JPH0220189B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a control method for duplex terminals in a loop transmission system, and more particularly to a mutual monitoring data transmission method for duplex intelligent terminals.

[Background of the invention]

Improving the reliability of data transmission systems is always a new proposition.

By the way, one of the commonly used techniques to deal with this problem is to create dual systems.

However, duplex systems in conventional data transmission systems have been mainly used in centralized systems, such as computer systems constituting the central control section.

However, when creating a dual system in such a centralized system, special tools are required for controlling the dual system in both computer hardware and software. In other words, on the hardware side, a device that can freely access the memory of both systems or a memory that can be shared by both systems is required, while on the other hand, on the software side, it is necessary to have a device that can freely access the memory of both systems, and on the other hand, on the software side, it is necessary to have a device that can freely access the memory of both systems. Various programs are required to maintain continuity.

Therefore, creating a duplex system from such a centralized system required an enormous amount of cost.

On the other hand, in recent years, such data transmission systems have shifted from the conventional centralized type to the decentralized type, and there is no longer any fear of a decrease in reliability due to the centralization of functions.

In such distributed systems, networks based on loop transmission dominate, and the reliability has improved significantly in this aspect as well, but on the other hand, in distributed systems, it is essential for terminals to be intelligent, and this Therefore, many microcomputers are now being used in terminals, and improving reliability in this area has become a new challenge.

Therefore, in such a system, a duplex system at the microcomputer level in the terminal is required in order to improve reliability.

However, considering the hardware and software capabilities of microcomputers, it is extremely difficult to realize redundancy at the computer level in conventional centralized systems. There is a problem in that if this was achieved with the support of

[Purpose of the invention]

In view of the above-mentioned problems with the conventional system, an object of the present invention is to enable dual systems in intelligent terminals based on the capability level of microcomputers, and to improve reliability with almost no increase in cost. The object of the present invention is to provide a dual-system control method for intelligent terminals in a loop transmission system.

[Summary of the invention]

In order to achieve this object, the present invention provides a predetermined monitoring method on the condition that no data is periodically transmitted to the loop transmission path from one of the two terminal processing means in the terminal at predetermined fixed period intervals. and means for monitoring the receiving state of the data and the monitoring data by the other of the two systems of terminal processing means, thereby ensuring that there is no abnormality in the loop transmission system and that the terminal As long as there is no abnormality, some data is always received, and as a result, abnormality monitoring of dual system terminals only needs to be done to monitor when the reception has been interrupted for a certain period of time, regardless of the data content. , is characterized by the fact that it does not require advanced capabilities to process monitoring data.

[Embodiments of the Invention] Hereinafter, embodiments of a dual system control system for intelligent terminals in a loop transmission system according to the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of the present invention as embodied by a double loop transmission system. In the figure, 1 is a loop transmission path with a clockwise data transmission direction, and 2 is a loop transmission path with a counterclockwise data transmission direction. Loop transmission lines 3a to 3e and 4a to 4e are transmission control devices (hereinafter referred to as
This is called NCP, which is Network Control.
5 to 9 are microcomputer information processing devices (hereinafter referred to as LCP, which is an abbreviation for Local Control Processor) in each of the terminals A to D, respectively.

Loop transmission lines 1 and 2 constitute a double loop transmission system, and data is normally transmitted through a clockwise route using loop transmission line 1. However, if a failure occurs in loop transmission line 1 due to a disconnection, etc. Data transmission is switched to counterclockwise transmission path 2,
There is no risk of the system going down. Furthermore, since the NCPs 3a to 3e and 4a to 4e are coupled at this time, transmission via a detour route is also possible and high reliability can be obtained.

NCP3a~, 4a~ constitute respective terminals A~D together with LCP5~9, and these terminals A~D
Among them, terminal C has a dual system.

Next, the operation of this embodiment will be explained with reference to FIG.

Terminal C, which has a dual system, has two systems of NCP3c, 3d, 4c, 4d and LCP7, 8, with NCP3d, 4c and LCP7 as the system, and NCP3 as the system.
c, 4c, and LCP8 constitute a system, which normally operates as a master system and a slave system.

Therefore, normally LCP7 connects to loop transmission line 1 via NCP3d and performs data transmission with other terminals A, B, and D, and data ○A sent from LCP7 is transmitted to the main system at this time. It is transmitted via the transmission path 1 that is working as a transmission path, is received by any of the necessary terminals A, B, and D, and is erased when it returns to the NCP 3d after going through loop transmission 1 once.

In this way, data transmission between terminals A to D is carried out in a well-known manner, and at this time, high reliability is achieved due to the double loop transmission system consisting of loop transmission lines 1 and 2, NCPs 3a to 3e, and NCPs 4a to 4e. It will be done.

On the other hand, during this period, the data ○i transmitted from the LCP 7 is also received by the LCP 8 of the slave system from the loop transmission line 1 via the NCP 3c.

Then, the LCP 8 monitors the operating state of the LCP 7 by receiving the data ○I transmitted from the LCP 7, and determines whether or not the LCP 7 is operating normally.

Therefore, even if there is a period in which no data to be transmitted to other terminals A, B, and D appears, LCP7, which constitutes the main system of terminal C, which is currently configured as a dual system, will It is programmed to always send some data every period _t1 . In other words, in this LCP7, data to be transmitted from this terminal C to other terminals A, B, and D is transmitted for a predetermined period.
While these data occur continuously within t ₁ , those data are transmitted one after another. However, if the data to be transmitted to other terminals A, B, and D does not appear for a predetermined period of time t ₁ or more, terminal A , B, and D, these terminals A, B, and D send monitoring data that has no particular meaning.
As long as the main system consisting of LCP7 is normal, some data will always be sent to LCP7 within a predetermined period _t1 .
It is set so that it is sent from . The monitoring data supplemented at this time will be collected from other terminals A,
This is not data needed by B and D, but simply data that when received by LCP8, which is operating as a slave system, can confirm that LCP7, which is operating as a main system, is operating normally. Any signal format may be used as long as it is sufficient.

On the other hand, the LCP operating as a slave system at this time
8 monitors the data received from the loop transmission path 1 or 2 via the NCP 3c or 4c, and each time data whose originating address is the terminal C to which it belongs appears, it updates the data from the previously received data. Check whether the period has reached a predetermined period _t1 . Then, the interval of sequentially received data is the period
As long as it is within t ₁ , it continues to operate as a slave system and continues to monitor the data described above, but even if the predetermined period t ₁ has passed after receiving the previous data, the next data will not be received. and soon after a predetermined period t ₁
When a longer predetermined period t ₂ has elapsed, the LCP 8 assumes that some abnormality has occurred in the LCP 7, which had been operating as the main system, and performs the process of switching from the main system to the slave system, and continues for this predetermined period t. When ₂ has elapsed, the terminal shifts to a data transmission operation using the LCP 8 as the main system, and performs control operations as a dual system terminal C.

Therefore, this switching operation is shown in a time chart as shown in FIG. 3.

The above explanation is for the case where the loop transmission line 1 is used, but it goes without saying that the same applies when switching to the loop transmission line 2.

Therefore, according to this embodiment, the monitoring data necessary for dual system control is transmitted via the loop transmission path in exactly the same way as the original data transmission with other terminals. No dedicated hardware is required for transmitting the monitoring data, and on the other hand, the processing that must be added for this purpose is extremely simple and can be kept within the range that is fully possible with the capabilities of the microcomputer.

In the above embodiment, the original data to be sent from the dual system terminal C to each terminal A, B, and D is also used as monitoring data for the dual system control, and as a result, Since the frequency of sending monitoring data is reduced, the load on the microcomputer can be reduced accordingly.

〔Effect of the invention〕

As explained above, according to the present invention, since the transmission of the supervisory signal for dual system control of the terminal can be performed in the same process as the original data transmission, the problems in the conventional system can be solved, and the loop transmission system Dual systems of intelligent terminals can be achieved at low cost, and a highly reliable data transmission system can be easily provided.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram showing an embodiment of the dual system control method for an intelligent terminal according to the present invention, Fig. 2 is an explanatory diagram of its data transmission operation, and Fig. 3 is a time chart for explaining the operation. be. 1, 2...Loop transmission line, 3a-3e, 4a-
4e...Transmission control device (NCP), 5-9... Information processing device (LCP).

Claims (1)

[Scope of Claims] 1. In a loop transmission system including a dual-system intelligent terminal, a loop transmission line is periodically transmitted from one of the two terminal processing means in the dual-system intelligent terminal at predetermined regular intervals. means for transmitting predetermined monitoring data on the condition that no data has been transmitted, and means for monitoring the reception status of the data and the monitoring data by the other of the two systems of terminal processing means, An intelligent system in a loop transmission system, characterized in that an abnormality in a dual system terminal is monitored by interrupting reception of the data and the monitoring data by the other of the two terminal processing means for a period exceeding the certain period. Dual system control method for client terminals. 2. A dual-system control method for an intelligent terminal in a loop transmission system according to claim 1, wherein the loop transmission path is constituted by a double loop transmission path. 3. A dual system control method for an intelligent terminal in a loop transmission system according to claim 1, wherein the dual system intelligent terminal is a dual system at a microcomputer level.