporary ID, for example, as shown in the figure, and sets the subsequent time as data from the slave station (as shown in the figure). To, for example, several tens of bytes
I) transmission time.

When the slave station receives its own temporary ID following the PID command, the slave station transmits necessary data (the figure shows an example in which slave station a is first selected). For example, in the case of the gate monitoring system as described above, ID information unique to the selected slave station is transmitted from the selected slave station, and if the master station receives the ID information normally, the gate can be opened or closed. Is identified from the ID information.

In order to control the transmission of required data from each slave station by the above-described communication procedure, it is necessary to register a temporary ID. The temporary ID transmission from each slave station for that
By transmitting in each transmission period as described above, it is necessary to control transmission of a plurality of slave stations so as not to collide, but the timing of the transmission period is individually controlled in each slave station, and is controlled by each slave station. Since the transmission timing may fluctuate, it is necessary for the master station to be able to correctly receive the temporary ID even if there is such fluctuation.

It is an object of the present invention to provide a multi-access communication device capable of maintaining the reliability of reception of a temporary ID transmitted in response to polling information at a master station.

[0015]

FIG. 1 is a block diagram showing the configuration of the present invention. The figure shows the configuration of a multi-access communication device, which has a master station 10 and one or more slave stations 2. The master station 10 communicates with each slave station 2. When the communication requires the communication, the slave station 2 receives a predetermined command transmitted from the master station 10, and from a plurality of transmission periods provided at predetermined time positions with respect to the reception time,
In the transmission period selected by the slave station 2 according to predetermined conditions,
Transmit a predetermined identification code (temporary identification code, omitted hereafter)
Notification of the transmission request, and
For a given command sent from the master station,
This is a system for transmitting station data .

In the master station 10, a control unit 11 and a reception monitoring timer 12
, A reception timing control unit 13 and a reception unit 14.
The control unit 11 activates the reception monitoring timer 12 in synchronization with the transmission of the command, and the reception monitoring timer 12 generates the monitoring signal 15 until a predetermined time elapses from the activation.

The reception timing control unit 13 outputs a monitoring signal 15
The setting signal 16 is generated when a first time elapses after receiving the rising edge of the transmission signal of the slave station 2 which is received first, and from the time when the first time elapses. The setting signal 16 is repeatedly generated every time the second time elapses.

The transmission period is a length obtained by adding the required buffer time to the transmission time of the identification code, the second time is the length of the transmission period, and the first time is calculated from the second time to the buffer time. The length is obtained by subtracting half of the length.

The receiving section 14 receives the transmission signal of the slave station 2 and stores the information received every time the setting signal 16 is generated as reception information of the identification code.

[0020]

According to the communication apparatus of the present invention, when an identification code is transmitted, each identification code transmits a transmission period corresponding to each area by measuring the time from the rise of the reception of the identification code in the first area in which transmission is performed. The transmission period can be separated and the received content of each transmission period can be extracted so that the standard timing to be performed is at the center.

Therefore, if the transmission period is determined to be a length obtained by adding an appropriate buffer time in consideration of the variation in the control time of each slave station to the net transmission time of the identification code, the individual slave stations can be individually assigned from a plurality of slave stations. The identification code transmitted at the timing of (1) can be reliably received.

[0022]

FIG. 4 is a block diagram showing the configuration of an embodiment of a master station according to the present invention. The control unit 11 includes a microprocessor (MPU).
20, a read-only memory (R
OM) 21, a readable and writable work random access memory (RAM) 22, a transmission unit 23, and the like. These, the reception monitoring timer 12, the reception timing control unit 13, the reception unit 14, and the like are connected to the MPU 20 of the control unit 11 by a bus.

The control unit 11 transmits the same polling information as the above-described conventional one at a suitable period via the transmission unit 23 by the execution of the program of the MPU 20 while there is no request from the slave station as described below. I do.

Upon receiving the polling information transmission end signal from the transmission unit 23, the MPU 20 immediately
Start 12 Reception monitoring timer 12 turns on the monitor in the signal 15 until the passage of T ₀ h of the conventional explanation since it is invoked.

The monitoring signal 15 is transmitted to the reception timing control unit.
When the signal from the slave station is received in this state, the output of the AND gate 30 is turned on, and the signal is sent to the character transmission timer 32 via the OR gate 31. to start.

[0026] character transmission timer 32 is started, it starts the buffer timer 33 to ₁ hour after T, buffer timer 33 generates a pulse signal to turn on a setting signal 16 to ₂ hours after T start finish.

The time T ₁ is set to a length equal to the transmission time of the identification code of each temporary ID, and T ₂ is set in consideration of a necessary buffer time so that (T ₁ + 2T ₂ ) is one transmission period. shall set the length of time, becomes, for example T ₁ and T ₂ are both values of the respective order of 1 millisecond.

When there are N areas during the time T ₀ , (T ₁ + 2T ₂ )
It is a length obtained by adding the time considering the processing time of the slave station to the × N time, which is several tens of milliseconds when the number of areas is ten and several. The setting signal 16 is also input to the AND gate 35, and turns on the AND output with the output of the RCV0 flip-flop 36 that was turned on at the output of the AND gate 30, so that the RCV1 flip-flop 37 is turned on. Become.

Then, the character transmission timer 32 is started again, and
Further, the count time of the buffer timer is set so as to be T ₂ × 2 hours thereafter by the output of the AND gate 34 until the RCV1 flip-flop 37 is turned on. Therefore,
T _One hour later, the buffer timer is again activated by the character transmission timer 32.
When 33 is started, a pulse signal for turning on the setting signal 16 is generated after 2T ₂ hours, and the processing is terminated. Thereafter, the setting signal 16 is repeatedly generated at the same timing.

[0030] Monitoring of the signal 15 with the lapse of T ₀ hours is turned off, so RCV0 flip-flops 36 and RCV1 flip-flop 37 by an inverted signal by an inverter 38 is reset, or more repeat operation ends.

As described above, the first time after receiving the rising edge of the transmission signal of the slave station 2 which is received _first (T ₁
+ T ₂ ) The setting signal 16 is generated when the time has elapsed, and then the second
The setting signal 16 is repeatedly generated every time (T ₁ + 2T ₂ ) elapses.

Therefore, if the lengths of T ₁ and T ₂ are set as described above, the second time is the length of the transmission period, and the first time is one second of the buffer time from the second time. / 2 is reduced.

In the receiving section 14, the serial / parallel converting section 40 includes a transmitter / receiver.
It is connected so as to receive, for example, a start-stop synchronization signal in the bit series from 18, receive character codes of the number of characters of the identification code, and send a bit parallel signal of the received character to the reception buffer 41. At the same time, the serial-parallel conversion unit 40 detects a start-stop synchronization error and a parity error of a received character code.

In the receiving buffer 41, when the setting signal 16 is turned on, the received character output from the serial / parallel conversion unit 40 is stored in the storage location specified by the address register 42, and the address of the address register 42 is stored in the next storage location. Proceed to indicate the position.

At this time, if the error detection signal 43 from the serial / parallel conversion unit 40 is ON, for example, the stored character is invalidated with an error display. The output of the AND gate 44 resets the error detection state of the serial / parallel converter 40 to enable the next reception.

The received character stored in the reception buffer 41 as described above is processed as a registration of a temporary ID by the control unit 11, and the communication procedure proceeds as in the conventional case. FIG. 5 is a diagram for explaining the reception timing by the above control.
At the end of the polling information transmission, T ₀ hour reception monitoring timer 12 is started.

When a signal from the first slave station is received at the position indicated by the reference timing as the standard timing for receiving the identification code, the RCV0 flip-flop is turned on, and the counting of the first time starts, and identification code as the temporary ID of the first area is stored in the receive buffer by setting signal occurring after ₁ + T _2.

At the same time, the RCV1 flip-flop is turned on, counting of the second time is started, and if the identification code of the standard position has been received by T ₁ + 2T ₂ later, it is stored in the reception buffer there. Thereafter, the same operation is repeated every T ₁ + 2T ₂ hours, and is completed at the end of T ₀ time.

[0039]

As is apparent from the above description, according to the present invention, the master station is a transmission / reception device for weak radio waves for monitoring gate passage, and the slave station is a so-called non-contact type mobile station carried by a passer. In a system such as a transceiver mounted on a card, each of the slave stations first enters the communication range.
When it comes, send a temporary identification code (temporary ID) and send
Make a request, and send from the master station after the transmission request.
Sends predetermined slave station data in response to certain commands.
And the transmission data transmitted by the slave station
A buffer time is provided in the middle of the corresponding transmission period.
Since it is, the temporary ID to be transmitted to the polling information
Has a remarkable industrial effect that the reliability of reception at the master station can be maintained.

[Brief description of the drawings]

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

FIG. 2 illustrates a configuration example of a communication device.

FIG. 3 is an explanatory diagram of a communication procedure.

FIG. 4 is a block diagram showing an embodiment of the present invention.

FIG. 5 is a diagram illustrating reception timing according to the present invention;

[Explanation of symbols]

 1, 10 Master station 2 Slave station 11 Control unit 12 Reception monitoring timer 13 Reception timing control unit 14 Reception unit 15 Monitoring signal 16 Setting signal 18 Transceiver 20 MPU 32 Character transmission timer 33 Buffering timer 36 RCV0 flip-flop 37 RCV1 flip-flop Step 40 Serial-parallel converter 41 Receive buffer 42 Address register

Claims (1)

(57) [Claims] 1. A communication system comprising a master station and one or more slave stations, wherein each of the slave stations requires the communication in order to perform communication between the master station and each of the slave stations. The slave station receives a predetermined command transmitted from the master station, and selects the slave station based on a predetermined condition from a plurality of transmission periods provided at predetermined time positions with respect to the reception time. during the transmission period, given provisional
By transmitting an identification code, a transmission request is notified,
A predetermined command transmitted from the master station after the transmission request
In the system for transmitting predetermined slave station data, the master station is provided with a control unit, a reception monitoring timer, a reception timing control unit, and a reception unit, and the control unit transmits the command. The reception monitoring timer activates the reception monitoring timer until the predetermined time elapses from the time when the reception monitoring timer is activated. It operates while the signal is being generated, and generates a setting signal when a first time elapses after receiving the rising edge of the transmission signal of the slave station to be received first. The setting signal is repeatedly generated every time the period of time elapses, and the transmission period for transmitting the predetermined temporary identification code is set to the temporary identification code.
The reception unit receives the temporary identification code of the slave station , and receives the received information every time the setting signal is generated.
A multi-access communication device configured to store the temporary identification code as received information.