JP2687726B2 - Failure detection device and method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a failure detection device and method, and more particularly to a programmable logic controller (hereinafter simply referred to as “PL”).
(Referred to as C) by detecting the internal state of the controlled device by detecting the detector or the input signal from the detector or the abnormal output signal to the actuator.

Background Art PLC is widely used for sequence control of many types of controlled objects (controlled devices).

The controlled device includes many detectors (proximity switches, limit switches, sensors such as photoelectric detectors and switches) for extracting its operating state, and a plurality of devices for driving each part of the controlled device. Actuators (air cylinder, hydraulic cylinder, motor, etc.) are provided.

The signal from the detector is given to the PLC as an input signal. A user program for controlling the controlled device is pre-installed in the PLC. The PLC generates an output signal (relay signal) for controlling the actuator according to a user program in response to the input signal.

The function of the PLC, that is, the user program set in the PLC is generally expressed by a ladder circuit. The ladder circuit is composed of a plurality of single ladder circuits.

FIG. 27 is a ladder diagram showing an example of the ladder circuit. This ladder circuit comprises a single ladder circuit L01, L02 and L03. The single ladder circuit L01 is a contact (actual input contact) 001 and 002 representing the state of the input signal given from the detector of the controlled device, and It consists of output relay 003. The single ladder circuit L02 includes actual input contacts 004, 005, 006 and 007, contacts (internal auxiliary contacts) 003 controlled by the output relay 003, and an output relay 008. The single ladder circuit L03 has actual input contacts 009 and 01.
0, internal auxiliary contact 00 controlled by output relay 008
The output relay 011 includes a self-holding contact 011 and an output relay 011.

The contacts 001, 003, 005, etc. are a contacts (make contacts), and the contacts 002, 004, 006, etc. are b contacts (break contacts).

When all the contacts connected in series are turned on (closed), the output relay connected to the contact is also turned on (closed). Then, this relay output is sent to some actuator, and the actuator operates. For example, in the single ladder circuit L01, when the contacts 001 and 002 are turned on, the output relay 003 is also turned on. In the single ladder circuit L02, contact 00
Output relay 008 will also be on when 4, 005, 003 and 006 are on or contacts 007 and 006 are on.

In a PLC configured with such a ladder circuit, if the prescribed operation is not performed due to a failure of the controlled device or a defective contact, the operator must check the state of the input / output signal and the PLC ladder diagram or ladder. -Refer to the program list of the program to find the abnormal point.

That is, the operator specifies an actuator that does not operate normally and an output relay that gives an output signal to the specified actuator. Then, the plurality of contacts connected to the specified output relay are traced with reference to the ladder diagram or the program list, and the contacts are checked one by one.

For example, a case is considered in which the specified output relay is the output relay 011 and is in the OFF state although it should be in the ON state originally.

First, the contacts 010, 00 connected to the output relay 011
Checks if 8, 009, and 011 are on.
If the contact 008 is off, the output relay 008 that controls the contact 008 and the output relay 008
The 006, 003, 005, 004, and 007 connected to the are tested to see if they are on. For example, if the contact 003 is in the OFF state, the output relay 003 and the contacts 001 and 002 connected to the output relay 003 are inspected. If the contact 001 is in the OFF state, the contact and the contact are input. The detector that gives the signal is taken as a candidate for the cause of the failure. Further, when the contact 007 is the actual input contact and is in the off state, the contact 007 and the detector that gives a signal to the contact are also taken up as candidates for the cause of failure.

In this way, the operator identifies an output relay that is not in a normal state, inspects the contacts connected to the output relay by tracing back in sequence, and checks the contact that causes the failure and the detector that gives a signal to the contact. Candidates are extracted and the failure location is finally specified.

However, in the detection of a failure point by such an operator, there is a problem that the actuator and the output relay of the ladder circuit that gives a signal to the actuator cannot be specified unless the operator understands the operation of the entire controlled device.

Even if the operator understands the operation of the controlled device as a whole, if the controlled device becomes large-scale and complicated, it is not easy to identify the actuator that performed the abnormal operation and the output relay that gives a signal to the actuator. It's gone.

Furthermore, even if the output relay of the ladder circuit can be specified, the operator needs to find out the abnormal point while sequentially referring to the input / output signal status and the PLC ladder circuit or program list, so that the failure point can be detected. The work is complicated and detection takes time. Therefore, it takes a long time to repair the failure and restart the controlled device. In particular, as the ladder circuit becomes larger and more complicated, it takes a longer time to detect a failure point.

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a failure detection device and method that can easily detect a detector that may be defective or a candidate of an input signal from the detector in a short time.

Another object of the present invention is to provide a failure detection device and method capable of easily detecting an output signal to an actuator that may be in failure in a short time.

The detector failure detection device according to the first invention is 1 or 2
A control device for controlling a controlled device including the above detector and one or more actuators stores actual input signal storage means for storing the state of the actual input signal from the detector in association with its identification code. Auxiliary input signal storage means for storing the state of the auxiliary input signal required for the arithmetic processing in the arithmetic means in association with the identification code, the state of the actual input signal stored in the actual input signal storage means and the auxiliary input The logical operation means for generating an output signal to be given to the actuator according to a predetermined logic according to the state of the auxiliary input signal stored in the signal storage means, and the output signal generated by the logical operation means Output signal storage means for storing the state of When a failure occurs in the controlled device, the failure detecting device detects a detector that may have a failure through the control device. A designated input device for identifying an identification code corresponding to an abnormal output signal given to a non-actuating actuator, and an abnormal output signal designated by the designated input device, which influences a logical operation by the logical operation means. Input signal extracting means for extracting an abnormal input signal, and determining whether the abnormal input signal extracted by the input signal extracting means is an actual input signal whose state is stored in the actual input signal storage means And the identification code corresponding to the actual input signal, if the determination means determines that the input signal is the actual input signal. And a storage device for storing as corresponds to the actual input signal from the detector with.

The detector failure detection method according to the first invention is 1 or 2
A control device for controlling a controlled device including the above detector and one or more actuators stores actual input signal storage means for storing the state of the actual input signal from the detector in association with its identification code. Auxiliary input signal storage means for storing the state of the auxiliary input signal required for the arithmetic processing in the arithmetic means in association with the identification code, the state of the actual input signal stored in the actual input signal storage means and the auxiliary input The logical operation means for generating an output signal to be given to the actuator according to a predetermined logic according to the state of the auxiliary input signal stored in the signal storage means, and the output signal generated by the logical operation means Output signal storage means for storing the state of When a failure occurs in the controlled device, a detector for detecting a possible failure in the controlled device is detected through the control device, and an identification corresponding to an abnormal output signal given to an actuator that does not operate normally is performed. An abnormal input signal that has received a designated input of a sign and has generated a specified abnormal output signal and has affected the logical operation by the logical operation means is extracted, and the extracted abnormal input signal is the actual input signal. It is determined whether or not the state is the actual input signal stored in the storage means, and if it is determined that the state is the actual input signal, the identification code corresponding to the actual input signal is used as a detector with a possibility of failure. It is stored in the storage device as corresponding to the actual input signal from.

According to the first aspect of the present invention, when the identification code of the abnormal output signal corresponding to the actuator that does not operate normally is designated, the abnormal input signal that has generated the designated abnormal output signal and has an influence on the logical operation is generated. Is extracted. It is determined whether the extracted abnormal input signal is the actual input signal whose state is stored in the actual input signal storage means, and if so, the identification code corresponding to the actual input signal indicates a possibility of failure. It is stored in the storage device as corresponding to the actual input signal from a certain detector.

The actual input signal in which the identification code is stored in the storage device is the input signal from the detector of the controlled device. When the actuator does not operate normally, the detector candidate that causes it can be easily and briefly. Can be detected and specified by.

Preferably, the identification code of the actual input signal stored in the storage device is displayed on the display device. This allows the user or operator to visually confirm the extracted actual input signal.

In a preferred embodiment of the first aspect of the invention, when it is determined that the extracted abnormal input signal is an auxiliary input signal stored in the signal storage means as an auxiliary, the logical operation by the logical operation means is affected. The process of extracting the given abnormal input signal is repeated.

Further, in another embodiment of the first aspect of the invention, the extraction signal of the abnormal input signal is generated when the number of abnormal input signals whose identification code is stored in the storage device is larger than a predetermined number, or It ends when there are no more input signals to extract. When there are a plurality of extracted abnormal input signals, the priority is calculated for those abnormal input signals. The above determination is performed in order from the calculated abnormal input signal having the highest priority.

If multiple abnormal input signals are extracted as candidates for the cause of failure, the candidate with the highest priority is used to determine whether the input signal is the actual input signal, so a detector that may cause a failure can be found in a shorter time. can do.

Preferably, the priority is calculated by performing fuzzy inference based on the characteristics obtained for each of the extracted abnormal input signals.

In still another embodiment of the first invention, the control device is constituted by a programmable logic controller, the state of the input corresponds to the state of contact of the programmable logic controller, and the state of the output signal is Corresponds to the state of the programmable logic controller relay.

According to a second aspect of the present invention, there is provided an input signal failure detection device, wherein a control device for controlling a controlled device including one or more detectors and one or more actuators changes the state of the input signal from the detector. Input signal storage means for storing in association with the identification code, logical operation for generating an output signal to be given to the actuator according to a predetermined logic according to the state of the input signal stored in the input signal storage means Means and output signal means for storing the state of the output signal generated by the logical operation means, and when there is an actuator that does not operate normally in the controlled device, an input signal that may be abnormal Is a failure detection device that detects an abnormal output signal applied to an actuator that does not operate normally. A designated input device for designating a sign, an abnormal signal output signal designated by the designated input device, an input signal extraction device for extracting an abnormal input signal that has affected a logical operation by the logical operation device, and the input A storage device is provided for storing an identification code corresponding to the abnormal input signal extracted by the signal extraction means.

According to a second aspect of the present invention, there is provided a method for detecting a failure of an input signal, wherein a control device for controlling a controlled device including one or more detectors and one or more actuators changes the state of the input signal from the detector. Input signal storage means for storing in association with the identification code, logical operation for generating an output signal to be given to the actuator according to a predetermined logic according to the state of the input signal stored in the input signal storage means Means and output signal storage means for storing the state of the output signal generated by the logical operation means, and when there is an actuator that does not operate normally in the controlled device, an input that may be abnormal A failure detection method that detects a signal, and handles abnormal output signals given to an actuator that does not operate normally Receiving the specified input of the identification code, generating the specified abnormal output signal, extracting the abnormal input signal that has affected the logical operation by the logical operation means, and identifying the abnormal input signal corresponding to the extracted abnormal input signal. The code is stored in the storage device.

According to the second invention, when the identification code of the abnormal output signal corresponding to the actuator that does not operate normally is designated,
The abnormal input signal that generated the specified abnormal output signal and affected the logical operation is not extracted. The identification code of the extracted abnormal input signal is stored in the storage device.

Therefore, when the actuator does not operate normally, all of the abnormal signal candidates that cause it can be detected easily and in a short time.

Preferably, the identification code of the abnormal input signal stored in the storage device is displayed on the display device. Thereby, the user or the operator can visually confirm the extracted abnormal input signal.

According to a third aspect of the present invention, there is provided a failure detection device for an output signal applied to an actuator, wherein a control device for controlling a controlled device including one or more detectors and one or more actuators is provided with an input signal from the detector. The input / output signal storage means for storing the state and the state of the output signal to be given to the actuator, and the input signal stored in the input / output signal storage means to the actuator according to a predetermined logic according to the state. A failure detection device, which is provided with a logical operation means for generating a state of an output signal to be given and storing it in the input / output signal storage means, for detecting an abnormality of an output signal to be given to a specific actuator through the control device. ， The normal state of the output signal to be given to the above specific actuator and the normal state of this output signal And a first determining means for determining whether or not the set condition for the state of the input signal is satisfied. In the case where the output signal does not occur in the set normal state even when a predetermined time has elapsed from the time point when it is determined that the above condition is satisfied, the second output signal is determined to be abnormal.
The determination means of

According to a third aspect of the present invention, there is provided a method of detecting a failure of an output signal supplied to an actuator, wherein a control device for controlling a controlled device including one or more detectors and one or more actuators is provided with The input / output signal storage means for storing the state and the output signal state to be given to the actuator, and the actuator according to a predetermined logic according to the state of the input signal stored in the input / output signal storage means. A fault detecting method for detecting an abnormality of an output signal to be given to a specific actuator through the control device, comprising a logical operation means for generating an output signal to be given and storing it in the input / output signal storage means. Generate the normal state of the output signal to be given to the specific actuator and the normal state of this output signal. The condition for the input signal state to be set is set in advance, and it is determined whether or not the set condition for the above input signal state is satisfied. From the time when it is determined that the above condition is satisfied, If the set normal state of the output signal does not occur even after a lapse of a predetermined time, the output signal is determined to be abnormal.

According to the third aspect of the present invention, the conditions for the normal state of the output signal to be given to the specific actuator and the state of the input signal that causes the normal state of the output signal are preset. First, it is determined whether or not the set condition for the state of the input signal is satisfied. If the condition of the output signal does not reach the set normal condition even after the lapse of a predetermined time even though the above conditions are satisfied, the output signal is determined to be abnormal. Therefore, whether or not the output signal to be given to the specific actuator is abnormal is automatically and promptly detected.

In one embodiment of the third invention, the control device is constituted by a programmable logic controller, the state of the input signal corresponds to the state of the contact of the programmable logic controller, and the state of the output signal is programmable. Corresponds to the relay state of the logic controller.

Further, in this embodiment, preferably, all the above determinations are performed by the programmable logic controller. The failure detection function of the output signal given to the actuator can be integrated by incorporating it in the programmable logic controller that is the control device.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing the configurations of a failure detection device, a PLC, and a controlled device.

 FIG. 2 is a block diagram showing an example of the controlled device.

FIG. 3 is a ladder diagram showing an example of the user program.

FIG. 4 is a ladder diagram showing an example of a user program.

5 and 6 are flowcharts showing the flow of the detector failure detection process.

FIG. 7 and FIG. 8 are flowcharts showing the flow of the process of extracting and storing the contact in the off state.

9 and 10 are flowcharts showing the flow of the process of extracting and storing the contact in the ON state.

FIG. 11 and FIG. 12 are flowcharts showing the flow of processing for automatic selection of contacts with a possibility of failure in the ladder program.

 Figures 13a to 13c show the structure of the stack.

FIG. 14 is a ladder diagram showing an example of a ladder program.

Figures 15a to 15f show the membership functions for each of Feature 1 to Feature 6 of the contact.

Figure 16a shows the rules of fuzzy reasoning for determining the priority of contacts. Figure 16b shows the membership function of the consequent part of the rule of Figure 16a.

FIG. 17a is a ladder diagram showing an example of a ladder program. FIG. 17b shows the values of features 1 to 6 of the contacts in FIG. 17a.

Figure 18a shows the suitability of the antecedent part and the consequent part when fuzzy inference is performed on the contact points in Fig. 17a.
Figure 18b shows the contact priorities determined by fuzzy reasoning.

FIG. 19 is a flowchart showing the flow of actuator failure detection processing.

FIG. 20 is a ladder diagram showing an example of a ladder program having an actuator failure detection function.

21 and 22 are flowcharts showing the flow of failure detection processing for the actuator and the detector.

FIG. 23 and FIG. 24 are flowcharts showing a flow of processing for detecting a failure or a programming error of the internal auxiliary contact and the special auxiliary contact.

25 and 26 are flowcharts showing the flow of processing for extracting and storing contacts other than the internal auxiliary contacts.

FIG. 27 is a ladder diagram showing an example of the ladder program.

BEST MODE FOR CARRYING OUT THE INVENTION I. Fault Detection Device and Control System FIG. 1 shows a fault detection device 1 and PLC2 and PLC2.
It is a block diagram showing the composition of the control system which consists of controlled device 3 controlled by.

The failure detection device 1 includes detectors (proximity switches, limit switches, sensors such as photoelectric detectors and switches) and actuators (air cylinders, hydraulic cylinders, motors, etc.) of the controlled device 3, as described later. It is a device that detects the failure of the PLC and the abnormality of the contact of the PLC2, and is configured as a unit separate from the PLC main body. Of course, the PLC main body may be provided with all the functions of the failure detection device 1, and the failure detection device 1 and the PLC 2 may be integrally configured.

The failure detection device 1 is composed of a PLC 11, a ROM 12, a RAM 13, a keyboard 14, a display device 15, and an interface circuit 16. Each of these devices is connected by a system bus 17.

The ROM 12 stores a program for detecting a failure location and a program for controlling other devices (the keyboard 14, the display device 15, etc.) of the failure detection device 1.

The CPU 11 performs a failure detection process according to a program stored in the ROM 12 and controls each device constituting the failure detection device 1.

RAM13 contains data of the processing results of CPU11, keyboard 14
Data input by the user or operator (user, etc.) via the PL, and PL via the interface circuit 16.
Data, etc. input / output to / from C2 are temporarily stored.

The keyboard 14 is a device for a user to input data. As will be described later, the input data includes the output relay number or contact number of the ladder circuit.

The display device 15 is a device for displaying the result of the failure detection processing, and is composed of a CRT or the like. For example, as a result of the failure detection process, the number of the contact extracted as the cause of the failure is displayed.

The interface circuit 16 performs data communication with the failure detection device 1PLC2 via the interface bus 18 and control for data communication.

PLC2 is CPU21, ROM22, RAM23, interface circuit 2
4 and I / O unit 25. Each of these devices is connected by a system bus 26.

The ROM 22 stores a ladder control system program.

A user program (ladder program) created by the user to control the controlled device is stored in part of the RAM23, and the other part of the RAM23 turns on the actual I / O signals of the PLC. , An I / O table holding the off state is stored.

The CPU 21 controls the controlled device 3 according to the ladder control system program stored in the ROM 22 and the user program stored in the RAM 23.

The interface circuit 24 is connected to the interface circuit 16 of the failure detection device 1 by the interface bus 18, and performs data communication and control for data communication between the failure detection device 1 and the PLC 2 as described above.

The I / O unit 25 transmits / receives input / output signals to / from the detector and actuator of the controlled device 3 via the PLC I / O data bus 27.

Although the details of the controlled device 3 will be described later,
A plurality of detectors for detecting a work or burrs on a work, and a plurality of actuators for controlling a pneumatic cylinder or a punching motor for discharging a defective work are provided. These detectors and actuators exchange input / output signals with the I / O unit 25 of the PLC 2 via the PLC I / O data bus 27.

II. Configuration of controlled device and example of control thereof FIG. 2 shows an example of the controlled device 3.

The work W is transported by the transport 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. During the operation of this cylinder 73, the rotation of the motor 72 is stopped and the conveyor
91 stops.

The work W that has been 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. If the state in which the stay detector 57 is detecting the work W continues for a certain time or longer, the abnormality lamp 71 of the operation panel 90 is turned on.

The work W transferred from the conveyor 91 to the reaction table 92
A second work detector 58 is provided to detect the. When the workpiece W is detected by the workpiece detector 58, the closing pneumatic cylinder 75 is driven, and the rod of the closing pneumatic cylinder 75 pushes the workpiece W on the transfer table 92 toward the processing table 93. The work W projected on 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 in which the work W is tightened. Further, the second motor (M2) 78 is rotationally driven, the drill 79 fixed to the rotation shaft of the motor 78 descends together with the motor 78, and the work W is drilled. After the drilling work, the drill 79 moves up together with the motor 78, and the rotation of the motor 78 stops. The drilled work 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 residence detector 57 continues for a certain period of 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 defect front end detector that detects that the rod has advanced (advanced) and reached its forward end in the defect elimination pneumatic cylinder 73, and a defect after detecting that the rod has retracted and reached its retracted end. An edge detector (neither shown) is provided. Similarly, the charging cylinder 75 is provided with a charging front end detector and a charging rear end detector, and the discharging cylinder 81 is provided with a discharging front end detector and a discharging rear end detector (both shown). Further, a drill top 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 descending detector that detects that the drill 79 has descended to reach its descending end. (All are not shown).

The signals input from the controlled device 3 to the PLC 2 are as follows. The numbers (000) to (015) at the beginning are the numbers of the input signals. Also, () at the end is an abbreviation.

(000) Operation switch 50 ON / OFF signal (operation SW) (001) Stop switch 51 ON / OFF signal (stop SW) (002) Release switch 52 ON / OFF signal (release SW) (003) Defective front end Detection signal of 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 detector 56 Burr detection signal (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 of loading) (010) Detection signal of back end detector (back end) (011) Work detection signal of third work detector 61 (detection 3) (012) Drill Top end detector detection signal (drill) Upper end) (013) Detection signal of drill lower end detector (drill lower end) (014) Discharge front end detector detection Are the following to No. (discharge front) (015) signal output from the detection signal (discharge rear end) PLC2 discharge rear end detector to the controlled device 3. The first (100) and (112) are output signal numbers. 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 (jig tightening) (108) Rotation drive control signal of second motor 78 (M2 rotation) (109) Drill 79 up drive control signal (drill up) (110) Drill 79 down drive control signal (drill down) (111) Discharge cylinder 81 forward drive control signal (discharging forward) (112) Discharge cylinder 81 backward drive control Signal (Discharge retreat) Figures 3 and 4 show PLC 2 shows a part of the program (user program) stored in the RAM 23 of 2. This program is expressed by using a contact that is turned on and off by an input signal, an output relay that generates an output signal, a contact that is turned on and off by the output relay, and an internal auxiliary relay and its contact.

The meanings of the internal auxiliary relay and its contacts shown in FIGS. 3 and 4 are as follows. “In setting” indicates the start of the entire drilling process, and is turned on until the drilling process and the discharge of the work are completed. “Set complete” indicates that the setting of the work on the processing table is completed. "Processing complete"
Indicates that the work has been completely discharged from the processing table.
The "loading memory" indicates that the work has been loaded onto the processing table, and is turned on until the processing and discharging are completed. “Drilling” indicates that the work is set on the processing table, and is turned on until the drilling is completed. "Drilling completed" means that the drilling of the workpiece is completed. "Drill memory"
Indicates that the drill has drilled the workpiece, and is turned on until the drilling is completed.

III. Failure detection processing by failure detection device (1) Failure detection processing of detector FIGS. 5 and 6 show the possibility of failure of the failure detection device 1 when the detector of the controlled device 3 has a failure. It is a flowchart which shows the flow of the process which detects the candidate of a certain detector. 7 and 8 are flowcharts showing the detailed processing flow of step 304 in FIG. 5, and FIGS. 9 and 10 are step 30 in FIG.
6 is a flowchart showing a detailed processing flow of 5.

The user or the like specifies an actuator that does not perform a predetermined operation in the controlled device 3. Then, the user or the like specifies a relay (output relay) that gives a signal to the actuator, and uses the keyboard 14 to provide information (for example, relay number) designating the output relay to the failure detection device 1. Input (step 301). The CPU 11 stores the input relay number in the RAM 13.

Next, the user or the like uses the keyboard 14 to input to the failure detection device 1 whether the designated relay should be in the on (closed) or off (open) state (step 30).
2). This state is also stored in the RAM 13 by the CPU 11.

When the designated relay is in the off state although it should be in the on state (YES in step 303),
Among the contacts connected to the designated relay, there should be an off-state contact that causes the contact, so the off-state contact is discharged and stored in the RAM 13 (step 304). If the specified relay is in the on state even though it should be in the off state (NO in step 303), the contact in the on state that causes the contact among the contacts connected to the specified relay. Therefore, the contact in the ON state is extracted and stored in the RAM 13 (step 305).

To extract contacts, the CPU 11 uses the interface circuit 16 and the interface bus 18 to access the PLC 2,
This is done by searching the ladder program stored in the RAM 23 of C2. Further, the on / off state of the extracted contacts is confirmed by searching the I / O table that holds the on / off state of each contact on the ladder program. Details of the processing of these steps 304 and 305 will be described later.

All the contacts extracted and stored in the RAM 13 are displayed on the display device 15 and notified to the user or the like (step 306).

When there are a plurality of contacts displayed on the display device 15 (YES in step 307), the user or the like selects one of the displayed contacts and specifies the contact (for example, contact number). Is input to the failure detection device 1 using the keyboard 14 (step 308). If there is only one contact displayed (NO in step 307), the CPU 11 automatically selects that contact.

The selected contact is written in the RAM 13 by the CPU 11 to indicate that it has been selected (for example, a flag indicating that the contact selected in the RAM 13 has been selected is set), and the same contact is processed in the subsequent processing. It is prevented from being selected (step 309).

Next, it is determined whether or not the selected contact is the actual input contact (step 310). The actual input contact refers to a contact indicating the state of the input signal given from the detector of the controlled device 3.

Whether or not it is an actual input contact is determined by storing a table in which the numbers of actual input contacts are registered in RAM13 or RAM23 in advance and checking whether or not the number of the selected contact is in this table. It can be carried out. If the contact number is selected in the table, that contact is the actual input contact. It is also possible to search the ladder program to check whether or not there is a relay having the same number as the contact number. If there is a relay with the same number as the selected contact, that contact is not an actual input contact. In FIG. 3, the contact 105 in the ladder circuit at address 00048 is not an actual input contact because the relay 105 with the same number is located at address 00039.

When the selected contact is an actual input contact (YES in step 310), the fact that the contact is a candidate for the cause of failure is displayed on the display device 15 to inform the user (step 311).

Next, the CPU 11 determines whether or not there is any unselected contact among the contacts stored in the RAM 13 (step 312). If there is a contact that has not been selected in the RAM 13 (YES in step 312), the user or the like inputs whether to continue investigating the contact that causes another failure. If you want to continue investigating other candidates (YES in step 313),
The process is repeated from step 307 in order to perform the process for other contacts.

If there are no unselected contacts in the RAM 13 (NO in step 312) or if the investigation of other candidates is not to be continued (NO in step 313), the process ends.

In step 310, if the selected contact is not the actual input contact, then it is determined whether the contact is an internal auxiliary contact (step 314).

The internal auxiliary contact does not mean an actual input contact (a contact indicating the state of an input signal from the detector of the controlled device 3), but a contact controlled by an output relay or an internal auxiliary relay. Whether it is an internal auxiliary contact or not can be determined by checking whether or not a relay having the same number as the contact exists in the ladder program. If there is a contact with the same number as that contact, then that contact is an internal auxiliary contact.

When the selected contact is the internal auxiliary contact (YES in step 314), the relay (output relay or internal auxiliary relay) having the same number as the contact is searched (step 315). The reason why the internal auxiliary contact is the cause of failure is that it is considered that the contact connected to the relay that controls the state of the internal auxiliary contact has the cause of failure. Then, the process is repeated from step 303 in order to extract a contact that is a candidate for a failure cause from the contacts connected to the retrieved relay and store it in the RAM 13.

If the selected contact is neither the actual input contact nor the internal auxiliary contact (NO in step 314), the process for that contact is not performed, and a step for performing the process for other contacts stored in the RAM 13 is performed. Processing starts from 312.

There are special auxiliary contacts or link relays that are neither actual input contacts nor internal auxiliary contacts.

The special auxiliary contact is a contact whose ON or OFF state is controlled by a ladder control system program or the like, and whose state is controlled by, for example, a clock signal,
It includes a contact or the like whose state is determined by an arithmetic command or a flag. The link relay is a contact whose state is controlled by a PLC other than the PLC 2 via a communication means.

These contacts do not contribute to the detection of the failure of the detector of the controlled device 3, and thus are not targeted for processing.

Next, referring to FIG. 7 and FIG. 8, step 304
The details of the processing will be described. The process of step 304 is to extract the contact in the OFF state that causes the relay when it is in the OFF state although it should be in the ON state.

As an example, consider the case where the closing cylinder 75 in FIG. 2 moves forward but does not move backward.

The user or the like finds out that the closing cylinder 75 does not move backward, so that the closing retraction signal 106, that is, the output relay 106 (closing reverse) in FIG. 3 is abnormal (OFF state), and outputs using the keyboard 14. Relay
The number 106 is input to the failure detection device 1.

As described above, the contact point is extracted by first searching the user program (ladder program) stored in the RAM 23. Next, the on / off state of the contact is confirmed by searching the I / O table stored in the RAM 23. Then, if the state of the contact is off, the contact is stored in the RAM 13.

In the following, the contact extraction processing will be described with reference to the ladder diagram of FIG.

The contact in the OFF state, which is a candidate for the cause of failure, is extracted by searching the ladder circuit (ladder program) from the output relay 106 toward the busbar R (FIG. 3).

First, the search point is advanced from the relay 106 toward the bus R on the line L1 (FIG. 3), and whether or not the contact point has passed the branch point (branch point P1 in FIG. 3) in which the contacts are connected in parallel. It is determined whether or not (step 321). When the ladder program is represented by mnemonic symbols, in the program that describes a single ladder circuit, a search is performed from the OUT instruction (out instruction) to the LD instruction (load instruction), and OR is executed in the program. Instruction (OR instruction) or
If there is an OR LD instruction (OR load instruction), etc., it can be known that the branch point has been reached.

Since the contacts 105 and 010 are in front of the branch point P1, the search point has not passed the branch point (step 32
If NO in 1), the contact 105 is extracted (step 323).

Next, it is determined whether the extracted contact 105 is in the on state (step 324). Contact 105 is assumed to be off. In this case (NO in step 324), the contact number 105 and the designated relay number 106 are compared (step 325). In this case, since the numbers do not match (NO in step 326), the contact 105 is a candidate for the cause of failure in RAM13.
(Step 327).

Here, the reason why the extracted contact number is compared with the designated relay number is to exclude the self-holding contact from the extraction target. For example, the contact 106 is a self-holding contact of the relay 106, and the contact 106 is also turned on / off by turning on / off the signal of the relay 106. Therefore, the self-holding contact need not be the target of extraction.

Next, it is determined whether the search point has reached the bus R of the ladder circuit (step 328). In the mnemonic notation, it can be seen that the bus has been reached if there is an LD instruction (load instruction) or the like.

The search point does not reach the bus bar R (step 328
NO), and the process is repeated from step 321. Then, the contact 010 is extracted in the same manner as the contact 105, and the contact 010 is extracted.
Is determined to be on (steps 321-32)
Four). Contact 010 is assumed to be in the on state. In this case (YES in step 324), the contact 010 is not stored in the RAM 13 because it is not the contact causing the failure.

When the search point is further advanced from the contact point 010 toward the busbar R, the search point passes through the branch point P1 (YES in step 321), and this branch point P1 is stored in the RAM 13 (step 322). Then, one line L2 branched from the branch point P1 is selected, and the contact 009 is extracted (step 323). Contact 009 is assumed to be off. The contact 009 is stored in the RAM 13 as a candidate for a failure cause (steps 324 to 327).

When the search point is advanced on the line L2, the search point reaches the bus line R (YES in step 328), and it is determined whether or not there is a stored branch point (step 330). Since the branch point P1 is stored (step 329
YES), the search point is moved to the latest (last) stored branch point P1 (in this example, there is either the branch point P1 or the only branch point, and thus the latest stored branch point) (step 330). Then, the branch point P1 is erased from the RAM 13 (step 331).

The search point is advanced on the other line L3 from the branch point P1 to extract contact points (steps 321 to 3).
twenty three). Although the contact 106 is extracted in the line L3, this contact is not stored in the RAM 13 even if it is in the OFF state (YES in step 326) because it constitutes the relay 106 and the self-holding circuit as described above.

Since the search point reaches the bus line R on the line L3 (YES in step 328) and there is no stored branch point (NO in step 329), the process of extracting the contact point causing the failure ends.

The contacts extracted and stored in RAM 13 are the contacts 105 and
It becomes 009. For these contacts, as mentioned above,
The processing from step 306 onward in FIG. 5 is performed. Here, when the contact 105 is selected in step 308, the relay 105 is searched in step 315 because the contact 105 is an internal auxiliary contact. Then, the ON / OFF states of the contacts 204, 106 and the like connected to the relay 105 are also checked, and if they are in the OFF state, they are stored in the RMA 13.

Next, based on FIG. 9 and FIG. 10, step 305
The details of the processing will be described. The process of step 305 is to extract the contact in the on-state that causes the relay when it is in the on-state although it should be in the off-state.

As an example, let us consider a case where the drill 79 in FIG. 2 remains lowered and does not rise.

When the user does not raise the drill 79, the user or the like outputs the drill down signal 110, that is, the output relay 1 in FIG.
Determine that 10 (drill down) is abnormal (on state) and use keyboard 14 to specify relay 110.

The on-state contact, which is a candidate for the cause of failure, is extracted by searching the ladder circuit from the designated relay 110 toward the bus bar R.

First, the search point is advanced along the line L4 (Fig. 4) from the relay 110 toward the bus R, and the search point is a branch point where the contacts are connected in parallel (the branch point in Fig. 4).
It is determined whether the vehicle has passed P2) (step 341).
Since the contacts 109 and 103 are located in front of the branch point P2, the search point has not passed the branch point (step 301
NO), the contact 109 is extracted (step 343).

Next, it is determined whether the extracted contact 109 is in the off state (step 344). Contact 109 is assumed to be in the on state. In this case (NO in step 344), the contact number 109 and the designated relay number 110 are compared (step 345). Since these numbers do not match (NO in step 346), the contact 109 is stored in the RAM 13 as a candidate for the cause of failure (step 347). This is because the self-holding contact is excluded from the extraction target, as described above.

Next, it is determined whether the search point has reached the bus R of the ladder circuit (step 351). Since the search point has not yet reached the bus bar R (NO in step 351),
The process is repeated from step 341. Assuming that the contact 013 is extracted in the same manner as the contact 109 and the contact 013 is in the ON state, the contact 013 is stored in the RAM 13 (step
341 to 347).

When the search point further advances from the contact point 013 toward the busbar R, the search point passes through the branch point P2 (YES in step 341), and this branch point P2 is stored in the RAM 13 (step 342). And the search point is the branch point P
It is advanced on one line L5 from 2 and contact 012 is extracted (step 343). Assuming that the contact 012 is in the ON state, the contact 012 is stored in the RAM 13 as a candidate for the cause of failure (steps 344 to 347).

Next, the contact 209 is extracted, and assuming that the contact 209 is in the ON state, this contact 209 is also stored in the RAM 13.

Next, the contact 107 is extracted (step 343). This contact is assumed to be off. In this case (YES in step 344), among the contacts stored in the RAM 13, the contacts 209 and 012 between the extracted contact 107 and the branch point P2.
Is erased from RAM 13 (step 348). This is because on line L5 between branch point P2 and bus R, if any contact is in the off state, even if the other contact is in the on state, the state of the entire line L5 is This is because the relay 110 is turned off and acts to turn off the relay 110, and therefore the contact on the line L5 is not considered to be the cause of the failure. In this case, the contact causing the failure will be on the line L4 or L6.

Next, the search point is moved to the latest (last) stored branch point P2 (step 349). The branch point P2 is erased from the RAM 13 (step 350).

Next, the contact 110 is extracted in the line L6 (step 343), but this contact is not stored in the RAM 13 because it is the self-holding contact as described above (step 346YES).

The search point reaches the bus bar R (YES in step 351),
And since there is no stored branch point (N in step 352
O), the process of extracting the contact that causes the failure ends.

The contacts extracted and stored in RAM 13 are contacts 109 and
013, and for these contacts, as described above,
The processing from step 306 onward in FIG. 5 is performed.

In this way, regardless of whether the designated relay is on or off, it is possible to automatically extract the contact that is a candidate for the cause of the failure among the contacts connected to the relay. If the extracted contact point is the actual input contact point, the user or the like is notified of that fact, and the extracted contact point corresponds to the actual input contact point. It is possible to easily and quickly identify a detector that may have a failure.

(2) Automatic selection of contacts In the above-described process of extracting contacts that are candidates for the cause of failure, when a plurality of contacts are extracted as candidates for the cause of failure, the result is presented to the user or the like, and the user or the like One contact was selected from the inside (Step 30 in Fig. 5)
8).

 It is also possible to automatically select this contact.

(2-1) Outline of Processing FIGS. 11 and 12 are flowcharts showing the flow of processing for automatic selection of contacts. As an example, consider the case where relay 110 (drill down) in FIG. 4 is in the off state although it should be in the on state.

The user or the like specifies an actuator that does not perform a predetermined operation in the controlled device 3, and specifies the relay 110 of the ladder program corresponding to the actuator. The user or the like specifies the specified relay (number of relay, etc.). ) Is input to the failure detection device 1 using the keyboard 14 (step 401). The CPU 11 stores the designated relay number in the RAM 13. Also, the designated relay 110
Is written in the RAM 13 by the CPU 11 (step 602). For example, the selected flag of the relay is prepared in the RAM 13, and this flag is set.

Next, the user or the like uses the keyboard 14 to input to the failure detection device 1 whether the relay 110 should originally be in the ON state or the OFF state (ON state in this example) (step 403). This state is also stored in the RAM 13 by the CPU 11.

Since relay 110 is originally in the off state although it should be in the on state (YES in step 404), the contact in the off state is extracted from the contacts connected to the designated relay and stored in RAM13. (Step 405). If the specified relay is in the ON state despite being supposed to be in the OFF state (NO in step 404), the ON state that causes the contact among the contacts connected to the specified relay Is extracted and stored in the RAM 13 (step 406). These processing steps are shown in FIGS. 7 to 10 above.
The processing is the same as that shown in the figure.

The process of step 405 results in contacts 107, 209 and 013.
Is extracted and stored in RAM 13. Since there are multiple contacts stored in RAM13 (YES in step 407), RA
For each contact stored in M13, the characteristics of that contact (detailed later) are sought (step 411).
Then, inference processing is performed for each of the contact points based on the characteristics thereof, and the priority (detailed later) is determined (step 412).

The number of each contact, the relay to which the contact is connected, and the priority of the contact are associated with each other and stored (PUSH) in the stack in the RAM 13 (step 413).

FIG. 13a shows the data thus stored in the stack. Regarding the priority, it is assumed that the contact 107 has a priority of 0.9, the contact 209 has a priority of 0.7, and the contact 013 has a priority of 0.5, as shown in FIG. 13a. Further, in the stack, data having a low priority value is stacked downward, and data having a high priority value is stacked upward. That is, the data with the lowest priority value is pushed in order (PU
SH).

Next, the data stored in the stack is popped (POP)
(Step 414). That is, the contact 107 having the highest priority among the contacts stored in the stack is taken out. As a result, the data of contacts 209 and 013 will remain in the stack of RAM 13 as shown in Figure 13b.

Next, it is judged whether or not the extracted contact 107 is an actual input contact (step 408). Since the contact 107 is not an actual input contact (NO in step 408), it is determined whether the contact 107 is an internal auxiliary contact (step 409). Since the contact 107 is an internal auxiliary contact (YES in step 409), the relay 107 that controls the state of the contact is searched (step 415).

Then, it is determined whether the retrieved relay 107 has already been selected (step 416). If the relay 107 has already been selected (YES in step 416), the contacts connected to the relay 107 are already investigated and are not investigated.

If relay 107 has not been selected (N in step 416)
O), the process is repeated from step 402 to perform the process for the contacts connected to the relay 107. Only the contact 205 is connected to the relay 107. It is assumed that this contact 205 is in the off state. The contact 205 is extracted in step 405 and stored in the RAM 13.

The contact stored in the RAM 13 is only one of the contacts 205 (NO in step 407) and is an internal auxiliary contact (NO in step 408, YES in step 409). Therefore, contact 2
The relay 205 that controls the state of 05 is searched, the contact in the OFF state connected to the relay 205 is extracted, and stored in the RAM 13 (steps 402 to 405).

Here, the contacts stored in RAM 13 are contacts 011 and 204.
And assume that their respective priorities are 0.9 and 0.6.
In this case, the process of step 413 brings the stack of the RAM 13 into the state shown in FIG. 13c.

Next, the data of contact 011 is popped from the stack (step 414). Since this contact is an actual input contact (YES in step 408), the contact 011 is stored in the RAM 13 as a failure cause candidate (step 410).

Then, it is determined whether or not the number of contacts stored as a failure cause candidate has reached a predetermined number (step 417). This predetermined number is input in advance to the failure detection device 1 by a user or the like, and is for ending the failure cause candidate detection process when a predetermined number of contacts are selected. is there.

Next, it is determined whether the stack is empty, that is, there is no data to pop from the stack (step 418). Since the stack has data such as the contact 204, the process is repeated from step 414.

If it is determined in step 417 that the number of contacts stored as candidates for the cause of failure has reached a predetermined number,
Alternatively, if it is determined in step 418 that the stack is empty, the process ends.

In step 409, if the designated contact is not an internal auxiliary contact (for example, a special auxiliary contact) (step
No at 409), this contact is not processed as it is not involved in detector failure detection. Then, the process is repeated from step 418.

Of course, the contact may be stored not by the stack but by another data structure.

(2-2) Features of contacts The features of the contacts described above are as follows.

[Characteristic 1] Nature of the contact The nature of the contact indicates that the contact is an actual input contact (J), an internal auxiliary contact (N), or a special auxiliary contact (T).

[Characteristic 2] Position of Contact on Ladder Circuit The position of the contact on the ladder circuit is an order indicating which contact is counted from the busbar R of the ladder circuit. For example, in FIG. 14, the contact point 02 is at the second position counted from the busbar R, so the position of the contact point on the ladder circuit is 2. The position of the contact point 05 on the ladder circuit is 1.

[Characteristic 3] Contact Connection Form The contact connection form indicates whether the contacts are connected in series (A) or in parallel (O). For example, in FIG. 14, the contacts 01, 02, and 03 are connected in series, so that the connection form of these contacts is a series connection. On the other hand, the contact point 05 is not a contact point connected in series next to the contact point point 05, but is connected in parallel with the contact point points 01, 02 and 03, and the contact point points 06 and 07.
The connection type of 05 will be parallel connection.

[Characteristic 4] Types of contacts The types of contacts are from a contact (a) to b contact (b).
It shows that.

[Characteristic 5] The number of steps to the actual input contact The number of steps to the actual input contact is, for example, in FIG. 14, the contact 09 which is an internal auxiliary contact is the contact which is the actual input contact that affects the state of the contact 09. It has to go through two stages of single ladder circuits L02 and L01 before reaching 04. Therefore, the number of stages of the contact 09 to the actual input contact is 2.

[Characteristic 6] The number of remaining contacts for the relay to be in a normal state (on or off state) For example, in the single ladder circuit L01 of Fig. 14, the relay 08 is in the off state although it should be in the on state. In this case, in the line A, if the contact 02 is turned on, the relay 08 is turned on. Therefore, in this case, the number of remaining contacts for the contact 02 for the relay to be in the normal state is one.

Similarly, regarding the contact 06 and the contact 07, the relay 08 is also turned on when these two contacts are turned on. Therefore, the number of remaining contacts of the contact 06 and the contact 07 is 2 respectively.
Becomes The number of remaining contact points of the contact point 05 is 1.

When obtaining the priority of the contact point, it may be obtained by using any one of these characteristics, or may be obtained by combining two or more thereof. Further, other contact characteristics than the characteristics 1 to 6 may be used.

(2-3) Inference Processing FIGS. 15a to 15f show an example of the membership functions of the features 1 to 6, respectively.

FIG. 16a shows an example of a rule for obtaining the priority for each contact point by fuzzy reasoning. FIG. 16b shows an example of the membership function of priority.

Rule 1 is "position of contact on ladder circuit (feature 2)
Is close to the busbar R (NB) and the contact type (feature 4) is a-contact (a) "(preceding part)," higher priority (PB) of the contact "( Consequent part).

This is because such an important contact is generally placed closer to the busbar R, and the a contact has a larger influence on the change of the state of the relay connected to the contact than the b contact, so The priority of the above is increased and such a contact is preferentially detected.

Rule 2 is "if the property (feature 1) of the contact is the actual input contact (J)" (preceding part), "higher priority (PB) of the contact" (consequent part). is there.

This is for preferentially detecting the actual input contact that may be out of order. When the contact is an internal auxiliary contact, it is necessary to further search the relay corresponding to the contact and inspect the contact connected to the relay, which requires time. On the other hand, if the contact is an actual input contact, it is not necessary to search for other relays, so it is possible to detect the faulty part in a short time by preferentially inspecting the actual input contact. . Further, when the contact is a special auxiliary contact, it is considered that the influence on the relay to which the contact is connected is small, and it is considered that it is not necessary to perform inspection preferentially as compared with the actual input contact.

Rule 3 states that "the contact type (feature 3) is serial connection (A) and the number of remaining contacts (feature 6) for the relay to be in the normal state (on or off state) is small (N
B) ”(the antecedent part),“ higher priority for that contact (P
B) ”(Consequent part).

For example, in FIG. 17a and FIG. 17b, assuming that the contacts of the cause of failure (NG) are contacts 04, 05, 06, 08, and 09, these contacts all correspond to series connection (A). As for the number of remaining contacts for the relay to be in the normal state, the number of contacts 09 is 1, which is the smallest. Therefore, in rule 3, the contact point 09 has the highest priority.

Rule 4 is "if the nature of the contact (feature 1) is the internal auxiliary contact (N) and the position of the contact on the ladder circuit (feature 2) is far from the busbar R (PB)" (preceding part) , "Lower priority (NB) of the contact" (consequent part).

In a ladder circuit, generally unimportant contacts are busbars R
It is placed at a distance from, and in the case of an internal auxiliary contact, it is necessary to search the relay corresponding to the contact, so that the priority is lowered.

Rule 5 is that "the connection form of the contact (feature 3) is parallel connection (O) and the number of stages (feature 5) up to the actual input contact affecting that contact is large, not small, medium (ZR ) ”(Antecedent),“ Slightly lower priority (NS)
Yes ”(consequent part).

If a contact is connected in parallel with another contact, that contact may not be the cause of the failure, but another contact connected in parallel may be the cause of the failure, and the number of stages to the actual input contact is medium. If so, it takes a little time to search for the actual input contact, so the priority is set to be slightly lower.

Rule 6 states that "the type of contact (characteristic 4) is b contact (b)"
And the relay is in normal state (on or off state)
If there is a large number of remaining contacts (feature 6) (PB) (preceding part), "Lower priority of contacts (NB)"
(Consequent part).

This is because the b contact generally has a smaller effect on the relay to which the contact is connected than the a contact. In addition, if the number of remaining contacts for the relay to be in the normal state is large, it is highly possible that other contacts have failed, and the time to search for an actual input contact that is likely to have failed is also high. This is because of this.

Rule 7 is "If there are many stages (feature 5) to the actual input contact (PB) and the number of remaining contacts (feature 6) for the relay to be in a normal state is medium (ZR)" (Previous Section), "Slightly lower the priority (NS) of the contact" (consequent section).

This means that if the number of stages to reach the actual input contact is large, it will take time to reach the actual input contact that is highly likely to be defective, and the relay connected to that contact will be in a normal state. This is because if the number of remaining contact points (feature 6) is medium, it does not take much time to search for an actual input contact point that is highly likely to be out of order.

Rule 8 is "position of contact on ladder circuit (feature 2)
Is near the busbar R (NB) and the number of stages (feature 5) to the actual input contact is small (NB) "(preceding part)," slightly increase the priority of that contact (PS) "(after) The part)

This is because in a ladder circuit, the more important the contact, the bus bar R
This is because it does not take much time to search for an actual input contact that is likely to be faulty if it is placed near the input terminal and the number of stages to the actual input contact is small.

The suitability of the antecedents of these rules is shown in Figure 15a to 1
It is obtained by the membership function of features 1 to 6 shown in Fig. 5f. The conformance of the consequent part is obtained for each of PB to NB in FIG. 16b based on the conformity of the antecedent part. Then, the priority of the contact point is obtained as a weighted average value of the membership function of FIG. 16b.

For example, assuming the values of the characteristics 1 to 6 of the contact 09 as shown in FIG. 17b, the priority of the contact 09 is obtained as follows.

Figure 18a shows rules 1 to 8 for contact point 09.
This is the degree of conformance of the antecedent part and the consequent part when is applied.

Since the value of feature 6 of contact 09 is 1 (Fig. 17b),
According to the membership function in Fig. 5f, the goodness of fit of feature 6 NB =
It becomes 1. Further, since the contact point 09 is the a-contact point, the compatibility of the feature 4 is 1. Therefore, the suitability of the antecedent part of rule 1 becomes 1 by the and operation of the suitability of the feature 4 as the suitability of the feature 6, and thus the suitability that the priority in the consequent part becomes PB becomes 1. .

Similarly, the suitability of the antecedent part of rule 2 is 0,
The suitability of the consequent part where the priority is PB is 0. The suitability of the antecedent part of rule 3 is 1, and the suitability 1 of which the priority is PB in the consequent part is 1. Therefore, when the rules 1 to 3 are combined, the degree of conformity at which the priority is PB is 1.

The suitability of the antecedent part of rule 4 is 0, and the suitability of the consequent part of which the priority is NB is 0. The suitability of the antecedent part of rule 6 is 0, and the suitability of the consequent part of which the priority is NB is 0. Therefore, the degree of conformity in which the priority is NB is 0.

According to the rules 5 and 7, the degree of conformity in which the priority is NS is 0.

Further, the conformance of the antecedent part of rule 8 is 1, and the conformity of the consequent part of which the priority is PS is 1.

Therefore, as shown in FIG. 18b, the degree of conformity for which the priority is NB and NS is 0, and the degree of conformity for which the priority is PS and PB is 1. When the degree of conformity at which the priority is ZR is 0, the priority is obtained as a weighted average value of these, and the priority is 0.875.

Further, as another example, when the priority of the contact point 06 is similarly obtained, the priority level of the contact point 06 is 0.75.

Rule 1 is an example of a rule in fuzzy reasoning.
However, other than these rules, other rules may be used as long as the rules can be appropriately inferred. Further, other rules may be used in combination with the above rules 1 to 8.

Further, it is needless to say that only the feature 1 of each contact can be obtained and only the actual input contact can be preferentially investigated without performing fuzzy inference. It is also possible to obtain only the feature 2 for each contact and preferentially investigate from the contact closest to the bus bar R.

(3) Actuator Failure Detection Processing FIG. 19 is a flowchart showing the flow of processing in which the failure detection device 1 detects a failure of the actuator of the controlled device 3.

The user or the like specifies the actuator that is the target of the failure detection among the actuators of the controlled device 3, and the information that specifies the relay corresponding to the actuator (for example,
The relay number) is input to the failure detection device 1 using the keyboard 14 (step 501). All the actuators of the controlled device 3 may be targets of failure detection.

In addition, the user or the like can determine the condition under which the specified relay (actuator) is turned on or off (operates), and the normal state of the relay when the condition is satisfied. The (on or off state) is also entered using the keyboard 14 (step 502). This condition is, for example, the ON or OFF state of the contact. Alternatively, as will be described in detail later, necessary conditions can be described in advance in the ladder program.

As a condition for this, when the ON or OFF state of the contact is designated by the user or the like, the CPU 1 of the failure detection device 1
When the controlled device 3 starts its operation, 1 refers to the I / O table in the RAM 23 of the PLC 2 to monitor whether the ON or OFF state (operating condition) of the designated contact is satisfied (step 503). ).

If the operating conditions are met (YES in step 503),
The timer is started (step 504). The time of this timer is also preset by the user or the like.

Next, the CPU 11 determines whether or not the designated relay is in a normal state (operated) (step 505). When the designated relay is operating (YES in step 505), the designated relay (and the actuator given the signal from the relay) is operating normally. The CPU 11 repeats the processing from step 503 to monitor whether the operation of another designated relay (actuator) or the next operation of the same relay is normally performed.

When the designated relay is not operating (NO in step 505), it is determined whether a predetermined time set in the timer has elapsed (step 506). If the predetermined time has not elapsed (NO in step 506), it is determined again whether the relay has started operating (step 505). If the relay does not start operating even after the lapse of a predetermined time (YES in step 506), it is determined that the relay (and the actuator to which the signal from the relay is given) has a failure (step 507). . Then, the fact that the designated actuator is out of order is displayed on the display device 15 to inform the user or the like.

FIG. 20 shows another example of detecting the failure of the actuator. As mentioned above, this is to describe the necessary conditions in the ladder program,
It is a ladder program with an actuator failure detection function.

In this ladder program, a single ladder circuit C78 including an application instruction C78C, a contact 110 and a contact 204 is inserted before the address 00078 in FIG. The ladder circuit including such application instructions is previously inserted by the user when the user creates the ladder program.

Actuators designated for inspection are relays
It is an actuator to which relay output from 110 (drill down) is given. Here, this relay 110 is
It is assumed that it will turn on within 5 seconds.

The application instruction C78C consists of a command block (FPD) and a timer block (# 0
050) and the message part (DM10).

The command section describes the contents of the processing of this application instruction. For example, when the application instruction is turned on, the timer is started, and after the time set in the timer elapses, the message described in the message section is issued.

The timer section describes the time counted by the timer. “# 0050” means 50 seconds.

A message issued from the application instruction is described in the message section. This message includes the relay number to be monitored, a message arbitrarily described by the user, and the like.

The application instruction C78C turns on when the contacts 204 and 110 turn on and starts the timer.
When either or both 4 and 110 are turned off, the timer is turned off and the timer is stopped.

If the contacts 204 and 110 are still in the ON state even after the time (50 seconds) set in the timer section has elapsed since the timer started, the application command C78C displays the message stored in the message section DM10. Output. This message is
It is sent to the failure detection device 1 and displayed on the display device 15.

That is, when the relay 110 is in the OFF state and the contact 110 and the contact 204 are in the ON state, the timer of the application command C78C is started. In the normal state, the relay 110 is turned on within 45 seconds after the contact 204 is turned on as described above.
When 0 is turned on, the contact 110 is turned off, the timer of the application instruction C78C is stopped, and no message is issued.

On the other hand, even if the contact 204 is in the ON state, the relay 110 (actuator) has failed, and if it is not in the ON state, the contact 110 remains in the ON state and the timer continues to operate. Then, after 50 seconds have passed, a message is issued. By including the relay number in the message, the user or the like can know that the relay 110 has a failure.

In this way, it is possible to confirm whether the specified actuator is operating normally, and if the actuator fails, identify which actuator is failing easily and quickly. it can.

In this embodiment, the application instruction C78C is described immediately before the relay 110 to be monitored. As described above, by writing the application instruction adjacent to the relay to be monitored, it is not necessary to specify the relay to be monitored in the application instruction. Therefore, when creating the ladder program, the relay to be monitored can be specified without checking whether or not the designation of the relay to be monitored is correct.

It should be noted that the ladder circuit C78 including the application instruction C78C may be described immediately after the relay 110, which is the monitoring target, instead of immediately before. Further, in addition to the output relay, an internal auxiliary relay, a timer, a counter, etc. can be targets for failure detection monitoring.

(4) Failure detection process for actuator and detector The failure detection device 1 can also perform the above-described actuator failure detection and detector failure detection in cooperation. That is, the failure detection device 1 can function as a comprehensive failure detection device that can easily detect a failure location candidate in a short time by combining these two processes.

FIG. 21 is a flow chart showing the flow of processing of the failure detection device 1 which cooperates with failure detection of an actuator and failure detection of a detector.

The processing from steps 601 to 606 are the steps shown in FIG.
It is the same as the processing from 501 to 506.

If the specified relay (actuator) does not perform the predetermined operation even after the lapse of the predetermined time set in the timer (YES in step 606), the contact connected to the actuator is Potential contact candidates are extracted by the CPU 11 and stored in the RAM 13 (step 607). The details of this contact extraction and storage processing are the same as the processing of steps 303 to 315 in FIGS. 5 and 6.

The contacts extracted by the CPU 11 and stored in the RAM 13 are
It is displayed on the display device 15 and notified to the user or the like (step 608). Then, the process ends.

In this way, in the failure detection process of the actuator and the detector, the detection of the abnormality of the detector that causes the abnormality of the actuator can be collectively performed by a series of processes.

FIG. 22 is a flow chart showing the flow of processing for detecting the failure of the actuator and the detector when the application instruction for detecting the failure of the actuator is described in the ladder program as shown in FIG.

As described above, the application command issues a message to the failure detection device 1 when the predetermined relay does not perform the predetermined operation within the time set in the timer. The message contains
Contains the number of the relay monitored by the application instruction.

Upon receiving the message from the PLC 2 (step 610), the CPU 11 searches the ladder program relay based on the relay number included in the message (step 611).

Then, the CPU 11 determines whether the retrieved relay is an output relay (step 612).

If the retrieved relay is an output relay (YES in step 612), the contact connected to the relay is extracted and stored in the RAM 13 (step 613). The process of extracting and storing the contact point is the same as the process of steps 303 to 315 in FIGS. 5 and 6.

The extraction result of the contact point is displayed on the display device 15 and notified to the user or the like (step 614), and the process ends.

If the searched relay is not an output relay (NO in step 612), error processing is performed. Non-output relays include, for example, a retrieved relay that outputs a keyboard, a relay that performs four arithmetic operations, and the like.

The error processing includes, for example, processing of displaying the searched relay on the display device 15 and notifying the user of the error.

The relay designated by the user or the like in step 601 in FIG. 21 and the relay to be monitored by the application command in FIG. 20 may include an internal auxiliary contact, a timer, a counter, or the like.

(5) Detection process of failure or program mistake of internal auxiliary contact and special auxiliary contact In FIGS. 23 and 24, the failure detection device 1 detects the failure (abnormality) of the internal auxiliary contact and special auxiliary contact in the ladder program or It is a flowchart which shows the flow of the process which detects a program mistake.

Regarding the internal auxiliary contact and the special auxiliary contact, for example, when a user creates a ladder program, there may be a program mistake such as making a mistake in the number of the contact, if a so-called program bug is included. There is also.

Similar to the failure detection processing of the detector (FIG. 5), the failure detection device 1 determines whether the information (for example, the relay number) specifying the relay and whether the relay should be in the on state or the off state. It is input (steps 701 and 702). CPU1
1 stores the input information in the RAM 13.

If the specified relay is in the off state even though it should be in the on state (YES in step 703),
Among the contacts connected to the designated relay, the contacts in the off state are extracted and stored in the RAM 13 (step 70).
Four). If the specified relay is in the ON state even though it should be in the OFF state (N in step 703).
O), the contact in the ON state is extracted from the contacts connected to the designated relay and stored in the RAM 13 (step 705).

The detailed processing of step 704 is the same as that of FIG. 7 and FIG. 8, and the detailed processing of step 705 is FIG. 9 and FIG.
It is the same as Fig. 0.

All the contacts extracted and stored in the RAM 13 are displayed on the display device 15 and notified to the user or the like (step 706).

When there are a plurality of contacts displayed on the display device 15 (YES in step 707), the user or the like selects one of the displayed contacts and assigns the contact number to the keyboard.
Input using 14 (step 708). If only one contact is displayed (NO in step 707), that contact is the CPU.
Automatically selected by 11.

The fact that the selected contact has been selected is written in the RAM 13 by the CPU 11 (for example, a flag indicating whether the selected contact has been selected is set in the RAM 13), and the same contact is used in the subsequent processing. Are not selected (step 709).

Next, it is determined whether or not the selected contact is the actual input contact (step 710). When the selected contact is the actual input contact (YES in step 710), it is displayed on the display device 15 that the contact is the actual input contact and not the internal auxiliary contact or the special auxiliary contact, and the user etc. Informed (step 711).

If the selected contact is not the actual input contact, that is, if it is the internal auxiliary contact or the special auxiliary contact (NO in step 710), it is displayed on the display device 15 that the contact is a candidate for the failure cause, and the user Etc. (step 714).

Further, when the selected contact is the internal auxiliary contact (YES in step 715), the user or the like inputs whether to search for the output relay or the internal auxiliary relay that controls the state of the contact (step 715). 716).

When the search is performed (YES in step 716), the relay corresponding to the contact is searched (step 717), and the process is repeated from step 703 to extract the contact connected to the searched relay. Be done.

If the contact selected in step 715 is not an internal auxiliary contact, or if the search is not performed in step 716, it is checked whether or not there is any unselected contact among the contacts stored in the RAM 13 ( Step 71
2).

If RAM13 has unselected contacts (Step 7
If YES in step 12), the user or the like inputs whether or not to continue the investigation for the non-selected contacts (step 71).
3). If the investigation is to be continued (YES in step 713), the process is repeated from step 707, and if not to be continued (NO in step 713), the process is ended. Even if there are no unselected contacts in RAM13 (NO in step 712),
The process ends.

Even after the processing of step 711, the processing of step 712 and the subsequent steps are performed.

In this way, with respect to the internal auxiliary contact and the special auxiliary contact, a candidate contact such as a failure or a program mistake can be automatically extracted. Further, by displaying the candidate contact point, the user or the like can easily confirm the abnormality or program mistake of the contact point.

Also in the process of detecting the internal auxiliary contact and the special auxiliary contact, the selection of the contact in step 708 can be automatically performed in the priority order by obtaining the priority for each extracted contact by the inference process described above. Further, it is also possible to obtain only the feature for each contact without performing the inference process and preferentially investigate only the contact having a certain feature (for example, the internal auxiliary contact).

(6) Application example As an application example of the detection process of the above-described detector or the detection process of the internal auxiliary contact and the special auxiliary contact, there is one in which contacts other than the internal auxiliary contact are extracted and stored. Contacts other than internal auxiliary contacts include actual input contacts, special auxiliary contacts, and the link relays described above.

25 and 26 are flowcharts showing the flow of processing of this application example.

The processing from step 801 to step 809 is the same as the processing from step 301 to step 309 in FIG.

At step 810, it is determined whether the selected contact is an internal auxiliary contact. Whether or not the contact is an internal auxiliary contact can be determined by checking whether or not a relay having the same number as the contact exists in the ladder program, as described above. If there is a relay with the same number as the contact, then that contact is an internal auxiliary contact.

If the selected contact is an internal auxiliary contact (YES in step 810), a relay having the same number as that contact (a relay controlling the state of the contact) is searched (step 813) and searched. The process is repeated from step 803 to investigate the contacts connected to the relay.

If the selected contact is not the internal auxiliary contact (NO in step 810), the contact is determined as a candidate for the cause of failure in RAM13.
Is stored. Then, it is determined whether or not there is a contact not selected in the RAM 13 (step 812), and if there is a contact, the process is repeated from step 807, and if not, the process ends.

It is also possible to select the contacts in step 808 in order of priority by obtaining the priorities for the extracted contacts by the inference process described above. Also, without performing inference processing,
It is also possible to obtain only the characteristics of each contact and preferentially investigate only the contact having a certain characteristic (for example, the internal auxiliary contact).

In this way, it becomes possible to detect abnormalities in the special auxiliary contacts, link relays, etc. in addition to the actual input contacts.

Front page continuation (72) Inventor Koji Soma 10 Ouron Co., Ltd., Hanazono Todo-cho, Ukyo-ku, Kyoto, Kyoto Prefecture (72) Inventor Naohiro Tabata 10 No. 10 Hanazono Todo-cho, Ukyo-ku, Kyoto, Kyoto Omron Co., Ltd. (56 ) Reference JP 63-223808 (JP, A) JP 61-59502 (JP, A) JP 54-102476 (JP, A) JP 63-240602 (JP, A)

Claims (18)

(57) [Claims] 1. One or more detectors and one or two
The control device for controlling the controlled device including the above actuator is required for the arithmetic processing in the actual input signal storage means and the logical operation means for storing the state of the actual input signal from the detector in association with its identification code. Auxiliary input signal storage means for storing the state of the auxiliary input signal associated with the identification code, the state of the actual input signal stored in the actual input signal storage means, and the auxiliary input signal storage means. The logical operation means for generating an output signal to be given to the actuator according to a predetermined logic according to the state of the auxiliary input signal, and the output signal storage for storing the state of the output signal generated by the logical operation means When the controlled device has an actuator that does not operate normally, the controlled device is provided with A failure detection device for detecting a detector having a possibility of failure through the control device, which is applied to an actuator that does not operate normally among the output signals whose states are stored in the output signal storage means. A designated input device that designates an identification code corresponding to an abnormal output signal, and an abnormal input signal that has generated an abnormal output signal designated by the designated input device and that has an effect on the logical operation by the logical operation means is extracted. Input signal extracting means, determining means for determining whether or not the abnormal input signal extracted by the input signal extracting means is an actual input signal whose state is stored in the actual input signal storing means, and the determining means If it is determined that the input signal is the actual input signal, the identification code corresponding to the actual input signal is used as the actual input from the detector with a possibility of failure. A detector failure detection device equipped with a storage device that stores signals as corresponding to signals. 2. One or more detectors and one or two
An input / output signal storage means for storing a state of an input signal from the detector and a state of an output signal to be given to the actuator by a control device for controlling a controlled device including the above actuator, and the input / output signal storage means. A logical operation means for generating a state of an output signal to be given to the actuator according to a predetermined logic according to a state of the input signal stored in A failure detection device for detecting an abnormality of an output signal to be given to a specific actuator through the control device, wherein a normal state of the output signal to be given to the specific actuator and an input for causing a normal state of this output signal The signal condition and the condition are set in advance. The first determination means for determining whether or not the set condition is satisfied, the output signal even if a predetermined time elapses from the time when the first determination means determines that the above condition is satisfied. A failure detection device for an output signal given to an actuator, comprising a second judging means for judging that the above output signal is abnormal when the set normal state of is not generated. 3. One or more detectors and one or two detectors.
An input signal storage means for storing a state of an input signal from the detector in association with the identification code, and an input stored in the input signal storage means. Depending on the state of the signal,
The controlled device includes logical operation means for generating an output signal to be given to the actuator according to a predetermined logic, and output signal storage means for storing the state of the output signal generated by the logical operation means. Is a failure detection device that detects an input signal that may be abnormal when there is an actuator that does not operate normally, and the identification code corresponding to the abnormal output signal given to the actuator that does not operate normally A designated input device for designating, an input signal extracting device for extracting an abnormal input signal that has generated an abnormal output signal designated by the specified input device and has affected a logical operation by the logical operation device, and the input signal extracting device A storage device for storing an identification code corresponding to the abnormal input signal extracted by the means. Input signal failure detection device. 4. One or more detectors and one or two detectors.
The control device for controlling the controlled device including the above actuator is required for the arithmetic processing in the actual input signal storage means and the logical operation means for storing the state of the actual input signal from the detector in association with its identification code. Auxiliary input signal storage means for storing the state of the auxiliary input signal associated with the identification code, the state of the actual input signal stored in the actual input signal storage means, and the auxiliary input signal storage means. The logical operation means for generating an output signal to be given to the actuator according to a predetermined logic according to the state of the auxiliary input signal, and the output signal storage for storing the state of the output signal generated by the logical operation means When the controlled device has an actuator that does not operate normally, the controlled device is provided with A failure detection method for detecting a detector with a possibility of failure in the above-mentioned control device by accepting a specified input of an identification code corresponding to an abnormal output signal given to an actuator that does not operate normally, An abnormal input signal that has generated a specified abnormal output signal and has an effect on the logical operation by the logical operation means is extracted, and the extracted abnormal input signal is stored in the actual input signal storage means in its state. If it is determined that it is a real input signal, the identification signal corresponding to the real input signal is used as the real input signal from the detector with a possibility of failure. A failure detection method for a detector, which is stored in a storage device as if it does. 5. One or more detectors and one or two
An input / output signal storage means for storing a state of an input signal from the detector and a state of an output signal to be given to the actuator by a control device for controlling a controlled device including the above actuator, and the input / output signal storage means. According to the state of the input signal stored in, the output signal to be given to the actuator is generated according to a predetermined logic, and is stored in the input / output signal storage means. A failure detection method for detecting an abnormality of an output signal to be given to an actuator through the control device, comprising: a normal state of an output signal to be given to the specific actuator; and an input signal which causes a normal state of the output signal. The conditions for the states and the conditions for the above input signals are set in advance. If it is determined that the output signal has not been set to the normal state even if a predetermined time has elapsed from the time when it is determined that the above condition is satisfied, The above output signal is judged to be abnormal. A failure detection method for the output signal given to the actuator. 6. One or more detectors and one or two
An input signal storage means for storing a state of an input signal from the detector in association with the identification code, and an input stored in the input signal storage means. Depending on the state of the signal,
The controlled device includes logical operation means for generating an output signal to be given to the actuator according to a predetermined logic, and output signal storage means for storing the state of the output signal generated by the logical operation means. Is a failure detection method that detects an input signal that may be abnormal when there is an actuator that does not operate normally, and the identification code corresponding to the abnormal output signal given to the actuator that does not operate normally. An abnormal input signal that has received a specified input and has generated a specified abnormal output signal and has affected the logical operation by the logical operation means is extracted, and an identification code corresponding to the extracted abnormal input signal is stored in a storage device. The method of detecting the failure of the input signal stored in. 7. One or more detectors and one or two
A control device for controlling a controlled device including the actuator described above, wherein the control device controls the device according to a predetermined logic according to a state of an actual input signal from the detector and a state of an auxiliary input signal necessary for a logical operation. Logical operation means for generating an output signal to be given to the actuator, designated input means for designating an identification code of an abnormal output signal corresponding to an actuator which does not operate normally in the controlled device, abnormal output designated by the designated input means The input signal extraction means for extracting an abnormal input signal that has generated a signal and has affected the logical operation by the logical operation means, and the abnormal input signal extracted by the input signal extraction means are output from the detector. If it is an actual input signal, it is equipped with a storage device that stores the identification code of the actual input signal. Control apparatus having a vessel failure detection function. 8. One or more detectors and one or two detectors
A control device for controlling a controlled device including the above actuator, which generates an output signal to be given to the actuator according to a predetermined logic according to a state of an input signal from the detector. , A means for setting the normal state of the output signal to be given to the specified specific actuator and the condition for the state of the input signal that causes the normal state of this output signal, and the normal state to be given to the specific actuator. If the set normal condition of the output signal does not occur within a predetermined time after the set condition of the state of the input signal that causes the output signal is satisfied, the output signal is A control device having a function of detecting a failure of an output signal given to an actuator, which is provided with a judging means for judging an abnormality. 9. One or more detectors and one or two detectors
A control device for controlling a controlled device including the above actuator, which generates an output signal to be given to the actuator according to a predetermined logic according to a state of an input signal from the detector. A designation input means for designating an identification code of an abnormal output signal corresponding to an actuator that does not operate normally in the controlled device; a logical operation by the logic operation means for generating an abnormal output signal designated by the specification input means Input signal failure detection function including input signal extraction means for extracting an abnormal input signal that has an effect on the input signal, and a storage device for storing the identification code of the abnormal input signal extracted by the input signal extraction means. Control device equipped with. 10. A control method for controlling a controlled device including one or more detectors and one or more actuators, the state of an actual input signal from the detector and an auxiliary required for logical operation. According to the state of the input signal, an output signal to be given to the actuator is generated according to a predetermined logic, and a specified input of the identification code of the abnormal output signal corresponding to the actuator that does not operate normally in the controlled device is input. The abnormal input that has received and specified the abnormal output signal and has affected the logical operation is extracted. If the extracted input signal is the actual input signal from the detector, the actual input signal is extracted. A control method for detecting a detector failure by storing the identification code of the input signal in a storage device. 11. A control method for controlling a controlled device including one or more detectors and one or more actuators, which is predetermined according to a state of an input signal from the detector. The output signal to be given to the actuator is generated according to the logic, and the normal state of the output signal to be given to the specified specific actuator and the condition about the state of the input signal which causes the normal state of the output signal are defined. The output signal is set in advance even if a predetermined time has elapsed after the set condition for the state of the input signal that causes the normal output signal to be given to the above-mentioned specific actuator is satisfied. If a normal state does not occur, the output signal is judged to be abnormal. Failure detection of the output signal given to the actuator is detected. The control method to perform. 12. A control method for controlling a controlled device including one or more detectors and one or more actuators, the method being predetermined according to a state of an input signal from the detectors. An output signal to be given to the actuator is generated according to the logic, and the designated input of the identification code of the abnormal output signal corresponding to the actuator that does not operate normally in the controlled device is accepted and the designated abnormal output signal is generated. A control method for detecting a failure of an input signal, extracting an input signal that has affected the logical operation, and storing an identification code of the extracted input signal in a storage device. 13. A programmable logic controller for controlling a controlled device including one or more detectors and one or more actuators, the state of a real input signal from the detector and a logical operation. Logical operation means for generating an output signal to be given to the actuator according to a predetermined logic according to a state of a necessary auxiliary input signal; and an abnormal output signal corresponding to an actuator which does not operate normally in the controlled device. Specifying input means for specifying an identification code; input signal extracting means for generating an abnormal output signal specified by the specifying input means; extracting an abnormal input signal that has affected a logical operation by the logical operation means; The abnormal input signal extracted by the input signal extraction means is actually input from the detector. In the case of a force signal, a storage device for storing the identification code of the actual input signal is provided. Programmable logic controller with detector failure detection function, 14. A computer system for controlling a controlled device including one or more detectors and one or more actuators, which is necessary for a state and a logical operation of an actual input signal from the detectors. Logical operation means for generating an output signal to be given to the actuator according to a predetermined logic according to the state of the auxiliary input signal, and an identification code of an abnormal output signal corresponding to the actuator not operating normally in the controlled device. Specifying input means for specifying, an input signal extracting means for generating an abnormal output signal specified by the specifying input means, an input signal extracting means for extracting an abnormal input signal that has affected a logical operation by the logical operation means, and the input signal When the abnormal input signal extracted by the extracting means is the actual input signal from the detector Is a computer system with a detector failure detection function that has a storage device that stores the identification code of the actual input signal. 15. A programmable logic controller for controlling a controlled device including one or more detectors and one or more actuators, which is preliminarily set according to a state of an input signal from the detector. A logical operation means for generating an output signal to be given to the actuator according to a defined logic; a normal state of an output signal to be given to a specified specific actuator; and an input signal for producing a normal state of the output signal. A means for setting the condition for the state, and the output even if a predetermined time has elapsed after the set condition for the state of the input signal that causes the normal output signal to be given to the specific actuator is satisfied. If the set normal state of the signal does not occur, the output signal is judged to be abnormal. Programmable logic controller with comprises means, the fault detecting function of the output signal given to the actuator. 16. A computer system for controlling a controlled device including one or more detectors and one or more actuators, which is predetermined according to a state of an input signal from the detectors. The logical operation means for generating an output signal to be given to the actuator according to the above logic, the normal state of the output signal to be given to the specified specific actuator, and the state of the input signal which causes the normal state of the output signal And the means for setting the condition of, and the condition of the input signal that causes the normal output signal to be given to the above-mentioned specific actuator is satisfied even after a predetermined time has elapsed from the satisfaction of the set condition. When the set normal state does not occur, the output signal is provided with a judging means for judging that it is abnormal. Computer system with fault detecting function of the output signal given to the actuator. 17. A programmable logic controller for controlling a controlled device including one or more detectors and one or more actuators, which is preliminarily set in accordance with a state of an input signal from the detector. Logical operation means for generating an output signal to be given to the actuator according to a defined logic; designation input means for designating an abnormal output signal identification code corresponding to an actuator not operating normally in the controlled device; Input signal extracting means for generating an abnormal output signal designated by the input means, for extracting an abnormal input signal that has affected a logical operation by the logical operation means, and an abnormal input extracted by the input signal extracting means Detecting failure of input signal, equipped with storage device for storing signal identification code Programmable logic controller with the ability. 18. A computer system for controlling a controlled device including one or more detectors and one or more actuators, which is predetermined according to a state of an input signal from the detectors. The logical operation means for generating an output signal to be given to the actuator according to the above logic, the designation input means for designating the identification code of the abnormal output signal corresponding to the actuator which does not operate normally in the controlled device, and the designation input means Input signal extraction means for extracting an abnormal input signal that has generated a specified abnormal output signal and has affected the logical operation by the logical operation means, and identification of the abnormal input signal extracted by the input signal extraction means A computer having a failure detection function of an input signal, which is provided with a storage device for storing a code. System.