JP2001306102A - Duplicate controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that a control MPU in a waiting side can not judge waiting/operating in the case that a link between the control MPUs fails. SOLUTION: In a duplicate controller wherein duplicate control MPUs 4A, 4B and links 5A, 5B between control MPU-IO devices are provided, the link 70 between the control MPUs is provided between the two control MPUs 4A, 4B, which exchanges a status through the link 70 between the control MPUs and operating/waiting are determined, a status writing memory is provided in an IO device 61'. The status of the control MPU 4A is written through the link 5A between the control MPU-IO devices in a certain period, in the case that the link 70 between the control MPUs fails, the control MPU in the waiting side reads the status of the memory in the certain period to judge the state of the control MPU 4A, and the waiting/operating of itself (control-MPU 4B) is determined.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a redundant controller used in a distributed control system.

[0002]

2. Description of the Related Art FIG. 3 shows a configuration example of a distributed control system. In FIG. 3, 1 is a man-machine interface device, 2 is a control LAN, and 31 to 3n are controllers connected to processes. The distributed control system is composed of a large number of distributed controllers 31 to 3n.
Is managed by one or several man-machine interface devices 1 such as control personal computers via a control LAN 2. FIG. 4 shows a configuration example of the controller 31. In FIG. 4, reference numeral 4 denotes a control MPU,
5 is a link between the control MPU and IO device, 61 to 6n are IO
Device. The controller 31 controls the one control MPU 4 to control the plurality of IO devices 61 to 6n.
It is configured by being connected by a U-IO device link 5. The other controllers 32 to 3n have the same configuration.
The IO devices 61 to 6n are various input / output devices that transmit and receive a detection signal and a control signal to and from a process.

FIG. 5 shows a highly reliable controller 31 '.
Here is an example. In FIG. 5, 4A and 4B are control MPUs,
5A and 5B are control MPU-IO device links, 61 to 6
n is an IO device, and 70 is a link between the control MPUs 4A and 4B. The control MPU link 70 performs equalization of control data and exchange of status information between the control MPUs 4A and 4B. Thus, the control MPU 4A,
Since the link 4B and the control MPU-IO device links 5A and 5B are duplicated, the controller has high reliability.

[0004]

In FIG. 5, the control M
The operation / standby of the PUs 4A and 4B is controlled by the link 7 between the control MPUs.
It is determined by exchanging each status via 0. That is, for example, the control MP of the operating state
When a failure occurs in the U4A, it is reported as a status via the inter-control MPU link 70 to the standby control MPU 4
B, and as a result, the control MPU 4B starts a new operation. The problem here is when the link 70 between control MPUs fails. In this case, the control MPU 4B
Means that the status cannot be received due to the failure of the link 70, so that it cannot be determined whether or not it should become the active side. As a countermeasure, it is conceivable to duplicate the control MPU-to-MPU link 70 itself, but this causes a problem that the hardware configuration increases and the cost increases. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a dual controller that improves reliability without depending on a method of making a link between control MPUs redundant.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a first aspect of the present invention provides a control MPU and a control MPU.
The link between PU-IO devices is duplicated, and a link between control MPUs is provided between two control MPUs.
In a redundant controller in which both control MPUs exchange statuses and determine operation / standby via a link between PUs, a status writing memory provided in an IO device and a status of an operating control MPU are controlled by a control MPU.
Means for writing to the memory at regular intervals via the link between the IO devices, and when the link between the control MPUs fails,
It is characterized by comprising means for causing the standby-side control MPU to read the status of the memory at regular intervals, and means for determining whether the standby-side control MPU is operating / standby from the status read by this means. The memory for writing the status can be provided on the transmission control module or the IO module in the IO device.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration in an IO device of a redundant controller according to the present invention. In the figure, 7
A and 7B are transmission control modules, 8 is a bus (hereinafter referred to as an IO bus) in the IO device 61 ', and 91 to 9n are IO buses.
Module. Here, the transmission control modules 7A, 7
B denotes control MPUs 4A and 4B and IO modules 91 to 9n
And the IO modules 91 to 9n perform signal level conversion and the like. The IO device 61 '
The overall configuration of the redundant controller including the above corresponds to a configuration in which the IO devices 61 to 6n in FIG. 5 are replaced with the IO devices 61 ′ in FIG.

In FIG. 1, an IO bus 8 includes transmission control modules 7A and 7B and IO modules 91 to 9n.
Are assigned to each of the slots in which is mounted. For example, the transmission control modules 7A and 7B are provided with slot addresses X "10" and X "11" (hereinafter, these slot addresses are referred to as link addresses).
The O module 91 to 9n has a slot address X "0
0 "to X" 0F ". X""
Represents a hexadecimal number. In this case, the number n of IO modules is 16. Although not shown, the transmission control modules 7A and 7B and the IO modules 91 to 9n include:
A two-port memory readable / writable from the IO bus 8 is mounted. This capacity is 256 bytes.

Next, the operation will be described. Control MPU
4A, via the control MPU-IO device link 5A, the transmission control module 7 of the link address X "10".
If the user is normal in A, status information as shown in FIG. 2 is cyclically written. In the illustrated example, the memory address X "FE" of the two-port memory in the transmission control module 7A of the link address X "10" is, for example, 20.
X "55" and X "AA" are written alternately every 0 ms.

On the other hand, the control MPU 4B controls the control M
PU-IO device link 5B, transmission control module 7
B, via the IO bus 8, the link address X "10" and the memory address X "FE" of the transmission control module 7A.
The status information of this is also cyclic, for example, 10
Read at 0 ms cycle. As a result, this area becomes 200
If it is alternately rewritten to X "55" and X "AA" in the ms cycle, it is determined that the control MPU 4A is operating normally. This state is a normal operation state.

Here, the operation state of the inter-control MPU link 70 is constantly monitored, and when the communication is interrupted, the standby control MPU 4B changes the status of the active control MPU 4A according to the above-described procedure. Link 5A, 5B without passing through 70, transmission control module 7
A, 7B, can be grasped via the IO bus 8.
When it is determined from the status read by the control MPU 4B that the active control MPU 4A is operating normally, it is considered that only the inter-MPU link 70 is abnormal and the standby control MPU 4B is switched to the active side. Never. If the status is read, the operation side control M
When it is determined that an abnormality has occurred in the PU 4A, the standby control MPU 4B is switched to the active side.

The transmission control module 7A is used as a place for displaying the status of the control MPU 4A.
This is not limited to the transmission control module 7A, and IO modules 91 to 9n can be used. FIG. 2 shows the case where the IO module 91 is used in parentheses. When the IO module 91 is used, the control MPU 4A writes status data to the 2-port memory of the IO module 91 via the control MPU-IO device link 5A, the transmission control module 7A, and the IO bus 8. . Next, control MPU4B
Via the control MPU-IO device link 5B, the transmission control module 7B, and the IO bus 8,
1 is read from the 2-port memory.

Although the status of the control MPU 4A is displayed on the transmission control module 7A with the link address X "10", the link address X "1
The transmission control modules 7A and 7B are not limited to 0 ", and may be different link addresses. It is also possible to write the status to the module, these things being I
The same applies to the O module.

[0013]

As described above, according to the present invention, the status of the operating control MPU is written to the memory in the IO device at a constant cycle via the link between the control MPU and the IO device, and the standby control is performed. The MPU reads the status of the memory at regular intervals, so that even if the link between the control MPUs fails, it is possible to determine whether to switch between operation and standby, thereby increasing reliability. That is, since the status of the control MPU can be transmitted and received using the memory of the transmission control module and the IO module without using the method of duplicating the link between the control MPUs, the configuration is prevented from becoming complicated and the cost is reduced. Can be.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration in an IO device of a redundant controller according to the present invention.

FIG. 2 is an explanatory diagram showing an example of the configuration and status of a memory.

FIG. 3 is a diagram illustrating a configuration example of a distributed control system to which the present invention is applied.

FIG. 4 is a diagram illustrating a configuration example of a conventional controller.

FIG. 5 is a diagram showing a configuration example of a conventional duplicated controller.

[Explanation of symbols]

 4A, 4B Control MPU 5A, 5B Control MPU-IO device link 7A, 7B Transmission control module 8 IO bus 31 'controller 61' IO device 70 Control MPU link 91-9n IO module

Claims (3)

[Claims] 1. A control MPU and a control MPU-IO device link are duplicated and a control MPU link is provided between two control MPUs. The two control MPUs exchange status via the control MPU link. In a redundant controller for determining operation / standby, a memory for status writing provided in an IO device, and means for writing the status of the operating control MPU to the memory at a constant period via a link between the control MPU and the IO device When the link between the control MPUs fails, the standby side control M
A duplex controller comprising: means for causing a PU to read the status of the memory at regular intervals; and means for determining whether to operate / standby the standby control MPU based on the status read by the means. 2. The dual controller according to claim 1, wherein the status writing memory is provided on a transmission control module in the IO device. 3. The redundant controller according to claim 1, wherein the status writing memory is provided on an IO module in the IO device.