JPH09311716A - Lan device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To judge the abnormality of a device related to computer with a simple system constitution. SOLUTION: When a computer 1 is normal, a counter 21 is periodically counted up and a transmission station 5 periodically writes the counted value in a self counter memory area 5m. The computer abnormality judgment means 22 of a controller periodically accesses to the counter memory area 6m of a transmission station 6, reads the counted value, and compares it with the counted value at the time of previous access. When they are changed, the computer is judged to be normal. When they are not changed, abnormality is judged to be generated. When abnormality is judged, plant control is switched to be executed by the self controller.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a LAN device, and more particularly to a LAN device having a simple computer abnormality determining mechanism.

[0002]

2. Description of the Related Art Conventionally, a LAN device used in a plant monitoring and control system has a system configuration shown in FIG. 2, in which a computer 1 for performing integrated control arithmetic processing, a controller 2 for monitoring and controlling a plant, and a remote process input. The output device (remote PI / O) 3 is connected to the transmission path 4 by transmission stations 5, 6 and 7, respectively, so as to mutually perform data transmission. Further, the transmission stations 5, 6 and 7 each have a memory area for sharing a memory, and also have a scan transmission function of periodically transferring the data stored in these memory areas one after another.

In order to monitor the normality / abnormality of the hardware, operating system, and software of each part of the system, the computer 1 incorporates a state determination program 8 for determining the normality / abnormality of the application software, and the controller 2 The computer normal recognition program 9 is installed in the computer, and the state monitoring device 10 is additionally provided separately from these system devices.

In such a LAN device, to the status monitoring device 10, the hardware normality judgment signal a of the computer 1, the normality judgment signal b of the operating system 11, and the normality judgment output c by the status judgment program 8 are outputted from the computer 1. Is input, the station normality determination signal d is input from the transmission station 5 connected to the computer 1,
The normal judgment signal e from the remote PI / O3, the transmission station 7 to which this remote PI / O3 is connected
The normality determination signal f is input from. Then, the status monitoring device 10 determines that all computer-related devices are normal when the normal determination signals a to f are input from all of these computer-related devices, and outputs the normal determination output g of this computer-related device to the remote PI / Send to O3 and controller 2.

The controller 2 outputs this normality determination output g
Received through two paths, a path g1 passing through the remote PI / O3 and a path g2 passing through the process input / output device (PI / O) 12, and the computer normal recognition program 9 determines whether the computer-related device is normal / abnormal depending on the state of the normal determination signal g Is recognized, and if it is abnormal, it is disconnected from the computer 1 and the control of the plant is independently executed by the control program installed in the own device.

[0006]

However, in such a conventional LAN device, the normal / normal operation of the computer-related device is externally performed.
There is a problem that a system is complicated because a state determination device for determining abnormality is required and a route for transmitting a normal determination signal from each computer-related device is required. And, this point is that one computer 1 is more than one LA
In the system commonly connected to the N devices, there is a problem that the system becomes more complicated.

In addition, in the case of a LAN device in which two computers, one for production and one for standby, are connected, a normality judgment signal is output from each computer, and a signal for identifying production and standby is also in a state. Since it is input to the judgment monitoring device, there is a problem that it becomes more complicated.

The present invention has been made in view of the above-mentioned conventional problems, and a LAN is designed so that a controller can determine an abnormality in a computer-related device with a simple system configuration and switch to control by the device itself. The purpose is to provide a device.

[0009]

According to a first aspect of the present invention, a computer and a controller for controlling a plant are connected by a transmission line, and each of the computer and the controller is connected to the transmission line by a transmission station having a memory. In a LAN device in which the transmission station shares the contents of the memory, the computer includes a counter that periodically counts up when the device itself is normal,
The transmission station includes a counter memory area that periodically captures the count value of the counter of the computer, and the controller periodically accesses the counter memory area of the transmission station to read the count value and read the previously read value. It is provided with a computer abnormality judging means for judging abnormality of the computer when there is no change as compared with.

In the LAN device according to the first aspect of the present invention, if the computer is normal, the counter periodically counts up, and the transmission station periodically writes the count value in its own counter memory area. Then, the computer abnormality determination means of the controller periodically accesses the counter memory area of the transmission station to which the controller is connected, reads the count value, compares it with the count value at the previous access, and if there is a change, It is determined that the computer-related device is normal, and if it has not changed, it is determined that an abnormality has occurred. When the abnormality is determined, the plant control is switched to be performed by the own controller.

Thus, the normal / abnormal determination of the computer-related device is performed by the simple periodic counter function and its check function.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a system configuration of one embodiment of the present invention, in which a computer 1, a controller 2, and a remote PI / O 3 are connected to a transmission line 4 via transmission stations 5, 6 and 7, respectively.

Each of the transmission stations 5, 6 and 7 has its own memory area and has a function of storing the data of the same content by periodically transferring the stored data between the stations periodically. Then, a specific address of the memory area of each transmission station 5, 6, 7 is assigned as a counter memory area 5m, 6m, 7m.

A normal output count-up program 21 is incorporated in the computer 1 as a counter, the hardware of the computer itself is normal, the operating system is normal, and the installed program is normal. The count value is periodically incremented and the count value is output.

The transmission station 5 has a scan transmission function, and writes the count value data A periodically output from the normal output count-up program 21 of the computer 1 into the counter memory area 5m thereof, and the written count. The value data is automatically transferred to each of the transmission stations 7 and 6 in sequence, so that each station 5,
Counter memory areas 5m, 6m, 7 of 6 and 7 respectively
The count value data of m are set to be the same.

The controller 2 periodically reads the data B in the counter memory area 6m of the transmission station 6 connected to it and compares it with the previously read count value to see if it changes by a certain value. , Normal if there is a change of a preset constant value,
A computer normality recognition program 22 for determining an abnormality if there is no change of a fixed value is incorporated.

Next, the operation of the LAN device having the above configuration will be described. In the computer 1, the normal output count-up program 21 periodically executes its own program to perform count-up processing if the hardware of the computer 1 is normal and the operating system 11 is also operating normally, and The count value data A is written in the counter memory area 5m of the transmission station 5 every time the count is incremented.

When the count value data A is newly written, the transmission station 5 sequentially transfers the contents of the memory areas to the transmission stations 7 and 6 through the transmission path 4, and the contents of the memory areas of the respective transmission stations 7 and 6. Are the same, and the contents of the counter memory areas 7m and 6m are the same as the contents of the counter memory area 5m of the transmission station 5.

In the controller 2, the computer normal recognition program 22 periodically reads the count value data B in the counter memory area 6m of the transmission station 6 to which the controller 2 is connected, and changes by a predetermined value as compared with the previously read value. If there is a change of a predetermined value, the computer 1, the transmission path 4, the transmission station 5,
It is determined that all 6 and 7 are operating normally, and if they have not changed by a predetermined value, it is determined that an abnormality has occurred in any of these, and the determination result is transmitted to the controller 2.

When the controller 2 receives an abnormality occurrence determination output from the computer normality recognition program 22, the computer 1
Instead of the control of No. 1, switching is performed so as to control the plant 13 by itself.

In this way, in the LAN device of this embodiment, the program 21 for periodically counting up is installed in the computer 1, and the count value data is transmitted by the transmission line 4
Transfer to all transmission stations 5, 6, 7 through
The controller 2 reads the count value data in the counter memory area 6m of the transmission station 6 to which it is connected, and determines whether the computer-related device is normal / abnormal depending on whether or not it has changed by a predetermined value from the previous read value. It is possible to determine the occurrence of a computer abnormality with a very simple system configuration.

The LAN device of the above embodiment is
When applied to a system in which one computer 1 is connected to a plurality of shared transmission lines 4, the count value data of the computer 1 is commonly used for normality / abnormality determination in the controllers connected to the respective transmission lines. It is possible,
There is no complexity in such a system expansion.

Also in a LAN device having a plurality of computers, if the above normal output count-up program 21 is incorporated in each computer, the count value data A is output from the production computer 1 to the transmission line 4 and the controller 2 is operated. Since it is used for determining whether the computer-related device is normal or abnormal, the computer abnormality determination mechanism does not become complicated.

In the above embodiment, a normal output count-up program similar to that incorporated in the computer 1 is incorporated in the controller 2 side, and the controller 2 is incorporated in the memory area of each transmission station 5, 6, 7.
The counter memory area for storing the count value data on the side of
Incorporate the same controller normality recognition program as above, and read the count value data in the counter memory area for normality / abnormality judgment on the controller side of the transmission station 5 by the controller normality recognition program on the computer 1 side and compare it with the previously read value. It is also possible to judge whether the controller is normal or abnormal.

[0025]

As described above, according to the invention of claim 1,
If the computer is normal, the counter periodically counts up, the transmission station periodically writes the count value to its own counter memory area, and the computer abnormality determination means of the controller is the transmission station to which the controller is connected. The counter memory area is periodically accessed, the count value is read out, compared with the count value at the time of the previous access, and if there is a change, it is determined that the computer-related device is normal. Since it is determined that it has occurred, it is possible to determine the normality / abnormality of the computer-related device by a simple periodic counter function and its check function.

[Brief description of drawings]

FIG. 1 is a system block diagram of one embodiment of the present invention.

FIG. 2 is a system block diagram of a conventional example.

[Explanation of symbols]

 1 computer 2 controller 3 remote process input / output device 4 transmission path 5, 6, 7 transmission station 5m, 6m, 7m counter memory area 11 operating system 21 normal output count-up program 22 computer normal recognition program

Claims (1)

[Claims] 1. A computer and a controller for controlling a plant are connected by a transmission line, and each of the computer and the controller is connected to the transmission line by a transmission station having a memory, and the transmission station shares the contents of the memory. In the LAN device, the computer includes a counter that periodically counts up when the device itself is normal, and the transmission station includes a counter memory area that periodically captures a count value of the counter of the computer, The controller comprises a computer abnormality judging means for periodically accessing the counter memory area of the transmission station, reading the count value, and comparing it with the previous read value to judge the abnormality of the computer when there is no change. apparatus.