JPH1117713A - Multicast communication processing method - Google Patents

Abstract

(57) [Problem] To provide an inexpensive, simple, and sufficiently reliable communication method in a field that does not require much real-time property. The communication includes a central control device, a plurality of subordinate devices connected to the central control device via a network, and assigned device numbers. In the multicast communication processing method for simultaneously transmitting data 9 to all of the subordinate devices, each subordinate device includes means 81 to 8n for setting and holding an arbitrary device number, and a response indicating completion of reception to transmission from the central control device. And a means 71-7n for periodically transmitting communication data including the device number of the subordinate device to the central control device, wherein the central control device has Means for determining that the communication between the central control device and the slave device has succeeded when the number of slave devices coincides with the number of slave devices.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multicast communication processing method, and more particularly, to a multicast communication processing method capable of managing communication states of a plurality of devices connected to a network by a simple method.

[0002]

2. Description of the Related Art Conventionally, there are the following means for connecting a central control device to a plurality of subordinate devices via a network and transmitting data from the central control device to each subordinate device.

[0003] 1. A method of transmitting data only to all N slave devices and not requiring a reception completion message from the slave devices. (Hereinafter referred to as non-acknowledgment response communication.) The node numbers (1,
2,... N) and transmit data to all N slave devices. If the central control unit receives a message indicating that reception has been completed from all N slave units, the communication is regarded as successful.
A method of retransmitting data only to the slave device that did not receive the message when the reception completion message was not received from all N slave devices. (Hereinafter, it will be referred to as acknowledgment response communication.) A method of transmitting data only to a device to be transmitted among N slave devices. (Hereinafter referred to as one-to-one communication.)

[0004]

In the non-acknowledgment type response communication system described above, there is no guarantee that each subordinate device has actually received data, and this poses a problem in terms of reliability.

In the above-mentioned acknowledged response communication method, it is necessary to continuously set the node numbers of the subordinate devices. When the number of nodes changes due to a failure or addition of a subordinate device, the node number must be assigned each time. And it takes an enormous amount of time to rebuild. In addition, there is a method in which the node number is freely set and the microprocessor converts the node number continuously. In such a case, it is necessary to create a conversion program.

In the above-mentioned one-to-one communication, transmission data areas for N slave devices must be secured in the memory of the central control device, and a large memory capacity is required. Also,
In the point-to-point communication, data is sent only to the subordinate apparatus that wants to transmit. Therefore, a network binding processing unit must be provided for each subordinate apparatus. In comparison, programming work becomes complicated and labor is required.

An object of the present invention is to provide an inexpensive, simple, and low-cost communication system in a field that does not require as much reliability as the acknowledged response communication method described above, for example, in a field that does not require much real-time properties such as a building management apparatus. Another object of the present invention is to provide a sufficiently reliable communication system.

[0008]

The present invention employs the following means in order to solve the above-mentioned problems.

A central control unit, and a plurality of subordinate devices connected to the central control unit via a network and each of which is assigned a device number, wherein the device of the subordinate device to be transmitted is transmitted from the central control unit. In a multicast communication processing system for simultaneously transmitting communication data with an embedded number to all of the subordinate devices via the network, the subordinate devices set and hold a randomly allocated device number, and Means for receiving the communication data transmitted from the central control device and transmitting a response indicating completion of reception regardless of whether or not the communication data is addressed to the received slave device; When the number of responses to the completion of reception transmitted from the slave device matches the number of slave devices, the central control device and each slave device are By communication between the device comprises means for determining that the success, and performs death management of the multicast communication system.

According to the first aspect of the present invention, each of the subordinate devices includes means for periodically transmitting device data in which the device number of each of the subordinate devices is embedded to the central control device. It is characterized by comprising means for controlling the number of slave devices based on the device data periodically transmitted from each of the slave devices.

Further, in any one of claims 1 and 2, after the power of the subordinate device is turned on, the subordinate device automatically stores the device number of the subordinate device in the memory of the subordinate device. It is characterized by having means for storing.

Further, in any one of the first to third aspects of the present invention, when the determination means determines that the communication has not been successful, the central control device transmits the communication data. A means is provided for displaying or storing the determination result together with the communication data when the communication is not successful at the end while retransmitting the data to each slave device.

Further, in any one of the first to fourth aspects of the present invention, the central control unit comprises a main function microprocessor and a communication microprocessor, and when the power of the central control unit is turned on. Means for notifying the number of connected slave devices from the main function microprocessor to the communication microprocessor.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a system configuration diagram of a multicast communication processing system according to the present embodiment, in which data is transmitted from a central control device to a subordinate device, and a response signal (Ack signal) is transmitted from the subordinate device to the central control device. Indicates a state in which

In FIG. 1, reference numeral 1 denotes a central control unit,
.., 2n are slave devices connected to the central control device 1 via transmission lines, and 3 is the central control device 1 and slave devices 21 to 21.
A transmission line 4 for transmitting signals between 2n is used for controlling the entire system and a microprocessor for a main function for outputting various data for controlling each of the slave devices 21 to 2n. Processor 4 and slave device 21
A communication microprocessor that manages communications with
Reference numeral 6 denotes a bus for exchanging data between the main function microprocessor 4 and the communication microprocessor 5.
.. 7n are provided in each of the subordinate devices 21 to 2n, execute predetermined processing based on data transmitted from the central control device 1, output a response signal (Ack signal) to the central control device 1, and Each slave device 2 is periodically sent to the central controller 1.
A microprocessor for transmitting status data of 1 to 2n,
.. 8n are provided in each of the subordinate devices, and DIP switches for setting the node numbers of the subordinate devices 21 to 2n; 9 are data transmitted from the central control device 1 to any of the subordinate devices; .., And 12n are control data of the slave devices to be transmitted, 121, 122,.
n is a response signal (Ack signal) transmitted to the central control device 1 from n.

The slave devices 21 to 2n are set with node numbers for the respective slave devices 21 to 2n by the dip switches 81 to 8n. This node number does not necessarily need to be continuously allocated through the subordinate devices 21 to 2n, and can be freely set to a number that is easily understood by each subordinate device. Here, the node numbers are 1, 2, 3,
... If n is set continuously, conventional acknowledgment response communication is performed. The microprocessors 71 to 7n provided in the subordinate devices 21 to 2n can not only communicate with the central control device 1 but also communicate with and control other subordinate devices 21 to 2n. 7n itself has a memory function and can perform various control processes.

The microprocessor 4 for the main function of the central control unit 1 is provided with data storage tables for the maximum number of connected slave units 21 to 2n. It is remembered.

FIG. 2 shows that, in the multicast communication processing system shown in FIG. 1, when a transmission error occurs in any of the slave devices 21 to 2n, an error message is sent from the communication microprocessor 5 to the main function microprocessor 4. It is a figure showing the state where it transmits.

In the figure, 13 is an error message, 1
Reference numeral 4 denotes an error bit composed of one bit, and the other configuration is the same as that shown in FIG.

FIG. 3 is a diagram showing a state in which data is transmitted from each of the subordinate devices 21 to 2n to the central control device 1 at a constant period in the multicast communication processing system shown in FIG.

In the figure, 151, 152,...
n is data transmitted from each of the subordinate devices 21 to 2n to the central control device 1 at a constant period, 161, 162,.
Are the node numbers of the slave devices 21 to 2n, 171, 17
2,... 17n are status data indicating the current status of each of the slave devices 21 to 2n. Other configurations are the same as those shown in FIG.

Next, the operation of the multicast communication processing system according to the present embodiment will be described with reference to FIGS.

First, referring to FIG.
When the power of the slave devices 21 to 2n is turned on, the central control device 1 notifies the main function microprocessor 4 of the number n of the slave devices 21 to 2n connected to the communication microprocessor 5. On the other hand, in the slave devices 21 to 2n, the dip switches 8 installed in the slave devices 21 to 2n are used.
The node numbers set in 1 to 8n are stored in the memories of the microprocessors 71 to 7n, respectively.

When the data 9 is transmitted from the central control unit 1 to the subordinate devices 21 to 2n, the main function microprocessor 4 transmits the node number 10 of the data 9 and the node of the subordinate device to be transmitted to the control data 11 respectively. The number and control data are written and transmitted to the communication microprocessor 5. The communication microprocessor 5 transmits the data 9 to all the slave devices 21 to 2n at the same time via the transmission path 3 regardless of the designated node number. All the slave devices 21 to 2n receive the data 9 and send the reception completion response signals (Ack signals) 121 to 12n to the communication microprocessor irrespective of whether the content of the data 9 is addressed to itself or not. Send to 5. Each slave device 21-2
n confirms the contents of the node number 10 of the received data 9 and, if it matches the node number of its own, the control data 11
Is input, and a predetermined process is executed based on the input. If it does not match its own node number, data 9
Is destroyed.

On the other hand, in the communication microprocessor 5,
The number n of connected slave devices currently active on the network is sequentially notified from the main function microprocessor 4, and
The number of response signals (Ack signals) 121 to 12n for completion of reception transmitted from the slave devices 21a to 2n is compared with the number of connected signals. If the sum of the reception completion response signals (Ack signals) 121 to 12n transmitted from the subordinate devices 21 to 2n does not match the number n of connected devices,
2n retransmits the same data 9 to all slaves 21-2n, whether or not it has received the previous data 9. After transmitting the data 9 again, the communication microprocessor 5 receives the response signals (Ack signals) 121 to 12 again received.
If the number n does not match the number of connected units n, it is regarded as a transmission error.

Next, when a transmission error has occurred, FIG.
As shown in (1), the communication microprocessor 5 transmits the error message 13 in which the bit “1” indicating the transmission error is written in the error flag 14 to the main function microprocessor 4.

The main function microprocessor 4 confirms the contents of the node number 10 and the control data 11 of the data 9 causing the transmission error from the error message 13,
The history is stored in the memory of the main function microprocessor 4.
Note that it is also possible to connect a personal computer to the central control device 1 and display error information on the screen of the personal computer to retain the error history.

On the other hand, in the multicast communication processing system of the present embodiment, as shown in FIG. 3, each of the subordinate devices 21 to 2n is transmitted from the subordinate devices 21 to 2n to the central control device 1 at a fixed period.
Are transmitted.

The slave devices 21 to 2n store data 151 to 1
5n state data 171 to 17n, each slave device 2
In addition to simply notifying the central control device 1 of the statuses 1 to 2n, the central control device 1 is notified that the slave devices 21 to 2n themselves are alive by periodically transmitting data 151 to 15n. Therefore, the slave devices 21 to 2
n, the main function microprocessor 4 in the central control unit 1 periodically updates the new current subordinate device even if the number of nodes or the node number of the subordinate devices 21 to 2n changes due to a failure or the addition of a subordinate device. The number n of connected devices 21 to 2n is known, and when the number n of connected devices is updated, the number n of connected devices is transmitted to the microprocessor 5 for communication. Therefore, even if the number of response signals (Ack signals) 121 to 12n for the data 9 transmitted from the central control device 1 changes, the number of connected units n is adjusted. Without knowing, it is possible to prevent erroneous determination that a communication error has occurred.

As described above, according to this embodiment, the data 151 to 1 are transmitted from the subordinate devices 21 to 2n to the central control device 1.
5n, that is, by embedding the own node numbers 161 to 16n and periodically transmitting the state data 171 to 17n, it is possible to manage the life and death of the subordinate devices 21 to 2n. Therefore, from the central control device 1 to the subordinate devices 21 to 21
2n, and the success of communication at that time is determined by the sum of the number of response signals (Ack signals) 121 to 12n returned from the subordinate devices 21 to 2n.
Even if it is determined only by whether or not the number of connected devices is equal to 1 to 2n, sufficiently high reliability can be obtained in a field where real-time performance is not so required, such as a building management device.

Since node management is not required for confirming the success of communication, the node numbers of the subordinate devices 21 to 2n can be set freely, and handling is very convenient. Also, if the node numbers are successively set to 1, 2, 3... N, the operation returns to the conventional acknowledged response communication, so that the same reliability as the conventional acknowledged response communication can be obtained.

Further, when the system needs to be reconstructed due to a failure or addition of the subordinate devices 21 to 2n, the current subordinate devices 21 to 2n are obtained from the life and death information based on the periodic transmission data from the subordinate devices 21 to 2n. Since the number of connected 2n devices can be known, reconfiguration can be easily performed. Therefore, it is possible to build a system having excellent expandability and maintainability.

Further, since the central control unit 1 only needs to transmit the same data to all the subordinate units 21 to 2n at the same time, the memory capacity of the communication microprocessor 5 can be small and an inexpensive one can be used. Can be. In addition, the microprocessors 71 to 7 of the subordinate devices 21 to 2n
n and the microprocessor for communication 5 separated from the microprocessor 4 for the main function in the central control unit 1 can be used for general purposes irrespective of the number of nodes and the node number, so that a low-cost system can be configured. Becomes

[0035]

As described above, according to the present invention, the setting of the device number is simple, and the survival monitoring of the subordinate device can be performed.
Even if the system changes due to the entry or detachment of a slave device, the system can be easily reconfigured.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a multicast communication processing method according to an embodiment of the present invention.

FIG. 2 is a diagram showing a state where an error message is transmitted from a communication microprocessor to a main function microprocessor when a transmission error occurs in the multicast communication processing method shown in FIG.

FIG. 3 is a diagram showing a state in which data is periodically transmitted from each slave device to a central control device in the multicast communication processing method shown in FIG. 1;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Central controller 21-2n Slave device 3 Transmission line 4 Microprocessor for main functions 5 Microprocessor for communication 71-7n Microprocessor in slave device 81-8n DIP switch 9 Data transmitted from central controller to slave device 10 Node number indicating slave device 11 Control data indicating control content of slave device 121 to 12n Response signal (Ack signal) 13 Error message 14 Error flag 151 to 15n Data periodically transmitted from slave device to central controller 161 to 16n Node number 171-17n of each slave device Status data indicating the current status of each slave device

Claims (5)

[Claims] 1. A central control unit, and a plurality of subordinate units connected to the central control unit via a network and each of which is assigned an apparatus number, wherein the subordinate unit to be transmitted from the central control unit In a multicast communication processing system for simultaneously transmitting communication data in which the device number is embedded to all of the subordinate devices via the network, each of the subordinate devices sets and holds a device number that is randomly allocated and Means for receiving the communication data transmitted from the central control device and transmitting a response indicating completion of reception regardless of whether the communication data is addressed to the slave device that has received the communication data, The device, the number of the response of the reception completion transmitted from the slave device, when the number of the slave device coincides with the central control device, By providing means for determining the communication between the expansion device is successful, the multicast communication processing method, which comprises carrying out the death management of the multicast communication system. 2. The central control device according to claim 1, wherein each of the subordinate devices includes means for periodically transmitting device data in which the device number of each subordinate device is embedded to the central control device. Comprises a means for controlling the number of slave devices based on device data periodically transmitted from each of the slave devices. 3. The method according to claim 1, wherein
The multicast communication processing as claimed in claim 1, wherein the slave device includes means for automatically storing a device number of the slave device in a memory of the slave device after power-on of the slave device. method. 4. The method according to claim 1, wherein
In the claims, the central control device retransmits the communication data to each of the subordinate devices when the determination unit determines that the communication has not succeeded, and finally, the communication has succeeded. A multicast communication processing system comprising means for displaying or storing a determination result together with the communication data when there is no communication data. 5. The method according to claim 1, wherein
In one claim, the central control device is composed of a main function microprocessor and a communication microprocessor, and when the power of the central control device is turned on, the main function microprocessor sends the communication microprocessor. A multicast communication processing method comprising means for notifying the number of connected slave devices.