JPH1021156A - Input/output equipment control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and speedily transfer the function of input/output device, where any fault is generated, to the other input/output device by switching the normal input/output device in standby system to an active system and designating an input/output address when the generation of fault at the input/output device in the active system is detected. SOLUTION: When accessing an input/output device 2, first of all, a central control unit 1 reads the contents in registers 5a and 5b where their own diagnosed results of respective input/output devices 3a and 3b are stored. Next, it is discriminated whether the read self-diagnosed result is 'normal' for both the registers 5a and 5b or not. As a result of discrimination, when both the results are not 'normal', it is discriminated whether the self-diagnosed result of the register 5b is normal or not. As a result, when the self-diagnosed result of the register 5b is 'normal', signals are inputted/outputted with input/output equipment 2 through the route shown by an arrow S2 via the input/output device 3b to which an address 'B' is applied as an input/output address 4b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an input / output device control method for controlling input / output devices with a multiplexed input / output device. The present invention relates to an input / output device control method that facilitates continuing the function of the active system to another normal standby system.

[0002]

2. Description of the Related Art FIG. 13 is a block diagram showing a system to which a conventional input / output device control method is applied. In the figure, reference numerals 1a and 1b denote a central control device as a control device for controlling the system, one of which is multiplexed with an active system and the other is a standby system, and 2 is a central control device which is an active system. It is an external input / output device controlled by the device 1a (1b). 3a and 3b, one of which is multiplexed in the active system and the other is multiplexed in the standby system and is switchably connected to each of the central control devices 1a and 1b. Working central controller 1a
This is an input / output device that controls the input / output device 2 by transferring a signal from the active central control device 1a (1b) to the input / output device 2 to (1b).

Next, the operation will be described. Now, the central controller 1a and the input / output device 3a, the central controller 1b and the input / output device 3b are connected, respectively, the central controller 1a and the input / output device 3a are working systems, and the central controller 1b and the input / output device 3b are connected. It is assumed that the system is a standby system. At this time, the active central controller 1a controls the input / output device 2 by exchanging signals with the input / output device 2 via the active input / output device 3a. Here, when a failure occurs in the input control device 3a, the central control device 1a and the input / output device 3a
Becomes a standby system, and the central control unit 1b and the input / output device 3b become active systems.
The input / output device 2 is controlled via the.

[0004] Incidentally, as a document which describes a technique relating to such a conventional input / output device control method, there is, for example, JP-A-2-199567.

In addition, as in the above input / output device control method,
There is also a configuration in which the central control device is not multiplexed and only the input / output device is multiplexed. FIG. 14 is a block diagram showing a system to which such a conventional input / output device control method is applied. In the figure, reference numeral 1 denotes a central control device, 2 denotes input / output devices, and 3a and 3b denote input / output devices. The input / output devices 3a and 3b do not have a self-diagnosis function for diagnosing their own normality.

Next, the operation will be described. The central control unit 1 inputs the same signal from each of the input / output devices 3a and 3b since the multiplexed input / output devices 3a and 3b do not have a self-diagnosis function. By determining the presence or absence of a failure in the output devices 3a and 3b by software and selecting a normal signal,
The control of the input / output device 2 is performed via the normal input / output device 3a (3b).

[0007]

Since the conventional input / output device control method is configured as described above, in the former method, when the active input / output device 3a (3b) fails,
Since the entire system including the central controllers 1a and 1b has been switched to the standby system, there has been a problem that it is necessary to multiplex even devices with relatively few failures. Further, in the latter method, software for judging the validity of signals from the plurality of input / output devices 3a and 3b and selecting a normal signal is required. There has been a problem that the load on the control device 1 increases and the performance of the entire system decreases.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems.
It is an object of the present invention to provide an input / output device control method capable of easily and promptly replacing the function of a failed input / output device with another input / output device.

[0009]

According to a first aspect of the present invention, there is provided a method for controlling an input / output device, wherein a control device specifies an input / output address of an active input / output device and controls the input / output device via the address. Each I / O device has a self-diagnosis function and displays the diagnosis result as a flag, and the control device monitors it and detects the occurrence of a failure in the active I / O device. By switching one of the output devices to the active system and designating its input / output address, the input / output device is controlled via the input / output device.

According to a second aspect of the present invention, there is provided a method for controlling an input / output device, wherein each input / output device displays a self-diagnosis result as a flag using a register in each input / output device to which the control device can refer. It was done.

According to a third aspect of the present invention, there is provided an input / output device control method using a memory area of a shared storage device provided separately from each input / output device, the memory area being allocated to each input / output device. The output devices each display a self-diagnosis result as a flag.

According to a fourth aspect of the present invention, there is provided a method for controlling an input / output device, wherein each of the input / output devices exchanges self-diagnosis results with each other, and one of the normal input / output devices is connected to a working system accessible from the control device. Other I / O devices become a standby system that is inaccessible to the control device. If a failure occurs in the active I / O device, it becomes inaccessible from the control device, and one of the normal I / O devices becomes the control device. The access system is switched to the working system in a more accessible state, and the control device controls the input / output device via the working input / output device.

According to a fifth aspect of the present invention, in the input / output device control method, an operation address is set in the active input / output device, and a dummy address is set in the standby input / output device. If an I / O address occurs, the I / O address is changed to a dummy address to prevent access from the control device, and the I / O address of the I / O device that has been switched to the active system is changed to an operation address to enable access from the control device. It was made.

According to a sixth aspect of the present invention, in the input / output device control method, the bus interface, the active input / output device is set to a bus enable state, and the standby input / output device is set to a high impedance state. If a failure occurs in the device, the bus interface is set to a high impedance state to prevent access from the control device, and the bus interface of the input / output device switched to the active system is set to the bus enable state to allow the control device to access the bus interface. It allows access.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1 FIG. FIG. 1 is a block diagram showing a system to which an input / output device control method according to Embodiment 1 of the present invention is applied. In the figure, reference numeral 1 denotes a central control device as a control device for controlling the system, and reference numeral 2 denotes an external input / output device controlled by the central control device 1.
3a and 3b, one of which is multiplexed in the working system and the other is in the standby system, and the one which has become the working system receives the signal from the input / output device 2 to the central control device 1 and the signal from the central control device 1 to the working system. By transferring to the input / output device 2, the input / output device 2
The input / output devices for controlling the
Each of a and 3b has a self-diagnosis function for diagnosing its own normality. Reference numerals 4a and 4b denote input / output addresses for the central controller 1 to access the input / output device 3a or 3b. In the illustrated case, the input / output device 3a has an address "A" and the input / output device 3b has Are each given an address "B". Reference numerals 5a and 5b denote registers provided in the input / output devices 3a and 3b, respectively, which can be referred to from the central control unit 1. One bit in the registers is the self-register of the input / output device 3a or 3b provided. It is used to display the diagnostic result flag.

FIG. 1 shows a state in which both the input / output devices 3a and 3b are normal, the input / output device 3a is in a working system, and the input / output device 3b is in a standby system. An arrow S1 indicates a path of a signal that the central control device 1 then exchanges with the input / output device 2 via the working input / output device 3a. FIG. 2 is a block diagram showing a system to which the input / output device control method according to the first embodiment of the present invention is similarly applied.
The state in which a failure has occurred is shown in FIG.
Indicates a path of a signal that the central control device 1 exchanges with the input / output device 2 via the input / output device 3b switched to the active system at that time.

Next, the operation will be described. Each of the input / output devices 3a and 3b diagnoses its own normality by its own self-diagnosis function, and displays the self-diagnosis result in a predetermined bit of a register 5a or 5b incorporated therein as a flag. That is, if the internal circuit is normal, a normal flag indicating that the self-diagnosis result is normal is set in the corresponding bit of the register 5a or 5b, and a failure such as damage to the internal circuit or power cut-off is detected. When this is done, a failure flag indicating that the self-diagnosis result is abnormal is set immediately. Specifically, when a normal flag is set, for example, “0” is stored in a bit assigned to the flag display, and when a failure flag is set, for example, “1” is stored in the bit. Is used.

FIG. 3 is a flowchart showing the flow of the operation. When accessing the input / output device 2, the central controller 1 first reads the contents of the registers 5a and 5b storing the self-diagnosis results of the input / output devices 3a and 3b in step ST1. Next, step S
At T2, it is determined whether the read self-diagnosis result is “normal” in both the registers 5a and 5b. As a result, if both are "normal", the process proceeds to step ST3, where the input / output device 3a to which the address "A" is given as the input / output address 4a or the address "B" is given as the input / output address 4b. Input / output of signals with the input / output device 2 is performed via one of the input / output devices 3b (the input / output device which is currently used). That is, in the case shown in FIG. 1, by inputting / outputting a signal through a path shown by an arrow S1 via an input / output device 3a which is an active system, the central control device 1 inputs / outputs the input / output device 2
Is controlled, and a series of processing ends.

On the other hand, as a result of the determination in step ST2,
If both are not “normal”, step S
Proceeding to T4, it is determined whether the self-diagnosis result of the register 5b is "normal". As a result, if the self-diagnosis result of the register 5b is “normal”, the process proceeds to step ST5,
A signal is input / output to / from the input / output device 2 via the input / output device 3b to which the address "B" is given as the input / output address 4b, via the path indicated by the arrow S2 in FIG. finish. If the result of the determination in step ST4 indicates that the self-diagnosis result of the register 5b is not "normal", the process proceeds to step ST6, and it is determined whether or not the self-diagnosis result of the register 5a is "normal". As a result, if the self-diagnosis result of the register 5a is "normal", step ST7 is executed.
To the input / output device 2 via the input / output device 3a to which the address "A" is given as the input / output address 4a.
And input and output of signals, and a series of processing ends. on the other hand,
As a result of the determination in step ST6, if the self-diagnosis result of the register 5a is not "normal", the control of the input / output device 2 is disabled.

As described above, according to the first embodiment, the self-diagnosis result of each input / output device can be displayed in a flag in the multiplexed register in each input / output device. The device simply and quickly substitutes the function of the failed I / O device with another normal I / O device simply by specifying the address given to the normal I / O device by referring to the flag display. This is possible without additional hardware such as a storage device, and the effect of preventing a decrease in performance of the entire system due to an increase in the load on the central control device due to an increase in software.

In the above description, a multiplex configuration is shown with two input / output devices. However, a multiplex configuration may be made using three or more input / output devices. It has the same effect as.

Embodiment 2 FIG. In the first embodiment, the self-diagnosis result of each input / output device is described as a flag using one bit of a built-in register. However, a shared storage provided separately from each input / output device is described. A flag display of each self-diagnosis result may be performed using the device. FIG. 4 is a block diagram showing a system to which such an input / output device control method according to Embodiment 2 of the present invention is applied, and the corresponding parts are denoted by the same reference numerals as in FIG. 1 and description thereof is omitted. In the figure, reference numeral 6 denotes the above-mentioned shared storage device which is provided separately from the input / output devices 3a and 3b and which can be referred to by the central control device 1.
Is a memory area of the shared storage device 6 in which one bit is assigned to each of the input / output devices 3a and 3b, and the self-diagnosis result is displayed as a flag.

FIG. 4 shows a state in which both the input / output devices 3a and 3b are normal and the input / output device 3a is in the active system. At this time, a path of a signal exchanged with the input / output device 2 via the working input / output device 3a is shown.
FIG. 5 is also a block diagram showing a system to which the input / output device control method according to the second embodiment of the present invention is applied, in which a failure has occurred in the input / output device 3a. The arrow S2 in the figure indicates the path of a signal that the central control device 1 exchanges with the input / output device 2 via the input / output device 3b that has been switched to the active system at that time.

Next, the operation will be described. Each input / output device 3a, 3b diagnoses its own normality by its own self-diagnosis function, and stores the self-diagnosis result in the allocated memory area 6a or 6b on the shared storage device 6.
Display a flag. That is, if the internal circuit is normal, for example, "0" is stored in the memory area 6a or 6b to set a normal flag indicating that the self-diagnosis result is normal, and a fault occurs in the internal circuit. If the self-diagnosis result is detected, for example, "1" is stored therein, thereby immediately setting a failure flag indicating that the self-diagnosis result is abnormal.

FIG. 6 is a flowchart showing the flow of the operation. When the central controller 1 accesses the input / output device 2, first, in step ST11, the contents of the respective memory areas 6a and 6b of the shared storage device 6 in which the self-diagnosis results of the respective input / output devices 3a and 3b are stored are read. . Next, in step ST12, it is determined whether or not the read self-diagnosis result is “normal” in both the memory areas 6a and 6b. As a result, if both are “normal”, the process proceeds to step ST13,
One of the I / O device 3a to which the address "A" is given as the I / O address 4a or the I / O device 3b to which the address "B" is given as the I / O address 4b ) To input and output signals to and from the input / output device 2. That is, in the case shown in FIG. 4, the input / output of signals is performed through a path shown by an arrow S1 via the active input / output device 3a, so that the input / output device 2 is controlled by the central control device 1, and a series of operations is performed. The process ends.

On the other hand, if both are not "normal", the process proceeds to step ST14 to determine whether or not the self-diagnosis result of the memory area 6b is "normal". If the self-diagnosis result is “normal”, the process proceeds to step ST15,
Via the input / output device 3b to which the address "B" is given as the input / output address 4b, signals are input / output to / from the input / output device 2 via the path indicated by the arrow S2 in FIG. I do. If the self-diagnosis result is not "normal", the process proceeds to step ST16, and it is determined whether the self-diagnosis result of the memory area 6a is "normal". If the self-diagnosis result is “normal”, step ST
The process proceeds to step S17, where signals are input / output to / from the input / output device 2 via the input / output device 3a to which the address "A" is given as the input / output address 4a, and a series of processing ends. On the other hand, if the self-diagnosis result is not “normal”, the control of the input / output device 2 is disabled.

As described above, according to the second embodiment, the self-diagnosis result of each input / output device can be flag-displayed on the shared storage device provided separately from the multiplexed input / output device. Since the central controller can specify the address given to the normal I / O device by referring to the flag display, the function of the failed I / O device can be easily transferred to other normal I / O devices. It is possible to make a quick and quick substitution without changing the configuration of registers etc. inside the input / output device, and also prevent the overall system performance from deteriorating due to an increase in the load on the central control unit due to an increase in software. There is an effect that can be done.

In this case, the multiplex configuration is not limited to the configuration multiplexed by two input / output devices, but may be multiplexed by three or more input / output devices. Has the effect of

Embodiment 3 FIG. 7 is a block diagram showing a system to which an input / output device control method according to Embodiment 3 of the present invention is applied. In the figure, 1 is a central control device as a control device, 2 is an input / output device, 3a and 3b are multiplexed input / output devices, 4a and 4b are input / output devices 3
a, 3b are input / output addresses for accessing
These correspond to those in the first and second embodiments. In addition, this input / output device 3a,
3b, each diagnoses its own normality, and exchanges fault information as a result of the diagnosis with each other. Based on the information, one of them becomes a working system and the other becomes a standby system. An operation address, for example, an address "A" that can be accessed from the central control device 1 is set in 4a (4b), and the input / output address 4a (4b) cannot be accessed from the central control device 1 in the standby system. This embodiment is different from those in the first and second embodiments in that it has a function of setting a dummy address, for example, the address “B”.

FIG. 7 also shows input / output devices 3a and 3a.
b indicates that the input / output device 3a is in the active system, and the arrow S1 in the figure indicates that the central control unit 1 has passed through the current input / output device 3a. 2 shows a path of a signal exchanged with the input / output device 2. FIG. 8 is a block diagram showing a system to which the input / output device control method according to the third embodiment of the present invention is applied. FIG. 8 shows a state in which a failure has occurred in the input / output device 3a. Arrow S2 indicates the path of a signal that the central control device 1 exchanges with the input / output device 2 via the input / output device 3b that has been switched to the active system at that time.

Next, the operation will be described. Here, FIG.
Is a flowchart showing the flow of the operation. Each of the input / output devices 3a and 3b diagnoses its own normality, and mutually exchanges failure information as a result of the self-diagnosis in step ST21. Next, in step ST22, it is determined whether or not the input / output device 3a is “normal” based on the failure information. If the input / output device 3a is “normal”, the process proceeds to step ST23. Step ST2
3, the input / output device 3a sets the input / output address 4a to the operation address "A" to become the active system, and the input / output device 3b sets the input / output address 4b
Is set to an address "B" which is a dummy address, and a standby system is set. On the other hand, if it is determined in step ST22 that the input / output device 3a is not “normal”, the process proceeds to step ST24, and the input / output device 3b is set to “normal” based on the mutually exchanged failure information. Is determined. As a result, if the input / output device 3b is “normal”, the process proceeds to step ST25, in which the input / output device 3b sets the input / output address 4b to the address “A” which is the operation address to become the active system, and Output device 3
a sets the input / output address 4a to the address "B" which is a dummy address, and becomes a standby system.

In step ST26, the central controller 1 accesses these input / output devices 3a and 3b using the address "A" as an operation address. Therefore, if the input / output device 3a is “normal”, the input / output device 3a inputs / outputs a signal to / from the input / output device 2 via the input / output device 3a via a path indicated by an arrow S1 in FIG. If the input / output device 3a is "failed" and the input / output device 3b is "normal", an arrow S2 shown in FIG.
A signal is input / output to / from the input / output device 2 via the path indicated by, the signal is controlled, and a series of processing ends. Step ST2
In 4, if it is determined that the input / output device 3 b is not “normal”, the control of the input / output device 2 is disabled.

As described above, according to the third embodiment, when one of the input / output devices detects a failure, the input / output device sets the input / output address to the operation address accessed by the central control unit as the dummy address. By changing the I / O address of the standby I / O device to the operation address based on the information, the switching of the I / O device can be performed.When controlling the I / O device, the central controller always has the same It is only necessary to access the operation address (address A), and there is no need to specify and access different input / output addresses in accordance with the normality of each multiplexed input / output device. This has the effect of reducing the load on the central control device.

In this case, the multiplex configuration is not limited to the configuration multiplexed by the two input / output devices, but may be configured by the multiplex configuration using three or more input / output devices. Has the effect of

Embodiment 4 FIG. In the third embodiment, based on the self-diagnosis result of each input / output device being exchanged with each other,
Although the description has been given of the case where the input / output address is switched between the operation address and the dummy address, the state of the bus interface of each input / output device is switched between the bus enable state and the high impedance state based on the self-diagnosis result exchanged with each other. It may be. FIG. 10 is a block diagram showing a system to which such an input / output device control method according to Embodiment 4 of the present invention is applied, and the corresponding parts are denoted by the same reference numerals as in FIG. 7 and description thereof is omitted. In this case, the same address "A" is set in the input / output addresses 4a and 4b of the input / output devices 3a and 3b, and the input / output devices 3a and 3b change their bus interface to the active system. It differs from that of the third embodiment in that it has a function of setting a high impedance state in the enable state and the standby system.

FIG. 10 also shows a state in which both the input / output devices 3a and 3b are normal and the input / output device 3a is the active system. The path of a signal exchanged with the input / output device 2 via the working input / output device 3a is shown. FIG. 11 is a block diagram showing a system to which the input / output device control method according to the fourth embodiment of the present invention is applied. FIG. 11 shows a state in which a failure has occurred in the input / output device 3a. S2 indicates a path of a signal that the central control device 1 exchanges with the input / output device 2 via the input / output device 3b switched to the active system at that time.

Next, the operation will be described. Here, FIG.
2 is a flowchart showing the flow of the operation. Each of the input / output devices 3a and 3b diagnoses its own normality, and mutually exchanges failure information as a result of the self-diagnosis in step ST31. Next, in step ST32, it is determined whether or not the input / output device 3a is “normal” based on the failure information. If it is “normal”, the process proceeds to step ST33. In step ST33, the input / output device 3a sets the state of the bus interface to the bus enable state, and the input / output device 3b sets the state of the bus interface to the high impedance state. As a result, the input / output device 3a becomes a working system by transmitting a signal, and the input / output device 3b becomes a standby system by not transmitting a signal. On the other hand, in step ST32,
If it is determined that the input / output device 3a is not “normal”, the process proceeds to step ST34, and it is determined whether the input / output device 3b is “normal” based on the mutually exchanged failure information. As a result, if the input / output device 3b is “normal”, the process proceeds to step ST35, where the input / output device 3b sets the state of the bus interface to the bus-enabled state and becomes the active system, and the input / output device 3a sets the bus interface to the active state. The state is set to the high impedance state and the standby system is set.

In step ST36, the central controller 1 accesses the input / output devices 3a and 3b using the address "A" as an operation address. However, in the standby input / output device 3a (3b), the bus interface is in a high impedance state and no signal is transmitted. Therefore, if the input / output device 3a is “normal”, the central control device 1 inputs and outputs signals to and from the input / output device 2 along the path indicated by the arrow S1 in FIG. And if the input / output device 3b is “normal”,
A signal is input / output to / from the input / output device 2 along a path indicated by an arrow S2 in FIG. 11, the input / output device 2 is controlled, and a series of processing is completed. On the other hand, if it is determined in step ST34 that the input / output device 3b is not “normal”, the control of the input / output device 2 is disabled.

As described above, according to the fourth embodiment, when one of the input / output devices detects a fault, the bus interface of the input / output device is immediately fixed to a high impedance state, and the standby system is used based on the information. By changing the bus interface of the I / O device to the bus enable state, it is possible to switch between the active system and the standby system of the I / O device, and the central controller always controls the same I / O device when controlling the I / O device. Since it is sufficient to access the address A, the number of software steps is reduced and the load on the central control unit is reduced, and the input / output address of each input / output device is changed according to the switching between the active system and the standby system. This eliminates the need to perform the process, and has the effect of simplifying the processing.

In this case, the multiplex configuration is not limited to the configuration multiplexed by the two input / output devices, but may be configured by the multiplex configuration by three or more input / output devices. Has the effect of

[0041]

As described above, according to the first aspect of the present invention, each input / output device displays the self-diagnosis result as a flag, and the control device monitoring the self-diagnosis result causes a failure of the active input / output device. Is detected, the normal input / output device of the standby system is switched to the active system, the input / output address is designated, and the input / output device is controlled via the input / output address. There is an effect that an input / output device control method is provided in which a failed input / output device can be easily replaced with another standby input / output device without interrupting control of the input / output device.

According to the second aspect of the present invention, the self-diagnosis result of each input / output device is displayed as a flag using the register in each input / output device which can be referred to by the control device. It is possible to easily replace the function of a failed input / output device with another standby input / output device without separately adding hardware for displaying a self-diagnosis result of the device as a flag. effective.

According to the third aspect of the present invention, the flag of the self-diagnosis result is displayed using the memory area allocated to each input / output device of the shared storage device provided separately from each input / output device. With this configuration, the functions of the failed I / O device can be transferred to other standby I / O devices without changing the configuration of the registers inside the I / O device to display the self-diagnosis result as a flag. This has the effect that it can be easily replaced.

According to the fourth aspect of the invention, the input / output devices exchange self-diagnosis results with each other, and one of the normal input / output devices is connected to the working system accessible from the control device by the other input / output device. The device becomes a standby system inaccessible from the control device. If a failure occurs in the active I / O device, it becomes inaccessible from the control device, and one of the normal I / O devices becomes accessible from the control device. Therefore, when controlling the input / output device, the control device only needs to access the input / output device which is always in an accessible state at the same address. There is an effect that an input / output device control method capable of reducing the load on the control device by reducing the number can be obtained.

According to the fifth aspect of the present invention, the operation address accessible from the control device to the active input / output device is
A dummy address inaccessible from the controller is set in the standby I / O device. If a failure occurs in the active I / O device, the I / O address is changed to a dummy address. Since the input / output address is changed to the operation address, the control device always has to specify the same operation address to access the input / output device when controlling the input / output device. There is an effect that the load on the control device can be reduced.

According to the present invention, the bus interface of the active system input / output device is set to the bus enable state.
The bus interface of the standby I / O device is set to the high impedance state, and if a failure occurs in the active I / O device, the bus interface is changed to the high impedance state, and the bus interface of the I / O device that has become the active system is set. Is changed to the bus enable state, so that the control device always specifies the same address when controlling the input / output device, and if the bus interface accesses the input / output device in the bus enable state, Since the bus interface can send and receive signals to and from the input / output device via the normal input / output device in the bus enable state, the number of steps in the software is reduced, and the load on the control device can be reduced. In the output device, it is necessary to change the input / output address according to the switching between the active system and the standby system. Kuna' Te, the process is effective, such is simplified.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a system to which an input / output device control method according to a first embodiment of the present invention is applied, when all of the input / output devices are normal;

FIG. 2 is a block diagram showing a system to which the input / output device control method according to the first embodiment is applied when one of the input / output devices has failed;

FIG. 3 is a flowchart showing the operation of the first embodiment.

FIG. 4 is a block diagram showing a system to which an input / output device control method according to a second embodiment of the present invention is applied, when all of the input / output devices are normal;

FIG. 5 is a block diagram illustrating a system to which the input / output device control method according to the second embodiment is applied when one of the input / output devices fails;

FIG. 6 is a flowchart showing the operation of the second embodiment.

FIG. 7 is a block diagram showing a system to which an input / output device control method according to a third embodiment of the present invention is applied when all of the input / output devices are normal;

FIG. 8 is a block diagram showing a system to which the input / output device control method according to the third embodiment is applied when one of the input / output devices fails;

FIG. 9 is a flowchart showing an operation of the third embodiment.

FIG. 10 is a block diagram showing a system to which an input / output device control method according to a fourth embodiment of the present invention is applied when all of the input / output devices are normal.

FIG. 11 is a block diagram showing a system to which the input / output device control method according to the fourth embodiment is applied when one of the input / output devices fails;

FIG. 12 is a flowchart showing an operation of the fourth embodiment.

FIG. 13 is a block diagram illustrating an example of a system to which a conventional input / output device control method is applied.

FIG. 14 is a block diagram showing another example of a system to which a conventional input / output device control method is applied.

[Explanation of symbols]

1 Central control unit (control unit), 2 input / output devices, 3
a, 3b input / output devices, 4a, 4b input / output addresses,
5a, 5b register, 6 shared storage device, 6a, 6b
Memory area.

Claims (6)

[Claims] An input / output device is connected to a plurality of input / output devices, and a normal one of the input / output devices is used for an active system.
An input / output device that controls the input / output device via the current input / output device by designating the input / output address given to the current input / output device by the control device In the control method, each of the input / output devices diagnoses its own normality, and displays the diagnosis result as a flag, and the control device refers to the flag-displayed diagnosis result to determine whether the input / output device is normal. If the flag display indicating the diagnosis result of the active I / O device indicates a failure, the flag is displayed as one of the standby I / O devices in which the flag display indicates normal. An input / output device control method comprising: specifying a given input / output address, switching the input / output device to a working input / output device, and controlling the input / output device via the input / output device. 2. The input / output device control method according to claim 1, wherein each input / output device displays its diagnosis result in a flag in a register in the input / output device which can be referred to by the control device. 3. An input / output device stores its own diagnosis result in a memory area allocated to each input / output device of a shared storage device which can be referred to by a control device provided separately from each of the input / output devices. 2. The input / output device control method according to claim 1, wherein a flag is displayed. 4. An input / output device is connected to a plurality of input / output devices, and a normal one of the input / output devices is used for an active system.
In an input / output device control method in which a control device controls the input / output device via the working input / output device, the other input / output device diagnoses its own normality and performs mutual diagnosis. The result of the diagnosis is exchanged, and one of the normal input / output devices becomes the active system and becomes accessible from the control device, and the other input / output device becomes the standby system and is accessed by the control device. If the input / output device becomes inaccessible and a failure occurs in the active input / output device, the input / output device becomes inaccessible from the control device and one of the standby input / output devices becomes active. A control system that is accessible by the control device; and wherein the control device controls the input / output device via an accessible working input / output device. Method. 5. The working I / O device sets an operation address as an I / O address and becomes accessible to the control device, and the standby I / O device sets a dummy address as an I / O address. When the controller becomes inaccessible and a failure occurs in the working I / O device, the dummy address is set to the I / O address and the I / O address of the working I / O device is set. 5 is set to the operation address. 6. The active input / output device is set to a bus enabled state to be accessible from the control device, and the standby input / output device is set to a high impedance state for the bus interface to be inaccessible from the control device. State, and when a failure occurs in the working I / O device, the bus interface is set to a high impedance state, and the bus interface of the working I / O device is set to a bus enable state. The input / output device control method according to claim 4, wherein