JPH0498501A - Controller - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a control device that controls equipment using a computer and a sequencer, and particularly to monitoring abnormal operations thereof.

(Prior Art) FIG. 4 shows a configuration for monitoring abnormal operations in a conventional control device as described above. In Figure 4, 21
is a computer, and 22 is a computer status output circuit that monitors the operating state of this computer 21 and outputs a signal during execution. 23 is a sequencer, and 24 is a computer abnormality detection circuit that monitors the signal from the computer status output circuit and detects that the execution of the computer has stopped for some reason when the signal input stops; when the signal input stops, an abnormality is detected. The signal is output to the output cutoff circuit 25. When the output cutoff circuit 25 receives an abnormal signal, it cuts off all outputs from the control device.

(Problem to be Solved by the Invention) However, in the above configuration, monitoring of the operating status of the computer detects whether the computer is running or stopped, and if the computer is stopped, the computer is considered to be abnormal. If the computer was operating abnormally in an infinite loop, no abnormality could be detected in the computer. In addition, there is no circuit to monitor the operating status of the sequencer, so abnormalities in the sequencer cannot be detected, and when an abnormality occurs in the sequencer, an abnormality signal cannot be output to the output cutoff circuit, so it is not possible to shut off all output from the control device. There wasn't.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a control device in which a computer and a sequencer mutually monitor operating states.

(Means for Solving the Problems) A control device of the present invention includes a sequencer abnormality detection circuit that detects an abnormality in a sequencer from a sequencer status signal output from the sequencer, and a computer status signal that detects an abnormality in the sequencer when there is no abnormality in the sequencer. The sequencer is equipped with a computer status output circuit that outputs a sequencer status signal, and a computer error detection circuit that detects an abnormality in the computer from the computer status signal output from the computer, and a sequencer status output circuit that outputs a sequencer status signal when there is no abnormality in the computer. An output circuit is provided, and an output cutoff circuit is provided which operates to cut off all outputs when an abnormality is detected by the sequencer abnormality detection circuit and the computer abnormality detection circuit.

The above-mentioned sequencer abnormality detection circuit and computer abnormality detection circuit monitor whether the status signal input from the other side changes within a certain period of time after the corresponding status output circuit changes and outputs the status signal. , it can be configured to detect as an abnormality when there is no change.

(Function) According to the present invention, the computer and the sequencer each have an abnormality detection circuit that detects an abnormality on the other side, and if an abnormality signal is received from either of the abnormality detection circuits, all outputs can be cut off. Since an output cutoff circuit is provided, all outputs can be cut off in the event of abnormal operation in either the computer or the sequencer, thereby preventing damage to equipment during abnormal operation.

In addition, if the computer and sequencer use a circuit that detects an abnormality on the other side as an abnormality detection circuit that detects an abnormality if there is no response signal from the other side in response to an output signal to the other side after a certain period of time has elapsed, Since the response signal to the signal from the other party only needs to be output within a certain period of time, the processing can be performed during free time, and the processing load on both the computer and the sequencer does not increase.

(Example) Hereinafter, a control device in an example of the present invention will be described with reference to the drawings.

FIG. 1 shows the configuration of the control device. In FIG. 1, ■ is a computer, and 2 is a sequencer.

The computer 1 includes a sequencer status input circuit 3 that inputs a sequencer status signal output from the sequencer 2, a sequencer abnormality detection circuit 4 that detects an abnormality in the sequencer 2 from the sequencer status signal, and a computer status input circuit that outputs a computer status signal. An output circuit 5 is provided. The sequencer abnormality detection circuit 4 outputs an abnormality signal to the output cutoff circuit 6 when detecting an abnormality in the sequencer. The sequencer 2 includes a computer status input circuit 7 that inputs a computer status signal output from the computer 1, a computer abnormality detection circuit 8 that detects an abnormality in the computer 1 from the computer status signal, and a sequencer status output that outputs a sequencer status signal. A circuit 9 is provided. When the computer abnormality detection circuit 8 detects an abnormality in the computer 1, it outputs an abnormality signal to the output cutoff circuit 6. The output cutoff circuit 6 cuts off all outputs from the control device when an abnormal signal is input.

With the above configuration, mutual monitoring between the computer and the sequencer can be realized, and if abnormal operation occurs in either one, all outputs from the control device can be cut off, and damage to equipment and machinery due to abnormal operation can be prevented. .

Furthermore, the sequencer abnormality detection circuit 4 of the computer 1 in this embodiment is composed of a sequencer input monitoring circuit 11 and a sequencer monitoring timer 12, and the computer abnormality detection circuit 8 of the sequencer 2 is composed of a computer input monitoring circuit 13 and a computer monitoring circuit 12. It is composed of a timer 14. The computer status signal is output from the computer status output circuit 5 according to instructions from the sequencer input monitoring circuit 11, and is passed through the computer status input circuit 7 to the computer input monitoring circuit 13.
is input. Further, the sequencer status signal is outputted from the sequencer status output circuit 9 according to an instruction from the computer input monitoring circuit 13, and is inputted to the sequencer input monitoring circuit 11 through the sequencer status input circuit 3.

The operation of the sequencer input monitoring circuit 1 of the computer I will be explained with reference to FIGS. is set, and it is monitored whether the sequencer status signal changes from off to on within a certain period of time until the sequencer monitoring timer 12 completes. If it does not change from OFF to ON within a certain period of time, it is determined that the sequencer is abnormal.

If the sequencer status signal changes from off to on before the sequencer monitoring timer 12 completes, the second
As shown in the figure, the sequencer monitoring timer 12 is reset, and then the computer status signal is changed from on to off within a predetermined period of time, and the sequencer monitoring timer 12 is set again, until the sequencer monitoring timer 12 completes. Monitor whether the sequencer status signal changes from on to off within a certain period of time.

As shown in FIG. 2, if it does not change from on to off within a certain period of time, it is determined that the sequencer is abnormal. If it changes from on to off, the computer status signal is turned from off to on within a predetermined time, and the sequencer monitoring timer 12 is set, and the same operation is repeated thereafter.

Next, the operation of the computer input monitoring circuit 13 of the sequencer 2 will be explained with reference to FIGS. 1 and 3. When the computer status signal input from the computer status input circuit 7 changes from OFF to ON,
The computer monitoring timer 14 is reset, and then the sequencer status signal is changed from OFF to ON within a predetermined period of time, and the computer monitoring timer 14 is set, and the computer status signal is changed within a certain period of time until the computer monitoring timer 14 is completed. Watch to see if it changes from on to off.

If it does not change from on to off within a certain period of time, it is determined that the computer is abnormal.

If the computer status signal changes from on to off before the computer monitoring timer 14 completes,
As shown in FIG. 3, the computer monitoring timer 14 is reset, and then the sequencer status signal is changed from on to off within a predetermined time, and the computer monitoring timer 14 is set again, and the computer monitoring timer 14 is completed. Monitor whether the computer status signal changes from off to on within a certain period of time. As shown in FIG. 3, if it does not change from OFF to ON within a certain period of time, it is determined that the computer is abnormal. If it changes from off to on, the sequencer status signal is turned from off to on within a predetermined time, the computer monitoring timer 14 is set, and the same operation is repeated.

In this way, if the sequencer input monitoring circuit 11 does not change the computer status signal within a certain period of time after detecting a change in the sequencer status signal, the computer abnormality detection circuit 8 will determine that the computer is abnormal. Since a length of 1 to 2 seconds can be used for the computer monitoring timer 14, the processing of the sequencer input monitoring circuit 11 can be executed during the idle time of the processing operation of the computer 1.

Similarly, if the computer input monitoring circuit 13 does not change the sequencer status signal within a certain period of time after detecting a change in the computer status signal, the sequencer abnormality detection circuit 4 determines that the sequencer is abnormal.
Since the sequencer monitoring timer 12 can have a length of 1 to 2 seconds, the processing of the computer input monitoring circuit 13 can be executed during the idle time of the processing operation of the sequencer 2.

(Effects of the Invention) As described above, according to the control device of the present invention, the computer and the sequencer each have an abnormality detection circuit that detects an abnormality on the other side, and an abnormality detection circuit that receives or receives an abnormality signal from either one of the abnormality detection circuits. Since we have installed an output cutoff circuit that can cut off all outputs in case of abnormal operation, all outputs can be cut off if either the computer or the sequencer malfunctions, which has the effect of preventing equipment damage in the event of abnormal operation. do.

In addition, if the computer and sequencer use a circuit that detects an abnormality on the other side as an abnormality detection circuit that detects an abnormality if there is no response signal from the other side in response to an output signal to the other side after a certain period of time has elapsed, Since it is sufficient to output a response signal to a signal from the other party within a certain period of time, the processing can be performed during free time, and the processing load on both the computer and the sequencer does not increase.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a control device in an embodiment of the present invention, FIG. 2 is an operational timing diagram of the sequencer input monitoring circuit, FIG. 3 is an operational timing diagram of the computer input monitoring circuit, and FIG. 4 is an operational timing diagram of the computer input monitoring circuit. FIG. 2 is a block diagram of a conventional example. Computer sequencer Sequencer status input circuit Sequencer abnormality detection circuit - Computer status output circuit Output cutoff circuit - Computer status input circuit Computer abnormality detection circuit Sequencer status output circuit Sequencer input monitoring circuit - Sequencer monitoring timer Computer input monitoring circuit Computer monitoring timer. FIG. 1・-1- 9-・ 11-・

Claims (2)

[Claims] (1) In a control device that uses a computer and a sequencer to control equipment, the computer includes a sequencer abnormality detection circuit that detects an abnormality in the sequencer from the sequencer status signal output from the sequencer, and a sequencer abnormality detection circuit that detects an abnormality in the sequencer from the sequencer status signal output from the sequencer. A computer status output circuit that outputs a status signal is provided, and the sequencer is provided with a computer abnormality detection circuit that detects an abnormality in the computer from the computer status signal output from the computer, and a sequencer status signal that outputs a sequencer status signal when there is no abnormality in the computer. A control device comprising a sequencer status output circuit and an output cutoff circuit that operates to cut off all outputs when an abnormality is detected by a sequencer abnormality detection circuit and a computer abnormality detection circuit. (2) After the status output circuit corresponding to the sequencer abnormality detection circuit and the computer abnormality detection circuit changes and outputs the status signal, check whether the status signal input from the other side changes within a certain period of time. 2. The control device according to claim 1, wherein the control device is configured to monitor and detect an abnormality if there is no change.