JP2919883B2 - Fault diagnosis method for production line - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for controlling a sequence of operations of a facility in a production line. The present invention relates to a method for diagnosing a failure in a production line for identifying an operating element that has caused a failure.

2. Description of the Related Art In a production line such as an automobile assembly line, a sequence control unit having a built-in computer is provided for various installed facilities, and the sequence control unit performs operations to be sequentially performed by each facility. It is known to perform the following sequence control. When such sequence control is performed, a sequence control program is loaded into a computer built in the sequence control unit, and the sequence control unit performs each step of operation control for each of various types of equipment installed on the production line. It is assumed that the processing proceeds sequentially according to the sequence control program.

When performing sequence control on the operation of various facilities installed in such a production line, a failure diagnosis for monitoring the control state and detecting a failure in each facility is performed in parallel with the sequence control. Often it is. The fault diagnosis related to the sequence control may take various forms. For example, Japanese Patent Application Laid-Open No. 60-238906 discloses a method under the condition that the equipment can be operated normally. The operation mode of the components of the sequence control circuit unit is set in advance as the reference operation mode, and the operation modes of the components of the sequence control circuit unit during the actual operation of the equipment are sequentially compared with the reference operation mode. Performing failure detection based on the difference has been proposed as one of failure diagnosis related to sequence control.

(Problems to be Solved by the Invention) As described above, the reference operation modes of the components of the sequence control circuit unit are set in advance, and the operation modes of the components of the sequence control circuit unit during the actual operation of the equipment. When performing a comparison between the reference operation mode and the base operation mode, and performing the abnormality detection of the equipment based on the comparison result,
The operation mode of the components of the sequence control circuit unit is determined by a combination of a number of requirements. Therefore, when the facility is actually operated, various operation modes of the components of the sequence control circuit unit can be taken. In other words, since the number of the operation modes set as the reference operation modes is limited, a selected one of the various operation modes is set as the reference operation mode. Under such circumstances, even though the equipment is actually operating normally, a situation occurs in which the actual operation mode of the components of the sequence control circuit unit does not match the preset reference operation mode. As a result, there is a possibility that erroneous detection that the equipment is abnormal may be performed, and when a failure of the equipment is detected, the operating element in the equipment that caused the failure is identified. In doing so, the operation mode of the components of the sequence control circuit unit that is determined not to match the reference operation mode and a number of operation elements in the equipment related to such an operation mode are sequentially checked and checked. In many cases, it is difficult to specify the failure-causing operating element in a short time.

In view of such a point, the present invention classifies various operations to be performed into a plurality of operation blocks as a maximum unit of a series of operations that are independently performed from start to end under a normal state as an operation block. Attention is paid to facilities on a production line that execute a plurality of operation steps in each of a plurality of operation blocks in accordance with a sequence control ladder program, with each of the plurality of operation blocks being divided into a plurality of operation steps. It is another object of the present invention to provide a method for diagnosing a failure in a production line, in which when a failure occurs during operation of such equipment, the operating element that caused the failure can be quickly and appropriately characterized. And

(Means and Actions for Solving the Problems) In order to achieve the above-described object, the method for diagnosing a failure in a production line according to the present invention is configured such that various operations to be performed by the facilities in the production line start from a normal state. A maximum unit of a series of operations to be performed independently until the end is divided into a plurality of operation blocks as an operation block, and each of the plurality of operation blocks is divided into a plurality of operation steps. When a plurality of operation steps in each of the operation blocks are controlled to be sequentially executed in accordance with the sequence control ladder program, an execution time from a start time to an end time of the plurality of operation steps in each of the plurality of operation blocks is measured and measured. If there is a specific operation block whose execution time is longer than the reference time, execute that specific operation block It is determined that a failure has occurred in the installed equipment, and each output device in the sequence control ladder program and the contact device connected thereto and forming a set of ladder elements together with the output device are defined as a ladder element device group, and A ladder element device group including an output device corresponding to the above-described specific output element for a portion of the sequence control ladder program corresponding to an operation step including an operation of a specific output element that is turned off due to a failure in the specific operation block , The contact device that takes the off state is detected without being connected in parallel with the contact device that takes the on state, and the contact device that takes the off state corresponds to the output device in the preceding ladder element device group If you do In the ladder element device group of the preceding stage, the contact device that takes the off state is detected as a contact device that takes the off state without being connected in parallel with the contact device that takes the on state. When the contact device does not correspond to the output device in the preceding ladder element device group, the contact device is determined to be the failure-causing operation element.

When a failure occurs during the operation of the equipment subjected to the sequence control as described above and a specific output element is turned off,
An investigation to identify the operating element that caused the failure is performed for a specific portion corresponding to an operation step including an operation of a specific output element that is turned off due to the failure in the sequence control ladder program. In addition, the investigation of the operating element that caused a failure in a specific part of the sequence control ladder program is based on the fact that a failure occurs in the equipment among a plurality of ladder element devices arranged in stages in the specific part. From the ladder element device group including the output device corresponding to the specific output element that is turned off when the ladder element device group is located earlier than the ladder element device group, the operation element causing the failure is detected. Until it is done retroactively. Therefore,
The operating element that caused the failure can be quickly and properly identified.

(Embodiment) Prior to description of a production line failure diagnosis method according to the present invention, an example of a vehicle assembly line to which the production line failure diagnosis method according to the present invention is applied will be described with reference to FIGS. 2 and 3. I will describe.

In the vehicle assembly line shown in FIG. 2 and FIG. 3, a positioning station for receiving a vehicle body 11 on a cradle 12 and controlling the position of the cradle 12 to position the body 11 on the cradle 12 is provided. A docking station ST2 for combining the ST1, the engine 14 placed at a predetermined position on the pallet 13, the front suspension assembly (not shown), the rear suspension assembly 15 and the body 11
And the engine 1 combined with it against the body 11
4, a fastening station ST3 for fastening and fixing the front suspension assembly and the rear suspension assembly 15 using screws. Further, between the positioning station ST1 and the docking station ST2, an overhead type transfer device 16 for holding and transporting the body 11 is provided.
Is provided, and the docking station ST2
A pallet transport device 17 for transporting the pallet 13 is provided between the pallet 13 and the fastening station ST3.

The pedestal 12 at the positioning station ST1
It is supposed to travel back and forth along 8,
Although not shown in the drawing, the positioning station ST1 is disposed in relation to the pedestal 12 and moves the pedestal 12 in a direction perpendicular to the rail 18 (vehicle width direction) and in a direction along the rail 18 (front-back direction). The positioning means (BF) for moving the body 11 placed on the cradle 12 to position the front part in the vehicle width direction, the positioning means (BR) for positioning the rear part in the vehicle width direction, And positioning means (TL) for performing positioning in the front-rear direction is provided.
Elevating reference pins (FL, FR, RL, RR) for positioning the body 11 with respect to the receiving table 12 are provided. The positioning device 19 in the positioning station ST1 is configured by these positioning means and the lifting reference pins.

The transfer device 16 is composed of a guide rail 20 that is arranged over the positioning station ST1 and the docking station ST2 and that is bridged therebetween, and a carrier 21 that moves along the guide rail 20. A lifting hanger frame 22 is attached to the carrier 21, and the body 11 is supported by the lifting hanger frame 22. Further, the pallet transport device 17 includes a pair of guide portions 24L and 24R provided with a plurality of support rollers 23 receiving the pallet 13 and the lower surface, respectively, and a pair of transport rails 25L extending parallel to the guide portions 24L and 24R, respectively. And 25R, each with 13 pallets
Pallet locking portions 26 for locking the transport rails 25
Pallet carrier that moves along L and 24R
27L and 27R, and a linear motor mechanism (not shown) for driving the pallet transfer tables 27L and 27.

When the front suspension assembly and the rear suspension assembly 15 are assembled, the docking station ST2 includes struts in the front suspension assembly and struts 15 in the as-suspension assembly 15.
A pair of left and right front clamp arms 30L and 30R, each supporting A, and taking an assembled posture, and a pair of left and right rear clamp arms 31L and 31R are provided. Left and right front clamp arms 30L and 30R are attached to mounting plate portions 32L and 32R, respectively.
It is mounted to be able to move forward and backward in the direction perpendicular to the transfer rails 25L and 25R, and has a left and right rear clamp arm.
31L and 31R are attached to the mounting plate portions 33L and 33R, respectively, so as to be able to advance and retreat in a direction orthogonal to the transport rails 25L and 25R, the left and right front clamp arms 30L and 30R oppose each other, and Each of the left and right rear clamp arms 31L and 31R has an engaging portion that engages with a strut in the front suspension assembly or a strut 15A in the rear suspension assembly 15. Then, the mounting plate portion 32L is fixed to the fixed base 35L by the arm slide 34L, and
L and 25R, and the mounting plate 32R is movable by the arm slide 34R with respect to the fixed base 35R in the direction along the transfer rails 25L and 25R.
33L is fixed to the fixed base 37L by arm slide 36L,
It can be moved in the direction along the transfer rails 25L and 25R, and the mounting plate 33R is fixed to the base by the arm slide 36R.
With respect to 37R, it is movable in a direction along the transfer rails 25L and 25R. Therefore, the left and right front clamp arms 30
L and 30R can be moved back and forth and left and right under the condition that their tips are engaged with struts in the front suspension assembly, and the left and right rear clamp arms 31L and 31R are Under the condition that the part is engaged with the strut 15A in the rear suspension assembly 15, it is possible to move forward and backward and left and right, the left and right front clamp arms 30L and 30R, the arm slides 34L and 34R, the left and right rear clamp arms 31L. And 31R, and the arm slides 36L and 36R constitute a docking device 40.

Further, in the docking station ST2, a pair of slide rails 41L and 41R, which are installed so as to extend in parallel with the transport rails 25L and 25R, respectively, and the slide rail 41L.
And movable member 42, which is supposed to slide along 41R,
A slide device including a motor 43 for driving a movable member 42 and the like
A movable member 42 of the slide device 45 is provided with an engagement means 46 which engages with a movable engine support member (not shown) provided on the pallet 13.
Is provided. Further, two lifting pallet reference pins for positioning the pallet 13 at a predetermined position.
47 are also provided. The slide device 45 is a body supported by the lifting hanger frame 22 of the transfer device 16.
When the engine 14, the front suspension assembly, and the rear suspension assembly 15 arranged on the pallet 13 are combined with the
It is moved back and forth while engaging with the movable engine support member on the pallet 13 positioned by 47, thereby moving the engine 14 back and forth with respect to the body 11 to avoid interference between the body 11 and the engine 14. To be.

In the fastening station ST3, a robot 48A that is to perform screw tightening work for fastening the engine 14 and the front suspension assembly combined with the body 41 to the body, and a rear suspension assembly 15 combined with the body 14 to the body 48 A robot 48B, which is to perform a screw tightening operation for fastening, is installed. Further, also at the fastening station ST3, two lifting / lowering pallet reference pins, which are to position the pallet 13 at a predetermined position. 47 are provided.

In the vehicle assembly line as described above, the positioning device 19 in the positioning station ST1, the transfer device 16, the docking device 40 and the slide device 45 in the docking station ST2, the pallet transport device 17, and the robots 48A and 48B in the fastening station ST3. The sequence control unit connected thereto is a facility (sequence control target facility) that performs sequence control of those operations based on a sequence control program.

The operation performed by each of these sequence control target facilities is divided into operation blocks defined as a maximum unit of a series of operations that can be independently performed from the start to the end, and B0 to B0 are as follows. 12 operation blocks of B11 are obtained.

B0: Body 11 on cradle 12 by positioning device 19
Operation block that performs positioning of cradle (pedestal positioning operation block).

B1: Operation block for preparing the transfer of the body 11 by the transfer device 16 (transfer device preparation operation block).

B2: Left and right front clamp arm 3 by docking device 40
Clamps the struts of the front suspension assembly with 0L and 30R, and the left and right rear clamp arms 31L
Strut 1 of rear suspension assembly 15 by 31R and 31R
Operation block for preparing to clamp 5A (Strut clamp preparation operation block).

B3: An operation block in which the body 11 on the receiving table 12 positioned by the positioning device 19 is transferred to the elevating hanger frame 22 in the transfer device 16 and is conveyed (transfer device receiving operation). block).

B4: Operation block (slide device preparation operation block) for preparing the engagement of the engagement means 46 provided on the movable member 42 with the movable engine support member on the pallet 13 by the slide device 45.

B5: An operation block for returning the cradle 12 to the original position by the positioning device 19 (a cradle original position return operation block).

B6: The engine 14 arranged on the pallet 13 and the body 14 supported by the lifting hanger frame 22 in the transfer device 16 and arranged on the pallet 13 and clamped by the left and right front clamp arms 30L and 30R. An operation block (engine / suspension docking operation block) combining the struts of the front suspension assembly and the struts 15A of the rear suspension assembly 15 clamped by the left and right rear clamp arms 31L and 31R.

B7: An operation block for returning to the original position by the transfer device 16 (transfer device original position return operation block).

B8: Left and right front clamp arm 3 by docking device 40
Operation block for returning the 0L and 30R and the left and right rear clamp arms 31L and 31R to their original positions (clamp arm original position return operation block).

B9: Bottom 11 in which engine 14, front suspension assembly and rear suspension assembly 15 are combined by operating linear motor mechanism by pallet transport device 17
An operation block (linear motor propulsion block) for transporting the pallet 13 on which is mounted to the fastening station ST3.

B10: An operation block (screw operation block) for performing a screw tightening operation by the robot 48A to fasten the engine 14 and the front suspension assembled with the body 11 to the body 41.

B11: An operation block (screw tightening operation block) for performing a screw tightening operation by the robot 48B to fasten the rear suspension assembly 15 combined with the body to the body 41.

These operation blocks B0 to B11 are represented in a time-series relationship with each other by the operation block flowchart shown in FIG.

Each of the above-described operation blocks B0 to B11 is divided into a plurality of operation steps, each of which includes an output operation.For example, for the cradle positioning operation block B0, the ten operations of B0S0 to B0S9 are performed as follows. It is divided into steps.

B0S0: Operation step for confirming various conditions (condition confirmation operation step).

B0S1: An operation step (BF positioning operation step) in which the cradle 12 is moved by the positioning means BF and the front part of the body 11 is positioned in the vehicle direction.

B0S2: An operation step (BR positioning operation step) in which the cradle 12 is moved by the positioning means BR and the rear part of the body 11 is positioned in the vehicle direction.

B0S3: Operation step (TL positioning operation step) in which the positioning means TL is moved to the receiving table 12 to perform positioning in the direction (front-back direction) along the rail 18 of the body 11.

B0S4: Operation step in which the lifting reference pin FL engages the front left side of the body 11 (FL engagement operation step).

B0S5: Operation step in which the lifting reference pin FR engages the front right side of the body 11 (FR engagement operation step).

B0S6: Operation step in which the lifting reference pin FL engages the rear left side of the body 11 (FL engagement operation step).

B0S7: Operation step in which the elevation reference pin RR engages the rear right side of the body 11 (RR engagement operation step).

B0S8: An operation step of returning to the original position from a state where the positioning means BF positions the front part of the body 11 in the vehicle direction (BF original position return operation step).

B0S9: An operation step of returning to the original position from a state where the positioning means BR has positioned the front portion of the body 11 in the vehicle direction (BR original position return operation step).

Next, an example of a method for diagnosing a failure in a production line according to the present invention, which is applied to a vehicle assembly line in which the equipment to be sequence-controlled as described above is installed, will be described.

FIG. 5 shows a failure diagnosis system in which an example of a failure diagnosis method for a production line according to the present invention is implemented, together with equipment to be sequence-controlled and a sequence control unit connected thereto. The sequence control target equipment 50 includes, as described above, the positioning device 19, the transfer device 16, the docking device 40, the slide device 45, the pallet transport device 17, and the robots 48A and 48B.
, And is subjected to sequence control by the sequence control unit 51.

Equipment 50 subject to sequence control by sequence controller 51
The sequence control for the operation of
The sequence control program is performed based on a sequence control program loaded into the CPU 51. For example, a ladder program as shown in FIG. 6 corresponds to one operation step in a certain operation block. And a sequence control ladder program. In the ladder program shown in FIG. 6, (M1), (M2) and (Y0) are output devices, and M1 and M2 are output devices (M1) and (M1).
Contact devices corresponding to 2), X0 to X16 and XA to XC, are contact devices not corresponding to output devices.

The failure diagnosis system includes a failure diagnosis controller 52. The failure diagnosis controller 52 includes a central processing unit (CPU) 62, a memory 63, and an input / output interface (I / O interface) connected through a bus line 61. / O interface) 64, a transmission / reception interface 65, and a hard disk device 66 as an auxiliary memory connected to the I / O interface 64, a cathode ray tube (CRT) 67 for display, and for inputting data and control codes. Keyboard 68 is provided. The transmission / reception interface 65 and the transmission / reception interface 51A provided in the sequence control unit 51 are interconnected.

The failure diagnosis controller 52 receives a transmission / reception interface from the sequence controller 51 in accordance with the operation of the keyboard 68.
Through 51A and 65, program processing data indicating the progress status of sequence control for the sequence control unit target equipment 50 is received, and the CPU 62 writes and reads data in the memory 63, and executes a program from the sequence control unit 51. The occurrence of a failure in the equipment 50 subject to sequence control is detected based on the processing data. When the occurrence of a failure is detected, an indication regarding the failure is displayed on the CRT 67 for display. The hard disk device 66 stores data representing each step ladder element in the sequence control ladder program loaded into the sequence control unit 51 in a state that is individually read out. The hard disk device 66 stores the sequence control ladder program. It is supposed to build a database for

In such a failure diagnosis control device 52, the CPU 62
From the sequence controller 51, the transmission / reception interface 21A
And 65, sequentially receives the program processing data indicating the progress of the sequence control for the sequence control target equipment 50, and according to the failure diagnosis program loaded into the CPU 62, the sequence control target based on the program processing data from the sequence control unit 51. In addition to detecting the occurrence of a failure in the equipment 50 and determining the operating element in the sequence-controlled equipment 50 that caused the failure, that is, the operating element that caused the failure, the CR for the display was also determined.
An example of the production line failure diagnosis method according to the present invention is performed by performing display control so that a display relating to the failure is performed at T67. The process will be described below.

The detection of the occurrence of a failure in the sequence control target equipment 50 by the CPU 62 in the failure diagnosis control device 52, and the investigation of the failure cause operation element when the occurrence of the failure is detected are sequentially performed according to the operation block flowchart shown in FIG. The failure diagnosis is performed individually through each of the executed operation blocks B0 to B11. For example, first, the detection of the occurrence of a failure through each of the operation blocks B0 to B11 is performed by measuring the execution time from the start time to the end time of a plurality of operation steps constituting the operation block, and measuring the actual execution time. The time is compared with a preset reference time, and when the actual execution time measured is longer than the reference time, the positioning device 1 in the sequence control target equipment 50 that executed the operation block concerned
9, This is performed by determining that any of the transfer device 16, the docking device 40, the slide device 45, the pallet transport device 17, and the robots 48A and 48B has a failure.
When the occurrence of a failure through each of the operation blocks B0 to B11 is detected, an operation step that includes the operation of the output element turned off due to the failure in the operation block is a failure-causing operation. An operation step including an operation of an element is specified, and further, in the equipment that has performed the specified operation step, an operation element that causes an output element to be turned off is specified, thereby causing a failure-caused operation. The elements are determined.

At this time, the operation performed by the CPU 62 to specify the failure cause operation element for the equipment that has performed the operation step specified as including the operation of the failure cause operation element will be described with reference to the flowchart shown in FIG. State.

First, in the sequence control program used for the sequence control of the operation of the sequence control target equipment 50, G _x−2 , G _x−1 , G _x
Each output device and the contact devices connected to it and forming a set of ladder elements with the output device are referred to as a ladder element device group, and a failure cause operation in a sequence control ladder program is performed. The part corresponding to the operation step specified as including the operation of the element is selected, and the output device (Y _n) corresponding to the output element assumed to be in the off state in the part of the selected sequence control ladder program is selected. ) ladder element devices group comprising (G _n) fetches data for (step R1). Next, in the ladder element device group _Gn , a contact device (OFF device) which is assumed to be in an OFF state without being connected in parallel to an ON device is detected (step R2), and the OFF device is detected. It is determined whether the output device (M _n-1 ) in the preceding ladder element device group (G _n-1 ) does not correspond to the output device (M _n-1 ) (step R3). As a result, if the OFF device is an X-contact device, the corresponding OFF device is determined to be the failure cause device, and the corresponding operation element is specified as the failure cause operation element (step R8).

On the other hand, _if the OFF device in the ladder element device group _Gn is not an X-contact device, the data of the preceding ladder element device group _Gn-1 including the output device ( _Mn-1 ) corresponding to the OFF device is transmitted. Capture (step R4). And the ladder element device group G
_{At n-1} , an OFF device, which is an off-state contact device, is detected without connecting the on-state contact device in parallel (step R
5), the OFF device in the ladder element device group G _n-1 does not correspond to the output device (M _n-2 ) in the preceding ladder element device group (G _n-2 ) (X contact device) It is determined whether or not (step R6). As a result, if the OFF device is an X-contact device, the corresponding OFF device is determined to be the failure cause device, and the corresponding operation element is specified as the failure cause operation element (step R8).

On the other hand, in the ladder element device group G _n-1
If the OFF device is not a contact device, decrement the variable n by 1 (step R7) and return to step R4.
In step R6, the operations from step R4 are repeated until the OFF device in the ladder element device group G _n-1 is determined to be the X contact device.
In R6, OFF in ladder element device group G _n-1
When it is determined that the device is an X contact device,
Proceed to step R8.

In this manner, the failure cause operation element for the equipment that has performed the operation step specified as including the operation of the failure cause operation element is specified.
In such a case, the detection of the OFF device in the ladder element device group _Gn , which is executed in step R2 of the flowchart shown in FIG. 1, and the ladder executed in step R5 of the flowchart shown in FIG. For details of the OFF device detection in the element device group G _n-1 , refer to the flow chart shown in FIG. 7 and FIG. 8, and further, the ladder element device group G _n is changed to the ladder element device group shown in FIG. G _{x, and} a case where the ladder element device group G _n-1 is configured like the ladder element device groups G _x-1 and G _x-2 shown in FIG. This will be described below.

Note that the ladder elements devices group G _x-1 and G _x-2, which is a ladder element devices group G _x and ladder element devices group G _n-1 is a ladder element devices group G _n, respectively, Figure 9 As shown in the figure, the device with hatching is assumed to be in the on state, the device without hatching is assumed to be in the off state, and the contact device X2 in the ladder element device group G _x-2 is the fault-causing device. by in the off state there is, it is assumed that the output devices Y0 in the ladder element devices group G _x is turned off.

First, when the detection of the OFF devices in ladder element devices group G _n, the data of each devices in the ladder element devices group G _n, a plurality of storage areas each of the address numbered in the memory, the ladder pattern is maintained Are allocated and stored under the state (step S1). At this time, the data of each device is stored with the ON state set to “1” and the OFF state set to “0”, the connection between the devices is stored as “1”, and the final address Data “Z” is stored in a storage area to which an address number smaller by 7 than the number is assigned. Therefore, the ladder element devices group G _x, which is a ladder element devices group G _n, in as shown in FIG. 8 A, the storage area address number A0 in the memory is attached (called the address portion A0, other The same applies to the storage area) to the address section A15 to store the data of each device.
Data “Z” is stored in A8.

Next, it is determined whether data "Z" is stored in the address section A8 (step S2). If "Z" is stored in the address section A8, the variable i is set to 1 and (Step S3), the data of the address part Ai and the address part A (i +
OR data ("0" or "1") with the data of 8) is obtained, and the obtained OR data is put into the bit of the bit number bi in the 8-bit register as an OR output (step S4).

Then, after increasing the variable i by 1 (step S
5) It is determined whether the variable i has become 7 (step S)
6). As a result, when the variable i is not 7,
Returning to step S4, the logical sum data of the data of the address part Ai and the data of the address part A (i + 8) is obtained, and this is used as an OR output to obtain the bit number bi in the 8-bit register.
Is performed, and such an operation is performed by setting the variable i to 7
Repeat until. As a result, when the variable i becomes 7, as shown in FIG. 8A, the bit number b0 of the bit numbers b1 to b7 in the 8-bit register
The address part in the memory for each of the bits up to b7
Will be the logical sum data is placed in the Ai data and data of the address section A (i + 8), for the ladder element devices group G _x, only the bits of the bit number b5 "0" is put, other Is set to "1".

Next, the logical sum data “0” in the 8-bit register
Bit number bZ of encased bits, i.e., bit number b5 is detected in the case of a ladder element devices group G _x (step S7), and the address unit A in the memory (Z + m8)
(Where m is 0, 1, 2,...) Detects a contact device in which data is stored as an OFF device (step R
8). Therefore, for the ladder element device group G _x ,
The contact device M2 is detected as an OFF device.

On the other hand, as a result of the determination in step S2, the address part A8
If the data “Z” is not stored in the
(Step s9), and the address number $ i + 8 (1
+ K) is stored (step s10). Next, it is determined whether data "Z" is stored in the address portion A8 (1 + k) in the memory (step S11), and the address portion A8 is determined.
If the data Z "is not stored in (1 + k), the variable k
Is incremented by 1 (step S12), and the process returns to step S10 to store the address number A {i + 8 (1 + k)}, and the data Z ″ is stored in the address section A8 (1 + k). Repeat until determined.

Thereafter, the variable i is set to 1 (step S13), and the data of the address part Ai in the memory and the address part A (i
+8) and the logical sum data (“0” or “1”) of the data in the storage area having each of the address numbers A {i + 8 (1 + k)} stored in step S10
Is obtained and put into the bit of bit number bi in the 8-bit register as an OR output (step S14).

Then, after increasing the variable i by 1 (step S1
5) It is determined whether or not the variable i has become 7 (step 1)
6). As a result, if the variable i is not 7, the process returns to step S14, and the address portion Ai in the memory is returned.
, The data of the address section A (i + 8), and the address number A @ i + 8 stored in step S10.
(1 + k)} is obtained, and OR operation is performed with the data of the storage area having each of (1 + k) 入 れ る, and the result is put into the bit of the bit number bi in the 8-bit register as an OR output.
This operation is repeated until the variable i becomes 7. And
When the variable i becomes 7, the process proceeds to step S7.

Incidentally, in the case of the ladder element devices group G _x is a ladder element devices group G _n, from step S9 S16
Until it is not executed.

The detection of the OFF device in the ladder element device group G _n-1 is also performed according to a flowchart similar to the flowchart shown in FIG. 7, and the ladder element device groups G _x-1 and G _x-2 are ladder elements. When the element device group G _n−1 is set, first, the ladder element device group
Regarding G _x−1 , in a step corresponding to step S1 of the flowchart shown in FIG. 7, as shown in FIG. 8B, the data of each device is allocated and stored in address portions A0 to A10 in the memory. . Also in this case, since the data “Z” is stored in the address section A8, the seventh
In a step corresponding to step S4 of the flowchart shown in the figure, the logical sum data of the data of the address section Ai and the data of the address section A (i + 8) in the memory is calculated.
By repeating the operation of putting the bit of the bit number bi in the 8-bit register as the OR output until the variable i becomes 7, when the variable i becomes 7, as shown in FIG. Bit numbers b0 to
A state is obtained in which the logical sum data of the data of the address portion Ai and the data of the address portion A (i + 8) in the memory is inserted in each of the bits of the bit numbers b1 to b7 among the bits up to b7. Then, also for the ladder element device group G _x-1 , the bit number bZ of the bit in which the logical sum data “0” is inserted in the 8-bit register becomes b5, and in the 8-bit register, the bit of the bit number b5 becomes Only "0" is entered and "1" is entered in other bits.

As a result, in a step corresponding to step S8 of the flowchart shown in FIG. 7, data was stored in the address portion A (Z + m8) (where m is 0, 1, 2,...) In the memory. A contact device, that is, a contact device M1 in which data is stored in an address portion A5 in the memory.
Is detected as an OFF device.

Next, regarding the ladder element device group G _x-2 , the seventh
In a step corresponding to step S1 of the flowchart shown in the figure, as shown in FIG. 8C, data of each device is allocated to and stored in address portions A0 to A23 in the memory. In this case, since the data “Z” is stored in the address section A16 instead of the address section A8, the data of the address section Ai in the memory is stored in the step corresponding to step S14 in the flowchart shown in FIG. The operation of putting the logical sum data of the data of the address portion A (i + 8) with the data of the address number A (i + 16) as an OR output into the bit of the bit number bi in the 8-bit register is repeated until the variable i becomes 7. Thus, when the variable i becomes 7, as shown in FIG. 8C, each of the bits of the bit numbers b1 to b7 of the bits of the bit numbers b0 to b7 in the 8-bit register is assigned to the address in the memory. The data of the section Ai and the address section (i
Thus, a state is obtained in which the logical sum data of the data of (+8) and the data of the address number A (i + 16) is entered.
Then, also for the ladder element device group G _x-2 , the bit number bZ of the bit in the 8-bit register in which the logical sum data “0” is inserted becomes b5, and in the 8-bit register, the bit of the bit number b5 becomes Only "0" is entered and "1" is entered in other bits.

As a result, in a step corresponding to step S8 in the flowchart shown in FIG. 7, a contact device in which data is stored in the address portion (Z + m8) (where m is 0, 1, 2,...) The contact device X2 in which data is stored in the address portion A5 of the memory is turned off.
Detected as an F device.

(Effects of the Invention) As is clear from the above description, according to the failure diagnosis method for a production line according to the present invention, various operations to be performed are performed independently from the start to the end under a normal state. While being divided into a plurality of operation blocks as a maximum unit operation block of a series of operations, each of the plurality of operation blocks is divided into a plurality of operation sticks,
A failure occurs in a facility controlled to sequentially execute a plurality of operation steps in each of a plurality of operation blocks according to a sequence control ladder program, and a failure that causes the failure when a specific output element is turned off. An investigation to identify the causal operating element is performed for a specific part corresponding to an operation step including an operation of a specific output element that is turned off due to a fault in the sequence control ladder program, and Investigation of the fault-causing operating element for a specific part of the program is performed for a plurality of ladder element devices arranged in a row in the specific part, for a specific output element that was turned off when the equipment failed. From the ladder element device group containing the corresponding output device, -For each ladder element device group, a contact device that is assumed to be in an off state is detected without being connected in parallel to each of the ladder element devices, and a contact that is assumed to be in an off state is detected. The process is performed retrospectively until it is determined that the device does not correspond to the output device in the preceding ladder element device group. As a result, when a failure occurs during the operation of the equipment for which sequence control is performed, it is possible to quickly and properly determine the operating element that caused the failure.

[Brief description of the drawings]

FIG. 1 is a flowchart for explaining the investigation of a failure-causing operating element performed according to an example of a production line failure diagnosis method according to the present invention. FIGS. 2 and 3 are production line failure diagnosis according to the present invention. FIG. 4 is a schematic side view and a schematic plan view showing an example of a vehicle assembly line to which the method is applied, FIG. 4 is an operation block flowchart for explaining sequence control for equipment to be sequence controlled, and FIG. 5 is production according to the present invention. FIG. 6 is a structural diagram showing a failure diagnosis control system in which an example of a line failure diagnosis method is implemented, together with a sequence control target facility and a sequence control unit. FIG. 6 is a sequence control used for sequence control of the sequence control target facility by the sequence control. Ladder diagrams showing part of an example of the program, FIG. 7, FIG. 8, and FIG. 9 are diagrams of a production line according to the present invention. Flowchart an example of a disabled diagnostic method is subjected to a description of a particular process at the time to be performed, the memory conceptual diagram, and a ladder diagram. In the figure, 16 is a transfer device, 17 is a pallet transport device, 19 is a positioning device, 40 is a docking device, 45 is a slide device, 48
A and 48B are robots, 50 is equipment subject to sequence control, 51
Is a sequence control unit, 52 is a failure diagnosis control device, 61 is a bus line, 62 is a central processing unit (CPU), 63 is a memory, 6
4 is an input / output interface (I / O interface),
66 is a hard disk drive, 67 is a cathode ray tube (CRC) for display, and 68 is a keyboard.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-235207 (JP, A) JP-A-58-172713 (JP, A) JP-A-1-251109 (JP, A) JP-A-1- 248206 (JP, A) JP-A-2-178706 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G05B 19/02-19/05

Claims (1)

(57) [Claims] 1. A maximum unit of a series of operations, which are to be performed independently from start to finish under normal conditions, are divided into a plurality of operation blocks as operation blocks. When each of the plurality of operation blocks is divided into a plurality of operation steps, and the plurality of operation blocks are controlled to sequentially execute a plurality of operation steps in each of the plurality of operation blocks according to a sequence control ladder program, The execution time from the start time to the end time of the plurality of operation steps in each of the plurality of operation blocks is measured, and when there is a specific operation block in which the measured execution time is longer than the reference time, the specific operation block Is determined to have failed in the equipment that executed The operation of a specific output element that is turned off due to the failure in the specific operation block, based on a device and a contact device connected thereto and forming a set of ladder elements together with the output device as a ladder element device group. For the part of the sequence control ladder program corresponding to the operation steps including
In the ladder element device group including the output device corresponding to the specific output element, the contact device in the on state is not connected in parallel, the contact device in the off state is detected, and the contact device in the off state is detected. If the output device corresponds to the output device in the preceding ladder element device group, the contact device in the ON state is detected in the further preceding ladder element device group without being connected in parallel. In other words, when the detected contact device in the off state does not correspond to the output device in the ladder element device group in the preceding stage, the contact device is determined to be a failure-causing operation element, and the failure of the production line is characterized by Diagnostic method.