JPH0247948A - Data communication system - Google Patents

Abstract

PURPOSE:To decrease the processing capability of a slave station and to reduce the cost of the communication system by sending a signal to plural master station equipments through one line and attaining the data security with less number of lines and a communication unit of the slave station. CONSTITUTION:A data communication system has a communication protocol of a command/response form and one to one or one to multi communication is applied between plural master equipments 101-103 and plural slave stations 111-114. A master station side line demultiplex section 121 of the system connects one line 14 to all master station equipments 101-103 and a slave station side line branch section 122 connects the line 14 to all slave stations 111-114. When a communication processing section 20 of the equipments 101-103 acquires the communication right, a communication control section 11 is operated and when no communication right is acquired, a communication intercept section 13 is acted. Then one and same slave data is processed in all the equipments 101-103 to secure the simultaneous performance of the slave station data and the system is attained with less number of lines and slave station communication units.

Description

[Detailed Description of the Invention] [Summary] Regarding data communication systems, particularly those having a command/response type communication protocol, one-on-one or one-on-one communication between multiple master station devices and multiple slave stations to improve communication openness. Regarding a data communication system that performs one-to-many communication, a data communication system that has a command/response format communication protocol and performs one-to-l or one-to-many communication between multiple master station devices and multiple slave stations. In order to enable multiple master station devices to process the same slave station data using a single line without causing communication failures (errors), one line is branched to all master station devices. It is equipped with a line branching unit on the master station side to which the line is connected, and a line branching unit on the slave station side that branches and connects the line to all slave stations. It includes a communication processing section that functions as a communication interception section when the master station has not acquired the communication processing section, and is configured so that all the master station devices process the same slave station data.

[Industrial application field]

TECHNICAL FIELD The present invention relates to a data communication system, and particularly to a command/command/communication system.
The present invention relates to a data communication system that has a response format communication protocol and performs one-to-one or one-to-many communication between a plurality of master station devices and a plurality of slave stations in order to improve reliability.

Systems that need to exchange data with remote locations using a data communication system with a command/response type communication protocol such as an HDLC line, such as a dam monitoring system (using a master station installed at the central management office, A system that collects data such as the opening degree of gates in various parts of the dam, water level gauges around the dam) or a building management system (
The master station in the central monitoring room collects/remotely controls the amount of electricity in various parts of the building, the operating status of air conditioners, etc. In this system, data such as the opening/closing of dam gates, fluctuations in the amount of water stored in the dam, and changes in the temperature of the building are collected. It is necessary to collect and record data continuously, 24 hours a day, without interruption.For this reason, in order to prepare for any abnormalities in the master station equipment, and to improve its reliability, multiple master station equipment are installed, and each parent station Data from multiple slave stations can be transferred to one station using the station device.
Processing is performed in a one-to-one or one-to-many relationship.

[Conventional technology]

Conventionally, a command/response format communication protocol such as an HDLC line (that is, as shown in FIG. After receiving the acknowledgment response from the stations 111-113, it sends data transmission command B and sends the data transmission command B to the slave stations 111-1.
A dumb control system that uses a data communication system that has a line that performs handshake between the master station device and the slave station, such as sending a notification C to indicate that the data was correctly received after receiving data from 13. etc., slave station 1
Missing data for a station is allowed to some extent because it can be replaced by data from another slave station. Therefore, originally there was no need to multiplex the communication units of the slave stations, and one unit was sufficient.

However, stopping the master station device is absolutely unacceptable because it will not be possible to collect all the data in the system while it is stopped. Therefore, multiple master station devices are installed to prevent missing data in the system. Was.

In this case, it is necessary to transmit the same data from each slave station to multiple master station devices, but as shown in FIG. If 101 and 102 are connected on one line, the control of the master station devices 101 and 102 will conflict on the line (point D), and the slave station 111 will not be able to receive data normally. The master station device 102 reports that data has been sent from the slave station 111 even though it is not controlling the device.
Due to the communication protocol, it was not possible to connect a plurality of master station apparatuses to a single line because the communication control error of the master station apparatus 102 would occur.

Therefore, as shown in FIG. 6, the line 14 is
Prepare as many as t-103, and each slave station 111 to 1
13 is provided with a plurality of communication units 15 connected to the lines 14 corresponding to the respective master stations 101 to 103, so that each of the master stations 101 to 103 can connect the lines 14 and communication units 15 corresponding to the respective master stations 101 to 103. via each slave station 1
Data from No. 11 to No. 113 was collected independently.

[Problem to be solved by the invention]

However, in the conventional data communication system as described above, (1) the number of lines required is equal to the number of master station devices; if there is one 0 line, one unit is sufficient; each slave station's communication unit has a number of lines; In other words, the number of devices required is equal to the number of master station devices;
Since a slave station must handle a plurality of communication units equal to the number of master station devices, a slave station with the processing capacity for the plurality of units is required, resulting in a problem of high cost.

Additionally, since the timing of data collection for multiple lines is independent, the simultaneity of data collected by each master station device may be lost, resulting in different processing results between the master station devices. There were also points.

Therefore, the present invention is applicable to a data communication system that has a command/response type communication protocol and performs l-to-l or one-to-many communication between a plurality of master station devices and a plurality of slave stations. Due to this, multiple master station devices may experience communication failure (
The purpose is to enable the same slave station data to be processed without causing errors.

[Means to solve the problem]

In order to achieve the above object, the data communication system according to the present invention has one line 1, as shown in the principle diagram of FIG.
4 to all the master station devices 101 to 103, and a master station side line branching unit 121 that branches and connects the line 14 to all the slave stations 111 to 114.
It is equipped with a slave station side line branching unit 122 that branches and connects to the slave station side line branching unit 122, and when each master station device flo1 to flo103 has acquired the communication right, it functions as the communication control unit 11, and when the communication right has not been acquired, it functions as the communication intercepting unit 13. The communication processing unit 20 is configured to process the same slave station data in all master station devices 101-103.

In addition, in the present invention, if a wireless line is used, the line branching section 12
This eliminates the need to use .

[For production]

In FIG. 1, for example, since the master station device 101 has communication rights, the communication processing section 20 functions as the communication control section 11, and this communication control section 11 functions as the line branching section 12.
1,122 to multiple slave stations 1 by one time m14.
11-114. Communication is performed using the predetermined communication protocol, and the collected data is processed by the master station bag 2101.

At this time, in the other master station bags z, toz, 103, communication between the master station device lot and each slave station 111-114 is carried out over line 1.
4 and the line branching unit 121, and the communication interception unit 1
The communication processing unit 20 functioning as 3 intercepts the received data, and processes the same data as the data received by the master station device IO1.

Here, the interception method will be explained based on FIG. At the same time, it is intercepted by the master station devices 102 and 103 which are branch-connected to the line 14 by the line branching unit 121. After that, when the slave station 111 (or 112) transmits an acknowledgment response B (or D), the master station device 101 receives this and sets communication rights, and the master station devices 102 and 1
03 also intercepts this, and can know from all master station bags 2101-103 that the preparation for transmission has been completed.

Then, a data transmission command E is issued from the communication control unit 11 of the master station device 101 that has acquired the communication right, and this is intercepted by the master station devices 102 and 103.
receives the data F from the slave station 111, while the master station devices 102 and 103 intercept the data F.

Since this is a method in which communication between one master station device and each of the slave stations 111-113 is intercepted by another master station device, the intercepting master station device sends commands to acquire communication rights. will not be emitted, communication failures will be prevented, and the data processed by all the master station devices toi-toa will be exactly the same, ensuring data simultaneity.

Furthermore, in the present invention, by using the same frequency radio line, the line branching sections 121 and 122 can be omitted.

〔Example〕

Embodiments of the data communication system according to the present invention will be described below.

FIG. 3 is a block diagram showing the configuration of an embodiment of the data communication system according to the present invention, in which 101 and 102 are a communication processing unit 20 having the functions of the communication control unit 11 and the communication interception unit 13, and a data processing unit 101 and 102. a master station device each having a section (including a data storage section and a data printing section) 16;
14 is a line connecting the master station device 101, 102 and a slave station to be described later, and 121 is a line on the master station side that branches one line 14 and transmits data from the slave station to the master station device 101, 102. A branching section 122 is a branching section on the slave station side that branches the line 14 and transmits data from the master station to the slave stations 111 to 114, respectively.

Next, the operation of this configuration will be described. FIG. 3 shows a normal situation, and it is assumed that the master station device 101 has the communication right. Therefore, in the master station device 101, the communication processing section 20 mainly functions as the communication control section 11, and the communication interception section 13 functions as the secondary function. Water level data, opening degree data, etc. of each slave station 111 to 114 are collected through the line branching section 121 and processed by the data processing section 16.

On the other hand, the main station! Since the communication right has not been acquired in 102, the communication processing section 20 mainly functions as the communication intercepting section 13, and has the secondary function of the communication control section 11.

Then, this communication interception section 13 transmits the data sent from each slave station 111 to l14 to the master station device flo1 to the line branching section 12.
The data is intercepted via flo1 and processed by the data processing unit 16 in the same way as the master station device flo1. Therefore, a dual system is formed in which the master station device W101 and the master station device 102 always process the same slave station data. Furthermore, polling operations from the master station device that does not have communication rights are no longer generated.

Incidentally, if a failure occurs in the master station device f101, the communication processing unit 20 of the master station:1 & 1f102 becomes the master station device fl.

A failure in the master station device 101 is detected through the interface 30 provided between the terminals 1 and 102. Then, the communication right is transferred from the master station device 101 to the master station device 102.
m1vp as the communication w4 control unit 11 of the communication processing unit 20 of
, and continues communication.

Since the master station device f102 had been intercepting the same data as the master station device 101 up until this point, it was able to continue processing the data even after acquiring communication rights, and from the slave station's perspective, the data could be processed without any abnormality. This means that it is being transmitted.

In the above embodiment, the line branching units 121 and 122 are required because the communication is performed using a wired line. However, when data communication between the master station device and the slave station is performed using a wireless line, the line branching units 121 and 122 are required. becomes unnecessary. E, the communication control unit 11 of the master station device 101 that has communication rights communicates with each slave station 111 to 114 via a wireless line, and in the master station device 1j102 that does not have communication rights, the communication processing unit of the master station device 101 This means that the communication interception section 13 of the communication processing section 20 can intercept the slave station data at the same frequency as the communication processing section 20.

In addition, in the above embodiment, two master station devices were taken as an example, but
It goes without saying that the same summary can be applied when three or more master station devices are used.

〔Effect of the invention〕

As explained above, in the data communication system according to the present invention, when one of the plurality of master station apparatuses that has communication rights performs data communication and data processing with each slave station through one line, Since the configuration is such that other master station devices can also process the same data intercepted via the line branching unit that branches the line, the following unique effects can be obtained.

i) Since it is possible to send data to multiple master station devices using one line, data security can be achieved with a small number of lines and communication units of slave stations, and the processing capacity of slave stations can be increased. Since it can be made small, costs can be reduced.

ii) Guaranteeing the simultaneity of the slave station data collected and processed by each master station device is the turning point.

ii) By intercepting, erroneous polling from a master station device that does not have communication rights can be eliminated, or communication failures due to crosstalk can be prevented.

In addition to the above-mentioned effects, the present invention can also be expected to reduce costs by eliminating the need for a line branch if a wireless line is used.

111-114...Slave stations.

In the figures, the same reference numerals indicate the same or corresponding parts.

[Brief explanation of the drawing]

FIG. 1 is a principle diagram showing a data communication system according to the present invention, FIG. 2 is an explanatory diagram of a method of intercepting communications in a data communication system according to the present invention, and FIG. 3 is a data communication system according to the present invention. FIG. 4 is an explanatory diagram of an example of a communication protocol, and FIG. 5 is a configuration block diagram of an embodiment.
FIG. 6 is a block diagram showing a conventional example. In Figure 1, ! ■...Communication control unit, 121.122...Line branching unit, 13...-Communication interception unit, 14...Line, 20...Communication processing unit, 101-103...Master station device,

Claims (2)

[Claims] (1) It has a command/response format communication protocol, and has multiple master station devices (101 to 103) and multiple slave stations (
In a data communication system that performs one-to-one or one-to-many communication between devices (111 to 114), a line branch on the master station side connects one line (14) to all master station devices (101 to 103). (121), and a slave station side line branching unit (122) for branching and connecting the line (14) to all slave stations (111 to 114), and each master station device (101 to 103) has communication rights. It includes a communication processing unit (20) which functions as a communication control unit (11) when the communication right is acquired, and a communication interception unit (13) when the communication right is not acquired, and in all master station devices (101 to 103). A data communication system characterized by processing the same slave station data. (2) It has a command/response format communication protocol, and has multiple master station devices (101 to 103) and multiple slave stations (
In a data communication system that performs one-to-one or one-to-many wireless communication using the same frequency between devices (111 to 114), when each master station device (101 to 103) acquires communication rights, the communication control unit (11 ) and a communication processing unit (20) which functions as a communication interception unit (13) when communication rights have not been acquired, and processes the same slave station data in all master station devices (101 to 103). A data communication system featuring