JPH0683408A - Fault diagnostic device - Google Patents

Abstract

PURPOSE:To provide the fault diagnostic device which securely diagnose a fault even if the input signal from a programmable logic controller contains chattering and bouncing. CONSTITUTION:A diagnostic program stored in a ROM 24 does not take a countermeasure against the chattering of the input signal from the programmable logic controller except in a transition monitor time zone registered in a RAM 25, and registers the transition of the input signal in the transition monitor time zone if the input signal has the transition and monitors the chattering of the input signal thereafter on the basis of a chattering monitor time set in the random access memory 25.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a failure diagnostic device for detecting an abnormal operation of a system controlled by a programmable logic controller by monitoring an input signal from the programmable logic controller (PLC), and more particularly to a programmable logic controller. The present invention relates to a failure diagnosis device effective when an input signal from the device includes chattering and bouncing.

[0002]

2. Description of the Related Art Conventionally, in a system controlled by a programmable logic controller, an abnormality detecting device for a programmable logic controller has been proposed as a device for detecting an abnormal operation of the system at an early stage. This programmable logic controller abnormality detection device stores or sets the normal input signal from the programmable logic controller, monitors the actual input signal from the programmable logic controller, and records or sets the normal input signal. It is configured to detect an abnormality in the operation of the system by comparing the input signal and the actually monitored input signal.

[0003]

By the way, in the abnormality detecting device of the programmable logic controller, if chattering or bouncing occurs in the input signal to be monitored, the input signal in the normal state which is recorded or set in advance in the collation is actually There is a problem that the input signal monitored in step 2 does not match, and this is detected as an abnormal operation of the system.

Therefore, the chattering or bouncing is absorbed from the monitored input signal, and the abnormal operation of the system is detected by comparing the input signal absorbing the chattering or bouncing with the prerecorded or set normal input signal. Although a method of absorbing chattering and bouncing from the monitored input signal may be absorbed, abnormal signals other than chattering and bouncing may also be absorbed from the monitored input signal. There was another inconvenience that this abnormal signal could not be detected. Further, according to this method, an abnormal signal may be detected as a transition of the input signal, and in this case, there is a disadvantage that the next transition of the input signal cannot be immediately determined.

Therefore, it is an object of the present invention to provide a failure diagnosis device which can reliably perform failure diagnosis even if chattering or bouncing is included in an input signal from a programmable logic controller.

Chattering and bouncing generally refer to a phenomenon in which a contact repeatedly opens and closes unnecessarily when the contact is closed or opened. The cause is mainly caused by a vibration of a local contact portion. The phenomenon in which the contact repeats opening and closing in a relatively short cycle is called chattering, and the phenomenon in which the contact repeats opening and closing in a relatively long cycle due to general vibration of the moving part is called bouncing. Unless otherwise understood, the term chattering is used to include bouncing.

[0007]

In order to achieve the above object, the present invention provides a fault diagnosis for detecting an abnormal operation of a system controlled by a programmable logic controller by monitoring an input signal from the programmable logic controller. In the apparatus, chattering monitoring condition setting means for setting chattering monitoring time corresponding to the input signal, transition monitoring condition setting means for setting presence or absence of chattering and transition monitoring time zone corresponding to the input signal, and the transition If there is a transition in the input signal in the transition monitoring time zone set by the monitoring condition setting means, this is registered, and if chattering is set by the transition monitoring condition setting means, then the chattering monitoring condition setting is performed. Based on the chattering monitoring time set by An input signal monitoring means for monitoring the chattering can the input signal, characterized by comprising a.

[0008]

In the failure diagnosing device of the present invention, the chattering countermeasure is not taken except in the transition monitoring time zone set by the transition monitoring condition setting means, and if there is a transition in the input signal in the transition monitoring time zone. If chattering is set by the transition monitoring condition setting means, then the chattering of the input signal is monitored based on the chattering monitoring time set by the chattering monitoring condition setting means.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the fault diagnosis apparatus of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the failure diagnosis apparatus of the present invention. The failure diagnosis apparatus shown in FIG. 1 is constructed as an apparatus independent of a programmable logic controller (not shown). That is,
As shown in FIG. 1, the failure diagnosis device 20 of this embodiment is
The whole is connected to a programmable logic controller side system bus (PLC side system bus) 10 which is connected to a programmable logic controller (not shown). Further, a console 30 is connected to the failure diagnosis device 20 to display the inside of abnormality detection by the failure diagnosis device and to perform various operation inputs.

The fault diagnosis device 20 is a programmable logic controller data interface (PLC data i / f) for connecting to the PLC side system bus 10.
21, a central processing unit (CPU) 22 that controls the entire operation of the failure diagnosis device 20, and a timer 2 used for chattering monitoring and transition monitoring described in detail later.
3, a read-only memory (ROM) 24 that stores a failure diagnosis program, a random access memory (RAM) 25 that stores determination reference data for failure diagnosis, a random access memory that constitutes a work area for failure diagnosis processing ( A RAM) 26 and an operation unit interface (operation unit i / f) 27 for connecting the console 30 are provided.

The fault diagnosing device 20 of this embodiment inputs operation monitor data, that is, an input signal from the PLC side system bus 10 via a programmable logic controller data interface (PLC data i / f) 21, and also Programmable logic controller data interface (PLC data i / f) 21
The abnormality detection content is notified to the PLC side system bus 10 via the.

By the way, the failure diagnosis device 20 of this embodiment.
In the random access memory 25, operation monitoring data from the PLC side system bus 10, that is, chattering monitoring condition information for monitoring chattering of an input signal and transition monitoring condition information for monitoring transition of this input signal are stored. It is set, and the input signal from the PLC side system bus 10 is monitored and abnormality is detected based on the chattering monitoring condition information and the transition monitoring condition information.

FIG. 2 shows an example of chattering monitoring condition information stored in the random access memory 25. In FIG. 2, the chattering monitoring condition information is stored in correspondence with an input signal in which chattering may occur. Chattering monitoring information F1 for distinguishing whether chattering is being monitored or not, chattering occurrence information, respectively. Initial transition level information F2 indicating the level of the input signal when the transition first occurs from the previous state, current level information F3 indicating the current level of the input signal, signal number information indicating the signal number of the input signal (signal No. .), It includes chattering monitoring time information for recognizing that chattering has subsided if the time is at a certain level. Here, as will be apparent from the following description, the information F1 to F3 is information that changes when an abnormality is detected, and the signal number information and the chattering monitoring time information are information that is set in advance before performing the abnormality detection. .

FIG. 3 shows an example of transition monitoring condition information stored in the random access memory 25.
In FIG. 3, the transition monitoring condition information is stored corresponding to each transition of the input signal, and chattering presence / absence information D for distinguishing whether each transition causes chattering or not.
1. Transition direction information D2 that distinguishes the transition direction (rising or falling), signal number information (signal No.) indicating the signal number of the input signal at which the transition occurs, and monitoring for checking this transition is started. It includes monitoring start time information indicating time, and transition monitoring time information indicating a time range in which this transition can occur. Here, the information D1 and D2, the signal number information, the monitoring start time information, and the transition monitoring time information are information set in advance before the abnormality detection.

FIG. 4 is a flow chart showing the flow of the abnormality detection processing of this embodiment. The operation of this embodiment will be described below with reference to the flow chart shown in FIG.
First, it is determined whether or not there is a transition occurrence section (step 101). This determination is made based on the monitoring start time information of the transition monitoring condition information shown in FIG. That is, when the monitoring start time set corresponding to the signal number information of the signal for which abnormality is monitored is reached, it is determined to be a section where transition occurs. Here, if it is determined that the section does not have transition occurrence,
Chattering occurrence check processing is performed (step 11).
2). Details of this chattering occurrence check processing are shown in FIG.
Is shown in the flow chart of. The chattering occurrence check process will be described in detail later.

Next, it is judged whether or not there is a transition (step 113), and if it is judged that there is a transition, the process proceeds to step 114, a predetermined abnormality is registered (step 114), and the process returns to step 101. .

If it is determined in step 113 that there is no transition, the process directly returns to step 101.

When it is in the transition occurrence section in step 101, next, the transition monitoring time indicated by the transition monitoring time information is set in the transition monitoring timer, and the transition monitoring timer is started (step 102). Here, this transition monitoring timer is the timer 23 shown in FIG.
include.

Next, chattering occurrence check processing is performed (step 103). Details of this chattering occurrence check processing are shown in the flowchart of FIG. The chattering occurrence check process will be described in detail later.

Then, it is checked whether or not the input signal has a transition (step 104). If there is no transition here, step 1
It is checked whether or not the transition monitoring timer started in 02 has timed out (step 110). If not, the process returns to step 103. But step 11
If it is determined that the transition monitoring timer has timed out at 0, it is determined that an abnormality has occurred in which transition does not occur within the predetermined transition monitoring time, the process proceeds to step 114, the predetermined abnormality is registered, and the process returns to step 101.

If it is determined in step 104 that there is a transition, it is checked whether this transition is a normal transition (step 105). If it is a normal transition, this transition is registered (step 106), and in step 102. The started transition monitoring timer is reset (step 107).
It should be noted that the determination in step 105 as to whether there is a normal transition is made by
The transition direction information D2 of the transition monitoring condition information shown in FIG. Further, if it is determined in step 105 that the transition is not normal, the abnormality is registered to that effect (step 11
1) and returns to step 103.

When the transition monitoring timer is reset in step 107, it is next determined whether or not chattering is set (step 108). This determination is made based on the chattering presence / absence information D1 of the transition monitoring condition information shown in FIG.

If it is determined in step 108 that chattering is set, chattering registration is performed (step 1
09). For this chattering registration, the chattering monitoring information F1 of the chattering monitoring condition information shown in FIG. 2, that is, the chattering monitoring flag is turned on, the first transition level is registered in the first transition level information F2, and the current level information F3 is registered. Is registered, the chattering monitoring timer is set with the chattering monitoring time shown in the chattering monitoring time information of the chattering monitoring condition information shown in FIG. 2, and the chattering monitoring timer is started. Here, this chattering monitoring timer is included in the timer 23 shown in FIG.

When the chattering registration in step 109 is completed in this way, the process returns to step 101.

Next, the chattering occurrence check processing will be described in detail with reference to the flow chart shown in FIG. When the chattering occurrence check process is started, it is first checked whether or not there is a chattering monitoring signal (step 201). The presence of the chattering monitoring signal is determined by the chattering monitoring information F1 of the chattering monitoring condition information shown in FIG. 2, that is, whether the chattering monitoring flag is on. If it is determined that there is no chattering monitoring signal, the chattering occurrence check process is terminated without performing any process.

If it is determined in step 201 that there is a chattering monitoring signal, it is then checked whether the chattering monitoring timer has timed out (step 202).
If the time is not up, then it is checked whether or not there is a contact transition during chattering (step 203). Here, if there is no contact transition, this chattering occurrence check processing is ended as it is.

However, if it is determined in step 203 that there is a contact transition during chattering, the chattering monitoring timer is set to the chattering monitoring time shown in the chattering monitoring time information of the chattering monitoring condition information shown in FIG. This chattering monitoring timer is started (step 204), the current level information F3 of the chattering monitoring condition information shown in FIG. 2 is inverted, and this chattering occurrence check processing is ended.

When it is determined in step 202 that the chattering monitoring timer has timed out, the chattering monitoring information F1 of the chattering monitoring condition information shown in FIG. 2, that is, the chattering monitoring flag is turned off (step 206). Then, it is determined whether the current level registered in the current level information F3 of the chattering monitoring condition information shown in FIG. 2 is the same as the initial transition level registered in the initial transition level information F2 (step 20).
7) If they are different, it is determined that there is a transition, transition registration is performed, and chattering registration is performed again (step 209). For this chattering registration, the chattering monitoring information F1 of the chattering monitoring condition information shown in FIG. 2, that is, the chattering monitoring flag is turned on, and the initial transition level information F2 is set.
The initial transition level is registered in, the current level is registered in the current level information F3, the chattering monitoring time shown in the chattering monitoring time information of the chattering monitoring condition information shown in FIG. 2 is set in the chattering monitoring timer, and this chattering monitoring is set. This is done by starting a timer.

If it is determined in step 207 that the level is the same as the initial transition level, the chattering occurrence check process is terminated.

As described above, in this embodiment, when a transition occurs, it is recognized as a transition even if it is chattering. However, for a signal with chattering setting, the next transition can be accepted only after the state of the same level has passed a preset time.

As for chattering occurrence in a portion where there is no possibility of transition, a measure against chattering is not taken, and diagnosis is performed with the waveform as it is. As a result, the response time of the next normal transition can be shortened as compared with the case of taking measures against chattering. Next, a specific diagnosis process according to this embodiment will be described with reference to FIGS. 6 to 8.

FIG. 6 shows a case where chattering occurs in a range where there is a possibility of transition. In FIG. 7, (a) shows a normal input signal and (b) shows a monitored actual input signal. In this case, if no countermeasure against chattering is taken, this input signal is recognized as shown in (c), and is abnormally processed at a plurality of points.

However, in this embodiment, since chattering countermeasures are taken in the range where there is a possibility of transition, the monitored input signal is recognized as the waveform shown in (d), and abnormal processing does not occur.

FIG. 7 shows a case where chattering occurs in a range where there is no possibility of transition. In FIG. 6, (a) shows the monitored actual input signal. In this case, if a countermeasure against chattering is taken within a range in which there is no possibility of transition of chattering, the input signal will be recognized as shown in (b). However, since this input signal also includes a transition in the normal range, the transition in this normal range is ignored.

However, in this embodiment, since chattering measures are not taken within the range where there is no possibility of transition,
The input signal is recognized as the waveform shown in (c), and in this case, the normal transition is not overlooked.

FIG. 8 shows an example of processing when chattering occurs when the input signal includes a range in which chattering has a possibility of transition and a range in which chattering does not have a possibility of transition. The processing in this case is divided into A section, B section, C point, D section, E point, F section, G point, and H section, and will be described with reference to the flowcharts shown in FIGS. 4 and 5.

1) Section A Since there is no possibility of occurrence of transition in this section, the process branches to Step 112 in Step 101 shown in FIG. 4 to perform chattering occurrence check processing. here,
Since there is no chattering monitoring signal, the process branches to the end in step 201 shown in FIG. 5, and the chattering occurrence check process ends without performing any process. Since there is no transition in this section, step 113 in FIG.
Then, the procedure returns to step 101, and continues to wait until the transition occurs.

2) Section B In this section, since the section has entered the section with transition occurrence,
In step 101 of FIG. 4, the process proceeds to step 102, the transition monitoring timer is started, and the chattering occurrence check process of step 103 is performed. However, since there is no chattering monitoring signal in this state, the process branches to the end in step 201 shown in FIG. 5, and the chattering occurrence check process ends without performing any process. And
Since there is no transition and the transition monitoring timer has not timed up, the process returns to step 103 and the above process is repeated.

3) Point C Normal transition occurs at point C. Therefore, it is determined that there is a transition in step 104 of FIG.
In 05, it is determined that there is a normal transition, and in step 106, transition registration is performed. In addition, since this transition eliminates the normal transition in this transition occurrence section, step 108
Reset the transition monitoring timer with. As a result, the subsequent section becomes a section in which no transition occurs. Also, step 108
Then, it is checked whether or not there is chattering setting in this transition. In this case, since chattering setting is present, in step 109, chattering registration for chattering monitoring is performed. As a result, the chattering monitoring time is set in the chattering monitoring timer, and the chattering monitoring timer is started. Then, the process returns to step 101 and waits for the next transition occurrence section.

4) Section D Since there is no transition occurrence section in section D, the process branches to step 112 in step 101 of FIG. 4 and chattering occurrence check processing is performed. Since there is a chattering monitoring signal here, in step 201 of FIG. 5, the process proceeds to step 202 to check whether the chattering monitoring timer has timed out. In this case, the chattering monitoring timer has not expired, so step 20
In step 4, it is checked whether or not the signal has a transition. Since there is no transition, the chattering occurrence check processing is ended, the process returns from step 113 to step 101 in FIG. 4 and waits for the next transition occurrence section.

5) Point E Since a transition occurs at point E, step 203
To step 204, the chattering monitoring timer was reset, and the signal level was inverted, so step 2
At 05, the current level of the chattering monitoring condition information of FIG. 2 is inverted. Then, from step 113 to step 1 in FIG.
Return to 01.

6) Section F Since this section F is a section in which no transition occurs like the section D, the same processing as the section D is performed. That is, in step 101 of FIG. 4, the process branches to step 112 to perform chattering occurrence check processing. Since there is a chattering monitoring signal here, step 201 in FIG.
It shifts to 2 and checks whether the chattering monitoring timer is up. In this case, since the chattering monitoring timer has not timed up, it is checked in step 204 whether there is a transition in the signal. Since there is no transition, this chattering occurrence check processing is terminated and step 11 in FIG.
The procedure returns from step 3 to step 101 and waits for the next transition occurrence section.

7) Point G When the point G is reached, the chattering monitoring timer times out, so the process branches to step 206 in step 202 of FIG. 5, the chattering monitoring flag is turned off in step 206, and the initial level is set in step 207. Check if the same. Since it is the same as the initial level here, the chattering occurrence check process is terminated, the process returns from step 113 to step 101 in FIG. 4, and waits for the next transition occurrence section.

8) Section H Since there is no possibility of transition occurring in this section, A
The same process as the section is performed. That is, in step 101 shown in FIG. 4, the process branches to step 112 to perform chattering occurrence check processing. Here, since there is no chattering monitoring signal, the process branches to the end in step 201 shown in FIG. 5, and the chattering occurrence check process ends without performing any process. Further, since there is no transition in this section, steps 113 to 1 in FIG.
Return to 01 and continue to wait until the next transition occurrence section.

In FIG. 8, (b) shows a chattering monitoring signal, (c) shows a transition recognition state, and (e) shows a change state of a section in which a transition may occur. By the way, in the above-described embodiment, the case where the failure diagnosis apparatus 20 is configured as an apparatus independent of the programmable logic controller is shown, but this failure diagnosis processing apparatus can be realized as a main function of the programmable logic controller. .

FIG. 9 shows another embodiment of the present invention in which the failure diagnosis processing device is realized as the main function of the programmable logic controller. The failure diagnosis processing device 50 of this embodiment is a programmable logic controller input / output data bus (PLCi / o data bus) 4
Connected to 0. Further, a console 60 is connected to the failure diagnosis device 50 for displaying the internal information of abnormality detection by the failure diagnosis device and for performing various operation inputs.

This failure diagnosis device 50 is an input / output unit interface (i / o unit i / f) 51 for connecting to the programmable logic controller input / output data bus 40, and a central control unit for controlling the overall operation of this failure diagnosis device. An arithmetic processing unit (CPU) 52, a timer 53 used for chattering monitoring and transition monitoring, a read only memory (RO) storing a ladder control system program, a failure diagnosis system program, and the like.
M) 54, random access memory (RAM) in which user programs, abnormality detection determination reference data, etc. are stored
55, a random access memory (RAM) 56 that constitutes a work area for failure diagnosis processing, and an operation unit interface (operation unit i / f) 5 for connecting the console 60.
It is configured by including 7. The operation of the failure diagnosis device 50 shown in FIG. 9 is basically the same as the operation of the failure diagnosis device 20 shown in FIG. 1, and the description of the operation is omitted.

[0049]

As described above, according to the present invention, the countermeasure against chattering is made only in the portion where there is a possibility of transition, so that the input signal from the programmable logic controller includes chattering and bouncing. Therefore, it is possible to provide a failure diagnosis device capable of surely performing failure diagnosis.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a failure diagnosis device of the present invention.

2 is a diagram showing an example of chattering monitoring condition information stored in a random access memory of the embodiment shown in FIG.

3 is a diagram showing an example of transition monitoring condition information stored in a random access memory of the embodiment shown in FIG.

FIG. 4 is a flowchart showing a flow of abnormality detection processing of the embodiment shown in FIG.

5 is a flowchart showing details of chattering occurrence check processing of the flowchart shown in FIG.

FIG. 6 is a signal waveform diagram illustrating processing when chattering occurs in a range where there is a possibility of transition in the embodiment shown in FIG.

FIG. 7 is a signal waveform diagram for explaining processing when chattering occurs in a range where there is no possibility of transition in the embodiment shown in FIG.

FIG. 8 is a diagram showing an example of processing when chattering occurs when the input signal includes a range in which chattering has a possibility of transition and a range in which chattering has no possibility of transition in the embodiment shown in FIG. 1;

FIG. 9 is a block diagram showing another embodiment of the present invention in which the failure diagnosis processing device is realized as a main function of a programmable logic controller.

[Explanation of symbols]

10 Programmable logic controller side system bus (PLC side system bus) 20 Fault diagnostic device 21 Programmable logic controller data interface (PLC data i / f) 22 Central processing unit (CPU) 23 Timer 24 Read only memory (ROM) 25 Random access Memory (RAM) 26 Random access memory (RAM) 27 Operating unit interface (operating unit i / f) 30 Console 40 Programmable logic controller input / output data bus (PLC i / o data bus) 50 Fault diagnosis processing device 51 Input / output unit interface ( i / o unit i / f) 52 central processing unit (CPU) 53 timer 54 read only memory (ROM) 55 random access memory (RAM) 56 random access memory (RAM) 57 operation unit interface (operation unit i / f) 60 console

Claims (1)

[Claims] 1. A failure diagnosis device for detecting an operation abnormality of a system controlled by the programmable logic controller by monitoring an input signal from the programmable logic controller, wherein a chattering monitoring time is set corresponding to the input signal. Chattering monitoring condition setting means, transition monitoring condition setting means for setting chattering presence or absence and transition monitoring time zone corresponding to the input signal, and the input signal in the transition monitoring time zone set by the transition monitoring condition setting means If the transition monitoring condition setting means sets chattering, the chattering of the input signal is performed based on the chattering monitoring time set by the chattering monitoring condition setting means. Input signal monitoring A failure diagnosis device comprising: