JPH0779371B2 - Transmission control device of distant monitoring control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a remote supervisory controller using a high level data link control procedure (HDLC), and more particularly to a transmission controller in a hierarchical system.

B. Outline of the Invention The present invention provides a remote monitoring and control apparatus that performs data transmission according to the HDLC method, in which a station separated when a data link is not established or in a hierarchical structure enables transmission and reception of upstream data. The monitoring control status can be monitored.

C. Conventional technology Conventionally, the cyclic transmission method has been adopted as the domestic standard method for the transmission method of the remote monitoring and control device. However, in the cyclic transmission method, since the transmission is repeated regardless of the presence or absence of a state change, the processing load on the computer side increases when the computers are connected, and it is necessary to increase the amount of information and types in order to expand the monitoring control range. However, since the data length of the cyclic transmission method is a fixed length with a small number of bits, there is a problem that it cannot be supported. In addition, the cyclic transmission method becomes a transmission method unique to Japan, making it difficult to expand the range of application to international communication networks.

With respect to these points, the HDLC system is a highly efficient synchronous data transmission, and international standardization without restrictions on codes is being pursued. This HDLC system performs variable-length frame-based frame-based transmission and error checking, and performs full-duplex communication while inquiring and confirming the receiving state of the receiving station on a frame-by-frame basis. Automatic resending is performed, and these functions are possessed by the LSI transmission control device itself, aiming to reduce the burden on the computer, improve transmission efficiency, and shorten transmission time.

D. Problems to be Solved by the Invention When applied to a distant monitoring control device, the HDLC method is superior in many points to the cyclic method, but has the following two problems.

The first problem is that one transmission failure disables all transmissions. In other words, the HDLC transmission procedure is performed while confirming the reception with the receiving station on the other end, so if a failure occurs in one transmission system and confirmation cannot be obtained, the data link will not be established and both upstream and downstream systems will It becomes impossible to transmit. In the case of the master station or its hierarchical structure, the higher-level computer cannot monitor the status change of the slave station. There is a risk that the start of restart will be worsened and that the history of state changes will be unknown, resulting in improper control. In this respect, since the cyclic transmission method does not require a transmission procedure, even if there is a failure in the downlink transmission, it is possible to monitor the uplink.

The second problem is the application to the hierarchical structure.

There are many application examples of a hierarchical structure in which a plurality of parent stations monitor and control a plurality of child stations, respectively, and the parent stations are comprehensively monitored from a higher level using a computer. In the HDLC method in a hierarchical system, the desired stations are connected / disconnected by connecting / disconnecting the data transmission lines, and the established stations establish a data link, transmit information, and terminate the data link. For example, in a hierarchical structure of a high-level computer, a master station, and a slave station, the computer-to-slave station has a two-step procedure of transmission from the computer to the master station corresponding to the relay station and transmission from the master station to the slave station. become. The transmission from the slave station to the computer is also performed in reverse. Therefore, there is a problem that the transmission reliability is lowered due to the occurrence of a relay error in the relay stations interposed between the stations and the transmission time required for the relay in the relay stations is increased.

Further, in the transmission / reception between the slave station and the master station, the higher-level computer cannot monitor the contents of the transmission / reception, and there is a problem similar to the above-mentioned failure of the transmission system. In this respect, since the cyclic transmission method does not require a transmission procedure as well, the communication between the computer and the slave station only needs to be made once, and the uplink information from the slave station can be known at the same time as the computer and the master station.

Moreover, the switching from the computer control or the master station control can be surely switched by the switch. In the HDLC system, if this configuration diagram is used, the separated side will not be able to receive upstream because the transmission procedure is not established.

An object of the present invention is to enable a station disconnected in a transmission system failure or a hierarchically separated station to monitor the status change and supervisory control status of a slave station, and improve the transmission reliability and shorten the transmission time. To provide an HDLC type transmission control device.

E. Means and Actions for Solving the Problems In order to achieve the above object, the present invention provides a master station that monitors and controls a plurality of slave stations by data transmission according to a high-level data link control procedure, and an upper station controls In a distant monitoring control device of a hierarchical structure for integrated monitoring, a master transmission procedure control unit for transmitting and receiving data according to a high level data link control transmission procedure is provided in the master station, slave station and upper station, and there is no high level data link control procedure. A slave transmission unit that has only the function of transmitting / receiving and transmits / receives data is provided in the master station, slave station, and higher station, and downlink transmission from the master station and higher station to each slave station according to the transceiver station of data. A switching switch for switching the path is provided, and a branching unit for branching and transmitting upstream data from each of the slave stations to the master station and a higher station is provided, and the master station or the higher station separated by the changeover switch, And a switching means for switching the master station, the slave station, or the upper station which has become unsatisfied with the data link to the data transmission / reception with the slave transmission section in place of the master transmission procedure control section. Status change by monitoring the data transmission / reception from the slave transmission unit and directly transmitting / receiving without interposing a relay station between the data transmission / reception stations to prevent data errors due to relay and shorten transmission time, and Monitors when the data link is not established and at the disconnected station.

F. Embodiment FIG. 1 is a device configuration diagram showing an embodiment of the present invention, which is applied to a hierarchical system. A host computer or the like is used as an upper control station 1, and a control station 2 serving as a master station or a relay station is provided as a lower level, and each device of a controlled station 3 serving as a slave station is monitored and controlled. Each station 1-
The transmission control device 3 has master transmission procedure control units 4 to 6 of the HDLC system, modulators 7 to 9 and demodulators 10 to 12 to transmit and receive transmission data. In addition, the transmission data of the host control station 1 is transmitted to the controlled station 3 via the line switching switch 13 of the control station 2, and the transmission data of the control station 2 is a downlink transmission by switching the transmission line by the line switching switch 13. Is done. On the other hand, in the upstream transmission, the transmission data from the controlled station 3 is input to the branch hybrid combiner 14 of the control station 2, and the hybrid combiner 14 branches the data so that the demodulator 11 and the upper control of the control station 2 are performed. It is transmitted to both of the demodulators 10 at station 1.

Here, the upper control station 1 and the control station 2 are provided with slave transmission units 15 and 16 dedicated to reception, and the controlled station 3 is provided with a slave transmission unit 17 dedicated to transmission. These slave transmitters
Unlike the master transmission procedure control units 4 to 6, 15 to 17 are HDLCs.
Without having the transmission procedure of the system, that is, without automatically retransmitting at the time of transmission failure by monitoring the transmission / reception number, each time the transmission / reception data is input, the data is subjected to HDLC format processing and further error checking. Send and receive. Further, the master transmission procedure control units 4 to 6 and the slave transmission units 15 to 17
Is determined by the transmission section changeover switches 18 to 20 which is responsible for transmitting and receiving the transmission data. For example, in the host control station 1, the received data from the demodulator 10 is received and decoded by the master transmission procedure control unit 4 and the slave transmission unit 15, but the data is read into an internal host computer by switching the transmission unit changeover switch 18. It is performed from one of the master transmission procedure control unit 4 and the slave transmission unit 15. Further, in the controlled station 3, the transmission data from the internal computer etc. is transferred to the master transmission procedure control unit 6
And the slave transmission unit 17 reads the output, but one output is given to the modulator 9 and transmitted by switching the transmission unit changeover switch 20.

In the above-mentioned configuration, for normal transmission control, data transmission / reception according to the HDLC transmission control procedure for confirming the receiving station with the host control station 1 or control station 2 according to the switching state of the line selector switch 13 is performed. Is done. At this time, the upstream transmission data is transmitted by the hybrid coupler 14 to the upstream transmission data.
And the control station 2 to monitor the upstream data by switching the transmission unit changeover switch to the slave transmission unit even in the disconnected station regardless of the line changeover state by the line changeover switch 13. You can Therefore, a station disconnected to a system having a hierarchical structure can monitor upstream data from a monitor including a history of changes in the state of the controlled station 3, and can quickly start monitoring control by switching lines. It is possible to obtain a reliable start.

Next, when a failure occurs in the transmission system and a data link is not established such as reception confirmation failure, the transmission section changeover switches 18 to 20 of each station are transferred from the master transmission procedure control section 4 to 6 to the slave transmission section 15 to 17 side. Is switched to. As a result, the controlled station 3
The state changes of the various devices are sequentially formatted by the slave transmission unit 17 and received by the slave transmission units 16 and 15 of the control station 2 and the host control station 1, and the received data are monitored by a computer or the like in the own station. Therefore, if the data link is not established, transmission by the HDLC method will be impossible, but changes in the status of each device in the controlled station 3 can be monitored by both the control station 2 and the host control station 1 using the slave transmission section. Appropriate monitoring control can be immediately entered when the above condition is established.

Next, data transmission / reception between the higher-level control station 1 and the controlled station 3 is performed via the line changeover switch 13 of the control station 2, but the control station 2 itself does not perform relay transmission / reception. Therefore, the transmission from the host control station 1 to the controlled station 3 is not relayed by the control station 2, and it is possible to improve the transmission reliability and shorten the transmission time by eliminating relay errors and the like.

In the embodiment, the case where the present invention is applied to a system having a two-level hierarchical structure is shown, but the same operational effect by the monitor function can be obtained by applying to a system having a three-level hierarchical structure or a one-to-one system.

G. Effect of the Invention As described above, according to the present invention, in data transmission by the HDLC method, since a station separated when a data link is not established or in a hierarchical structure can transmit and receive upstream data, a device to be monitored and controlled. Each station can constantly monitor the status change of, and it has the effect of making the rise of transmission system switching and transmission restart quick and reliable. Further, in the hierarchical structure, the transmitting / receiving station can perform transmission / reception without going through a relay, which can improve the transmission reliability and shorten the transmission time.

[Brief description of drawings]

The drawings are device configuration diagrams showing an embodiment of the present invention. 1 ... Host control station, 2 ... Control station, 3 ... Controlled station, 4, 5, 6 ...
Master transmission procedure control unit, 13 ... Line changeover switch, 14 ... Hybrid coupler, 15, 16, 17 ... Slave transmission unit, 18, 19,
20 ... Transmission section changeover switch.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koichi Kawabe 2-1-1-17 Osaki, Shinagawa-ku, Tokyo Stock company inside Meidensha (72) Inventor Tetsuro Akashi 2-1-1-17 Osaki, Shinagawa-ku, Tokyo Stocks Inside the company Meidensha (56) References JP-A-61-270953 (JP, A)

Claims (1)

[Claims] 1. A high level data link control in a remote monitoring control device of a hierarchical structure in which a master station monitors and controls a plurality of slave stations by data transmission according to a high level data link control procedure, and an upper station integrally monitors the master station. A master transmission procedure control unit that performs data transmission / reception according to the transmission procedure is provided in the master station, slave station, and higher station, and a slave transmission unit that performs data transmission / reception with a non-procedure high-level data link control only transmission / reception function is provided. Provided in the master station, slave stations and upper station, provided with a changeover switch for switching the downlink transmission path from the master station and the higher station to each slave station according to the transmitting / receiving station of data, the upstream data from each slave station Is provided with a branching unit for branching and transmitting to the parent station and an upper station, the parent station or the upper station separated by the changeover switch,
And a remote monitoring and control device, characterized by further comprising switching means for switching the master station, the slave station, or the host station, which has not established a data link, to the data transmission / reception by the slave transmission section in place of the master transmission procedure control section. Transmission control device.