JPS6350740B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field to which the Invention Pertains] This invention aims to improve reliability by duplicating a common bus to which a controller having a built-in processor such as a microprocessor is connected. Regarding the redundant system.

[Prior art and its problems]

Generally, a control device with a built-in program has the advantage that its processing method can be changed by the program, that is, the functions and performance of the control device can be developed and improved without changing the hardware. It has been widely adopted in devices with simple functions to devices with relatively complex and important functions. However, in such a case, if a failure occurs in the central processing unit such as the processor, the entire system will lose its functionality, so appropriate protection measures such as installing protection devices on such main control equipment should be taken. It is desirable that the

Figure 1 is a block diagram showing the basic configuration of the control system, Figure 2 is a block diagram showing the control system equipped with a backup device, and Figure 3 is a block diagram showing the control system equipped with a backup device.
The figure is a block diagram showing a system in which the main parts are duplicated.

That is, a generally well-known control system includes a processor 1, memory 2, system bus 3, and I/O as shown in FIG.
It is composed of controllers 4 (4 ₁ to 4 _o ) and the like.
The following methods can be considered as protection measures against the above-mentioned hardware failure in such a system. One of them is, as shown in Figure 2,
This is a method of providing a backup device 15 ₁ . . . 15 _o . In this case, the backup device 15 ₁ ...
...15 _o has at least a function to monitor the state of the process and change the amount of operation so that the process can be completely and appropriately changed as needed, either manually or automatically. Note that 11, 12, 13, and 14 (14 ₁ to 14 _o ) are the same processor, memory, system bus, and I/O controller as in FIG. Such a backup device 1
By providing 5 ₁ to 15 _o , the devices 11 to 14
Even if a failure occurs in one of the devices and the device loses its function, the minimum necessary control function can be guaranteed.

On the other hand, there is also a method as shown in FIG.
In the same figure, 21M and 21S are processors;
2M, 22S are memories, 23 is a system bus, 2
4 (24 ₁ to 24 _o ) is an I/O controller, 25
is a bus switch. In other words, two sets of common parts such as processors and memories are provided, and one is connected to the master 21.
M, 22M, and the other are slaves 21S and 22S, and when the master side stops functioning due to a failure, etc., the bus switch 25 automatically or manually switches to the slave side, so that the function of the entire system does not stop. This is what I did. Note that 24 ₁ to 24 _o are individual interface units corresponding to process equipment, and even if a failure were to occur in these units, the impact would be limited to a certain area, so such individual interface units Similarly to common parts such as processors and memories, whether or not these should be duplicated can be determined as appropriate depending on the application. In this example as well, the backup device as shown in _FIG .
24 _o .

That is, in any of the above systems, the common section and the individual sections are connected to each other by a common system bus, and information is exchanged via the system bus. This system bus usually consists of an address bus, a data bus, a control information bus, etc., and these information are sent in parallel.
A so-called word-serious bus is used for receiving. Additionally, the components connected to this bus are
It is often mounted on multiple printed boards, but in such cases, if a fault occurs in a component mounted on one of the printed boards, the common bus line becomes "0" or "1". The disadvantage of latching is that normal information exchange is no longer possible. For this reason, it is possible to duplicate various devices or functional elements as described above, but since the system bus is composed of a large number of signal lines, there may be restrictions due to the number of terminals on the printed circuit board, or due to duplication. The drawback is that it is difficult to realize due to significant cost increases and other reasons.

[Purpose of the invention]

The present invention was made under the above circumstances, and an object of the present invention is to provide a means for simply and easily realizing duplication of a control system.

[Key points of the invention]

Information is serially transmitted bit by bit to a system in which a common control unit such as a processor, memory, etc. and individual units such as input/output devices controlled by the common control unit are installed in parallel via a word serial bus. The present invention is characterized in that a bit-serious bus is provided, and a common control section and individual sections are arranged in parallel on the bus via respective predetermined interface sections.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 4 is a block diagram showing an embodiment of the present invention. In the figure, 41 is a processor and memory displayed together, 42 is a local bus, 44 ₁ and 44 ₂ are system bus interfaces, and 46 is a system (word serial).
48 is a control circuit, 50 is a process interface section, 43 ₁ and 43 ₂ are serial bus interfaces, 45 is a serial (bit serial) bus, and 47 is a control circuit. In other words, the processor and memory 41 are connected via the interface ₄₄₁ , and the control circuit ₄₈ and the process interface 50 are connected via the interface 442 to the word serial bus 46, which can transmit information in parallel in units of words. A bit serial bus 45 capable of serially transmitting information in bit units is provided, and the processor and memory 41 and the control circuit 47 are connected to the serial bus interface 4, respectively.
3 ₁ and 43 ₂ to connect to the bus 45 to make the system redundant. Therefore, the serial interfaces 43 ₁ and 43 ₂ have at least the function of exchanging data on the bus 45, which is exchanged in bit serial mode, in units of words. Note that the switching selection circuit 49 selects either the control circuit 47 or 48, similar to the bus switching device 25 in FIG.

The operation shown in FIG. 4 will be explained.

The microprocessor 41 performs predetermined control based on the program stored in the memory, and provides control information to the control circuit 48 via the local bus 42 and system bus interfaces 44 ₁ and 44 ₂ as necessary. At this time, if the switching selection circuit 49 is configured to make use of the signal on the control circuit 48 side during normal operation and disconnect the signal on the control circuit 47 side, the control information from the control circuit 48 is transferred to the process interface 50. is output to predetermined process equipment via. Note that the status information etc. taken in from the process equipment is routed through the opposite route to the above, that is, the process interface 5.
0, switching selection circuit 49, control circuit 48, system bus interface 44 ₂ , system bus 46,
Processor and memory 41 via system bus interface 44 ₁ and local bus 42
is given, and the system operates normally with this operation as the basic operation. Here, a failure occurs in either the bus 46, the interfaces 44 ₁ , 44 ₂ or the control circuit 48 , and one of the signal lines making up the bus 46 becomes latched up, causing the common control unit 4A and the individual If information exchange with the unit 4B becomes impossible, there is a risk that not only the control function for the individual unit 4B will be stopped, but also the functions of all other devices or devices will be stopped. Therefore, when such a situation occurs, the processor 41 switches the control logic (software or program), stops information communication via the system bus 46 that was used during normal operation, and switches the serial interface 43 ₁ , the serial bus 45, the serial interface 43 ₂ , the control circuit 47, the switching selection circuit 49, and the process interface 50, and thereby continue and maintain the control function. The switching selection circuit 49 may be set so that the switching from the control circuit 47 to the control circuit 48 is performed after the function test of the individual section 4B by the processor 41 is confirmed to be normal at the time of system startup, for example. do. Also, individual part 4B
Although only one is shown here, a plurality of units are normally installed, and control by the common unit 4A is also normally executed in a time-sharing manner. Therefore, since the common section 4A must exchange information with a large number of individual sections 4B, a word serious bus is used for its bus configuration, which can transmit multiple bits of information at once. or regular use)
However, it is of course possible to use a system consisting of a serial bus and its interface section as main or regular use, and to provide a system consisting of a word serial bus as a backup.

The embodiment shown in FIG. 4 is an example in which the system bus in the basic control system is duplicated using a word serial bus and a bit serial bus, but the following configuration is also possible.

FIG. 5 is a block diagram showing another embodiment of the present invention. As is clear from the figure, in this example, not only a system bus but also a common section 4A' is added to achieve duplication. Here, the common part 4A is used regularly, the common part 4A' is used as a spare, and the serial bus 4 is used on the spare common part 4A' side.
System status or common side common part 4 via 5
Since the contents of the memory of A can be traced without going through the bus 46 and therefore without any damage to the control function of the common section 4A on the regular side, even if the regular side fails, By instantaneously switching to the standby side, it is possible to realize a non-stop system. It goes without saying that the individual section 4B may also be duplicated in the same manner as described above. Note that since other points are the same as those in FIG. 4, detailed explanation will be omitted.

FIG. 6 is a block diagram showing yet another embodiment of the invention. In other words, the above individual part 4B
By further promoting duplication of the individual parts 4B, 4
Divide B' into three each (4B1 to 4B3, 4B
1' to 4B3'), and for example, when 4B1 on the regular side fails and is switched to the 4B2 side, the failed card 4B1 can be restored to a normal state based on the 4B1' card on the spare side. It is. In addition, in each example of FIGS. 4 to 6,
A comparison circuit is provided in the switching selection path 49, and
If the control results from the common section are always output via both buses 45 and 46, the circuit 49
In this case, only when the outputs of both the control circuits 47 and 48 match, the data can be given to the predetermined process equipment as correct, thereby reducing the possibility of erroneous output and improving reliability. It is. Note that this point can be similarly applied to each input from the process equipment.

〔Effect of the invention〕

According to this invention, control is always performed using a word serial bus with high-speed response, and even if the response is slightly lower than that of a word serial bus in the event of a failure, the bit serial bus has good noise resistance and is easy to insulate. By using a bus, it is possible to realize a fault-tolerant system that is economically superior. In other words, bit serial buses are generally superior to word serial buses in terms of noise resistance, are easier to insulate, and are less expensive. This has an advantage beyond that of duplexing the bus. In addition, it is possible to easily upgrade the level from a relatively simple system, such as duplicating the bus and duplicating only the common parts, to a complete duplex system, in which all components are duplexed, without changing the architecture. It is what it is. Furthermore, when the common part is duplicated, the contents of the memory can be constantly traced using the standby bus, making it possible to realize an uninterrupted system and improving reliability.

Note that the present invention can be applied not only to the above-mentioned process equipment but also to general input/output equipment.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing the basic configuration of the control system, Figure 2 is a block diagram showing the control system equipped with a backup device, and Figure 3 is a block diagram showing the control system equipped with a backup device.
The figure is a block diagram showing an example of a system in which the main parts are duplicated, FIG. 4 is a block diagram showing an embodiment of this invention, FIG. 5 is a block diagram showing another embodiment of this invention, and FIG. FIG. 3 is a block configuration diagram showing still another embodiment of the present invention. Code explanation, 11, 21M, 21S... Processor, 12, 22M, 22S... Memory, 3, 1
3, 23, 46...System bus, 4 ₁ ~ 4 _o , 1
4 ₁ to 14 _o , 24 ₁ to 24 _o ...I/O controller, 15 ₁ to 15 _o ... Backup device, 25...
... bus switcher, 41 ... processor and memory, 42 ... local bus, 43 ₁ , 43 ₂ ... serial bus interface, 44 ₁ , 44 ₂ ... system bus interface, 45 ... serial bus, 47, 48...Control circuit, 49...Switching selection circuit, 50...Process interface circuit.

Claims (1)

[Scope of Claims] 1. A controller comprising a memory that stores at least a program on a common bus that transmits information in parallel, and a processor that executes a predetermined control operation based on the program stored in the memory; In a control system in which various input/output units controlled by a controller are arranged in parallel via predetermined interface sections, another common bus for serially transmitting information is provided in parallel with the common bus, These controllers and various input/output units are arranged in parallel on the other common bus via an interface section for transmitting the serially transmitted information in a format acceptable to the controller and various input/output units. A redundant system characterized by: 2. The duplex system according to claim 1, wherein at least one of the controller or various input/output units is duplexed, and one is operated as an active unit and the other as a standby unit.