JP3380912B2 - Method and apparatus for grouping diagnosis targets for failure diagnosis - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diagnostic object grouping method and device for fault diagnosis, and more particularly to a programmable logic controller (hereinafter simply referred to as PLC).
PLC in the fault diagnosis to detect the abnormality that occurs in the system (including equipment) controlled by
The invention relates to a method and a device for dividing a controlled system into parts to be monitored independently of one another in terms of input and output signals.

[0002]

[Background Art and Problems] In order to detect an abnormality in the operation of a system controlled by a PLC at an early stage, the PLC program includes an abnormality detection (fault diagnosis) function,
Alternatively, it is required to add a failure diagnosis unit to the PLC, and the demand is increasing day by day.

In order to deal with this, an operating condition, which is a normal reference of the system controlled by the PLC, is observed in advance and the result is stored. Then, a method of detecting an abnormality of the system in real time has been proposed by monitoring the actual operation of the system and comparing it in real time with an operating state that is a normal reference stored in advance. .

PLC is used as a normal reference operating state.
The input and output states, the ON and OFF states of output signals, the transition order of these states, and the time required for state transition (standard value and allowable width or minimum value and maximum value) are considered.

In practice, a single PLC often controls a system composed of a plurality of manufacturing or processing steps. In such a system, a buffer area for a workpiece may be provided between processes. Since the work can be temporarily stored in the buffer area, the operation in the previous process and the operation in the subsequent process of the buffer area do not necessarily need to be synchronized.

As shown in FIG. 34, it is assumed that a buffer area is provided between step I and step II. Workpieces a, b, c, d are each processed in the process I,
It is sent to Process II via the buffer area, where it is subjected to the next processing. Focusing on one work, the process I
After the processing in step 2 is completed, the processing in step II is performed. However, the processing work is performed in the process I and the process II without mutual relation. That is, when the work a is being processed in the process I, the process II may not be operated at all, or while the work c is being processed in the process I, the work II is not performed in the process II. Processing may end.

Assuming that the states of the input and output signals of both of the two processes I and II operating completely asynchronously are monitored at the same time, the actual states of the input and output signals will be the same as those of both the processes I and II. Even if the operation in (1) is normal, it may frequently happen that the input and output signals that are the reference that are registered in advance do not match. Therefore, it is impossible to perform unified monitoring.

Therefore, it is conceivable to separately monitor the operation of the asynchronous parts as in steps I and II. The input and output signal states that are the basis for the fault diagnosis of the process I and the input and output signal states that are the reference for the fault diagnosis of the process II are created separately in advance, and the actual input of the process I is performed. , The state of the output signal is checked against the input / output signal state which is the reference prepared in advance for the process I, and the state of the actual input / output signal of the process II is the process
The input and output signal states, which are the standards created in advance for II, are checked.

However, the scale of the controlled system tends to be large, and a single PLC nowadays has a scale of 1,000 to 1,000.
It is not uncommon to handle thousands of input and output signals.

When the concept of performing fault diagnosis separately for asynchronous processes is adopted, it is necessary to group the enormous number of input / output signals as described above into groups that are asynchronous with each other. It takes a lot of effort.

[0011]

SUMMARY OF THE INVENTION The present invention is a method and method for automatically grouping output signals that can be, to be monitored, or preferably monitored, independently of each other in terms of a PLC ladder program. The purpose is to provide a device.

In the method of grouping diagnostic objects for fault diagnosis according to the present invention, input / output contacts associated with each monitored object output (corresponding to the monitored object output coil in the embodiment) are extracted in the program executed by the PLC. The above processing is performed for all the above-mentioned monitored outputs, data regarding the connectivity between any two monitored outputs is calculated from the viewpoint of the commonality of the extracted input and output contacts, and the data regarding the calculated connectivity is used. From the viewpoint of the strength of the coupling between the monitored outputs shown, the groups to which the above-mentioned monitored outputs belong are formed.

Preferably, the formed groups and the identification numbers of the monitored outputs belonging to them are output (for example, displayed or printed).

The diagnosis target grouping device for fault diagnosis according to the present invention extracts, for each selected monitoring target output, the input / output contacts referred to by the monitoring target output in the program executed by the PLC. Means, for all combinations of the two monitored outputs selected from the monitored outputs, from the viewpoint of commonality of input and output contacts referred to by these two monitored outputs.
It is provided with means for calculating the degree of coupling between the two monitored outputs, means for grouping the monitored outputs based on the calculated degree of coupling, and means for outputting the result of grouping the monitored outputs.

It is preferable to include a step of selecting an output to be monitored from data related to a program executed by the PLC, and to execute the grouping after the output to be monitored is determined.

In a preferred embodiment of the present invention,
The input and output contacts to be extracted also include the internal auxiliary contacts existing only on the program.

In another embodiment of the present invention, when the monitored output refers to only one contact on the program, all the monitored outputs associated with the referenced contact are Input and output contacts are extracted.

There are several methods of calculating data or degree of connectivity for connectivity. In the case of 1, the data regarding the connectivity or the degree of connectivity is determined as 1 if there is a contact point common to the two outputs to be monitored, and 0 if not.
The second is to obtain the data regarding the connectivity or the degree of connectivity as the number of contacts common to the two monitored outputs. In the third method, the data or the degree of connection is calculated as a value obtained by dividing the number of contacts common to the two monitored outputs by the total number of the contacts related to the two monitored outputs.

There are several ways to form a group. One of them is to form a group so that the data regarding the connectivity or the output of the monitored object having the coupling degree other than 0 belongs to one group. 2 is 1
It sets an upper limit on the number of monitored outputs that belong to one group. In this case, the monitoring target outputs having strong coupling are grouped in order, and the monitoring target outputs are prohibited from being registered to the group whose number of included monitoring target outputs reaches the upper limit.

As described above, according to the present invention, the outputs to be monitored, that is, the output signals, which are related to each other are automatically grouped, so that the controlled system can be divided into a plurality of groups. Especially when one PLC controls input / output of 1,000 to several thousand, it is not necessary to manually grasp the entire system control while following the ladder program, and it is possible to deal with each group. This makes it extremely easy to create a failure diagnosis program.

Fault diagnosis is possible for each group formed by grouping, and the parts that operate asynchronously with each other belong to different groups, so that independent fault diagnosis for each part is possible. , Debugging and maintenance are also easy. Also, the burden of creating a failure diagnosis program is reduced.

[0022]

[0023]

[0024]

[0025]

[0026]

[0027]

[Explanation of Examples]

(1) System Configuration FIG. 1 shows the configuration of the entire system including a PLC as a control device and a device for realizing the grouping method according to the present invention.

The PLC 10 is for controlling a controlled system to be described later, and includes a CPU 11 for executing control processing according to a ladder program, a ROM 12 storing a ladder control system program, and a user for controlling the controlled system. I / O for transmitting / receiving input / output signals to / from the controlled system via a RAM 13 for storing a user program (ladder program) created by the user, a work RAM 14, a timer 15, and a PLC I / O data bus.
I / for communicating with unit 16 and console 20
It has an F (interface) 17. The I / O table that holds the actual input / output signal status of the PLC is RAM
It is provided in 14.

The console 20 executes a grouping method for dividing the controlled system into parts which can be monitored independently of each other, and is executed by the CPU 21 and the CPU 21 which are the main executing bodies of this grouping method. Memory device 22 for storing a program to be stored, memory device 23 for storing data required or generated in processing execution, output device 2 including a display device and a printer for outputting a grouping result
4. It includes an input device including a keyboard, and an I / F 27 for connecting to the PLC 10 and I / Fs 29 and 28 for input and output devices 25 and 24. Memory devices 22 and 23 are RO
It can be realized by a hard disk or a floppy disk as well as a semiconductor memory such as M or RAM. The console 20 may be realized by a so-called personal computer or the like.

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

(2) Example of Controlled System Configuration and Control Program Thereof FIG. 2 shows an example of the controlled system.

The work W is conveyed by the conveyor 91. The transport conveyor 91 is driven by the first motor (M1) 72. On the way of the conveyor 91, the presence of the work W and the burrs on the work W are automatically detected. Therefore, the first work detector 55 and the burr detector 56 are arranged. When it is detected that the work W has burrs or burrs larger than a predetermined amount, the work W is removed from the conveyor 91 by the defective exclusion pneumatic cylinder 73. While the cylinder 73 is operating, the rotation of the motor 72 is stopped and the conveyor 91 is stopped.

The work W transported to the end by the transport conveyor 91 is transferred onto the transport table 92. A stay detector 57 is provided for detecting the work W conveyed near the end of the conveyor 91. When the stay detector 57 continues to detect the work W for a certain period of time or longer, the abnormality lamp 71 of the operation panel 90 is turned on.

A second work detector 58 is provided to detect the work W carried from the carrying conveyor 91 onto the carrying table 92. When the work W is detected by the work detector 58, the loading pneumatic cylinder 75 is driven and the rod of the loading cylinder 75 pushes the work W onto the transport table 92 toward the processing table 93. The work W transferred onto the processing table 93 is detected by the third work detector 61.

When the work W is transferred onto the processing table 93, the jig 77 for fixing the work W is driven in the direction for tightening the work W. In addition, the second motor M278 is driven to rotate, and the drill 79 fixed to the rotary shaft of the motor 78 rotates the motor 78.
Along with it, the workpiece W is drilled. After drilling, the drill 79 and the motor 78 move up
78 rotation stops. The workpiece having the holes drilled 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 series of steps described above starting from the start 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 process is stopped and the in-operation lamp 70 is turned off. As described above, when the detection signal of the staying detector 57 continues for a certain time or longer, 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.

A defective front end detector that detects that the rod has advanced (advanced) to the advanced end of the defective discharge cylinder 73, and a defective that detects that the rod has retracted and has reached its retracted end. A trailing edge detector (neither 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, a drill lift detector that detects that the drill 79 (and the motor 78 to which it is attached) has risen to reach its ascending end, and a drill descend detector that detects that the drill 79 has descended to reach its descending end. (All are not shown).

The signals input to the PLC 10 from this controlled system are as follows. The first (000) to (01
5) is the number of the input signal. Also, () at the end is an abbreviation.

(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 (defective 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 (stagnation detection) (008) Work detection signal of second work detector 58 (detection 2) (009) Detection signal of front end detector (front end) (010) Detection signal from rear end detector (rear end) (011) Work detection signal of third work detector 61 (detection 3) (012) Drill top end Detector detection signal (drill top) (013) Drill bottom detector detection signal (drill bottom) (014) Discharge front end detector detection signal (discharging front end) (015) Discharge rear end detector detection signal (discharge) Rear end)

The signals output from the PLC 10 to this controlled system are as follows. The first (100) to (1
12) is the number of the output signal. Also, () at the end is an abbreviation.

(100) ON / OFF control signal of operating lamp 70 (L in operation) (101) Abnormal ON / OFF control signal of lamp 71 (abnormal L) (102) Rotation drive control signal of first motor 72 (M1 rotation) (103) Forward drive control signal for defect elimination cylinder 73 (defective forward) (104) Reverse drive control signal for defect elimination cylinder 73 (defective backward) (105) Forward drive control signal for closing cylinder 75 (close forward) ) (106) Reverse drive control signal of closing cylinder 75 (close backward) (107) Tightening drive control signal of fixing jig 77 (fixing jig) (108) Rotation drive control signal of second motor 78 (M2 rotation) (109) Ascending drive control signal of the drill 79 (drill ascent) (110) Ascending drive control signal of the drill 79 (drill descending) (111) Forward drive control signal of the discharging cylinder 81 (discharging forward) (112) Reverse drive control signal of the discharge cylinder 81 (ejection retracted)

FIGS. 3 to 9 show a program (a user program) set in the PLC 10 (stored in the RAM 13) for controlling the above-mentioned controlled system to perform the above-described operation. 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 this relay, and internal auxiliary relays and their contacts. In these figures, the three-digit numbers of the input and output signals described above are represented by five digits by adding two-digit 00 to the upper part thereof.

The meanings of the internal auxiliary relay and its contacts shown in FIGS. 3 to 9 are as follows. Also in this case, the numbers of the internal auxiliary relay and its contacts (they have the same numbers) are expressed in the lower 3 digits except for the upper 2 digits.

(200) 1U operation: Represents the conditions for operating the entire defective work discharge section. (201) 2U operation: Represents the conditions for operating the entire drilling unit. (202) Defect elimination: Indicates that a defective work is detected, and is turned on until the elimination is completed. (203) During setting: Represents the start of the entire drilling operation, and is turned on until the processing and discharging are completed. (204) Completed setting: Indicates that the setting of the work on the processing table is completed. (205) During drilling: Indicates that the work is set on the processing table, and is turned on until drilling is completed. (206) Hole drilling complete: Indicates that drilling of the workpiece is completed. (207) Completion of processing: Indicates that the discharge of the work is completed. (208) Input memory: Indicates that the workpiece has been input to the processing table, and is turned on until the processing and discharging are completed. (209) Drill memory: Indicates that the drill has drilled a hole in the work, and is turned on until the drilling is completed. (210) Ejection memory: indicates that the work has been ejected,
It is turned on until the discharge is completed.

Further, in FIG. 3, TIM represents a timer element. This is for determining whether or not the staying detection signal continues for a certain time.

(3) Grouping Processing Using the above-mentioned controlled system as an example, processing for forming groups in which failure diagnosis can be performed independently of each other will be described.

FIG. 10 shows the overall processing procedure of this grouping processing. This process is mainly for console 20
CPU21 of.

(3-1) As will be made clear by showing an example of the failure diagnosis processing in detail after selecting the output coil to be monitored, the failure diagnosis processing is performed as follows. As the first step, only the output signal is constantly monitored (the output pattern and the reference pattern are compared) to determine whether or not the output signal is abnormal. When an abnormality is detected,
The state (input pattern) of the input signal at that time is compared with a preset input expected pattern, and the input signal causing the abnormality is specified.

For such a failure diagnosis process, it is necessary to determine the output signal to be monitored.

The PLC 10 has a function of extracting the used I / O relay list from the set user program (ladder program). This list extracted by the PLC 10 is output from the output device 24 of the console 20. An example of the output I / O relay list is shown in the figure.
Shown in 11. 000CH is a relay related to an input signal, 001CH is a relay related to an output signal, 002
CH is an internal auxiliary relay. These relays (contacts)
The number (5 digits) is configured by setting the 3 digits before CH as the upper 3 digits and the 2 digits in the bit column as the lower 2 digits.
These numbers are the same as those described above, and their contents are also as described above.

The output signals to be monitored (hereinafter referred to as monitoring target output coils) are 13 of 001CH, that is, output coils with numbers (only the lower three digits) of 100 to 112.

In this way, the output coil to be monitored is determined (step 101).

The output coil to be monitored can be obtained from the I / O table provided in the RAM 14 of the PLC 10 without extracting it from the ladder program. Further, it goes without saying that the user may manually create the monitored output coil list.

From the list of output coil to be monitored created in this way, only those that need special monitoring are selected, and outputs that are not so important and outputs that are not particularly problematic without monitoring are excluded. May be. The final determination of the monitored output coil will be made by inputting from the input device 25 what is necessary or unnecessary on the list displayed on the output (display) device 24.

In any case, when the output coil to be monitored is finally determined, for convenience of later processing,
The numbers of these output coils are initialized (step 10
2). As described above, the number of the output coil to be monitored is 100
~ 112. These numbers are converted into consecutive numbers starting from 0 (or starting from a predetermined initial number). In this embodiment, the output coil numbers 100 to 112 are 0 to 12
Shall be converted to. This process is especially important when the output target output coil number is missing or not continuous.

(3-2) Creation of Input Contact List Next, an input contact list related to each monitored output coil is created (steps 103, 104, 105).

An example of the created input contact list is shown in FIG. In this list, in the ladder program shown in FIGS. 3 to 9, the input contacts referred to by each monitored output coil (contacts turned on and off by an input signal: the same number as the input signal is attached. ), Internal auxiliary contacts, and output contacts (contacts that are turned on and off by the output coil; are numbered the same as the output coil: the output coil is numbered the same as the output signal). . This is because not only the input contact but also the internal auxiliary contact and the output contact are used for the grouping process.

Points to be especially noted will be described.
In the ladder diagram shown in FIG. 7, the output coil "jig tightening (107)" refers only to the internal auxiliary contact "during drilling (205)" (see address 0704). In such a case, it is considered that the output coil (107) and the internal auxiliary contact (205) have the same function. Therefore, the internal auxiliary relay (coil) corresponding to the internal auxiliary contact (205) "drilling (205)" refers to the contact "Detection 3 (011)", "Set complete (2)".
04) ”,“ drilling (205) ”, and“ drilling completed (206) ”are also regarded as the contacts referred to by the output coil“ jig tightening (107) ”(see address 0609).
Therefore, in the list of FIG. 12, in the jig tightening column, the number 205 of the equivalent internal auxiliary relay is entered together with the number 107, and the numbers 011, 204, 205 and 206 are used as the reference input contact and the internal auxiliary contact. It is filled in.

Similarly, the output coil "M2 rotation (10
8) ”is 1 of the output coil contact“ jig tightening (107) ”
Only one is referenced (see address 00006). From this output contact 107, the output coil “jig tightening (10
7) ”and similarly contact points 011, 204, 20
5,206 will be referred to.

The process of creating such an input / output contact list is executed by the CPU 21 as follows.

First, the ladder programs (circuits) shown in FIGS. 3 to 9 are converted into mnemonic (or mnemonic) lists as shown in FIGS. 13 to 15. This conversion process can also be executed by the CPU 11 of the PLC 10.

The mnemonic list is a language converted into a one-to-one correspondence with a ladder program (circuit).
It has a one-to-one correspondence with the machine language of the CPU 11 of the C10. Figure 3
-By comparing Fig. 9 with Fig. 13-Fig. 15, mutual relations will be easily understood. The addresses are common in these figures.

An input / output (and internal auxiliary) contact list to which each of the above-mentioned 13 output coils to be monitored is sequentially referenced is created (step 104). The output coil that is the target of the input / output contact list creation process is called the focused output coil.

The details of the process of creating the input / output contact list for each output coil of interest are shown in FIG.

First, in the mnemonic list, the number of the output coil of interest is searched from the operand code, and the address of the statement in which the mnemonic code is OUT is searched for. This address is set as A (step 111). The code OUT means that it is an output coil.

For example, let us focus on the above-mentioned output coil "jig tightening (107)". The address of the statement in which the mnemonic code of the jig fastening 107 is OUT is 00007 (see FIG. 14).

This address A = 000075 is stored in the storage device 23.
Alternatively, it is temporarily stored in another register or the like (step 11
2).

A-1 = 00075-1 = 00074 is calculated, and this is set as a new address A (step 113).
).

It is checked whether the mnemonic code of the new address A = 000074 is LD (step
114). Code LD means the start of each ladder in the ladder circuit. The mnemonic at address A = 000074
The code is LD.

That is, this step 114 is to check whether the output coil of interest refers to only one contact on the ladder. As described above, the output coil "jig tightening (107)" refers only to the internal auxiliary contact "drilling (205)". In such a case, the output coil (107) and the internal auxiliary contact (205) are considered to be equivalent, and the contact referred to by the coil (205) of the internal auxiliary contact (205) is searched for next. Become.

Therefore, it is checked whether or not there is a statement in which the mnemonic code is OUT among the contact numbers represented by the operand code of address A, and if there is, the address is set to A (step 118). , 119, 112).

The operand code of address A = 00074 is 00205, and the contact number 205 (the upper 2 digits are omitted) represented by this is checked in the operand column of the mnemonic list, and the corresponding mnemonic
Check if there is a statement whose code is OUT. Since the statement at address 0703 is “OUT 00205”, A =
00073 will be stored.

In this way, the internal auxiliary relay "during drilling (2
05) ”was sought out, and this internal auxiliary relay (205)
The input / output contact that it refers to is searched for in the subsequent processing, and the input / output contact list is created.

That is, the stored address A = 000
By subtracting 1 from 73, a new address A =
00072 is obtained (step 113) and the mnemonic code of the statement at this new address is L
It is judged whether or not it is D (step 114). The new address A = 000072 mnemonic code is ANDNO
Since it is T, the result of this step 114 is NO.

Contact number 2 of this address A = 00072
06 shows the internal auxiliary contact “drilling completed (20) in the input / output contact list related to the focused output coil“ jig tightening (107) ”.
6) ”(step 115).

The address A is decremented again (step 117), and the internal auxiliary contact "during drilling (205)" of the address A = 000071 immediately before is similarly registered in the input contact list (step 115). .

The processing of steps 117 and 115 is continued until the mnemonic code at address A becomes LD. If the mnemonic code LD is present (the code LD appears at address 0609), the output coil of interest "jig tightening (107 ) ”, The processing for creating the input / output contact list ends (step 116).

As a result, the output coil of interest "jig tightening (1
07) ”in the input / output contact list for
06) ”,“ drilling (205) ”,“ set complete (20
4) ”and“ Detection 3 (00011) ”are registered.

The output coil "jig tightening (10
7) ”and“ M2 rotation (108) ”only, the process of returning from step 114 to steps 118 and 119 and returning to step 112 is performed. For the other output coils, the process directly moves from step 114 to step 115.

The statement that becomes NO in step 119 and advances to step 120 does not exist in the mnemonic list shown in FIGS. 13 to 15. This processing is for processing in which one output signal is generated by only one input signal and is not related to other input signals or internal auxiliary relays at all. For example, this applies to the case where the indicator light is only turned on when the water in the tank rises to a predetermined level and there is no other related process. In such a case, one input contact (input signal) that causes the output coil (output signal) is registered in the input / output contact list of that output coil (step 120), and the processing for that output coil ends.

When the input contact list creation process shown in FIG. 16 related to one output coil is completed, the next output coil is called (FIG. 10, step 105), and similar processing is performed for that output coil. It is repeatedly executed. If an input / output contact list is created for all monitored output coils selected in step 101 (step 103
If YES, the process proceeds to the next step 106, the coupling degree calculation process.
The processing of steps 103 to 105 completes the input / output contact list shown in FIG.

(3-3) Calculation of degree of coupling The degree of coupling between the two output coils is obtained from the viewpoint of input / output contacts (including internal auxiliary contacts) common to those output coils. There are several methods for calculating the degree of coupling, and examples are given below.

Calculation method based on presence / absence of common contact If there is a contact (input / output contact or internal auxiliary contact) commonly referred to by the output coil i and the output coil j, the coupling degree R _{ij of} these contacts is set to 1, and if not 0 And

Calculation Method Based on the Number of Common Contacts The number of contacts commonly referred to by the output coils i and j is defined as the coupling degree R _ij . For example, if the number of common contacts is 4, and the coupling degree R _ij is 4,0, then R _ij = 0.

Calculation method based on common contacts and all reference contacts The number of contacts commonly referenced by the output coils i and j is divided by the total number of contacts referenced by the coils i and j (excluding duplicate contacts). The value is the coupling degree R _ij .

Coupling degree R _ij = (number of common contacts of output coils i and j) / (total number of reference contacts of output coils i and j)

In the input / output contact list shown in FIG. 12, for example, the contact point referred to by the output coil "make-up advance (105)" is 008,009,010,01.
There are eight, 1, 201, 204, 105 and 106. The numbers of the contacts referred to by the output coil “close and retract (106)” are 009, 010, 201, 105 and 106.
It is five of. There are five contacts 009, 010, 201, 105 and 106 common to both output coils. The contacts referenced by both output coils are 008,
There are a total of 8 of 009,010,011,201,204,105 and 106.

Therefore, according to the above method, the coupling degree is R _ij = 1, and according to the above method, the coupling degree is R _ij = 5.
According to the above method, the coupling degree is R _ij = _5/8 .

13 calculated according to the above method
The degree of coupling between any two output coils selected from the output coils is shown in FIG. This is called a monitoring target output coil coupling degree table. A blank column indicates a bond degree of 0. The molecules of these degrees of binding represent the degrees of binding calculated by the above method. Fraction with a degree of coupling other than 0 (other than blank) is 1
Then, Fig. 17 can be easily converted into the coupling degree table by the above method.

FIG. 18 shows the procedure of the processing for calculating the degree of coupling between two output coils for all the monitoring target output coils and creating a coupling degree table as shown in FIG. This corresponds to details of the processing in step 106 in FIG.

As described above, the monitoring target output coil numbers 100 to 112 are initialized and converted to 0 to 12. This initialized output coil number is set as i or j. The number of output coils is n. In this example, n = 13.

The output coil numbers i and j are set to 0 (step 121). The output coil number i is fixed, the number j is incremented (step 122), and the coupling degree R _ij between the output coil of number i and the output coil of number j is calculated according to the above-described calculation method. (Step 123). In this process, the number j is incremented by n while incrementing the number j.
Repeat until (step 124).

Next, the number i is incremented (step 126), the number j is set as j = i (step 127), and the above-mentioned steps 122 to 124 are repeated.

When the number i reaches n, the coupling degree calculation process is terminated (step 125).

From the above, the degree of connection R _ij is calculated for all combinations of numbers i and j (excluding i = j),
A coupling degree table as shown in FIG. 17 is created.

(3-4) Group Formation (Part 1) The output coil grouping table is used to group the output coils (FIG. 10, step 107).
).

An example of this grouping process is shown in FIG. This grouping process is based on the idea that output coils with coupling degrees other than 0 belong to the same group.

The numbers i and j of the initialized output coils are both set to 0 (step 131), the number i is fixed and the number j is incremented (step 132).

The coupling degree R _ij of the output coil of number i and the output coil of number j is read from the coupling degree table described above, and is read as 0.
It is checked whether or not (step 133).

If the coupling degree R _ij is not 0, the output coil with number i and the output coil with number j must belong to the same group. Therefore, it is first checked whether or not at least one of the output coils i and j is registered in the already created group (step 134). If the output coil i and the output coil j already belong to the same group, new registration is unnecessary. If one of the output coils i and j belongs to a certain group, the other output coil that does not yet belong to that group is additionally registered in the same group. If the output coils i and j are registered in separate groups, these two groups are merged into one group (step 135). If both the output coils i and j do not belong to the group already created, a new group is formed by the output coils i and j, and the output coils i and j are registered in the group (step 136). .

If the coupling degree R _ij of the output coils i and j is 0, no processing is required.

Until the number j reaches n, the above steps 132 to 136 are repeated while incrementing the number j (step 137).

When j = n, the number i is incremented (step 139) and j = i is set (step 140).
), And returns to step 132 and repeats the above processing again.

When the number i reaches n, the grouping process ends (step 138).

The group (generally a plurality) thus formed is displayed on the output (display) device 24 (see FIG. 10,
Step 108). The display example is shown in FIG.

The above-mentioned 13 output coils 100 to 112
Are divided into three groups as follows.

Group I: Output coils 100, 101 Group II: Output coils 102, 103, 104 Group III: Output coils 105, 106, 107, 1
08,109,110,111,112

The controlled system shown in FIG. 2 will be described. Group I relates to a process for blinking the operating lamp 70 and the abnormal lamp 71 on the operation panel 90. An overview of this process is shown in FIG.

Group II relates to the process of eliminating defective work. In this group II, the motor 72 and the defect elimination cylinder 73 are controlled based on the output signals of the work detector 55 and the burr detector 56. The outline of the control in this step is shown in FIG.

Group III relates to the process of drilling a workpiece. In this group III, the loading cylinder 75
The work is loaded into the processing table 93, the work is clamped and fixed by the jig 77, the hole is drilled by the drill 79, and the work is discharged from the processing table by the discharge cylinder 81. The outline of the control in this step is shown in FIG.

In this way, the output coils can be grouped in terms of the commonality of the input / output contacts. The operation of each unit is related to each other in each group. The groups have little relevance to each other.

(3-5) Group Formation (Part 2) Another method of grouping will be described. This grouping method limits the number of output coils belonging to one group. The degree of coupling calculated by the above method or is used. When the number of output coils belonging to the group reaches the limit number, registration of the output coil to the group is prohibited and a new group is formed.

FIG. 24 shows the processing procedure of this grouping method. The maximum number of output coils that can belong to one group is a.

Referring to the monitoring target output coil coupling degree table,
The output coils i and j having the maximum coupling degree R _ij are searched (step 141).

It is confirmed that the coupling degree R _ij is not 0 (step 142), and one of the output coils i and j has a group already formed (of the first coupling degree R _ij ). It is determined whether or not the group has not been formed at the time of the processing (step 143). If both output coils i and j are not already registered in the existing group, a new group is formed by these output coils i and j, and this group is registered in the memory (step 144). And
The coupling degree R _ij that has been the object of processing (searched in step 141) is deleted from the monitoring target output coil coupling degree table (step 145).

If any one of the output coils i and j is registered in the existing group (step 14
3 YES), then whether both output coils i and j are already registered in the existing group (the output coils i and j may be the same group or different groups)
Is determined (step 146).

If both output coils i and j are not group-registered, one of the output coils is registered (YES condition is satisfied in step 143). It is judged whether or not the number of output coils belonging to the group in which has been registered has reached the maximum number a (step 147). If the number of output coils belonging to the group has not reached the maximum number a,
The other output coil that does not belong to any group is registered in the group (step 148), and the coupling degree R _ij to be processed is deleted from the coupling degree table (step 145). If the number of output coils included in the group in which one of the output coils is registered has already reached the maximum number a (YES in step 147), the coupling degree R _{ij is set} to the coupling degree without performing anything. Delete from table (step
145). In this case, the other output coil that does not yet belong to the group is not registered as a group, but it is expected that it will eventually be registered in one of the groups in the subsequent iterative processing. If output coils that do not belong to any group (coupling degree with other output coils is not 0) remain at the end of the group forming process, the output coil is registered in some way (for example, the number of registrations is a. Even if it becomes larger than that, it is forcibly put in any group, it is judged by the user to be put in any group, etc.), and it is recommended to belong to any group.

If both output coils i and j already belong to either group, those output coils i
It is determined whether and j are registered in the same group (step 149). If the output coils i and j are registered in the same group, no processing is required and the coupling degree R _ij is deleted from the coupling degree table (step
145).

If the output coils i and j belong to different groups, it is determined whether the sum of the numbers of output coils registered in these two groups is less than or equal to the maximum number a (step 150). ). If the sum of the numbers of output coils belonging to the two groups is a or less, these two groups are merged into one (step 151). If the sum of the numbers of coils belonging to the two groups exceeds a, nothing is done.
After that, the connection degree R _ij which is the object of processing is deleted from the connection degree table (step 145).

After the processing of step 145, the step is repeated again.
Returning to step 141, the highest bond degree remaining in the bond degree table is selected and the same process is repeated. And
When all the bond degrees remaining in the bond degree table become 0, the group forming process ends (step 142).

FIG. 25 shows a display example of a group created by this grouping method. The number of output coils that can belong to one group is a = 6.
Four groups I, II, III and IV have been formed. FIG. 26 shows another display example of the created group.

(4) Example of Fault Diagnosis Process As described above, it was found that the output coils for controlling the system shown in FIG. 2 are divided into three or four groups by the grouping process. For each of the groups thus divided, failure diagnosis is performed independently of each other.

As an example of the failure diagnosis processing, the failure diagnosis processing for the group III related to drilling among the three groups grouped in (3-4) Group formation (Part 1) will be specifically described below. explain.

FIG. 27 shows the entire drilling process (transfer of the work W from the transfer table 92 to the processing table 93 by the loading cylinder 75, the jig 77).
The operation of fixing the work W by means of, the drilling of the work W by means of the motor 78 and the drill 79, and the discharge of the hole-finished work from the processing table 93 by means of the discharge cylinder 81). P
The input signal to LC10 and the output signal from PLC10 are shown. Further, it is shown that the state of the output signal (output pattern) changes with the passage of time. The numbers [1] to [7] are assigned to the respective states of the output signal that transits (state of the signal at the position where the broken line is drawn). Hereinafter, each of these states will be referred to as a state.

The rise of the input signal "Detection 2" is used as a trigger to shift from the state [7] described later to the state [1] (the relationship between the trigger input signal and the output signal is indicated by a chain line and an arrow). This state transition is executed by the program at address 00039 shown in FIG. When the second work detector 58 detects the work W, the rod of the closing cylinder 75 advances and pushes the work W toward the working table 93.

Next, when it is detected by the closing front end detector that the rod of the closing cylinder 75 has reached its forward end (input signal "closing front end" is on), the state [1] transits to the state [2]. Then, the rod of the charging 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 rotationally driven. This is the address 00052 shown in FIG.
Etc. are executed according to the program.

When it is detected by the closing trailing end detector that the rod of the closing cylinder 75 has reached the retracted end (input signal "closing rear end" is off), the state [2] transits to the state [3], The backward movement of the closing cylinder 75 stops,
The drill 79 starts descending. As a result, the work 79 is drilled by the drill 79.

When the drill bottom end detector detects that the drill 79 has reached the lower end (input signal “drill bottom end” is on), the state [3] transits to the state [4], and the drill 79 descends. Stop and drill 79 begins to rise.

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 [4] transits to the state [5], and the jig 77 moves the workpiece. Release, the rotation of the motor 78 stops,
The drill 79 stops rising, and the rod of the discharge cylinder 81 starts moving forward. By advancing the rod of the discharge cylinder 81,
The work W that has been drilled is discharged from the processing table 93.

When the discharge front end detector detects that the rod of the discharge cylinder 81 reaches the forward end (input signal "discharge front end" is on), the state [5] transits to the state [6], and the discharge cylinder The forward movement of 81 stops, and the backward movement starts.

When the discharge rear end detector detects that the rod of the discharge cylinder 81 has reached the retracted end (input signal "rear discharge end" is on), the state [6] transits to the state [7]. This completes one drilling process.

FIG. 28 shows a part of the abnormality determination reference data for abnormality detection. The abnormality determination reference data is provided for each state, and is composed of the output pattern data of that state, the average transition time from the previous state, and the allowable fluctuation range of the transition time.

The output pattern data is a collection of data representing the states of all output signals to be monitored. The state of each output signal is represented by 1 bit. In this embodiment, the ON state is represented by 1 and the OFF state is represented by 0.

FIG. 29 shows the seven states [1] to
The output pattern data of [7] is extracted and summarized from the abnormality determination reference data, and represents the states of eight types of output signals (output coils) belonging to Group III. The correspondence will be easily understood by comparing the timing chart shown in FIG. 27 with the table shown in FIG.

Such output pattern data is obtained by actually operating the controlled system under the control of the PLC 10 and extracting the state of the output signal when it operates normally when it changes. Can be created. Most commonly, I / O provided in RAM14 of PLC10
It can be created by sampling the O table at regular intervals and processing it. The details will be described in the description of the creation of the reference data for detecting abnormal points.

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

The permissible fluctuation range of the transition time represents the permissible range of the deviation of the actual transition time from the average transition time, and will generally be input by the user. However, all the allowable widths may be values proportional to the average transition time, and the proportional constant may be uniformly set.

As the data regarding the transition time, in addition to the above-mentioned combination of the average value and the allowable width, for example, a combination of a reference value, a lower allowable width and an upper allowable width, a combination of a maximum value and a minimum value, etc. it can.

The abnormal point detection reference data is composed of data representing the expected state (input expected pattern) of the input signal corresponding to each abnormality determination reference data in each state described above. That is, the abnormal point detection reference data is composed of input expected patterns preset for each state.

The abnormal point detection reference data is used to specify a point or a portion which causes the detected abnormality when an abnormality is detected in the abnormality detection process using the abnormality determination reference data described above. . Therefore, in principle, all input signals that directly or indirectly influence the output signal being monitored are selected. However, it is also possible to intentionally remove the input signal related to the part that has no problem even if it leaks from the abnormal part identification processing. It is not necessary to select an input signal that is unrelated to the output signal being monitored.

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

FIG. 30 shows an example of abnormal point detection reference data, which is composed of input expected patterns corresponding to the respective states shown in FIG. Also in this input expectation 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. Input Signal Timing Chart Shown in Figure 27 and Figure 30
By comparing the tables in, it will be easy to understand their correspondence.

The abnormal point detection reference data including such an expected input pattern is used to output the output signal when the controlled system is operated under the control of the PLC 10 and 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 regarding the state transition of the output signal.

Particularly in the control of the controlled system by the PLC 10, since the RAM 14 of the PLC 10 is provided with an I / O table, this I / O table can be used to
The output reference pattern shown in FIG. 29 and the input expected pattern shown in FIG. 30 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 out at regular sampling time intervals.
Check to see if there is a change in the output signal state from the read input and output signal states. When the state of the output signal changes, the changed state of the output signal 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 abnormal part detection reference data is created by storing the state of the input signal immediately after the change of the state of the output signal as an input expected pattern in association with the above state number.

In the following description, the failure diagnosis processing is basically executed by the CPU 11 of the PLC 10. P
A failure diagnostic program is stored in advance in the ROM 12 of the LC10.

In the abnormality detection process, reference is always made to the abnormality determination reference data. Therefore, it is preferable to store the abnormality determination reference data in the RAM 13 that can be quickly accessed by the CPU 11. On the other hand, since the abnormal point detection reference data is first referenced when an abnormality is detected, high speed is not always required and is stored in the storage device 23 (hard disk, floppy disk, etc.) of the console 20. can do. Of course, it goes without saying that the abnormal point detection reference data may be stored in the RAM 13.

FIG. 31 shows an algorithm of failure diagnosis processing executed by the CPU 11 of the PLC 10.

When the failure diagnosis function is added as a part of the function of the PLC 10, the CPU 11 performs the failure diagnosis processing as well as the original processing of the PLC, that is, according to the user program shown in FIGS. 3 to 9. Performs control processing of the control system. The CPU 11 repeats a series of processing in a fixed cycle, and executes the control processing of the controlled system in the first half of each cycle and the failure diagnosis processing in the second half. Therefore, the failure diagnosis process shown in FIG. 31 is repeated at regular intervals.

The failure diagnosis process shown in FIG. 31 is composed of an abnormality detection process and an abnormal point specifying process. The abnormality detection process is performed with reference to the abnormality determination reference data. The reference data for abnormality determination is related only to the state of the output signal as described above. In this way, it is possible to sufficiently detect the occurrence of abnormality by monitoring only the state of the output signal. The anomaly detection process must be executed in real time.
By monitoring only the output signal state in the abnormality detection processing, the processing can be speeded up, and C
The burden on PU11 is reduced. In the abnormality detection processing of this embodiment shown in FIG. 31, the state transition order and transition time are checked. Only when an abnormality is detected in the abnormality detection process, the process proceeds to the abnormal point identification process with reference to the abnormal point detection reference data.

The state (output pattern) of the output signal is read (sampled) from the I / O table of the RAM 14.
(Step 161). Since the previously sampled output pattern is stored in a predetermined area of the RAM 14, the previous sample pattern and the current sample pattern are compared (step 162).

The timer 15 is activated when the previous state transits to the current state, and measures the time from the moment when the current state transits.

If it is determined in step 102 that the previous sample pattern and the current sample pattern are the same, it is checked whether the time is within the range allowed for the transition from the current state to the next state. (Step 166).

That is, the current state is set to the state [i]. The next state is state [i + 1]. The timer 15 measures the time from the time when the previous state [i-1] transits to the current state [i]. The time allowed to transit from the current state [i] to the next state [i + 1] depends on the “average transition time from the previous state” and the “transition time fluctuation allowance” in the reference data of the next state [i + 1]. Desired. At step 166, it is determined whether the time measured by the timer 15 is within 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 sample pattern this time is stored in the above area of the RAM 14 and the process returns to the step 161 (step 167).

If the elapsed time measured by the timer 15 exceeds the transition allowable time, it means that the state has not transitioned to the next state even after the time allowed for the state transition has elapsed. , It is determined that some kind of abnormality has occurred, the fact that the abnormality is detected is displayed on the display device 24 of the console 20 and the output signal with the abnormality is displayed (step 168), and the abnormal point detection processing starting from step 169 is performed. move on. The output signal in which the abnormality has occurred can be identified as a mismatched portion in the comparison between the sample pattern of this time and the output pattern of the next state [i + 1].

In step 162, if the previous sample pattern and the current sample pattern are different,
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 163). Further, the sample pattern this time is compared with the output pattern included in the reference data of the state [i + 1] after the transition (step 164).
).

If the sample pattern this time matches the reference output pattern (step 165), the process proceeds to the next step 166 to check the transition time. This sample
If the pattern and the reference output pattern do not match, it is determined that there is an abnormality, the abnormality detection result and the output signal indicating the abnormality are displayed on the display device 24 (step 168), and the abnormal portion starting from step 169 is identified. Go to processing. In the comparison between the sample pattern and the reference output pattern this time, the mismatched portion corresponds to the abnormal output signal.

The timer is also used for checking the transition time when the state [i] transits to the state [i + 1].
The actual transition time obtained from 15 is the state [i + 1]
It is determined whether or not it is within the range of the transition allowable time obtained from the data on the “average transition time from the previous state” and the “transition allowable variation range” stored as the reference data of. If the actual transition time is within the transition allowable time,
The sample pattern this time is stored in the RAM 14 (step 167) and the process returns to step 161. If the actual transition time is out of the transition allowable time, the fact that an abnormality has occurred and the abnormality output signal are displayed on the display device 24 of the console 20 (step 168), and the process proceeds to the abnormal point identification processing after step 169.

Timer 15 measures the time required for the transition.
It goes without saying that it is also possible to use a predetermined area of the RAM 14 without using.

In the process of identifying the abnormal portion, 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 ( Step
169).

Then, from the abnormal point detection reference data, the state [i + 1] (corresponding to the next state when the current state does not transit to the next state even after the transition allowable time elapses, the current state changes to the next state). If a transition is made but the time required for the transition exceeds the permissible time, it corresponds to the next state: that is, in any case, if the current state is [i], the next state [i + 1])
The input expected pattern at is read and compared with the temporarily stored sample input pattern (step 170).
).

If there is a state of the input signal 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 portion (step 171).

The processing of steps 168 to 171 is performed by the console 20.
It may be executed by the internal CPU 21. In this case, data relating to the abnormality detection (abnormality output signal and state number) is sent from the CPU 11 of the PLC 10 to the console 20.
CPU21 of will be notified.

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

From the timing chart shown in FIG. 27, the output signal "make-up forward" is turned on by the input signal "detection 2" as a trigger. However, looking at the ladder program (address 00039) shown in FIG. 5, the output signal "make-up advance" is not only the input signal "detection 2" being on, but also the input signal "make-up rear end" is on. It also turns on as a condition. Further, in order for the output signal "make-up forward" to be turned on, it is also a condition that the input signal "detection 3", "make-up front end", the output signal "make-up backward" and the internal auxiliary relay "set complete" are turned on. .

FIG. 32 shows the input expected pattern in the state [1] and the sample input pattern (abnormal pattern) sampled when an abnormality is detected. By comparing these patterns, it is specified that there is an abnormality in the input signal "closing end", that is, the closing rear end detector of the closing cylinder 75.

If the input expected pattern includes not only the input signal directly related to the output signal but also the input signal indirectly related to the output completion auxiliary relay, the input expected pattern and the sample input By collating with the pattern, it becomes possible to immediately identify the part where the failure has occurred, without performing the work of checking the program list.

FIG. 33 shows the console when an abnormality is detected.
The example of a display displayed on 20 display devices 24 is shown. When an abnormality is detected, the occurrence of an abnormality such as "output:" make-up advance "is not turned on" and an abnormal output signal are first displayed (step 168). Next, the abnormal point identification process is performed, and the input signal and the guidance for inspection found by this process are as follows: "The trailing end of the disc does not match the reference. Check the sensor / wiring for the above signal." It is displayed (step 171).

[Brief description of drawings]

FIG. 1 is a block diagram showing configurations of a PLC and a console (grouping device).

FIG. 2 is a configuration diagram showing an example of a controlled system.

FIG. 3 is a ladder diagram showing a user program.

FIG. 4 is a ladder diagram showing a user program.

FIG. 5 is a ladder diagram showing a user program.

FIG. 6 is a ladder diagram showing a user program.

FIG. 7 is a ladder diagram showing a user program.

FIG. 8 is a ladder diagram showing a user program.

FIG. 9 is a ladder diagram showing a user program.

FIG. 10 is a flowchart showing the entire grouping process.

FIG. 11 shows an example of an I / O relay list.

FIG. 12 shows an example of an input / output contact list.

FIG. 13 shows a mnemonic list.

FIG. 14 shows a mnemonic list.

FIG. 15 shows a mnemonic list.

FIG. 16 is a flowchart showing an input / output contact list creation processing procedure.

FIG. 17 shows a monitored output coil coupling degree table.

FIG. 18 is a flowchart showing a coupling degree calculation processing procedure.

FIG. 19 is a flowchart showing a procedure for forming a group of output coils.

FIG. 20 shows a display example of a grouping result.

FIG. 21 shows an outline of processing in the operation panel.

FIG. 22 shows an outline of a defective work elimination process.

FIG. 23 shows an outline of a work drilling process.

FIG. 24 is a flowchart showing another example of a procedure for forming a group of output coils.

FIG. 25 shows another display example of the grouping result.

FIG. 26 shows still another display example of the grouping result.

FIG. 27 is a timing chart showing the control operation of the controlled system.

FIG. 28 shows an example of abnormality determination reference data.

FIG. 29 shows an example of an output reference pattern.

FIG. 30 shows an example of reference data (expected input pattern) for detecting an abnormal portion.

FIG. 31 is a flow chart showing a failure diagnosis processing procedure.

FIG. 32 shows how an input expected pattern is compared with a sample input pattern (abnormal pattern).

FIG. 33 shows a display example of a failure diagnosis result.

FIG. 34 shows the operation of two steps asynchronous with each other.

[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

Front Page Continuation (72) Inventor Susumu Ishiguro 10 Hanazono Dodo-cho, Ukyo-ku, Kyoto Omron Co., Ltd. (56) References JP-A-58-97703 (JP, A) JP-A-58-94005 (JP, A) JP 2-16603 (JP, A) JP 1-134503 (JP, A) JP 62-117010 (JP, A) JP 62-86408 (JP, A) JP 58 -62709 (JP, A) Actual development Sho 61-65507 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G05B 19/04-19/05

Claims (3)

(57) [Claims] 1. A program executed by a programmable logic controller performs a process of extracting input / output contacts related to each monitored output for all the monitored outputs, and commonality of the extracted input / output contacts. From the viewpoint, the data regarding the connectivity between any two monitored outputs are calculated, and the above monitored outputs belong to the viewpoint of the strength of the coupling between the monitored outputs represented by the calculated connectivity data. A method of grouping diagnostic targets for fault diagnosis that forms a group. 2. An upper limit is set for the number of monitoring target outputs belonging to one group, and the monitoring target outputs having strong coupling are grouped in order, and the group whose number of monitoring target outputs included therein reaches the upper limit is The grouping method according to claim 1, wherein registration of monitored output to a group is prohibited. 3. For each of the selected monitored outputs, a means for extracting the input / output contact referred to by the monitored output in the program executed by the programmable logic controller, and selected from the monitored outputs. For all combinations of the two monitored outputs that have been selected, means for calculating the degree of coupling between the two monitored outputs from the viewpoint of the commonality of the input and output contacts that the two monitored outputs refer to, A diagnostic target grouping device for fault diagnosis, comprising: means for grouping the monitored outputs based on the degree of coupling; and means for outputting a result of grouping the monitored outputs.