JPH05103033A - Multiple-address communication system and multiple address communication reply circuit used for it - Google Patents

Abstract

PURPOSE:To eliminate a defect of a conventional multiple-address communication in which each slave station cannot return its reply to a master station, in the 2-way branch type system where one master station and plural slave stations are in multi-drop connection. CONSTITUTION:A reply transmission section 20 is controlled by a timer section 17 taking a timing of a time proportional to an order of its own station address in a header of master station data or a reply signal station address comparison section 14 monitoring a station address included in a reply signal and sends a result of a CRC check section 19 and a station address to a master station and a slave station as a reply signal. The master station confirms whether or not all slave stations receive data correctly by allowing each slave station receiving the master station data to apply multiple-address communication to the reply in the order of the station address written in a header part of the master station data while monitoring a reply signal of other slave station.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication system in which one master station and a plurality of slave stations are multi-drop connected, and in particular, the master station transmits master station data by a polling method, and each slave station Broadcast communication method that returns a response signal to the main station,
Also, the present invention relates to a broadcast communication response circuit provided in each slave station to realize this broadcast communication system.

[0002]

2. Description of the Related Art As one of communication systems, there is a system in which one master station and a plurality of slave stations are multi-drop connected on a line as shown in FIG. In such a communication system, different slave station addresses are assigned to the plurality of slave stations. The master station transmits master station data by the polling method. This master station data specifies the station address. Therefore, the designated slave station responds to the poll of this master station. Such a communication procedure is called a bidirectional branch method.

In such a two-way branching communication system, broadcast communication is conventionally performed as follows. The master station data from the master station to the slave stations branch at each connection point. In this case, the master station data specifies the station addresses of all slave stations. Therefore, this master station data is transmitted to all slave stations at the same time.

[0004]

However, if the response signals from the slave stations to the master station are returned at the same time, the response signals collide on the line. Therefore, each slave station could not return a response signal to the master station.

Therefore, an object of the present invention is to provide a broadcast communication in which each slave station can return a response signal to the master station in the case of broadcast communication in which the master station simultaneously transmits the same master station data to a plurality of slave stations. To provide a method.

Another object of the present invention is to provide a broadcast communication system which enables a master station to confirm whether or not correct data has been transmitted to each slave station.

A further object of the present invention is to provide a broadcast communication response circuit provided in each slave station to realize the above broadcast communication system.

[0008]

The broadcast communication system according to the first aspect of the present invention uses a polling system to a master station by polling a plurality of slave stations which are assigned different station addresses and are multi-drop connected on a line. Is a broadcast communication method in a communication system in which master stations transmit master station data and each slave station returns a response signal to the master station, the master station data having a header section and a data section, and the header section is concerned. The master station includes the station address of the slave station to which the master station data is to be transmitted, and the master station broadcasts the master station data in a state where the header section includes the station addresses of all slave stations when performing broadcast communication. And each of the slaves receives the broadcast signal,
It is characterized in that the response signal including the own station address is returned to the main station after a lapse of time proportional to the order in which the own station address appears in the station address of the header part in the broadcast signal.

Further, in the above-mentioned broadcast communication system, it is preferable that the main station data further includes a check unit, and the response signal includes a check result of the check unit.

In the broadcast communication method according to the second aspect of the present invention, a master station transmits master station data by a polling method to a plurality of slave stations that are respectively assigned different station addresses and are multi-drop connected on a line. However, in the communication system in which each slave station returns a response signal to the master station, the master station data has a header part and a data part, and the header part sends the master station data. The master station including the station address of the slave station to be transmitted, the master station transmits the master station data as a broadcast signal in a state of including the station addresses of all slave stations in the header section when performing broadcast communication, When the slave station receives the broadcast signal, it stores the station address immediately before its own station address in the station addresses of the header part in the broadcast signal, and when receiving a response signal from another slave station, In the response signal When Murrell station address matches the station address said storage, characterized by sending the response signal in the state including the local address.

Further, in the above-mentioned broadcast communication system, it is preferable that the main station data further includes a check unit, and the response signal includes a check result of the check unit.

The broadcast response circuit according to the present invention is provided in each of a plurality of slave stations in a two-way branch communication system in which one master station and a plurality of slave stations are multi-drop connected on a line. In the response circuit, different station addresses are assigned to the plurality of slave stations, and the master station has a header section, a data section, and a CRC (cy
The master station data having a clic redundancy check) section is transmitted to the line, and the header section of the master station data is an ID for identifying the master station data and the slave station to which the master station data should be transmitted. In the case of performing broadcast communication, the master station transmits the master station data as a broadcast signal with the station addresses of all slave stations included in the broadcast signal, Each of the slave stations sends a response signal including a header portion and a data portion onto the line, and the header portion of the response signal has an ID for identifying the response signal. The data section has its own station address and the check result of the CRC section, is inserted into the line, and receives the master station data from the master station and a response signal from another slave station as a reception signal. Then
A bidirectional branching unit that transmits the response signal of the self-subordinate station as a transmission signal to the master station and the other subordinate stations; a header ID detection unit that detects the ID included in the header portion of the received signal; and the header ID detection unit When the ID detected in step 1 indicates main station data, the station address included in the header of the main station data is compared with the own station address, and when a match is detected, the first match signal is output. Together with a main station data station address comparing section that outputs a timer value corresponding to the order in which the local station address appears in the station address of the main station data header section; all of the main station data included in the header section A memory unit for storing the station address immediately before the own station address among the station addresses as a memory station address; and when the ID detected by the header ID detection unit indicates a response signal, the response signal A response signal station address comparing section that compares a station address included in the data section of the memory module with the memory station address and outputs a second match signal when a match is detected; A gate section for receiving the main station data in response; a transmission end detecting section for detecting an end of the main station data taken by the gate section and outputting a transmission end signal when the end is detected; A timer unit which is activated in response and outputs a time-up signal when the time represented by the timer value has elapsed from the time of activation; a station address holding unit which holds an own station address; A CRC check unit for checking the CRC unit in the main station data and outputting a CRC check result; and, in response to the time-up signal or the second match signal, Characterized by having a; said signal including a local address held serial CRC check result and the station address holding unit and the response transmission unit for sending to the bi-directional branching unit as a response signal of the own slave station.

[0013]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. In FIG. 1, an embodiment of the broadcast communication response circuit according to the present invention is shown in FIG.
Detection unit 11, master station data station address comparison unit, memory unit 1
3, response signal station address comparison unit 14, gate unit 15, transmission end detection unit 16, timer unit 17, station address unit 18,
It has a CRC check unit 19 and a response sending unit 20.

FIG. 2 is a diagram showing an embodiment of a data format broadcasted from a master station or a slave station. The data broadcast from the master station has a header section 21, a data section 22, and a CRC section 23. The data broadcast from the slave station has a header section 31 and a data section 32.

The bidirectional branching unit 10 takes in signals from the master station and other slave stations together, and sends out signals to be output to both the master station and other slave stations. Header ID detector 1
1 detects an ID added to the header portion 21 (31) of the master station data or the response signal to distinguish the master station data or the response signal. This header ID detector 11 is an ID
Indicates the master station data, the master station data is sent to the master station data station address comparison unit 12, and when the ID indicates a response signal, the reply signal is sent to the response signal station address comparison unit 14.

The master station data station address comparing section 12 which has received the master station data compares all station addresses written in the header section 21 of the master station data and the own station address written in the station address section 18. When a match is detected, the gate unit 15 is opened to take in the main station data, and at the same time, the memory unit 13 stores the station address immediately preceding the own station address.

When the transmission end detecting section 16 detects the end of the main station data, it starts the timer section 17. Timer unit 17
In order to perform broadcast communication, the response sending unit 20
To control. That is, the timer unit 17 receives from the main station data station address comparison unit 12 the value of the order in which the own station address is written in the header of the main station data, and supplies the response sending unit 20 with the timing of the time proportional to the value. To do.
In response to the signal supplied from the timer unit 17, the response sending unit 20 combines the CRC check result of the CRC check unit 19 and the value of the station address unit 18 into a response signal.
The response sending unit 20 further supplies the response signal to the bidirectional branching unit 10. When the response signal is sent, the bidirectional branch section 10 broadcasts to all the master stations and slave stations.

When the response signal of another slave station which has been broadcasted is received from the header ID detection section 11, the response signal station address comparison section 14 performs the following broadcast communication with the master station and other slave stations. The response sending unit 20 is controlled as described above. That is, the response signal station address comparison unit 14 includes the station address and memory unit 13 included in the response signal data unit 32.
When it detects a match with the station address (one station address before the own station address) read from, the response sending unit 20 is controlled to send the response signal of the own station.

As described above, the response sending section 20 is controlled by the signal supplied from the timer section 17 or the response signal station address comparing section 14. That is, before the timer unit 17 outputs the timing of the time proportional to the order value in which the own station address is written in the header of the master station data, the slave station having the station address immediately before the own station address is transmitted. When receiving the response signal, the response sending unit 20 sends the response signal of its own station immediately after the reception of the response signal is completed. In other cases, the response signal of the own station is transmitted after receiving the timing of the time proportional to the order value in which the own station address is written in the header of the main station data. The response signal is
It will be returned every time the main station data is received.

The master station monitors the response signals sequentially sent from each slave station with a time lag, and detects a response signal that the result of the CRC check is incorrect, or a slave station that does not return a response signal. Check if there is.

If the result of the CRC check is incorrect or there is a slave station that does not return a response signal, there are two types of measures in the master station. One is to create a header part 21 having only such a station address of a slave station, and to add a recalculated part 23 to the data part 22 as the same data as the original data and send it by broadcast communication.

The other is that the same process as described above is repeated when the result of the CRC check is incorrect or there is a slave station which does not return a response signal. Is the result of the CRC check incorrect even if the broadcast communication is repeated?
Alternatively, when there is a slave station that does not return a response signal, the broadcast communication is performed a predetermined number of times and the transmission to that slave station is terminated. At this time, the slave station whose transmission has been terminated is excluded from the target of the subsequent broadcast communication.

[0024]

As described above, according to the present invention,
When performing broadcast communication that specifies all station addresses, each slave station that receives data monitors the response signal of the other slave stations that are broadcast, and at the same time, its own station address is written in the header of the master station data. Since the response signals are sequentially broadcast to the master station and other slave stations in the order in which they are present, the master station can be notified of the response signals from the slave stations without collision on the line. Therefore, the master station has an effect of being able to confirm whether or not all slave stations have correctly received the data.

Further, according to the present invention, the master station monitors the response signals sequentially transmitted from each slave station with a time difference, and the slave station which is not correct in the CRC check or which does not return the response signal is detected. In some cases, the master station retransmits the same data by broadcast communication, or it transmits data having only the station address of such slave station in the header by broadcast communication, so when there are multiple such slave stations. In addition, the number of times of transmission is smaller than that of retransmitting data individually to these slave stations, and data can be transmitted in a short time. This will allow you to take advantage of broadcast
The effect that the same data can be transmitted to a plurality of slave stations can be obtained more reliably.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a broadcast communication response circuit according to the present invention.

FIG. 2 is a diagram showing an example of a format of data broadcast from a master station or a slave station.

FIG. 3 is a block diagram showing a configuration of a communication system to which the present invention is applied.

[Explanation of symbols]

 10 bidirectional branching unit 11 header ID detecting unit 12 main station data station address comparing unit 13 memory unit 14 response signal station address comparing unit 15 gate unit 16 transmission end detecting unit 17 timer unit 18 station address unit 19 CRC checking unit 20 response sending unit

Claims (5)

[Claims] 1. A plurality of slave stations which are respectively assigned different station addresses and are multi-drop connected on a line,
A master station transmits master station data by a polling method, and is a broadcast communication method in a communication system in which each slave station returns a response signal to the master station, wherein the master station data has a header section and a data section, The header section includes the station address of the slave station to which the master station data should be transmitted, and the master station, when performing the broadcast communication, in the header section including the station addresses of all slave stations. When each slave station receives the broadcast signal, the slave station transmits data as a broadcast signal, and when the slave station receives the broadcast signal, the slave station receives the broadcast signal after a time proportional to the order in which the station address appears in the station address of the header portion of the broadcast signal. A broadcast communication system characterized in that the response signal including an address is returned to the master station. 2. The broadcast communication system according to claim 1, wherein the master station data further includes a check unit, and the response signal includes a check result of the check unit. 3. A plurality of slave stations, which are respectively assigned different station addresses and are multi-drop connected on a line,
A master station transmits master station data by a polling method, and is a broadcast communication method in a communication system in which each slave station returns a response signal to the master station, wherein the master station data has a header section and a data section, The header section includes the station address of the slave station to which the master station data should be transmitted, and the master station, when performing the broadcast communication, in the header section including the station addresses of all slave stations. When data is transmitted as a broadcast signal, and each of the slave stations receives the broadcast signal, one of the local station addresses in the station address of the header section in the broadcast signal is transmitted.
When the station address of the immediately preceding station is stored and a response signal from another slave station is received, when the station address included in the response signal matches the stored station address, the station address including the own station address is stored. A broadcast communication method characterized by transmitting a response signal. 4. The broadcast communication system according to claim 3, wherein the master station data further includes a check unit, and the response signal includes a check result of the check unit. 5. A broadcast response circuit provided in each of the plurality of slave stations in a two-way branch communication system in which one master station and a plurality of slave stations are multi-drop connected on a line. Different station addresses are assigned to the slave stations, the master station sends master station data having a header section, a data section, and a CRC section onto the line, and the header section of the master station data is I for identifying the main station data
D and the station address of the slave station to which the master station data is to be transmitted, the master station, when performing the broadcast communication, in the header part including the station addresses of all slave stations. Data is transmitted as a broadcast signal, each of the plurality of slave stations sends a response signal consisting of a header section and a data section onto the line, and the header section of the response signal identifies that it is a response signal. And a data portion of the response signal includes an own address and the C
It has a check result of the RC section, is inserted into the line, receives the master station data from the master station and the response signal from another slave station as a reception signal, and transmits the response signal of the self-slave station. A bidirectional branching unit for transmitting as a signal to the master station and the other slave station; a header I for detecting the ID contained in the header section of the received signal
D detection section; when the ID detected by the header ID detection section indicates main station data, the station address included in the header section of the main station data is compared with its own address, and a match is detected. And a main station data station address comparing section that outputs a first match signal and a timer value corresponding to the order in which the local station address appears in the station address of the header section of the main station data; A memory unit that stores, as a storage station address, the station address immediately before the own station address among all the station addresses included in the header section of the station data; the ID detected by the header ID detection section indicates a response signal. At this time, a station address included in the data part of the response signal is compared with the memory station address, and when a match is detected, a response signal station address comparison section that outputs a second match signal; A gate unit for taking in the master station data in response to the first coincidence detection signal; a transmission end detection for detecting the end of the main station data taken in by the gate unit and outputting a transmission end signal when the end is detected. A timer unit which is activated in response to the transmission end signal and outputs a time-up signal when the time represented by the timer value has elapsed from the time of activation; a station address holding unit which holds its own station address A CRC check unit for checking the CRC unit in the main station data fetched by the gate unit and outputting a CRC check result; and; for the CRC in response to the time-up signal or the second coincidence signal;
And a response sending unit that sends a signal including the check result and the own station address held in the station address holding unit to the bidirectional branch unit as a response signal of the own slave station; circuit.