JPS61109336A - Private multiplex transmitter - Google Patents

Abstract

PURPOSE:To minimize the fault restoration time by allowing all terminal devices and a transmission master station to detect individually a fault of each terminal device and a transmission line so as to discriminate easily the faulty location. CONSTITUTION:A transmission/reception control section B receives a data from a transmission line A and transmits the received data in a reception buffer E. The control section B checks the data for reception error or parity check, and if a fault is found out, it is registered at each error kind in an error message file Q to abolish the data. The address is decoded by the buffer E, a transmission station of the reception data is discriminated, the result is stored in a reception history register D and the transmission data is stored in an arithmetic control unit I. Further, a print data fed to the unit I is transferred to a transmission buffer H at each prescribed period, the own station address is added, the transmission data is transferred to the control section B to check and process similarly various errors as the case with the reception data. Then troubleshooting of the fault of the transmission line is attained easily.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a transmission system that emphasizes reliability compared to normal transmission, such as in-plant transmission in the electric power field, and relates to a communication system that requires a short failure recovery time. .

[Background of the invention]

In order to increase reliability and availability, a system is often used in which computers are decentralized and the computers are connected via a bus. Considering that the local multiplex transmission system increases the distance of this bus and installs a computer as the transmission terminal device, the conventional communication system itself can be used as the communication protocol. However, when transmitting control and protection information for electric power, especially in power plant multiplex transmission, to this communication system, reliability is concentrated on one set of transmission lines. in this case,
Normally, in order to increase the operating rate, systems such as duplicating transmission lines are adopted, but this is not a means to shorten the failure recovery time, and at best the details of the failure can only be determined when the transmission master station is connected to the terminal station. All I can say is whether or not communication has become impossible.

Furthermore, if we try to break down the causes of these failures in detail and centrally manage this information all at once at the master station, a lot of time will be spent on processing for communication, and the processing performance of the original control device will be poor. Not only that, but if the transmission master station breaks down, this means that the recovery time will be prolonged. Furthermore, since reliability is concentrated in the transmission master station, the transmission master station requires a highly reliable computer system. This increases the cost of the entire transmission system, making it economically disadvantageous to apply it to small-scale power plants.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a local multiplex transmission system that can immediately detect the occurrence of a failure in the multiplex transmission system and minimize the time required to recover from the failure.

[Summary of the invention]

In the present invention, in a local multiplex transmission system, in addition to the transmission master station, each terminal station also performs a data check on all received and transmitted data, and creates a reception history table after confirming all normal reception from each station. A feature of this system is that when a failure occurs, the location of the failure can be easily determined by examining the contents of the reception history table of each station. Furthermore, since each terminal station has the same failure detection function, it is not necessary to install a highly reliable computer in the master station, and an economical system can be realized.

[Embodiments of the invention] An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a diagram showing a transmission control unit in a transmission master station and a transmission terminal station. Data is received from the transmission line A, and the data is transferred to the reception buffer E by the transmission/reception control section B. During reception, the transmission/reception control unit B performs a reception error check, Fe2 (frame check sequence; a type of harness check) check, etc. for - times of transmission, and if an abnormality is found by these checks, an error is detected. Each type of error is registered in the message file Q.

The data in which an error has been detected is discarded by the transmission/reception control unit B.
It is not transferred to receive buffer E.

In the reception buffer E, the address information AD at the beginning of the data
R is decoded to determine from which station the currently received data was transmitted. This information is stored in reception history register D. The reception history register D has a corresponding pip/no position for each station, and is set to rlJe upon successful completion of reception. Furthermore, the control information CTL of the reception buffer E contains information λ that indicates a message from the transmitting station (for example, that the transmitting station has recovered from a failure, or that a retransmission process is required). The information is stored in history register C. By reading the contents of register C, this terminal station determines what to do as a subsequent system operation.

The transmission data DATA of the reception buffer E is stored in a reception file inside the arithmetic and control unit (1), and the contents of this file are output to the plant via the interface section.

On the other hand, the plant data input through the interface section is temporarily stored in a transmission file within the arithmetic and control unit (I). This data is transferred to the data area MD AT AK of the transmission buffer H at certain regular intervals. Here, address information ADRt is added to the beginning of the transmission buffer (1) from the own station address register G, which sets the address of the own station. Furthermore, the data is transferred from the own station operation mode register F to the control information CTL in which the message to be transmitted from the own station to the other station is set. In this way, transmission data is set in the transmission buffer H, and this data is transmitted to the transmission line input via the transmission/reception control section fl. The transmission/reception control unit B performs a loop check (
Receives the own station's transmission data, compares the transmitted data with the received data, and determines whether there is any abnormality in the transmitting/receiving circuit), Transmission monitoring timer check (monitors that the transmission ends within a certain period of time) ), etc., and if an abnormality is found through these checks, the error type and error type are registered in the error message file Q.

If the faulty station of the present multiplex transmission device is identified as soon as possible, the details of the fault are in such a form that the cause can be determined by examining the contents of the error message file Q.

Next, the reception history register D will be further explained using FIG. 2. FIG. 2 shows a method for creating a station's reception history. First, the LSI, circuits, etc. of the receiving section are initialized and placed in a reception waiting state.

When data from another station starts to be received, a reception interrupt is generated and the data is received. If another station has a problem and transmission is no longer possible, wait for a certain period of time, confirm that no reception has been received, and then return to the receiving unit initial processing. In this case, nothing is set in the reception history register D. It means that it is not.

When the reception is completed, check the received data such as FCS check, and if a transmission error is detected,
Since the process returns to the receiving unit initial process, nothing is set in the reception history register D in this case as well. Only in the case of normal reception, the transmitting station sends l1 to the corresponding PIP No. position.
jk will be set. In other words, what is the contents of the reception history register after each station has finished transmitting? If you look, you can see that the data from the station corresponding to the No position is not being received due to a disturbance from the other side. Furthermore, the details of the failure can be determined from the error message file.

FIG. 3 shows an example in which the present in-plant multiplex transmission system was applied to a hydroelectric power plant. The transmission master station P is installed in a switchboard room, and the transmission terminal stations J to φ are often installed on site. According to FIG. 3, for example, if the terminal station J is in failure 1 or higher, a person can immediately discover the loss of received data from the terminal station J by investigating the reception history register of the transmission master station P. These pieces of information can also be checked in the reception history register of ~φ in the terminal station.

Furthermore, assuming that the cable between J and P is disconnected, the terminal station has ~φ, and since Ill is not set in the Pip) No position of terminal station J in the reception history register of master station P, the terminal The failure of station J can be determined. However, even though the error message file of terminal station J shows that the transmission is normal, it can be seen that no station is receiving the message, so by combining the above conditions, it is necessary to solve the problem of cable breakage between J and P. It can be discovered.

According to this embodiment, in a transmission system where it is difficult to determine the location of a fault, it is possible to easily identify the faulty station based on the reception history register of each station, and furthermore, the details of the fault can be determined by each station. The effect can be determined individually based on the error message file.

〔Effect of the invention〕

According to the present invention, since each station manages its own reception history table, when a failure occurs, it is possible to easily identify whether it is a failure or not by investigating the contents of this table. Furthermore, since the fault detection function is not concentrated in one station, there is no need to install a highly reliable computer in a station that has this function as in the past, and the transmission apparatus as a whole has the effect of being economical.

If data, reception history registers, and error message registers are sent as transmission data to a distant central monitoring device, it is possible to easily determine the location of a failure from a distance, even in an unmanned power plant, and even take some measures. This has the effect of

[Brief explanation of drawings]

Fig. 1 is a block diagram of the transmission control unit of a local multiplex transmission device according to an embodiment of the present invention, Fig. 2 is a flowchart showing a method of creating a reception history at a transmission station, and Fig. 3 is a flowchart showing a method for creating a reception history at a transmission station. FIG. 2 is a configuration diagram showing an example of application. M...Transmission line, B...Transmission/reception control unit, C...Operation mode history register, D...Reception history register, E...
...Reception buffer, H...Transmission buffer, ■...Arithmetic control unit, J~φ...Transmission terminal station, P...Transmission master station, Q...(lO)

Claims (1)

[Claims] 1. In-plant multiplex transmission equipment consisting of a transmission terminal station that converts control/protection information within the power plant premises into parallel/serial, or converts data from a transmission master station into serial/parallel and outputs it to the plant, a transmission master station, and a transmission line that connects them. A local multiplex transmission device characterized in that it is possible to shorten failure recovery time by detecting failures in each terminal device and abnormalities in transmission lines at all terminal devices and transmission master station respectively. .