JPH0319961B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of an n+1 redundant control device.

As the n+1 redundant control device, as shown in _FIG .
When one of the process control units 4 ₁ to 4n fails, a redundant unit 5 is used to perform backup through communication. Process control units 4 ₁ to 4n and redundant unit 5
Both have intelligence, and are configured as shown in FIG. 2 and FIG. 3, respectively.

In FIG. 2, the process control unit 4 _j
(j=1 to n) are the communication controller NCM, processor NPU, memory NMU, and input/output device I/O
have. These components are interconnected by a data bus DBS to form an intelligent process control unit. The processor NPU and memory NMU form the core of intelligence. Input/output data is held in the input/output device I/O, accessed by the processor NPU, and processed for process control. The input/output device I/O belongs to a common memory space with the memory NMU. For data processing, the database in the memory NMU is used.
Data processing appropriate to the process that the unit is in charge of is performed.

The communication controller NCM controls communication to the communication line 6, and also controls the memory NMU and input/output device I/O by direct memory access (DMA).
have the ability to access. Such functions are realized by a microprogram built into the communication controller NCM.

The redundant unit 5 in Fig. 3 is also a similar communication controller.
It has an NCM, a processor NPU, and a memory NMU. Each of these components also has a data bus
They are interconnected by DBS to form an intelligent redundancy unit 5. This redundant unit 5 uses its intelligence to update the databases of all process control units 4 ₁ to 4n.
It is periodically read out and uploaded to the NMU via communication, so that the latest database of each process control unit _4j is always kept in memory.
It is becoming present in NMU. The database is uploaded by the communication controller NCM in the redundant unit 5 and each process control unit 4j.
This is done using the DMA function.

Any one of process control units 4 ₁ to 4n
When the redundant unit 5 _malfunctions , the intelligence of the redundant unit 5 is
Performs backup on behalf of the failed process control unit _4jp .

In this case, conventionally, the intelligence of the redundant unit 5 accessed the input/output device I/O of the failed process control unit _4jp through communication. Therefore, different process control programs are required for the redundant unit 5 and the process control unit _4jp even if they relate to the same control object. However, since it is unreasonable to create separate process control programs for the same control object, it is desirable that the same program as the process control unit can be used on the redundant unit side as well.

Also, when the redundant unit 5 is backing up the failed process control unit _4jp ,
From redundant unit 5 to process control unit 4 _jp
It is necessary to communicate some information to the computer's intelligence, such as backup status signals, stop commands, or reset/start commands. In this case, the failed process control unit _4jp is like a shadow of itself from the redundant unit 5's point of view, so communication with it is not conscious of communication, unlike other process control units. It would be convenient if we could make it good.

An object of the present invention is to provide an integrated circuit in which a plurality of process control units and one redundant unit are connected by a communication line.
In the +1 redundancy control device, the redundancy unit is
The same process control program as the process control unit can be used, and information can be transmitted from the redundant unit to the backed up unit during backup without being aware of communication.
The object of the present invention is to provide a redundant control device.

In the present invention, a plurality of process control units each having a communication function, intelligence, and an input/output device and one redundant unit having a communication function and intelligence are connected by a communication line, and a plurality of process control units are connected by a communication line. When one of the process control units fails, the intelligence of the redundant unit takes over the intelligence of the failed process control unit through communication and performs backup control of the process.
In a redundant control device, each process control unit has a memory space that includes mounted equipment such as input/output devices, and the redundant unit has the same size as the process control unit without mounting some of the input/output devices. priority based on memory no response when memory space allocated to a non-implemented device is accessed according to the same program as the process control program executed by the process control unit. The communication program is started when an interrupt occurs, and the process control unit being backed up uses the information obtained when the memory space allocated to the non-implemented device is accessed to access the memory space allocated to the actual device. The above object is achieved by an n+1 redundant control device having a means for communication.

Hereinafter, the present invention will be explained in detail with reference to Examples. The device according to the embodiment of the present invention has almost the same hardware configuration as the n+1 redundancy control device shown in FIGS. 1 to 3. In such an apparatus, both the process control unit _4j and the redundancy unit 5 have memory spaces defined as shown in FIG. 4, for example. In Figure 4, the memory space is
Addresses #O to #FFFF are set, and within this memory space, RAM and ROM that make up the memory NMU are stored.
It also includes input/output devices I/O. In such a memory space, the input/output device I/O area is allocated, for example, from address #FOOO onwards. This I/O area is the process control unit 4
Although it physically exists in redundant unit 5, it does not physically exist in redundant _unit 5 because the input/output device I/O class is not implemented.

The process control program is created to access the I/O area after address #FOOO, and exactly the same program is stored in the memory NMU of the process control unit _4j and the redundant unit 5, respectively.

The program by which the intelligence accesses the input/output device I/O, etc. in the process control unit _4j is similar to a normal program which accesses the memory for writing and reading.

Redundant unit 5 with such a program
However, when backing up the failed process control unit _4jp and accessing the input/output device I/O, a memory no response occurs in the redundant unit 5 because the input/output device I/O is not mounted. .

Since the occurrence of a memory no response normally causes an interrupt of the highest priority (O level), an O level interrupt is generated at this time, and the interrupt processing is immediately performed.

The O-level interrupt processing program is, for example, as shown in Figure 5. First, it determines the address to be accessed, and if it is in the I/O area, it branches to communication parameter creation processing. After creating communication parameters, execute communication processing. Then, after one communication transaction is completed, the original program is returned to. Note that when an O-level interrupt occurs due to a cause other than I/O area access, normal O-level interrupt processing is performed.

When such interrupt processing is performed,
A conceptual diagram of the operation of the redundant unit 5 and the process control unit _4jp is shown in FIG. The communication program activated by the O-level interrupt is activated by the process control unit 4 based on the communication parameters.
The communication parameters at this time are created based on the information for accessing the I/O area, so after one communication transaction, the process control unit ₄ communicates with the input/output device of _jp . I/O is accessed.

The information transmitted when the redundancy unit 5 accesses a virtual input/output device includes the address to be accessed, information specifying whether the access is for writing or reading, and the like. In the virtual input/output device, there is no response even if this information is transmitted, so a memory no response occurs.

When a memory no response occurs, a communication program is activated and accesses the actual input/output devices in the process control unit. Therefore, the information transmitted when the redundant unit accesses the virtual input/output device will be used again by the program accessing the actual input/output device in the process control unit.

After returning from O-level interrupt handling, the process control program continues, and in the same way, each time an access to the I/O area occurs.
A communication program activated by an O-level interrupt accesses the input/output device I/O of the process control unit _4jp , and processes are controlled through it.

Therefore, in the redundant unit 5, the input/output device I/O that does not exist in its own memory space can be accessed as if it actually existed, so the process control program can access the process to be backed up. It can be exactly the same as that of the control unit.

In FIG. 6, the same process control program stored in the process control unit _4j and the redundant unit 5 starts the communication program by an O level interrupt when a memory no response occurs. When the redundant unit 5 accesses a virtual input/output device, it can access the actual input/output device of the process control unit again due to memory no response.

Furthermore, if a communication program activated by an O-level interrupt is used, the redundant unit 5 can communicate with the process control unit _4jp in the following manner.
Information can be transmitted without being conscious of communication.

That is, as shown in FIG. 7, a storage area for communication data is provided in a part of the I/O area of the memory space of the process control unit _4j , for example #F8FO to #F8FF, and a corresponding memory is mounted, For example, to the appropriate address as shown in the figure.
Assign NCM status signals, reset/start commands, stop commands, backup/status signals, general communication information, etc. When this address is accessed in the redundant unit 5, the process control unit 4 _jp is accessed by a communication program activated by an O-level interrupt.
The corresponding address in the memory of is accessed. Therefore, the redundant unit 5 can send and receive information to and from the process control unit _4jp that is being backed up using procedures similar to accessing its own memory without being aware of communication.

Although the present invention has been described above with reference to preferred embodiments, the present invention may have various embodiments within the scope of the claims.

[Brief explanation of the drawing]

FIG. 1 is a conceptual configuration diagram of an n+1 redundancy control device to which the present invention is applied, and FIGS. 2 and 3 are
A detailed configuration diagram of a part of Fig. 1 and Fig. 4 are, respectively.
Configuration diagram of memory space in the embodiment of the present invention, fifth
6 is a flowchart of the O-level interrupt processing program, FIG. 6 is a conceptual diagram of the operation of the embodiment of the present invention, and FIG. 7 is a detailed diagram of a part of the memory space of the embodiment of the present invention. 4 ₁ to 4n...process control unit, 5...
Redundant unit, 6...Communication line, NPU...Processor, NMU...Memory, NCM...Communication controller,
I/O...Input/output device.

Claims (1)

[Claims] 1. A plurality of process control units each having a communication function, intelligence, and an input/output device and one redundant unit having a communication function and intelligence are connected by a communication line, and a plurality of process When one of the control units fails, the intelligence of the redundant unit takes over the intelligence of the failed process control unit through communication and performs backup control of the process.
In a redundant control device, each process control unit has a memory space that includes mounted equipment such as input/output devices, and the redundant unit has the same size as the process control unit without mounting some of the input/output devices. based on a memory no response when a memory space allocated to a non-implemented device is accessed according to the same program as the process control program executed by the process control unit. When a priority interrupt occurs, a communication program is started, and the process control unit being backed up uses the information when it accesses the memory space allocated to the non-implemented device to access the memory space allocated to the existing device. An n+1 redundant control device having means for communicating with.