JPH0566799B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a remote monitoring and control system, and particularly to a technique for detecting an abnormality in a system that transmits monitoring information to an information processing device.

<Prior Art> The following system configuration is well known for remote monitoring and control systems. A large number of remote monitoring and control devices (including a control information transmission circuit and a monitoring information transmission circuit) corresponding to the monitored and controlled equipment and a series of information processing devices (computers) are provided at the control center. Remote monitoring and control device (hereinafter referred to as remote control device)
The input information (monitoring information) from the
(memory access) is transferred. Information processing equipment
Based on the DMA-transferred input information, monitor control processing (such as state change detection processing) is executed to create control information, which is then given to the remote control device.

Thus, a DMA area for the main memory is allocated for each remote control device, and the coupling device DMA transfers input information from each remote control device to a predetermined area of the main memory.

<Problems to be Solved by the Invention> One of the abnormalities in the remote control system as described above is when the coupling device malfunctions for some reason.
When input information is DMA transferred to main memory, the address is incorrect and the assigned legitimate address is
There is an error in which data is written to areas other than the DMA area.

When this abnormality occurs, the monitoring information is not correctly transmitted to the information processing device, and the control information created based on it also becomes haphazard, leading to a serious abnormal state.

In order to detect the above-mentioned DMA transfer address error, it is conceivable to provide a transfer address monitoring circuit in the coupling device and monitor whether the address signal at the time of DMA transfer matches a set one. However, in this configuration, if the number of remote control devices increases, the hardware of the monitoring circuit becomes large-scale, which is not preferable.

This invention was made in view of the above-mentioned conventional problems, and its purpose is to detect abnormalities caused by DMA transfer address errors from the coupling device to the main memory by simple processing by the information processing device. The goal is to make it possible.

<Means for Solving the Problems> Therefore, in the present invention, in the information processing device, in parallel with the monitoring control processing based on the input information transferred to the main memory by DMA, the unused empty area in the main memory is The system is configured to execute processing to detect the presence or absence of data changes, and perform abnormality processing when data changes in the sky area are detected.

<Operation> Normally, data in empty areas of the main memory that are not being used does not change. to main memory
When a DMA transfer address error occurs, data is often written to the empty area. When data is written into the empty area, the data in the empty area will change. This data change is detected by the information processing device.

<Example> The figure schematically shows the configuration of a control center in a remote monitoring and control system to which the present invention is applied. As shown in the figure, a large number of remote control devices TC ₁ to _{TC o} corresponding to monitored control equipment are coupled to an information processing device 12 via a coupling device 10 .
2, the remote control processing for each of the remote control devices TC ₁ to _{T O} is intensively performed.

The coupling device 10 inputs the input information from each of the remote control devices TC ₁ to _{TC o} to the main memory 14 of the information processing device 12.
Perform DMA transfer. The main memory 14 includes each remote control device TC ₁
DMA areas ETC ₁ - ETC _o corresponding to ~TC _o are allocated in advance. ETC _i is for remote control device TC _i .
It is a DMA area. (i=1-n). Between each DMA area ETC ₁ ~ ETC _o , there is an unused empty area A ₁ ~
_Ao is set. That is, the DMA area
The final address of ETC _i and the start address of DMA area ETC _i+1 are not connected, and an empty area A _i with some capacity exists between them.

The CPU of the information processing device 12 executes the state change detection program 16, the state change processing program 18, and the output processing program 20, thereby controlling each remote control device TC ₁ to
Perform distant processing on TC _o . That is, each
Changes in the input information stored in the DMA areas ETC ₁ to ETC _o are detected by the status change detection program 16, and control information corresponding to the change is sent to the status change processing program 1.
8, and the output information program 20 transmits the control information to the remote control devices TC ₁ to _{T O} .

In parallel with the remote control processing described above, the information processing device 12
The CPU executes the status change detection program 22 and checks whether there is any data change in the empty areas A ₁ to A _o of the main memory 14 . When a data change is detected in any of the empty areas _A1 to _Ao , the abnormality processing program 24 is executed, predetermined abnormality information is transmitted to the output processing program 20, and abnormality notification output operation (buzzer ringing, (CRT display, recording by printer, etc.)
Do this.

It is desirable that the state change detection program 16 for the DMA areas ETC ₁ to ETC _o and the state change detection program 22 for the empty areas A ₁ to A _o be executed completely in parallel from the viewpoint of processing speed. However, if processing speed is not so much of an issue, the condition change detection programs 16 and 22 can be processed all at once. Similarly, the status change processing program 18 and the abnormality processing program 24 may be processed at once.
Furthermore, there is almost no problem even if the condition change detection program 16 is executed at a high speed, and the condition change detection program 22 is executed at a speed of about one-tenth of that speed. In this way, the increase in the load on the software for abnormality monitoring will be extremely small.

In the above configuration, if the input information is correctly transferred to the DMA areas TC ₁ to _{T o} of the main memory 14, the data in the empty areas A ₁ to _{A o} will not change at all (remain cleared initially). of the coupling device 10
When a DMA transfer address error occurs, the empty area A ₁ to A _o that exists between DMA areas ETC ₁ to ETC _o
Data is written to either. Then, the data of sky areas A ₁ to A _o will change,
This is detected by the state change detection program 22, and the above-mentioned abnormality notification output is generated.

Note that the empty areas A ₁ to _{A o} can of course also include reserve areas that will be implemented in the future.

<Effects of the Invention> As described above in detail, the remote monitoring and control system according to the present invention is capable of DMA transfer of input information from a coupling device to the main memory of an information processing device, and is free from DMA transfer address errors and the like. The resulting abnormality can be detected by simple processing by the information processing device.

[Brief explanation of the drawing]

The figure is a block diagram showing the main structure of an embodiment of the present invention. TC ₁ ~TC _o ... Remote monitoring control device, 10... Coupling device, 12... Information processing device, 14... All memory, ETC ₁ ~ ETC _o ... DMA area, A ₁ ~ A _o ...
...Empty area.

Claims (1)

[Claims] 1. In a system in which input information from a remote monitoring and control device is DMA transferred to the main memory of an information processing device via a coupling device, and the information processing device executes monitoring and control processing based on the information, the information processing device Changes in the input information stored in the DMA area of the main memory are detected, control information corresponding to the change is created and transmitted to the remote monitoring and control device, and the unused empty area of the main memory is A remote monitoring and control system is characterized in that it executes processing to detect the presence or absence of a data change, and performs abnormality processing when a data change in a sky area is detected.