JPS6224822B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to a failure detection device for an information processing device. In particular, the present invention relates to a failure detection device for a common line failure in a control device that uses a common bus for address, data, etc. between a central control unit such as a CPU.

[Description of prior art]

Conventionally, this type of failure detection device has detected by a parity check or the like, and when this method is used, it is possible to guard against common line failures due to short-term noise and the like. Furthermore, it is possible to detect permanent failures due to IC failures in input/output devices, etc.
In the case of such a failure, since the common line causes the failure, the central control unit cannot isolate the location of the failure, and the operation of the central control unit must be stopped. Furthermore, it takes a lot of time to isolate the location of the failure, and it is difficult to do so. In particular, as the number of input/output devices connected to a common line increases, the probability of such a failure occurring increases, and some countermeasures are required.

[Purpose of the invention]

The present invention provides a circuit that can detect a failure in the common line and disconnect the failed part from the common line of the central control unit, thereby disconnecting the part where a permanent failure has occurred from the central control unit. To provide a failure detection device that prevents the operation from being stopped, and that can significantly limit the range from the location of the failure detection circuit that performed the disconnection operation to the location where the failure occurred, and is useful for fault isolation. The purpose is to

[Key points of the invention]

The present invention detects that each common line is "1" or "0" for a preset detection time or more in a control circuit that performs control from a central control unit using common lines for addresses, data, etc. Sometimes it is determined that there is a failure, and at the same time, the common line from there (therefore, the part where the failure occurs)
Provide a circuit that separates the signal, insert this circuit in cascade at key points on the common line, set the detection time close to the central control unit to be long, and set the detection time of the detection circuits in areas far from the central control unit to be short. The system is characterized in that it separates parts of the system from the system depending on the location of the failure.

[Explanation based on examples]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a block diagram of an apparatus according to an embodiment of the present invention.

In the figure, failure detection circuits 21, 22, and 23 having the same configuration are connected to the central control unit 1 through a common line 4, respectively.
1, 42, 43 are connected in cascade, and each common line 42,
43 and 44 are connected to input/output devices 31, 32, and 33, respectively.

FIG. 2 shows the failure detection circuit 21 in FIG.
22 and 23, each failure detection circuit includes a disconnection switch 51, a detection time setting circuit 52, and an alarm circuit 5.
3 and a disconnection circuit 54.

Each failure detection circuit 21, 22, 23 detects that the signal on the common line 42, 43, 44 is continuously in the state of "0" or "1" for a predetermined detection time or more, and the detection time setting circuit 52 and When detected by the alarm circuit 53, it is determined that there is a failure in the common line, and the common line after the setting point is disconnected by the circuit 54 and the disconnect switch 51.
This is a circuit that is separated from the central control unit 1. The detection time of each failure detection circuit 21, 22, 23 can be set by a detection time setting circuit 52,
This detection time is set so that the closer it is set to the central control unit 1, the shorter it is, and the farther away it is set, the longer it becomes.

Next, the operation of this device will be explained.

Now, to explain the case where a common line failure occurs in the input/output device 33, in this case, the failure detection circuit 23 detects that the signal on the common line 44 has been abnormal for more than a predetermined detection time, and a failure occurs. The common line 44 to which the input/output device 33 is connected is disconnected from the central control unit 1.

In this case, the failure detection circuits 21 and 22 also detect that there is an abnormality on the common line, but since the detection time of each is set longer than that of the failure detection circuit 23, the failure detection circuit 23 operates first. The fault detection circuits 21 and 22 do not operate because the common line fault is recovered by isolating the faulty part. Therefore, the control device becomes equivalent to the state without the input/output device 33, and continues to operate on its reduced scale.

As described above, according to the present invention, the part that caused the common line failure is automatically disconnected, and the operation continues in the disconnected state, so that the status of each failure detection circuit can be observed from the central control unit. With this configuration, it is extremely easy to isolate a faulty part using the central control unit.

In this embodiment, the failure detection circuit and the input/output device are made independent, but by incorporating the failure detection circuit of the present invention into each input/output device, failure detection of each input/output device, It is also possible to configure it to perform cutting, and the applications of the present invention are extremely wide. Furthermore, in this embodiment, the configuration in which the failure detection circuits are connected in cascade in one row has been explained, but it is also possible to change the configuration by connecting them in parallel or in series depending on the importance of the input/output device, and to detect failures. The method of connecting the detection circuit is not limited to this embodiment.

[Explanation of effects]

As described above, the present invention can minimize the influence of common line failure, which is a concern in a configuration in which a large number of input/output devices are controlled from a central control unit using a common line.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention.
FIG. 2 is a block diagram showing a specific example of a failure detection circuit. 1... Central control unit, 21, 22, 23... Failure detection circuit, 31, 32, 33... Input/output device, 4
1, 42, 43, 44... Common line, 51... Disconnection switch, 52... Detection time setting circuit, 53...
...Alarm circuit, 54...Disconnection circuit.

Claims (1)

[Scope of Claims] 1. In a control device comprising a central control unit and a common line connected to the central control unit for transmitting and receiving signals, failure detection means is provided at one or more locations on the common line. However, this failure detection means includes means for detecting that the signal transmitted on the common line of the installation location is abnormal after exceeding a predetermined detection time, and a means for receiving a detection signal from this means for detecting. and a means for separating the common line from the central control section after the installation point, and the predetermined detection time of each of the above failure detection means is longer when the failure detection means is installed closer to the central control section, and when the failure detection means is installed further away from the central control section, A fault detection device characterized in that the fault detection device is set such that the shorter it is, the shorter it is.