JP3211099B2 - Data sequence period determination device and failure diagnosis method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data sequence period determining apparatus for automatically finding a repetition period of data contained in a given data sequence and specifying a data sequence constituting the period.

[0002] The present invention also relates to a method and apparatus for diagnosing a failure of a system (including equipment) controlled by a control device such as a programmable logic controller (PLC). The above-described method and apparatus for determining the cycle of the data sequence are suitably used to grasp the type of operation of the controlled system, and provide basic data for convenience in creating data that serves as a reference for failure diagnosis. .

[0003]

BACKGROUND OF THE INVENTION Data having a periodically given periodic characteristic, for example, data received in data communication, data to be processed in speech analysis waveform analysis, a controlled system or a controlled system for failure diagnosis of the controlled system. When data obtained from the control device is received, it is necessary to specify a periodic pattern included in the data.

As a method of specifying a periodic pattern included in a data string having a periodic property, there are the following methods. 1. A synchronization signal is added in advance to the data sequence for each cycle, and the synchronization signal is used. 2. If no synchronization signal is added, the period is identified using a computer by some means, or A human observes the data sequence to find the cycle (used when creating reference data for failure diagnosis, for example).

[0005] 1. In the method (1), the data becomes redundant and the data length becomes longer by adding a synchronization signal.
Also, when no synchronization signal is added, it cannot be used.

[0006] 2. This method can be realized by a method using a correlation coefficient at present, but the amount of calculation becomes enormous and the calculation takes time. Further, it is difficult to apply the present invention to a branching data string structure.

[0007] 3. This method requires a considerable amount of time and effort to be performed by humans.

[0008]

SUMMARY OF THE INVENTION The present invention provides a method and an apparatus which can specify the period of a given data sequence using a computer, even if it has a relatively simple structure having branches. is there.

Another object of the present invention is to provide a failure diagnosis method and apparatus suitable for failure diagnosis of a controlled system in which a state transition pattern of a structure having a branch appears.

A data string period determining apparatus according to the present invention includes means for extracting all types of data transition patterns consisting of continuous data of a predetermined length from a given data string, and among the extracted data transition patterns, Is placed at the beginning, and another data transition pattern having the same data sequence as the rear part of the preceding data transition pattern at the front is made to follow the preceding data transition pattern, and Means for creating a chain of data transition patterns by using different data transition patterns, and changing the chain of data transition patterns arranged at the head, causing the chain creation means to repeat the creation of the chain of data transition patterns, Means for checking whether there is a chain that returns to the data transition pattern again, and the first data transition pattern When came back over down, by utilizing the fact that corresponding to one period of the data string given a chain created, and a means for determining the period.

[0011]

In the above, even if all the extracted data transition patterns are arranged at the head of the chain, if they do not return to the first data transition pattern in the created chain, they are extracted from a given data string. It is preferable to change the data length of the data transition pattern.

[0013]

[0014]

[0015]

According to the present invention , there is provided an apparatus for determining a cycle of a data sequence, comprising: means for extracting, from a given data sequence, all types of data transition patterns consisting of continuous data of a predetermined length; Means for storing in association with all types of unit data constituting the data string, a data transition pattern relating to and including any unit data at the beginning, and common with the rear part of the preceding data transition pattern Means for forming a chain of data transition patterns by causing another data transition pattern having a sequence of data at the front to follow the preceding data transition pattern, and by changing the data transition pattern placed at the head, Repeat the formation of a chain of transition patterns,
A first checking means for checking whether or not the unit data associated with the first data transition pattern appears again in the subsequent data transition pattern; the unit data associated with the first data transition pattern reappears in the subsequent data transition pattern Means for judging the unit data to be related to the cycle of the data sequence, placing a data transition pattern related to the unit data determined to be related to the cycle at the head, and a trailing part of the preceding data transition pattern Another data transition pattern that has a common data sequence at the front and
By following the preceding data transition pattern and using a data transition pattern that is as different as possible, a chain of data transition patterns is formed, and it is inevitable to return to the data transition pattern placed at the top. Second check means for checking whether there is any data, and if there is no choice but to return, the data sequence constituting the cycle is obtained by dividing the given data sequence using the data transition pattern. A first determining means for determining the cycle is provided.

[0017] The above apparatus further comprises: if there is no leading data transition pattern which reappears even if the formation of a chain is repeated for all data transition patterns related to the unit data determined to be related to the cycle, There is provided a data string constituting a cycle by dividing a given data string using the unit data, and a second determining means for determining the cycle.

In the above, even if all the extracted data transition patterns are placed at the head of the chain, if the unit data associated with the head data transition pattern does not reappear in the created chain, it is given. It is preferable to change the data length of the data transition pattern extracted from the data sequence.

In the above, data includes a signal. The data sequence includes a signal sequence.

According to the present invention, the cycle of a data string having a periodically given periodic element can be automatically specified using processing means such as a computer.

Therefore, there is no need to add a synchronization signal on the transmission side even in data communication or the like. Even if there is no synchronization signal in the given data sequence, its period is specified,
Periodic patterns can be extracted.

It has a structure in which a given data string branches, and even when there are two or more types of periods, these periods can be automatically specified.

According to the present invention, a data transition pattern is extracted from a given data sequence, and a cycle included therein is specified while forming a chain thereof. Therefore, the cycle can be specified and the cycle pattern can be determined with a small amount of calculation. Becomes

The period determination method and apparatus according to the present invention can also determine a period pattern of an operation of a failure diagnosis target by processing data representing a temporal change of a signal pattern obtained from the failure diagnosis target. Since the present invention can be applied, it is possible to easily create reference data for failure diagnosis using the determined periodic pattern.

The present invention also provides an apparatus for finding data relating to a cycle useful for the cycle determining apparatus.

[0026]

According to the present invention, there is provided an apparatus for finding data related to a cycle, comprising: means for extracting all types of data transition patterns consisting of continuous data of a predetermined length from a given data sequence; Means for storing a pattern in association with all types of unit data constituting the above data sequence; a data transition pattern relating to and including any unit data at the beginning; Another data transition pattern having a common data sequence at the front is made to follow the preceding data transition pattern, and the data transition pattern is selected while selecting the data transition pattern so that the unit data does not appear as much as possible. Means to form a chain,
Means for repeating the formation of a chain of data transition patterns while changing the data transition pattern placed at the head, and checking whether unit data associated with the head data transition pattern has to appear again in the subsequent data transition pattern , And when the unit data associated with the first data transition pattern reappears in the subsequent data transition pattern, the unit data is determined to be related to the cycle of the data string.

In the above, even if all the extracted data transition patterns are placed at the head of the chain, if the unit data associated with the head data transition pattern does not reappear in the created chain, it is given. The data length of the data transition pattern extracted from the data sequence may be changed.

The device for finding the data related to the cycle can be effectively used in the above-described cycle determination device.

The failure diagnosis method according to the present invention extracts all types of data transition patterns composed of continuous data of a predetermined length from at least a data string of an output signal of a control device, and includes the extracted data transition patterns among the extracted data transition patterns. Arbitrary ones are placed at the head, and another data transition pattern that has the same data sequence as the rear part of the preceding data transition pattern at the front is made to follow the preceding data transition pattern, and is as different as possible. By using a data transition pattern to create a chain of data transition patterns, and by repeatedly creating a chain of data transition patterns while changing the data transition pattern placed at the top, the process returns to the top data transition pattern again. Check if there is a chain that comes in and return to the first data transition pattern Utilizing the fact that the created chain corresponds to one cycle of a given data sequence, the cycle is determined, and includes a reference pattern of each state appearing in one cycle and data on a connection between the states. Abnormality determination reference data is created and stored in advance, and at least a change in the pattern of the output signal of the control device during operation of the control device accompanies a state transition represented by the abnormality determination reference data. The presence or absence of an abnormality in the system controlled by the control device is determined by checking whether or not the change matches the reference pattern.

In one embodiment of the present invention, the reference data for abnormality determination includes time data allowed for the transition of the output pattern, and whether or not the output pattern of the control device has transitioned within the allowable time. Perform a check.

In another embodiment of the present invention, the reference data for detecting an abnormal part including the expected input pattern of the control device corresponding to each output reference pattern in the reference data for determining abnormality is prepared and stored in advance. Every
When it is determined that there is an abnormality, the part where the abnormality has occurred is specified by comparing the input pattern of the control device at that time with the corresponding expected input pattern.

In still another embodiment of the present invention, when it is determined that there is an abnormality, that fact is visually output,
When an abnormal site is specified, it is output visually.

The fault diagnosing device according to the present invention comprises means for extracting all types of data transition patterns consisting of continuous data of a predetermined length from at least a data string of an output signal of the control device, and a means for extracting the extracted data transition patterns. Any of the preceding data transition patterns is arranged at the beginning, and another data transition pattern having a data sequence common to the rear part of the preceding data transition pattern at the front is made to follow the preceding data transition pattern, and A means for creating a chain of data transition patterns by using different data transition patterns as much as possible, and changing the chain of data transition patterns arranged at the head while causing the chain creation means to repeat the creation of a chain of data transition patterns. To check if there is a chain that returns to the data transition pattern of the first data transition Means for determining the cycle by using the fact that the created chain corresponds to one cycle of the given data sequence when returning to the pattern, the reference pattern and state of each state appearing in one cycle Storage means for preliminarily storing reference data for abnormality determination including data relating to the connection between them, and at least a change in a pattern of an output signal of the control device during the operation of the control device is represented by the reference data for abnormality determination. Means for determining whether or not there is an abnormality in a system controlled by the control device by checking whether or not the change corresponds to a reference pattern accompanying a state transition.

In one embodiment of the present invention, the reference data for abnormality determination includes time data allowed for transition of the output pattern, and the determination means determines that the output pattern of the control device is within the allowable time. Check whether the transition has occurred.

Preferably, the failure diagnosis apparatus according to the present invention further stores in advance the abnormal point detection reference data including the expected input pattern of the control device corresponding to each output reference pattern in the abnormality determination reference data. And a means for identifying the part where the abnormality has occurred by comparing the input pattern of the control device at that time with the corresponding expected input pattern when it is determined that there is an abnormality.

The failure diagnosis apparatus further includes output means for visually outputting the specified abnormality occurrence site.

According to the failure diagnosis method and apparatus according to the present invention, since the reference data for failure diagnosis includes data relating to the connection between the states, the state branches and transits, and a plurality of different periods are included. Even in this case, the failure diagnosis process can be continued while referring to the data relating to the connection between the states, and the state transition can be tracked correctly.

[0039]

[Explanation of the embodiment]

(1) Algorithm for Determining the Period of the Data Sequence The period of the data sequence is determined by the computer system. A small computer system such as a so-called personal computer is sufficient. The computer system includes input devices such as a keyboard and a mouse, display devices, output devices such as a printer,
If necessary, an interface for communicating with another computer system or controller is provided.
The computer system naturally includes an internal memory (semiconductor memory) and an external memory (disk memory or the like).

(1-1) Example 1 FIG. 1 shows an outline of a processing procedure for determining a cycle of a data string. This processing is mainly performed by the C in the computer system.
Performed by PU. A program representing this processing procedure is stored in the memory of the computer system. FIG. 2 shows the details of the processing in step 103 shown in FIG. 1, and FIG. 3 shows the details of the processing in step 104, respectively.

First, a data string whose cycle is to be determined is input (step 101). The data sequence may be input from an input device or transmitted from another computer system or controller via a communication interface.

FIG. 4 shows an example of the input data sequence. This is referred to as a data string example 1.

All types of data transition patterns composed of continuous data of a predetermined length are extracted from the input data sequence (step 102). The data length of the data transition pattern is arbitrary, but is 4 in this case. As shown in FIG. 5, four continuous data may be extracted from the data string while avoiding duplicate data. Nine types of data transition patterns extracted from the data string example 1 are shown in FIG.
Is shown in

There are five types of unit data (hereinafter, simply referred to as characters) used in the first example of the data string, namely, A, B, C, D, and E. The nine types of extracted data transition patterns are classified for each of these characters.

FIG. 7 shows an example of classification based on the first character of the data transition pattern. FIG. 8 shows an example of classification based on the character located at the second position in the data transition pattern. These classified data transition patterns are stored in the memory. However, this classification is performed in step 10 described later.
Since it can be performed each time a character or data transition pattern is specified in the processing of 3 or 104, it is not always necessary to store the transition pattern in a classified form, and it is also possible to store it in an unclassified form as shown in FIG. it can.

When the character to be focused on for classification is located at the center of the character string constituting the data transition pattern, not at the beginning and end, as shown in FIG. It turned out to be easy to do. However,
In the following description, for ease of understanding, the classification shown in FIG. 7 performed by focusing on the first character of the data transition pattern will be used.

Next, using the data transition pattern created in this way, a process of determining characters related to the cycle is performed (step 103).

Referring to FIG. 2, one of the characters A to E included in the input data string is designated (step 111). Any character can be specified. In order to reduce the amount of processing involved in determining characters related to this cycle and to obtain conclusions as quickly and accurately as possible, the order of data transition patterns classified into each character is as follows. It is preferable to specify a character for. In the example shown in FIG.
, The number of data transition patterns is one each, characters A and E each have two, and character B has three. Therefore, these characters are C,
It is preferable to specify D (or D, C), A, E, (or E, A), and B in this order.

The data transition pattern having the designated character at the beginning (in the second position in the classification of FIG. 8) is placed at the beginning, and the data sequence common to the rear part of the preceding data transition pattern is placed at the front part. A chain of data transition patterns is formed by causing another data transition pattern of the data transition pattern to follow the preceding data transition pattern (step 112).
). Forming this chain of data transition patterns is called transition simulation. In this transition simulation, if there is a data transition pattern that does not include the character placed at the beginning and can be used, the usable data transition pattern is used.

For example, as shown in FIG. 9, a data transition pattern CEAB having a character C at the beginning is placed at the beginning, and a data transition pattern EABD having an EAB at the front except for the leading C of the pattern CEAB is made to follow it. , And a chain of data transition patterns such as ABDB, BDBE, and DBEA. In this transition simulation, it is possible to form a chain using the other data transition pattern EABD without using one data transition pattern EABC including the character C classified as the character E, and the data transition pattern EABD has a constant period. Since an infinite repeating chain is formed by appearing in,
The leading character C does not appear at all. Therefore, step
NO at 113.

Next, another character D is designated (step 116).
), Even if the transition simulation is performed in the same manner (step 112), the designated character D does not appear again as shown in FIG. 10 (NO in step 113).

Further, when a character A other than the characters C and D is designated (step 116) and the transition simulation is performed in the same manner, as shown in FIGS. 11 and 12, a chain of two types of data transition patterns is formed. The specified character A appears again (step 113).

In this way, when the designated character A reappears in the transition simulation, it is determined that this character A is related to the cycle (step 114).
).

If the specified character A is also
If NO at 113, a transition simulation is performed for the remaining characters E and B in the same manner. If NO in step 113 for any of these characters E and B, even if all the characters are specified, no character related to the cycle is found (YES in step 115). In such a case, it is determined that the extracted data transition pattern is not appropriate, and the data length of the data transition pattern to be extracted from the input data sequence is increased, and the process returns to step 102 again to perform the data transition pattern extraction processing. Will be redone (step
117). In the above example, if no character related to the cycle is found when a data transition pattern with a data length of 4 is extracted, the data length of the data transition pattern is set to 5 next.

When the characters related to the cycle are determined, the process proceeds to the processing for determining the pattern constituting the cycle of the data string, the cycle, and the cycle pattern (step 104).
).

Referring to FIG. 3, n = 1 is set (step
121). n is the number of data transition patterns specified in the next step 122.

Next, n data transition patterns among the m data transition patterns classified into the characters determined to be related to the period in step 103 are specified (step 122).

In the first example of the data string described above, the character A
Has been determined to be related to the period. Referring to FIG. 7, the data transition pattern classified into character A is ABCE
And ABDB. Since n = 1, one of these two data transition patterns is specified.

It is assumed that the data transition pattern ABCE has been designated. With the specified data transition pattern at the top, a transition simulation is performed while using the specified data transition pattern ABCE as little as possible (step 123). The result of the transition simulation is shown in FIG. As is apparent from this figure, when a chain of data transition patterns is created while using the data transition pattern ABCE as little as possible, a repeated pattern is generated. Since the transition simulation can be performed without using the leading data transition pattern ABCE again, the result of step 124 is NO.

In step 125, the data transition pattern ABDB has not been specified yet.
YES, the process returns to step 122, and specifies the data transition pattern ABDB.

Data transition pattern ABD newly specified
When the transition simulation is performed with B at the top,
As shown in (1), an infinite repetition is formed without using the data transition pattern ABDB again. Therefore, also in this case, the answer at step 124 is NO.

Since the designation and the transition simulation are completed for the two data transition patterns ABCE and ABDB classified into the character A related to the cycle, step 12 is executed.
5 is NO.

In step 126, n is incremented so that n = 2. Since m = 2, n = m (YES in step 127).

Therefore, the process proceeds to step 128, where n = m
In the case of, the input data string is divided using the character A determined to be related to the cycle. FIG. 15 shows a state in which Example 1 of the input data string shown in FIG. 4 is divided using the character A. The division points are indicated by / (slash).

Thus, in example 1 of the input data string, it can be seen that the data string ABCE and the data string ADBBE each form a cycle. The cycle of the data string ABCE is 4 and the cycle of the data string ADBBE is 5 (step 129). In this way, the period pattern and the period are determined.

Periodic patterns (data strings) ABCE and AB
As shown in FIG. 16, the DBE has a structure in which the character B branches to C and D at the character B, and returns from the last E of each branch to A again.

As described above, according to the above-described cycle determination method, it is possible to specify a data string forming a cycle and determine the cycle even for transition of data (character) having a branching structure.

The cycle pattern and the cycle determined in this way are output from an output device such as a display device or a printer (step 105).

(1-2) Example 2 Next, let's try to trace the period determination processing using the input data sequence shown in FIG. 17 as Example 2.

The characters used in Example 2 are A, B, C, D,
There are six types, E and F. It is assumed that a data transition pattern having a data length of 3 is extracted from the data string example 2. 12
The types of data transition patterns are extracted, and these are classified by focusing on the six types of characters as shown in FIG. 18 (step 102 in FIG. 1).

The character related to the cycle is determined to be A by the processing of step 103 in FIG. 1 (processing shown in detail in FIG. 2).

The process proceeds to step 104 in FIG. 1, that is, the process of FIG.

Set n = 1 (step 121).

The data transition patterns classified into the character A determined to be related to the cycle are ABC, ADE, and AF.
A. That is, m = 3. One of the three data transition patterns (n = 1) is designated, and the transition simulation is performed while using the designated data transition pattern as little as possible (steps 122 and 1).
twenty three ).

When the data transition pattern ABC is specified, as shown in FIG.
Since repetition occurs without using BC, step 124 is used.
Is NO.

Whether the transition simulation is executed by specifying another data transition pattern ADE or the transition simulation is executed by specifying another data transition pattern AFA, as shown in FIGS. The chain of data transition patterns can be continued without using these designated transition patterns. (Step 124
NO).

The combinations that specify one of the three data transition patterns are all described above, and there is no combination that is no longer specified. Therefore, the answer is NO in step 125, and n is incremented. That is, n = 1 + 1 =
It becomes 2 (step 126).

Since n = m is not satisfied (n = 2, m = 3),
In step 127, the result is NO, and the process returns to step 122 again.

In step 122, two of the three data transition patterns are specified.

Data transition patterns ABC, ADE, AF
The transition simulation is performed by designating ABC and ADE of A (step 123). In this case, as shown in FIG. 22, no matter how the data transition pattern is created with ABC at the top, or how the data transition pattern is created with ADE at the top, One of the transition patterns ABC and ADE always appears, and the transition simulation cannot be continued unless it is used. Therefore, YES in step 124
Becomes

Thereafter, the flow advances to step 128, where n and m are not equal, so that the two designated data transition patterns A
The input data sequence (example 2) is divided using BC and ADE. The result of this division is shown in FIG. It is divided into data strings starting with ABC or ADE.

Data sequence (period pattern) constituting the period
Are ABC, ABEF, and ADEAF, and their periods are determined to be 3, 4, and 5 (step 12).
9).

It can be seen that the data string of Example 2 described above has a complicated structure as shown in FIG.

(1-3) Example 3 Further, Example 3 of the input data string shown in FIG. 25 will be examined.

The characters used in Example 3 are 80, 70, 3
8, 34, 02, 01, and 00. It is assumed that a data transition pattern having a data length of 3 is extracted from the data sequence of Example 3. The seven types of data transition patterns shown in FIG. 26 are extracted. These seven types of data transition patterns respectively correspond to the above seven types of characters (step 102 in FIG. 1).

By the process of step 103 in FIG. 1 (FIG. 2),
The first character 80 is determined to be related to the cycle. Although all seven types of characters are related to the cycle, if character 80 is specified first, step 113 in FIG.
Since the answer is YES, it is determined that the character related to the cycle is 80 only. That is, the other six types of characters need not be considered.

The data transition patterns branched to the character 80 are only 80, 70 and 38 (m = 1). When the transition simulation is executed by designating the data transition patterns 80, 70, and 38 and placing them at the head, the designated data transition pattern always appears as shown in FIG. 27 (YES in step 124).

Therefore, when the input data sequence is divided using the designated data transition patterns 80, 70, and 38 (in this case, n = m from the beginning, step 124
From step 128, it is handled in this way. Even if the input data is divided using the determined character 80, the same result is obtained. ) And the results shown in FIG. 28 are obtained. That is, the periodic pattern is 80, 70, 38, 34, 0
2,01,00, and the cycle is 7.

The structure of this input data string is simple as shown in FIG.

(2) Application to Failure Diagnosis The cycle of the data string determined by the above-described processing can be suitably used for failure diagnosis of the controlled system (including equipment).

A failure diagnosis of a system controlled by a control device, for example, a programmable logic controller (hereinafter, simply referred to as PLC) is performed as follows.

The normal operation state of the system controlled by the PLC is observed in advance, and the result is stored. Then, the actual operation of the system is monitored and compared with a normal operating state stored in advance to detect a system abnormality in real time.

As an index indicating a normal operation state, PL
There are ON and OFF states of the input and output of C, the order of transition of the state, and the time required for the state transition (standard value and allowable width or minimum value and maximum value).

If the states of both the input signal and the output signal for each operating state are created together as a criterion, erroneous diagnosis is likely to occur, so that the output signal state and the input state corresponding to each output signal state The state of the signal is created separately as reference data. The state of the actual output signal is monitored, and the presence or absence of an abnormality is determined by comparing the output signal with reference data of the output signal. Only when an abnormality is detected, an abnormal part is detected by comparing the actual state of the input signal at that time with reference data of the corresponding input signal.

In such a fault diagnosis, the state of the output signal changes according to the operation of the system. Since the operation of the system is often repeated, the state of the output signal is considered to be repeated at a constant period as shown in FIG. In some cases, the state may branch as shown in FIG. 16 or FIG. In this case, the controlled system is considered to be operating with two or more cycles of state transition.

In any case, when the controlled system is operating normally, the transition of the state of the output signal of the PLC is observed, and the transition cycle and the transition pattern are specified. Reference data can be created.

(2-1) System Configuration FIG. 30 shows the overall configuration of a system including a PLC as a control device and a device for realizing the cycle determination method according to the present invention.

The PLC 10 controls a controlled system, which will be described later. The CPU 10 executes a control process in accordance with a ladder program, a ROM 12 storing a ladder control system program, and a user for controlling the controlled system. , A RAM for storing a user program (ladder program), a RAM for work (work) 14, a timer 15, an I / O for transmitting / receiving input / output signals to / from the controlled system via a PLC I / O data bus.
I / O for communicating with unit 16 and console 20
An F (interface) 17 is provided. The I / O table that holds the actual input / output signal status of the PLC is RAM
14 is provided.

The console 20 executes the above-described cycle determination method based on a data sequence representing the transition of the state of the output signal output from the PLC 10 and applied to the controlled system. CP
U21, a memory device 22 for storing a program to be executed by the CPU 21, a memory device 23 for storing data required or generated in the execution of the process, an output device 24 including a display device and a printer for outputting a result of the cycle determination process, and a keyboard. Input device 25, and an I / O for connection to the PLC 10.
/ F27, and I / Fs 29 and 28 with the input and output devices 25 and 24. The memory devices 22 and 23 include not only semiconductor memories such as ROM and RAM but also hard disks and floppy disks.
It can be realized by a disk. The console 20 may be realized by a so-called personal computer or the like.

The failure diagnosis processing of the controlled system is performed by the PLC 10
May be configured to be executed, or the console 20 may be executed. In the former case, ROM12
A failure diagnosis program will be stored in the RAM 13 and reference data for failure diagnosis will be stored in the RAM 13 respectively. In the latter case,
A failure diagnosis program will be stored in the memory device 22, and reference data for failure diagnosis will be stored in the memory device 23, respectively.
However, the PLC 10 may execute a part of the failure diagnosis processing and the console 20 may share the other part.

(2-2) Configuration of Controlled System and Example of Control (Part 1) FIG. 31 shows an example of the controlled system.

The work W is transported by the transport conveyor 91. The transport conveyor 91 is driven by a first motor (M1) 72. In the course of the conveyor 91, the detection of the presence of the work W and the detection of burrs on the work W are automatically performed. For this purpose, a first work detector 55 and a burr detector 56 are provided. When it is detected that the work W has burrs or that there is a burr larger than a predetermined amount, the work W is removed from the conveyor 91 by the defective removal pneumatic cylinder 73. During the operation of the cylinder 73, the rotation of the motor 72 is stopped, and the conveyor 91 is stopped.

The work W conveyed to the end by the conveyor 91 is moved to the carrier 92. A stay detector 57 for detecting the work W transported to near the end of the conveyor 91 is provided. When the state in which the stay detector 57 detects the work W has continued for a certain period of time or more, the abnormal lamp 71 of the operation panel 90 is turned on.

A second work detector 58 is provided for detecting the work W transferred from the transfer conveyor 91 onto the transfer table 92. When the work W is detected by the work detector 58, the input pneumatic cylinder 75 is driven, and the work W is pushed out onto the transfer table 92 toward the processing table 93 by the rod of the input cylinder 75. The work W transferred to the processing table 93 is detected by the third work detector 61.

When the work W is moved onto the worktable 93, a jig 77 for fixing the work W is driven in a direction for tightening the work W. A second motor (M2) 78 is driven to rotate, and a drill 79 fixed to the rotating shaft of the motor 78
The work W is lowered with 78, and a hole is formed in the work W. After the drilling operation, the drill 79 moves up with the motor 78, and the rotation of the motor 78 stops. The workpiece on which the holes are formed is finally discharged from the processing table 93 by the discharge pneumatic cylinder 81.

The operation panel 90 is provided with an operation switch 50, a stop switch 51, a release switch 52, a running lamp 70 and an abnormal lamp 71. When the operation switch 50 is turned on, the above-described series of steps starting from the activation of the motor 72 is started, and the in-operation lamp 70 is turned on.
When the stop switch 51 is turned on, the operation of the above steps is stopped, and the running lamp 70 is turned off. As described above, when the detection signal of the stay detector 57 continues for a predetermined time or more, the abnormal lamp 71 is turned on, and the operating lamp 70 is turned off. When the release switch 52 is turned on in this state, the abnormal lamp 71 is turned off.

The defective discharge cylinder 73 has a defective front end detector for detecting that the rod has advanced (advanced) and has reached the advanced end, and a defective front end detector for detecting that the rod has retracted and reached the retracted end. A rear end detector (both not shown) is provided. Similarly, the charging cylinder 75 has a charging front end detector and a charging rear end detector, and the discharging cylinder 81 has a discharging front end detector and a discharging rear end detector (both not shown).
Are provided respectively. Further, the upper end detector of the drill detects that the drill 79 (and the motor 78 to which it is attached) is raised and reaches its rising end, and the lower end detector of the drill which detects that the drill 79 is lowered and reaches its falling end. (Both not shown) are provided.

The signals input from the controlled system to the PLC 10 are as follows. (000) to (01
5) is the number of the input signal. The abbreviations are shown in parentheses at the end.

(000) ON / OFF signal of operation switch 50 (operation SW) (001) ON / OFF signal of stop switch 51 (stop S
W) (002) ON / OFF signal of release switch 52 (release S
W) (003) Detection signal of defective front end detector (Front front end) (004) Detection signal of defective rear end detector (Defective rear end) (005) Work detection signal of first work detector 55 (Detection 1) (006) Burr detection signal of burr detector 56 (burr detection) (007) Detection signal of stay detector 57 (stay detection) (008) Work detection signal of second work detector 58 (detection 2) (009) Detection signal of input front end detector (front end of input) (010) Detection signal of input rear end detector (rear end of input) (011) Work detection signal of third work detector 61 (detection 3) (012) Upper end of drill Detector detection signal (Drill upper end) (013) Drill lower end detector detection signal (Drill lower end) (014) Detection signal of discharge front end detector (Ejection front end) (015) Detection signal of discharge rear end detector (Ejection) Rear end)

The signals output from the PLC 10 to the controlled system include the following. (100) to (1
12) is the number of the output signal. The abbreviations in parentheses are used.

(100) ON / OFF control signal of operating lamp 70 (operating L) (101) ON / OFF control signal of abnormal lamp 71 (abnormal L) (102) Rotation drive control signal of first motor 72 (M1 rotation) (103) Forward drive control signal of defective exclusion cylinder 73 (defective forward) (104) Reverse drive control signal of defective exclusion cylinder 73 (defective backward) (105) Forward drive control signal of input cylinder 75 (input forward) (106) Retraction drive control signal of the input cylinder 75 (input retraction) (107) Tightening drive control signal of the fixing jig 77 (jig tightening) (108) Rotation drive control signal of the second motor 78 (M2 rotation) (109) Drill 79 up drive control signal (drill up) (110) Drill 79 down drive control signal (drill down) (111) Forward drive control signal of discharge cylinder 81 (discharge forward) (112) Reverse drive control signal of the discharge cylinder 81 (ejection retracted)

FIG. 32 shows a part of a program (user program) set in the PLC 10 for controlling the above-mentioned controlled system. This program is expressed using contacts that are turned on and off by input signals, relays that generate output signals, contacts that are turned on and off by the relays, and internal auxiliary relays and their contacts.

The meanings of the internal auxiliary relay and its contacts shown in FIG. 32 are as follows. During the setting, it indicates the start of the entire drilling operation, and is turned on until the drilling operation and the discharge of the work are completed. The completion of the setting indicates that the setting of the work on the processing table is completed. Completion of processing indicates that the discharge of the work from the processing table has been completed. The loading memory indicates that the workpiece has been loaded into the processing table, and is turned on until processing and discharging are completed.

FIG. 33 shows the entire drilling operation (transfer of the workpiece W from the transfer table 92 to the processing table 93 by the input cylinder 75,
3 shows the operation of fixing the work W, the drilling of the work W by the motor 78 and the drill 79, and the discharge of the drilled work from the processing table 93 by the discharge cylinder 81). P
An input signal to the LC 10 and an output signal from the PLC 10 are shown. Further, a state in which the state of the output signal (output pattern) changes with the transition of time is shown. Numbers [1] to [7] are assigned to each state of the transitioning output signal (the state of the signal at the position where the broken line is drawn). Each of these states is hereinafter referred to as a state.

With the rising edge of the input signal "detection 2" as a trigger, a transition is made from state [7] to state [1] to be described later (the relationship between the input signal and output signal serving as a trigger is indicated by a chain line and an arrow). This state transition is executed by the program at the address 0039 shown in FIG. When the second work detector 58 detects the work W, the rod of the input cylinder 75 advances, and pushes the work W in the direction of the processing table 93.

Next, when the input front end detector detects that the rod of the input cylinder 75 has reached its forward end (input signal “input front end” is ON), the state transits from state [1] to state [2]. Then, the rod of the input cylinder 75 stops the forward movement and starts the backward movement, the jig 77 starts fixing the work sent to the processing table 93, and the motor 78 is further driven to rotate. This is the address 00005 shown in FIG.
And so on.

When the input rear end detector detects that the rod of the input cylinder 75 has reached the retreat end (input signal “input rear end” is OFF), the state transits from state [2] to state [3]. The retraction operation of the charging cylinder 75 stops,
Drill 79 begins to descend. Thus, a hole is formed in the work W by the drill 79.

When the drill lower end detector detects that the drill 79 has reached the lower end (input signal "drill lower end" is ON), the state transits from the state [3] to the state [4], and the lowering of the drill 79 is performed. Stop and drill 79 begins to ascend.

When the drill upper end detector detects that the drill 79 has reached the rising end (input signal “drill upper end” is ON), the state transits from the state [4] to the state [5], and the jig 77 moves the work piece 77 to the work. And the rotation of the motor 78 stops.
The lifting of the drill 79 stops, and the rod of the discharge cylinder 81 starts to move forward. As the rod of the discharge cylinder 81 advances,
The drilled workpiece W is discharged from the processing table 93.

When the discharge front end detector detects that the rod of the discharge cylinder 81 has reached the forward end (input signal “discharge front end” is on), the state shifts from state [5] to state [6], and the discharge cylinder 81 81 stops moving forward and starts retreating.

When the discharge rear end detector detects that the rod of the discharge cylinder 81 has reached the retreat end (input signal “discharge rear end” is on), the state transits from state [6] to state [7]. Thus, one drilling step is completed.

(2-3) Failure Diagnosis Processing (Part 1) In the controlled system shown in FIG. 31, the control of defective product removal by the defective cylinder 73 based on the detection of burrs and the above-described drilling control are mutually reciprocal. Has little relevance to Therefore, the fault diagnosis of the rejection operation and the fault diagnosis of the drilling operation can be performed separately and independently. Hereinafter, the description will be limited to the failure diagnosis of the drilling operation.

In order to create reference data to be referred to for failure diagnosis, the operation cycle of the controlled system must be specified.

Data strings are collected in order to determine at what cycle the transition of the output pattern is performed according to the above-described cycle determination algorithm. Here, each unit data (the above-mentioned characters) of the data string becomes each output pattern.

The controlled system is operated under the control of the PLC 10, and when the controlled system is operating normally, a change in the state of the output signal is read, and a data string representing the transition of the state of the output signal is read. Create Since an I / O table is provided in the RAM 14 of the PLC 10, output signal data is read from the I / O table at a constant sampling cycle, and it is checked whether or not the state of the read output signal has changed. When the state of the output signal changes, the state of the output signal is sequentially stored.

FIG. 34 shows the transition of the state (output pattern) of the output signal corresponding to each of the above-mentioned states [1] to [7]. The state of each output signal is represented by one bit. In this embodiment, the ON state is represented by 1 and the OFF state is represented by 0. At the bottom of FIG. 34, 8-bit data (this is referred to as an output pattern) representing the state of eight types of output signals is shown in hexadecimal notation.

With this controlled system, the same data string as in the input data string example 3 shown in FIG. 25 is obtained. Therefore, the cycle of this data string is determined by the above-described cycle determination algorithm to be 7, and the cycle pattern is determined as shown in FIG.

As for output patterns, it is understood that reference data only needs to be created for seven types of output patterns that constitute one cycle.

FIG. 35 shows a part of the abnormality determination reference data for abnormality detection. The abnormality determination reference data is provided for each state, and includes output pattern data of the state, an average transition time from the previous state, and a permissible range of the transition time. Output pattern
The data is a collection of data representing the states of all output signals to be monitored as described above. The output pattern data of the seven states [1] to [7] is extracted from the abnormality determination reference data. Figure 34 shows the summary.

[0130] Such output pattern data shows the state of the output signal when the controlled system is actually operated under the control of the PLC 10 after the cycle is determined, and it operates normally. It can be created by extracting when it changes. Most commonly, the R
It can be created by sampling the I / O table provided in the AM 14 at a constant period and processing it.

The average transition time from the previous state is the average time required to transition from the previous state to the state. This can be determined by repeatedly operating the controlled system under the control of the PLC 10 and calculating the average transition time when the system operates normally. Of course, when the time is known in advance, such as the set time of the timer, or when it can be theoretically easily obtained, the user may input.

The permissible range of the transition time fluctuation indicates the permissible range of deviation of the actual transition time from the average transition time, and will generally be input by the user. Of course, this proportionality constant may be determined uniformly, with all allowable widths being values proportional to the average transition time.

As the data relating to the transition time, in addition to the above-described combination of the average value and the allowable width, for example, a combination of the reference value, the lower allowable width and the upper allowable width, and the combination of the maximum value and the minimum value may be used. it can.

The abnormal point detection reference data is constituted by data representing an expected state (input expected pattern) of an input signal corresponding to each of the abnormality judgment reference data in each state described above. That is, the abnormal point detection reference data includes an expected input pattern set in advance for each state.

The abnormal point detection reference data is used to specify a point or a part that causes the detected abnormality when an abnormality is detected in the abnormality detection processing using the above-described abnormality determination reference data. . Therefore, in principle, all input signals which directly or indirectly affect the output signal to be monitored are selected. However, it is also possible to intentionally remove an input signal relating to a part that does not cause a problem even if it leaks from the abnormal part specifying process. It is not necessary to select an input signal that is unrelated to the output signal being monitored. For example, since there is no relationship between the drilling process and the defective work elimination process shown in FIG. 31, the input signal related to the work exclusion process is included in the abnormal position detection reference data in association with the abnormality determination reference data for the drilling process. It need not be included.

In some cases, there may be a plurality of expected input patterns corresponding to one output reference pattern (an example will be described later). O of multiple input signals
This is the case where the process proceeds to the next state depending on the R condition. In such a case, a plurality of expected input patterns are registered in advance in association with the one-state abnormality determination reference data.

FIG. 36 shows an example of the abnormal point detection reference data, which is composed of expected input patterns corresponding to the respective states shown in FIG. Also in this input expected pattern, the expected state of each input signal is represented by 1 bit, and ON is represented by 1 and OFF is represented by 0. The timing chart of the input signal shown in Figure 33 and Figure 36
By comparing the tables, the correspondence between them can be easily understood.

The reference data for detecting an abnormal part including such an expected input pattern is obtained by outputting the output signal when the controlled system is operating normally under the control of the PLC 10 while the controlled system is operating normally. It can be created by reading the state of the input signal when the state changes, and storing the read state of the input signal corresponding to the abnormality determination reference data relating to the state transition of the output signal.

In the control of the controlled system by the PLC 10 in particular, since the I / O table is provided in the RAM 14 of the PLC 10, the I / O table is used for the control.
The output reference pattern shown in FIG. 34 and the expected input pattern shown in FIG. 36 can be created as follows.

The controlled system is operated under the control of the PLC 10. The data of the I / O table in the RAM 14, which stores the state of the input / output signals when the controlled system is operating normally, is read at regular sampling intervals.
It is checked whether the state of the output signal has changed among the states of the read input and output signals. When there is a change in the state of the output signal, the state of the output signal after the change is stored as an output reference pattern corresponding to the state number, and a part of the abnormality determination reference data is created. Further, the state of the input signal immediately after the change of the state of the output signal is stored as an expected input pattern in association with the above-mentioned state number, thereby creating abnormal point detection reference data.

As described above, what is constantly referred to in the abnormality detection processing is the abnormality determination reference data. Therefore, it is preferable to store the abnormality determination reference data in the RAM 13 which can be quickly accessed by the CPU 11. On the other hand, the abnormal point detection reference data is referred to for the first time when an abnormality is detected.
High speed is not always required and the storage device 23 of the console 20
Can be stored. Of course, it goes without saying that the abnormal point detection reference data may be stored in the RAM 13.

FIG. 37 shows an algorithm of a failure diagnosis process executed by the CPU 11 of the PLC 10.

When a failure diagnosis function is added as a part of the function of the PLC 10, the CPU 11 follows the PLC original processing, that is, a user program partially shown in FIG. 32, in addition to the failure diagnosis processing. Execute the control process of the controlled system. The CPU 11 repeats a series of processing at a fixed cycle (cycle), and executes control processing of the controlled system in the first half of each cycle and failure diagnosis processing in the second half. Therefore, the failure diagnosis processing shown in FIG. 37 is repeated at a constant cycle.

The failure diagnosis processing shown in FIG. 37 includes an abnormality detection processing and an abnormal point specifying processing. The abnormality detection processing is performed with reference to the abnormality determination reference data. The abnormality determination reference data is related only to the state of the output signal as described above. As described above, even if only the state of the output signal is monitored, it is possible to sufficiently detect the occurrence of the abnormality. The abnormality detection process must be performed in real time.
By monitoring only the output signal state in the abnormality detection processing, the processing can be speeded up.
The burden on PU11 is reduced. In the abnormality detection processing of this embodiment shown in FIG. 37, the order of state transition and the transition time are checked. When an abnormality is detected in the abnormality detection process, the process first proceeds to the process of specifying an abnormal portion with reference to the abnormal portion detection reference data.

The state (output pattern) of the output signal is read (sampled) from the I / O table of the RAM 14.
(Step 131). Since the output pattern sampled last time is stored in the predetermined area of the RAM 14, the previous sample pattern is compared with the current sample pattern (step 132).

The timer 15 is started when a transition is made from the previous state to the current state, and measures the time from the point of transition to the current state.

If it is determined in step 132 that the previous sample pattern is the same as the current sample pattern, it is determined whether the current sample pattern is within the time range allowed to transition from the current state to the next state. It is checked (step 136).

That is, the current state is set to state [i]. The next state is state [i + 1]. The timer 15 counts the time from the time when the previous state [i-1] transits to the current state [i]. The time allowed to transition from the current state [i] to the next state [i + 1] is determined by the “average transition time from the previous state” and the “permissible range of transition time” in the reference data of the next state [i + 1]. Desired. It is determined in step 136 whether the time measured by the timer 15 is within the range of the allowable transition time obtained from the reference data of the next state [i + 1].

If the elapsed time is within the allowable range, the current sample pattern is stored in the above-mentioned area of the RAM 14 and the process returns to the step 131 (step 137).

If the elapsed time measured by the timer 15 exceeds the allowable transition time, it means that the transition to the next state has not been made even after the time allowed for the state transition has elapsed. It is determined that an abnormality has occurred, and the display device 24 of the console 20 indicates that the abnormality has been detected and an output signal indicating that the abnormality has occurred (step 138). move on. An output signal in which an abnormality has occurred can be identified as a non-coincidence point in comparison between the current sample pattern and the output pattern of the next state [i + 1].

In step 132, if the previous sample pattern is different from the current sample pattern,
It is determined that the state of the output signal, that is, the state has transitioned. In this case, the time measured by the timer 15 is read as the actual transition time from the state [i] to the state [i + 1] (step 133). Also, the current sample pattern is compared with the output pattern included in the reference data of the state [i + 1] after the transition (step 134).
).

If the current sample pattern matches the reference output pattern (step 135), the flow advances to the next step 136 for checking the transition time. This sample
If the pattern and the reference output pattern do not match, it is determined that an error has occurred, an error is detected, and an output signal indicating that the error has occurred is displayed on the display device (step 138). Proceed to. In the comparison between the current sample pattern and the reference output pattern, a mismatched portion corresponds to an abnormal output signal.

In checking the transition time when transitioning from state [i] to state [i + 1], the timer
The actual transition time obtained from 15 is the state [i + 1]
Is determined to be within the range of the allowable transition time obtained from the data relating to the “average transition time from the previous state” and the “permissible variation of the transition time” stored as the reference data. If the actual transition time is within the transition allowable time,
The current sample pattern is stored in the RAM 14 (step 137), and the process returns to step 131. If the actual transition time is outside the transition allowable time, a message indicating that an abnormality has occurred and an abnormality output signal are displayed on the display device of the console 20 (step 138), and the process proceeds to the abnormal point specifying process from step 109 onward.

The time required for the transition is measured by the timer 15
It is needless to say that the processing can be performed using a predetermined area of the RAM 14 without using the above.

In the process of specifying an abnormal part, first, the state (input pattern) of the input signal at the time when the abnormality is detected is read from the I / O table, and this sample input pattern is temporarily stored in the RAM 104 ( Steps
139).

Subsequently, state [i + 1] from the abnormal point detection reference data (if the transition from the current state to the next state does not occur even after the permissible transition time elapses, this corresponds to the next state, and the current state changes to the next state. If the transition is made but the time required for the transition exceeds the allowable time, it corresponds to the next state: that is, in any case, if the current state is [i], the next state [i + 1]).
Is read and compared with the temporarily stored sample input pattern (step 140).
).

If there is an input signal state that does not match in the comparison between the expected input pattern and the sample input pattern, the input signal is displayed on the display device 24 of the console 20 as an abnormal point (step 141).

The processing in steps 138 to 141 is performed by the console 20
May be executed by the CPU 21. In this case, data (error output signal or state number) relating to abnormality detection is sent from the CPU 11 of the PLC 10 to the console 20.
Will be notified.

As an example, it is assumed that the bit of the output signal “input advance” in state [1] has not become 1 even after the transition allowable time has elapsed.

According to the timing chart shown in FIG. 33, the output signal “input advance” is turned on by the input signal “detection 2” as a trigger. However, looking at the ladder program (address 0309) shown in FIG. 32, the output signal “input advance” indicates that not only the input signal “detection 2” is turned on but also the input signal “input rear end” is turned on. Is turned on as a condition. Further, in order for the output signal “input forward” to be turned on, the input signal “detection 3”, “input front end”, the output signal “input reverse” and “set complete” must be on.

FIG. 38 shows an expected input pattern in state [1] and a sample input pattern (abnormal pattern) sampled when an abnormality is detected. By comparing these patterns, it is specified that the input signal “rear end”, that is, the input rear detector of the input cylinder 75 is abnormal.

If the expected input patterns include not only those directly related to the output signal but also the input signals indirectly related through an auxiliary relay such as set completion, the expected input pattern and the sample input By collating with the pattern, it is possible to immediately identify the portion where the failure has occurred without performing the operation of checking the program list.

FIG. 39 shows a console when an abnormality is detected.
9 shows a display example displayed on 20 display devices 24. When an abnormality is detected, first, the occurrence of an abnormality such as "output:" input forward "does not turn on" in the upper stage and an abnormal output signal are displayed (step 138). Subsequently, abnormal point identification processing is performed, and the input signal found in this processing and the guidance for inspection are displayed as follows: "The" rear end "does not match the standard. Check the sensor / wiring of the above signal." (Step 141).

(2-4) Example of Configuration of Controlled System and Its Control (Part 2) FIG. 40 shows another example of the controlled system. In addition,
Reference numeral 41 is a timing chart showing input and output signals of the PLC 10 for controlling the controlled system.

When the work W is loaded into the conveyor 41 from the initial state, this is detected by the fourth work detector 31 (input signal "detection 4" to the PLC 10). In response to the fourth work detection signal, the motor 36 for driving the conveyor 41 is started (the output signal “C” from the PLC 10).
One drive ”).

When the work W is transferred from the conveyor 41 to the conveyor 42, it is detected by the fifth work detector 32 ("Detection 5"). In response to the fifth work detection signal, the drive of the conveyor 41 (motor 36) is stopped, and the motor 37 for driving the conveyor 42 is started ("C2 drive").

In the process of transporting the workpiece W by the transport conveyor 42, the defective detector 33 determines whether or not the workpiece W is defective. When the failure detector 33 determines that the product is defective, a failure detection signal is output and given to the PLC 10 (“failure detection”). In response to the failure detection, the drive of the conveyor 42 (motor 37) is stopped, and the discharge cylinder 38 is driven ("discharge drive"). When the discharge of the defective product is completed, the state returns to the initial state.

If the failure detector 33 does not determine that the failure occurs, the driving of the conveyor 42 is continued. When the workpiece W is transported to the position of the processing machine 39, the sixth workpiece detector 34
("Detection 6"). In response to the sixth work detection signal, the drive of the conveyor 42 (motor 37) is stopped, and the processing machine 39 is driven ("processing drive").

When the processing of the workpiece W by the processing machine 39 is completed, a processing end signal rises (“processing end”). In response to the rise of the processing end signal, the driving of the processing machine 39 is stopped, and the transport conveyor 42 (motor 37) is driven again.

The processed work W is transported again by the transport conveyor 42 and is transferred to the transport conveyor 43. The conveyor 43 is constantly driven. When the processed work W transferred to the conveyor 43 is detected by the seventh work detector 35 ("Detection 7"), the conveyor 42 (motor 3
7) Driving stops and returns to the initial state.

Each state representing the state of the output signal is shown in FIG.
[A], [B], [C], [D], and [E].

(2-5) Failure Diagnosis Processing (Part 2) As in the case described above, in order to specify the operation cycle of the controlled system, the controlled system operates normally under the control of the PLC 10. A data string representing the transition of the state of the output signal when the signal is present is created with reference to the I / O table. This data string is the data string of Example 1 shown in FIG.

FIG. 42 is a table showing states of output signals in each of the states [A] to [E]. The hexadecimal representations 8, 4, 2, 1 and 0 of the output pattern correspond to states [A], [B], [C], [D] and [E]. In the following description, [A] ~
A symbol representing the state of [E] is used.

By the processing according to the above-described cycle determination algorithm, it is found that the data sequence representing the state transition regarding the controlled system in this example has a branch structure as shown in FIG. Based on such a structure, the reference data for abnormality determination and the reference data for abnormality detection are created.

FIG. 43 shows an example of abnormality determination reference data for abnormality detection.

As shown in FIG. 16, the connection between the states is relatively complicated. The state always transitions from the initial state [E] to the state [A], and the state [A] always transitions to the state [B]. However, transition from state [B] to any of states [C], [D], or [E]. The state before transition to the state [E] is [B] or [C]. As described above, since there is a case where there is not one connection of the transitions between the states but a plurality of them, data on a combination of transitions allowed between the two states is required. It is also necessary to define data indicating the allowable range of the time required for the transition.

The start addresses of the storage locations where the reference data of each state are stored are addA and add, respectively.
B, addC, addD and addE.

The reference data relating to the state [A] includes the output data pattern of the state [A], the allowable range of the time required for transition from the previous state [E] (that is, the upper limit and the lower limit), and the state [A]. ] Is [B] and there is a head address addB of a storage location where reference data relating to the subsequent state [B] is stored.

If the state is shifted from state [B] to state [A] via [E], or from state [C] to state [E]
If the allowable range of the transition time is different between the case where the state transitions to the state [A] through the above, it is necessary to separately store the upper limit value and the lower limit value of the transition time separately.

The reference data relating to the state [B] is complicated. The reference data includes the output pattern data of the state [B].

The reference data includes the range (upper limit value, lower limit value) of the transition time allowed when the previous state is [A], and the transition time allowed when the previous state is [D]. (Upper limit, lower limit).

Further, when the previous state is [A], the succeeding state is [C] or [D], and the reference data of the succeeding states [C] and [D] are included in the reference data. Are stored at the addresses addC and addD of the storage location in which is stored, and when the previous state is [D], the subsequent state is [E], and reference data of the subsequent state [E] is stored. Contains the address addE of the storage location.

The reference data of states [C] and [D] are similar to those of state [A].

With respect to the reference data of the state [E],
The allowable range of the transition time is stored separately for the case where the previous state is [B] and the case where the previous state is [C].

FIG. 44 shows reference data for detecting a failure point. An expected input pattern is stored for each state.

As can be seen from FIG. 41, the expected input pattern of state [B] differs depending on whether state [B] follows state [A] or state [D]. Regarding the state [E], the expected input pattern differs between the case following the state [C] and the case following the state [B]. As described above, when there are two or more types of expected input patterns for one state, all the expected input patterns are set in advance in relation to the corresponding states.

In FIG. 42, in each of the states [A] to [E], there is only one output signal whose state is 1 (there is no state signal in the state [E]). In such a case, each state may be replaced by an output signal that becomes state 1 in that state. The output pattern or state is a concept including one consisting of a single output signal.

FIG. 45 shows the flow of a failure diagnosis process using the abnormality determination reference data shown in FIG. 43 and the abnormal point detection reference data shown in FIG. Basically, it is the same as the failure diagnosis processing shown in FIG. 37, except for the part corresponding to the specificity of the abnormality determination reference data and the abnormality location detection reference data.

The state (output pattern) of the output signal of the PLC 10 is sampled and compared with the previous sample output pattern stored in the RAM 14 (steps 151 and 15).
2). If the current sample output pattern is the same as the previous sample output pattern, check all possible next states to see if they are within the time range allowed to transition from the current state to the possible next state Is performed (step 157).

For example, when the current state is [B] (assuming that the previous state is [A]), the next state is [C] or [D]. Therefore, the upper limit value and the lower limit value of the transition time from the previous state included in the reference data of one next state [C], and the upper limit of the transition time from the previous state included in the reference data of the other next state [D] The value and the lower limit are read and compared with the time measured by the timer 15. If the time counted by the timer 15 exceeds any of these transition times, it is determined that an abnormality has occurred, and that fact is displayed (step 159). In this case, the sampled output pattern is compared with the respective output reference patterns of the following states [C] and [D], and an output signal that does not match is displayed. There may be not only one output signal but also a plurality of output signals that do not match.

If the time measured by the timer 15 is within one of the transition set times, the current sample pattern is stored (step 158), and the flow returns to step 151.

If the output pattern sampled this time is different from the previous sample pattern, the state may have transitioned (step 152). Therefore, the time measured by the timer 15 is read as the time required for the transition, and the timer 15 is reset (step 153). When reset, the timer 15 starts counting from 0 again.

Then, according to the previous state, the output reference patterns included in the reference data of all the states that may possibly follow the previous state are sequentially compared with the sampled output patterns (steps 154, 155, 156). ).

For example, when it is determined that there is a possibility that a transition has occurred from state [B] to the next state (NO in step 152), if state [B] is changed to state [A]
, The state that may follow the state [B] is [C] or [D]. Then, the current sample pattern is compared with the reference output pattern of state [C]. If they do not match (NO in step 155), the current sample pattern is compared with the reference output pattern of state [D]. Is done. If the current sample pattern does not match the reference output pattern of state [C] or the reference output pattern of state [D] (YES in step 156), it is determined that an error has occurred and an output signal indicating that an error has occurred and a mismatch output signal are present. It is displayed (step 159). In this case, the state [C] or the state [D] may be abnormal.

If the current sample pattern matches the reference output pattern of any of the following possible states (step 155), it is determined that a transition has been made to the matched reference output pattern, and the transition time is determined. Moves on to check whether or not is within the set range (step 157). In this case, the allowable range of the time required to transition to the state having the reference output pattern that matches the current sample pattern may be compared with the time measured by the timer 15.

If an abnormality is detected, the state (input pattern) of the input signal at that time is captured and stored (step 160). And it is determined that there is a possibility of abnormality 1
Alternatively, all of the expected input patterns set corresponding to the plurality of states are compared with the fetched input patterns (step 161). In this comparison, an input signal with a mismatched state is additionally displayed as an abnormal point candidate (possibly one or more) (step 162).
). The task of searching for a truly abnormal location from among the abnormal location candidates will be performed by an operator.

[Brief description of the drawings]

FIG. 1 is a flow chart showing the overall processing flow of cycle determination.
It is a chart.

FIG. 2 is a flowchart illustrating a flow of processing for determining a character related to a cycle.

FIG. 3 is a flowchart illustrating a flow of a process for determining a periodic pattern and a periodicity.

FIG. 4 shows a first example of a data string.

FIG. 5 shows a process of extracting a data transition pattern from a data sequence.

FIG. 6 shows extracted data transition patterns.

FIG. 7 shows a classification table of data transition patterns.

FIG. 8 shows another example of a classification table of data transition patterns.

FIG. 9 shows an example of processing for searching for a character related to a cycle.

FIG. 10 shows an example of a process of searching for a character related to a cycle.

FIG. 11 shows an example of processing for searching for a character related to a cycle.

FIG. 12 shows an example of a process of searching for a character related to a cycle.

FIG. 13 shows an example of a process of searching for a data transition pattern constituting a cycle.

FIG. 14 shows an example of a process of searching for a data transition pattern constituting a cycle.

FIG. 15 shows a divided data string.

FIG. 16 shows the structure of a data string.

FIG. 17 shows a second example of the data string.

FIG. 18 shows a classification table of data transition patterns.

FIG. 19 shows an example of a process of searching for a data transition pattern constituting a cycle.

FIG. 20 shows an example of a process of searching for a data transition pattern constituting a cycle.

FIG. 21 shows an example of a process of searching for a data transition pattern constituting a cycle.

FIG. 22 shows an example of a process of searching for a data transition pattern constituting a cycle.

FIG. 23 shows a divided data string.

FIG. 24 shows the structure of a data string.

FIG. 25 shows a third example of the data string.

FIG. 26 shows a data transition pattern.

FIG. 27 shows an example of a process of searching for a data transition pattern constituting a cycle.

FIG. 28 shows a divided data string.

FIG. 29 shows the structure of a data string.

FIG. 30 is a block diagram showing a configuration of a PLC and a console (cycle determination device).

FIG. 31 is a configuration diagram illustrating an example of a controlled system.

FIG. 32 is a ladder diagram showing a part of a user program.

FIG. 33 is a timing chart showing a control operation of the controlled system.

FIG. 34 shows an example of an output reference pattern.

FIG. 35 shows an example of abnormality determination reference data.

FIG. 36 shows an example of abnormal point detection reference data (expected input pattern).

FIG. 37 is a flowchart showing a failure diagnosis processing procedure.

FIG. 38 shows how an expected input pattern is compared with a sample input pattern (abnormal pattern).

FIG. 39 shows a display example when an abnormality occurs.

FIG. 40 is a configuration diagram showing another example of the controlled system.

FIG. 41 is a timing chart showing a control operation of the controlled system.

FIG. 42 shows another example of the output reference pattern.

FIG. 43 shows another example of the abnormality determination reference data.

FIG. 44 shows another example of the reference data for detecting an abnormal portion (expected input pattern).

FIG. 45 is a flowchart showing a failure diagnosis processing procedure.

[Explanation of symbols]

10 PLC (Programmable Logic Controller) 11, 21 CPU 12 ROM 13 RAM 14 RAM 15 Timer 20 Console 22, 23 Memory device 24 Output device 25 Input device

Continued on the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G06F 11/22-11/277 G01R 23/02 G01R 31/28-31/30

Claims (5)

(57) [Claims] 1. A means for extracting all types of data transition patterns consisting of continuous data of a predetermined length from a given data string, and arranging an arbitrary one of the extracted data transition patterns at the head. The other data transition pattern having the same sequence of data as the rear part of the preceding data transition pattern at the front is made to follow the preceding data transition pattern, and using a data transition pattern that is as different as possible. Means for creating a chain of data transition patterns. Changing the data transition pattern arranged at the head, causing the chain creation means to repeat the creation of the chain of data transition patterns, and returning to the head data transition pattern again. Means to check whether there is any data, and the sequence created when returning to the first data transition pattern. By utilizing the fact that corresponding to one period of the data row that has been given, means for determining the period, the period determination device data string having a. 2. A means for extracting, from a given data sequence, all types of data transition patterns composed of continuous data of a predetermined length, and extracting the extracted data transition patterns with all types constituting the data sequence. Means for storing the data transition pattern related to and including any unit data at the beginning, and other data having a common data arrangement at the front with the rear part of the preceding data transition pattern Means for forming a chain of data transition patterns by causing the data transition pattern to follow the preceding data transition pattern. Repeating the formation of the chain of data transition patterns while changing the data transition pattern placed at the head, A first step of checking whether the unit data associated with the data transition pattern reappears in the subsequent data transition pattern Checking means, means for determining, when unit data associated with the first data transition pattern reappears in a subsequent data transition pattern, the unit data to be associated with the cycle of the data sequence, and means associated with the cycle The data transition pattern related to the determined unit data is placed at the head, and another data transition pattern having the same data sequence as the rear part of the preceding data transition pattern at the front is made to follow the preceding data transition pattern. In this way, and by using different data transition patterns as much as possible, a chain of data transition patterns is formed, and it is checked whether there is any inevitable return to the data transition pattern placed at the top. If there is any checking means and if there is no choice but to return, use the data transition pattern Data train constituting a cycle by dividing the given data sequence and the first determining means for determining the period, the period determination device data string having a. 3. A means for extracting all types of data transition patterns composed of continuous data of a predetermined length from a given data sequence, and extracting the extracted data transition patterns with all types of data constituting the data sequence. Means for storing the data transition pattern related to and including any unit data at the beginning, and other data having a common data arrangement at the front with the rear part of the preceding data transition pattern Means for forming a chain of data transition patterns while selecting a data transition pattern so that the data transition pattern follows the preceding data transition pattern and so that the unit data does not appear as much as possible; Repeat the formation of the chain of data transition patterns while changing the pattern, and the leading data transition pattern Means for checking whether a unit data that has to be reappeared in a subsequent data transition pattern, and when the unit data associated with the first data transition pattern reappears in a subsequent data transition pattern, the unit data Means for determining that the data sequence is related to the cycle of the data sequence, and an apparatus for finding data related to the cycle. 4. Extracting all types of data transition patterns composed of continuous data of a predetermined length from at least a data sequence of an output signal of the control device, and arbitrarily selecting any of the extracted data transition patterns at the beginning. The data transition pattern is arranged so that another data transition pattern having the same data sequence as the rear part of the preceding data transition pattern at the front thereof follows the preceding data transition pattern, and uses a data transition pattern that is as different as possible. Then, create a chain of data transition patterns and repeat the creation of a chain of data transition patterns while changing the data transition pattern placed at the top, so that there is a chain that returns to the top data transition pattern again. Check if it returns and return to the first data transition pattern. Utilizing the fact that it corresponds to one cycle of the data sequence, the cycle is determined, and the abnormality determination reference data including the reference pattern of each state appearing in one cycle and the data on the connection between the states is created in advance. During the operation of the control device, at least a change in the pattern of the output signal of the control device coincides with a change in the reference pattern associated with a state transition represented by the abnormality determination reference data. A failure diagnosis method that determines whether there is an abnormality in a system controlled by the control device by checking whether the system is operating. 5. A means for extracting all types of data transition patterns composed of continuous data of a predetermined length from at least a data sequence of an output signal of a control device, and selecting any one of the extracted data transition patterns. The other data transition pattern, which is placed at the beginning and has the same data sequence as the rear part of the preceding data transition pattern at the front, is made to follow the preceding data transition pattern, and a data transition pattern that is as different as possible Means for creating a chain of data transition patterns, by changing the data transition pattern arranged at the head, causing the chain creation means to repeat the creation of the chain of data transition patterns, Means to check if there is a returning chain. When returning to the first data transition pattern Means for determining the cycle using the fact that the created chain is equivalent to one cycle of a given data sequence. The reference pattern of each state appearing in one cycle and the data on the connection between the states are determined. Storage means for preliminarily storing abnormality determination reference data, and at least a change in a pattern of an output signal of the control device during operation of the control device, the reference being accompanied by a state transition represented by the abnormality determination reference data. Means for judging the presence or absence of an abnormality in a system controlled by the control device by checking whether or not the change corresponds to a change in the pattern.