JPH06202717A - Method for verifying sequence operation of equipment - Google Patents

Abstract

PURPOSE:To prevent the breakdown of equipment by issuing a warning at the time of finding a sequence operation which satisfies the condition that either of sequence operations having step numbers other than a held step number is started simultaneously with the sequence operation to be executed. CONSTITUTION:When a ladder program in an operation step will be executed, it is checked whether this program has operations which will be simultaneously executed in parallel in steps following this step number or not. Thereby, the breakdown of the equipment due to an unexpected operation is prevented. This check function is executed by the depression of a switch 401 at the time of restart of the system after a fault is detected to shut off the system and the cause of the fault is removed. If operation steps which may be operated in parallel are found, an operator is warned of it and the restart operation is not performed for the purpose of preventing the breakdown of the equipment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for verifying the sequence operation of production equipment controlled by, for example, a sequencer, and more particularly to a method for verifying the sequence operation of equipment operating according to the sequence operation specified in the order of step numbers. Regarding improvement.

[0002]

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 a sequence of operations to be performed by each facility. It is known to have control.
In such sequence control, a control program is loaded into a computer incorporated in the sequence control unit, and the sequence control unit sequentially advances each step of operation control for each of various equipment installed in the production line in accordance with the sequence operation control program. It is designed to work.

As a control method for such sequence control, the present applicant has filed Japanese Patent Application No. 1-335271, 2-1.
No. 10977, 2-30379, 1-253991
No. 2-304022, 2-304023, 2-3
0402, 3-67290, 3-67291,
No. 3-67292 is filed. The production line management method in these applications describes general control conditions by a sequencer of all equipment of the production line as an input / output map, while the concrete sequential operation of the line is called an operation block and an operation step. And then on that,
The ladder program is generated based on the input / output map, the operation step flow map, and the operation block flow map.

[0004]

In the above-mentioned so-called "block step system" sequence program,
Within one block, sequence operations involving two or more steps are not executed simultaneously (in parallel). Although it is logically possible that a problem does not occur even if parallel operations of multiple operations involving two or more steps are originally allowed, if parallel execution is allowed, unexpected failures or abnormalities occur. In this case, it is difficult to investigate the cause, and the arrangement is made so that the sequence operations involving two or more steps are not executed simultaneously (in parallel).

However, when the sequence program is described in the ladder program format, it is difficult to describe a plurality of sequence operations with a huge number of steps so that they are executed completely in the order of step numbers. Therefore,
Even a program including a so-called minor bug in which a plurality of steps are executed in parallel at the same time may be introduced and run on an actual production line without noticing it in the test stage.

The program operated in this way is
If the entire production equipment is normal, it will operate smoothly without any problems. However, once a failure occurs in any of the equipment, all the equipment is stopped. When the cause of a failure is detected, the cause is removed, and the production line is restarted, all equipment must be returned to the state immediately before the occurrence of the failure. Most of this work is done manually. For example, a workpiece that is being moved may have to be returned to its original position before stopping, and in some cases, a robot that moves the workpiece may have to be returned to its initial position.

[0007] Such restoration work must be carried out for a huge number of equipments, so that there are many mistakes. Due to this erroneous restoration work, parallel execution of a plurality of steps that could not occur at the normal time may occur. In addition, even if there is no mistake in the recovery work, the operation of multiple equipment interferes with each other in order to restart from the middle that was not experienced during normal operation, and in some cases equipment (for example, robot arm or fin) It may be damaged.

Therefore, according to the present invention, by verifying whether or not two or more sequence operations associated with a plurality of step numbers are executed in parallel, it is possible to prevent the equipment from being damaged in advance. It proposes a method.

[0009]

The verification method of the present invention for achieving the above object is a method for verifying a sequence operation of equipment which operates according to a sequence operation defined in the order of step numbers, and is intended to be executed. The step number for the sequence operation is held, and it is checked whether any of the sequence operations related to the step number different from the held step number is ready to start at the same time as the sequence operation to be executed. , A warning is issued when a sequence operation with a condition to be started simultaneously is found.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to the sequence control of an automobile production line will be described below. First, an example of a vehicle assembly line that is a control target of a sequence control program to be generated will be described with reference to FIGS. 1 and 2.

A part of a vehicle assembly line is shown in FIGS. 1 and 2. This line illustratively consists of three stations ST1, ST2, ST3. At the positioning station ST1, the body 11 of the vehicle is pedestal 12
The body 11 is positioned by controlling the position of the pedestal 12 which is received above. Docking station ST2
Then, the engine 14, the front suspension assembly (not shown), the rear suspension assembly 15, and the body 1 which are mounted at predetermined positions on the pallet 13 are mounted.
Combine with 1. At the fastening station ST3, the engine 14 and the front suspension assembly 15 combined at ST2 are fastened and fixed to the body 11 using screws. Also, the positioning station ST
1 and the docking station ST2, an overhead transfer position 1 for holding and transporting the body 11.
6 is provided. A pallet transfer position 17 for transferring the pallet 13 is provided between the docking station ST2 and the fastening station ST3.

The pedestal 12 in the positioning station ST1 reciprocates along a rail 18. In the positioning station ST1, the pedestal 12 is moved in a direction (vehicle width direction) orthogonal to the rails 18 to position the body 11 placed on the pedestal 12 in the vehicle width direction of its front portion. Positioning means (BF) and positioning means (B) for positioning the rear portion in the vehicle width direction.
R) and the pedestal 12 along the rail 18 (front-back direction)
And a positioning unit (TL) for performing positioning in the front-rear direction by moving the position. Further, ST1 is engaged with front left and right portions and rear left and right portions of the body 11 to position the body 11 with respect to the pedestal 12.
R, RL, RR) are provided. The positioning device and the elevating / lowering reference pin constitute the positioning device 19 in the positioning station ST1. That is, the positioning means and the lifting reference pins are control targets of the positioning device 19 of the sequence control program.

The transfer device 16 includes a positioning station S.
The guide rail 20 is provided above the T1 and the docking station ST2 so as to be bridged therebetween, and the carrier 21 that moves along the guide rail 20. An elevating hanger frame 22 is attached to the carrier 21, and the body 11 is supported by the elevating hanger frame 22. Lifting hanger frame 22
As shown in FIG. 3, the left front support arm 22
The FL and the right front support arm 22FR are attached via the pair of front arm clamp portions 22A, respectively, and the left rear support arm 22RL and the right rear support arm 22RR are also mounted.
(Not shown) are attached via a pair of front arm clamp portions 22B, respectively. Left front support arm 22FL,
Each of the right front support arms 22FR rotates around the front arm arm clamp portion 22A as a rotation center, and when the clamp by the front arm clamp 22A is released, it takes a position extending along the guide rail 20. When the front arm clamp portion 22A is clamped, as shown in FIG.
The position is set to extend in the direction orthogonal to 0. Similarly, each of the left rear support arm 22RL and the right rear support arm 22RR also rotates about the rear arm clamp portion 22B, and when the clamp by the rear arm clamp portion 22A is released, the guide 20 is rotated. It also has a position that extends along it, and when it is clamped by the rear arm clamp portion 22B, it has a position that extends in a direction orthogonal to the guide rail 20.

When the body 11 is transferred to the transfer device 16, the transfer device 16 is moved to the position (original position) above the front end of the rail 18 as shown by the alternate long and short dash line in FIG. The left front support arm 22FL and the right front support arm 22FR each extend along the guide rail 20 after the clamp by the front arm clamp portion 22A is released. Further, each of the left rear support arm 22RL and the right rear support arm 22RR is released from the rear arm clamp portion 22B, extends along the guide rail 20, and then the elevating hanger frame 21B is lowered. In this state, the pedestal 1 on which the body 11 is placed
2 is moved along the rail 18 to the front end portion thereof so as to take a position corresponding to the lifted hanger frame 21B of the transfer device 16 that has been lowered. And
Left front support arm 22FL, right front support arm 22FR
Each of them is rotated to take a position below the front part of the body 11 to extend in a direction orthogonal to the guide rail 20, and is clamped by the front arm clamp part 22A. In addition, the left rear support arm 22RL and the right rear support arm 22RR are each rotated to move the body 1
The rear arm clamp portion 22B is positioned below the rear portion of the rear arm 1 and extends in a direction orthogonal to the guide rail 20.
It will be in the state of being clamped by. Then, the elevating hanger frame 21B is raised, and the body 11 is moved to the left front support arm 22 attached to the elevating hanger frame 21B of the transfer device 16 as shown in FIG.
FL, right front support arm 22FR and left rear support arm 2
It is supported by 2RL and the right rear support arm 22RR.

Further, the pallet conveying device 17 is provided with a pair of guide portions 24L and 24R provided with a large number of supporting rollers 23 for receiving the lower surface of the pallet 13, and the guide portions 24L and 24R, respectively, extending in parallel. And a pair of transport rails 25L and 25R, and a pallet locking portion 26 that locks the pallet 13, respectively.
And pallet transfer tables 27L and 27R that are designed to move along the pallet transfer table 27L and the pallet transfer table 27L.
And a linear motor mechanism (not shown) that drives 27R.

When the front suspension assembly and the rear suspension assembly 15 are respectively assembled to the docking station ST2, a pair of strut of the front suspension assembly and a strut 15A of the rear suspension assembly 15 are respectively supported to take an assembly posture. Left and right front clamp arms 30L and 30R and a pair of left and right rear clamp arms 31L and 31R are provided. The left and right front clamp arms 30L and 30R are attached to the attachment plate portions 32L and 32R so as to be movable back and forth in a direction orthogonal to the transport rails 25L and 25R, respectively, and the left and right rear clamp arms 31L and 31R are attached respectively. It is attached to the plate portions 33L and 33R so as to be movable back and forth in a direction orthogonal to the transport rails 25L and 25R. The front end portions of the left and right front clamp arms 30L and 30R that face each other and the front end portions of the left and right rear clamp arms 31L and 31R that face the front suspension assembly strut 15A or the rear suspension assembly 15 strut 15A, respectively. It has a mating engaging portion. Then, the mounting plate portion 32L
Can be moved by the arm slide 34L with respect to the fixed base 35L in the direction along the transport rails 25L and 25R. The mounting plate portion 32R is attached to the fixed base 35R by the arm slide 34R, and the transport rails 25L and 25R are attached to the fixed base 35R.
It is movable in the direction along R. The mounting plate portion 33L is
With respect to the fixed base 37L by the arm slide 36L,
It is movable in the direction along the transport rails 25L and 25R. Further, the mounting plate portion 33R includes the arm slide 36.
By R, it is movable with respect to the fixed base 37R in the direction along the transport rails 25L and 25R. Therefore,
The left and right front clamp arms 30L and 30R can move back and forth and left and right under the condition that their tips are engaged with the struts of the front suspension assembly. Also, left and right rear clamp arms 31L and 31R
Are movable in the front-rear direction and the left-right direction while their front ends are engaged with the struts 15A of the rear suspension assembly 15. 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 configure a docking device 40.

Further, in the docking station ST2, a pair of slide rails 41L and 41R installed so as to extend in parallel to the transport rails 25L and 25R, respectively.
And a slide device 45 including a movable member 42 that slides along the slide rails 41L and 41R, a motor 43 that drives the movable member 42, and the like. Movable member 4 in this slide device 45
In FIG. 2, engaging means 46 for engaging a movable engine support member (not shown) provided on the pallet 13 is provided.
And 2 for positioning the pallet 13 at a predetermined position.
Elevating pallet reference pins 47 are provided. In the slide device 45, the body 11 supported by the elevating hanger frame 22 in the transfer device 16 is
When the engine 14, the front suspension assembly, and the rear suspension assembly 15 arranged on the pallet 13 are combined, the engaging means 46 engages with the movable engine support member on the pallet 13 positioned by the lifting pallet reference pin 47. In this state, the engine 14 is moved back and forth, whereby the engine 14 is moved back and forth with respect to the body 11 to avoid interference between the body 11 and the engine 14.

At the fastening station ST3, the body 11
A robot 48A for performing a screw tightening work for fastening the engine 14 and the front suspension assembly combined with the rear suspension assembly 15 combined with the robot 48A.
Robot 4 for performing screw tightening work for fastening
8B and are arranged. Furthermore, the fastening station S
At T3, two lifting pallet reference pins 47 for positioning the pallet 13 at a predetermined position are provided.

In the vehicle assembly line described with reference to FIGS. 1 to 3, the positioning device 19 and the transfer device 16 at the positioning station ST1, and the docking device 40 and the slide device 45 and the pallet transfer device 17 at the docking station ST2, Then, the robots 48A and 48B at the fastening station ST3
The sequence control unit connected to them performs sequence control based on the sequence control program generated by the program generation device of this embodiment. That is, these positioning device 19 and transfer device 1
6 and the like are "equipment" that are the sequence control targets.

<Operation Block and Operation Step> FIG. 1,
The assembling operation in the production line in FIG. 2, that is, the operation performed by all the "equipment" to be sequence-controlled can be decomposed into a plurality of "operation blocks". Here, the “motion block” can be defined as “a set of a plurality of unit motions”. The most important property of the motion block is that the motion block is one block (lump).
Can be written as. In order for an operation block to start operation, it is necessary to end the operation in another operation block. There may be one or more other operation blocks. That is, the end of the operation of one operation block becomes a start condition of another operation block (one or a plurality of operation blocks) connected to it, or the end of the operation of a plurality of operation blocks becomes a start condition. is there.

There is no activation of other operation blocks in the intermediate stage of the operation in the operation block. In addition, there is no need to wait for activation from another operation block in the intermediate stage of the operation block. The action block has the following ancillary action block properties. The action block is preferably the largest of the set of unit actions. This property is not absolutely necessary,
When satisfied, the number of motion blocks that describe the production line is reduced, the description of the entire process is simplified, and is very easy to see.

The operation block is also limited according to the type of operation performed in the operation block. That is,
The operation of the device is "repetitive operation", "continuous operation",
It is roughly divided into "robot movements". In this system, a ladder program is automatically generated from a standard ladder pattern. However, since this ladder pattern differs greatly depending on the operation, a device that performs only the same type of operation in one operation block. Collect.

FIG. 4 shows an overall flow of operations in the production line shown in FIGS. 1 and 2. Figure 1,
When the production line shown in FIG. 2 is described by operation blocks that satisfy the above-mentioned conditions, 19 operation blocks a to s are obtained as shown in FIG. The block diagram thus obtained is obtained after the operator analyzes the operation in the production line shown in FIGS. 1 to 3. In the figure, two (or more) operation blocks connected by a horizontal double line mean that they operate in parallel. Further, when the two operation blocks are vertically connected by a solid line, the operation of the operation block in the upper position is completed and the operation of the block in the lower operation is started. The double-lined square means the beginning of each block.

The operation block a means the forward movement of the pedestal 12 and is called "advance receiving". When this "load forward" block is completed, a block "b" called "reference" and a block "c" called "receive" are performed in parallel. In the “reference output” block b, the reference pins (F
The L reference pin and the RR reference pin are driven to a position named "out", and the TL positioning means and the like are driven to a position named "return". In block c, the pedestal 12 moves to the docking position. In the block named “transfer lifting” of the block d, the transfer device 16 moves up at the station ST1. When the operation of the block d is completed, the operation block is processed in two flows following the block d. That is, following the "transfer rising" block, a block e named "reference return" and a block h named "transfer forward" operate in parallel. In block e, the operation of returning the reference pin issued in block b to the "return" position is performed. On the other hand, in the block h, the transfer device 16 advances to the station 2.

In a block f named "Receiving cargo" following the block e, the cradle 12 is retracted. In block h, the transfer device 16 advances to the station ST2. On the other hand, in the guide part, strut clamp part, and pallet slide part, the block 1
("Pin lift"), block m ("lift lift"), and block n ("pallet advance") are executed respectively. Completion of block m ("lift lift") and block n ("pallet advance") activates block o ("arm out").

When the operations in the blocks h, 1, and o are completed, the operation block i named "transfer lowering" is executed. The above-described flowchart of the operation block set in FIG. 4 is a block of the operation set that meets the above-described conditions. As described above, the operator creates the operation using the flow chart creation program described later. It was done. The name given to each motion block expresses the characteristics of the motions (plurality) in the motion block in short words.

Each operation block consists of a plurality of operation steps. In principle, the operation in one operation step corresponds to the operation by one actuator (solenoid or the like). FIG. 7 is a flow chart including a plurality of operation steps performed in the "reference output" block b. In the figure, the label attached to each step is the name of the step given by the operator. According to the flow chart of FIG. 7, in the "RR slide out" step, the right slide rail 41R on the rear side is set to the "out" state, and "FL reference pin A out" and "FL reference pin B out".
In step, the above-mentioned raising / lowering reference pins A and B (left side of the front part) for positioning the vehicle body 12 with respect to the pedestal 12 are set to the “out” state. In the "RR reference pin output" step, the raising / lowering reference pin on the right side of the rear portion is also set to the "out" state. Also, "TL position return", "BR position return",
In each step of "BF position return", the positioning means TL, BR, BF are returned to the "return" position. In this way, the “reference output” block b in FIG.
This is represented by the step operation shown in the figure. This operation step flow chart is also created by the above-mentioned flow chart creating program.

As described above, each label expressing the operation of one operation block in the operation step flowchart as shown in FIG. It is a simple expression. For example, the name "RR reference pin out" is given to the step "RR reference pin out" in which the RR reference pin is in the "out" state. Here, the "RR reference pin" in the first half of this name specifies the actuator driven in that operation step, and the next "exit" means the drive state of that actuator. In other words, Figs. 4 and 7
For humans and devices who can understand the meanings given to the names of the operation blocks and operation steps in the flowchart of the figure, those flow charts understand the operations in the production line of FIG. It's easy.

The ladder programs shown in FIGS. 8 to 10 are
It is a ladder program element corresponding to a part of the operation of the operation block b shown in FIG. <Ladder Program Symbol> Here, the ladder program symbol will be described. The equipment itself, such as the lifting reference pin, of the production line in FIG. 1 is not a control target on the ladder program, and the solenoid that drives it, for example, poses a problem. Therefore, the equipment of the production line can be equivalentized by a cylinder actuator as shown in FIG. The "out" state and the "return" state of this actuator are defined by the position of the piston that moves left and right in the cylinder in the drawing. The piston takes one of its "out" state and "return" state by being energized or deenergized by the signal B0 input to the solenoid valve. These two states are confirmed by two limit switches. That is, the first
As the output from the "equipment" in Fig. 1, the output A _O ("outgoing confirmation" signal) from the limit switch to confirm that it was driven and the limit switch to confirm that it was returned to the original position Output A _i (return confirmation signal).

FIG. 12 is a diagram for explaining the logic of the output drive operation of the element of FIG. In order for the solenoid to turn on, the interlock condition ILC is satisfied. The interlock condition ILC generally includes various activation conditions specific to its operating step. Since the execution condition of each operation step is the end of the operation of the operation step of the preceding stage, the interlock condition ILC indicates, for example, a signal indicating that the output state of the operation step of the preceding stage is confirmed (for example, FIG. 11). A _O ) is usually included. In addition, it contains external signals that are not generated by this program.

FIG. 13 shows an example of a typical operation circuit used when automatically generating the entire sequence. In FIG. 13, the condition C _A is closed when the operating circuit is operating in the automatic mode (the mode in which the production line operates according to the sequence control program). Condition C _S
Is closed when this operating circuit is operating in manual mode. C _S is normally closed. Therefore, in the normal automatic mode, if the interlock conditions ILC ₀ and _Al are satisfied, the output B _O is output. On the other hand, ILC ₁ describes the logic of operating conditions in the manual mode. In the manual mode, the contact C _S is opened, so if the conditions X _k and ILC ₁ are simultaneously satisfied, or if the conditions X _k and C _I are simultaneously satisfied, B _O is output. In general, C _I is the logic for killing the manually operated interlock condition ILC ₁ .

Labels 1360 and 1372 in FIG.
This is a ladder program corresponding to "RR slide out" in the figure. In the logic of label 1360, “B4 step 1 output” at address 5041 is (B4 step OFF * reference pin return * container forward + B
4 Step 1 output) * B4 Step 2 output / * B4 Step 3 output / = 1 is satisfied, "1" is output. Here, B4 is the block number of the "reference output" block b in FIG. Further, "/" represents a logical NOT. Also, "B
"4 steps off" means that all steps of block 4 are off (i.e. not executed). Further, “reference pin return” and “advancement of the receiving tray” at the address 1753 mean the end of the operation in the “advancement receiving” block preceding the “reference output” of block 4. Also, B4
It can be easily guessed about the step 2 output / and B4 step 3 output /. Thus, the action at label 1360 represents the condition under which the first motion step "RR slide out" of the "reference out" block should be activated correctly. Therefore, if all the operation steps of "blocking forward" of the block are completed, the above conditional expression is satisfied and "B4 step 1 output" becomes "1". Once the "B4 step 1 output" becomes "1", the "B4 step 1 output" remains "1" due to the latch condition of the label 1360.

The output "B4St" of the label 1372 of FIG.
"1RR slide out" becomes "1" because B4 step 1 output * cargo cradle forward * B4 operation ON * RR slide out /
= 1 is satisfied. Here, it is noted that B4St1 is the first step of block number 4.
The operation of "RR slide out" is performed because "B4 step 1 output" is "1" and the "advance receiving tray advance" step is executed when the actuator of "RR slide" is not turned on. It's time.

The ladder programs shown in FIGS. 9 and 10 are
"FL reference pin A output" and "FL reference pin B output" in FIG.
It is easily understood that the above two operation steps correspond to each other. Thus, when the "reference output" block of the block b in FIG. 4 is represented in a form corresponding to the operation step flow chart in FIG. 7, "RR slide out" and "FL reference pin A" in the operation step flow chart are shown. Out ”,
The three steps called "FL reference pin B output" are shown in Fig. 8 ~.
It will be understood that this corresponds to the ladder program of FIG.

<System Configuration> FIG. 14 shows the entire production line management system of the embodiment. This system consists of four subsystems: “data generation” 102, “automatic programming” 104, “simulation” 105, and “fault diagnosis / recovery” 106.

"Automatic Programming" Subsystem 10
4 automatically generates a ladder program for sequence control. The “simulation” subsystem 105 automatically generates a program for simulating the ladder program generated by the automatic programming 104. "Fault diagnosis / recovery" subsystem 106 is "trial"
In a stage or an "operating" stage, a simulation result is diagnosed or a failure in an actual operating stage is diagnosed, and those diagnostic results are mainly displayed on a CRT display device.

As shown in FIG. 14, controlled equipment 50
It comprises (corresponding to various “equipment” in FIG. 1), a host computer 60, a CRT panel control unit 53 for controlling a CRT as a user interface, and a data file 56 for storing the above-mentioned map and database. The host computer 60 includes three subsystems, an automatic programming / data input subsystem 104 (102) that automatically generates a ladder program and the above-described map, and a failure diagnosis / recovery subsystem that performs failure diagnosis and recovery. 106 and a simulation subsystem 105 for performing simulation control.
These units are connected by a communication line 61, and a semiconductor memory or a high-speed hard disk drive is suitable for the data file 56 in order to increase the speed.

The CRT panel control section 53 has a CRT display device 58 and a touch panel 57 mounted on its display screen. This system requires an interface with the operator during the automatic programming process, simulation process, failure diagnosis process, etc.
The control unit 53 displays a plurality of windows on the CRT 58 by the well-known multi-window display control, and the operator selects a desired item from the plurality of items in the displayed window by using the touch panel 57. <Features of Example System> The above is the description of the configuration of the example system. The characteristic functions related to restoration, which are given to the system having such a configuration, are listed below. : When attempting to execute the ladder program of a certain operation step, check whether there is a program that is executed concurrently in parallel in the steps after that step number. As a result, it is possible to prevent the facility from being damaged due to an unexpected operation. This check function is executed after the switch 401 in FIG. 28 is pressed when the system is restarted after the failure is detected and the system is stopped and the cause of the failure is removed. : If an operation step (step jump) suspected of parallel operation is found, -1: first, a warning is given to the operator, and the restart operation is not performed. This is to prevent equipment damage. -2: Next, when the operator commands the forced restart, the execution of the operation step in which the parallel operation is suspected is suppressed. Then, the operation steps from the step number to be originally restarted are sequentially executed, and when the operation step suspected of the parallel operation discovered in advance is reached, that step is executed. This allows
The time required for restarting is shortened as much as possible, and a reliable restart is guaranteed.

The logic for step jump detection will be described in connection with the symbol S _xhold shown in FIG. Also, the logic for preventing step skipping will be described with reference to the flow chart of FIG. As described above, the recovery from a reliable failure, which is a feature of this embodiment, is premised on the detection of the failure location. <Program execution / fault monitoring / fault diagnosis>
It is composed of a failure detection operation for specifying that a failure has occurred and an operation for specifying (analyzing) the location where the failure actually occurred. Detection of Failure Occurrence A program configuration for sequence control, monitoring, and failure diagnosis will be described with reference to FIGS. 15 and 16. The detailed procedure of FIGS. 15 and 16 is described in Japanese Patent Application No.
No. 237740, the description will be omitted here.

In FIGS. 15 and 16, the ladder program 220 describes the specific operation of each actuator in each operation step. Further, the map control program 201 monitors the operation of the equipment executed by the ladder program 220 while referring to the operation block map and the operation step map. Also,
The operation monitoring program 202 is the map control program 2
The occurrence of a failure is detected while monitoring the communication between 01 and the ladder program 220. Further, the failure diagnosis program 203, when notified by the notification of the monitoring program 202 that a failure has occurred, performs a failure diagnosis. The actuator (that is, the operation step) in which this failure has occurred is monitored by the monitoring program 202.
It is known by the diagnostic program 203 checking the contents of a step counter, which will be described later, recorded by the map control program 201 and The diagnostic program 203 can detect a specific device or contact in the actuator based on the data of the input / output map.

In order to understand the failure diagnosis system, it is necessary to understand the above-mentioned SC-REG (abbreviated as CS) set for each operation block. FIG. 17 illustrates the CS register, the time register (TS _si , TS _ei ) and the block time register TBS provided in a certain operation block i (BL _i ). The CS register CS _i stores the number of the operation step last executed in block i. Further, the step time register TS _Si stores the time when the last executed operation step or the currently executed operation step is started. TS _ei stores the time at which the operation step at the end of execution is finished. The block time register TB _i is zero until the block can be activated. When the activation becomes possible, the time when the activation becomes possible is stored in TB _i . Step Time Over FIG. 18 shows how each CS register is set in each block.

At the time when the execution of a certain operation step is completed, TS _xi = TS _ei -TS _Si (1) is the time required to execute that operation step.
As described above, the counter CSi stores the number of the operation step at the end of execution of the block i (actually, indicates the operation step number next to the operation step). It is possible to calculate the time TS _xi required to execute the operation step that has ended. In the failure diagnosis system of the present embodiment, by comparing this TS _xi with the standard time τ _Si required to execute each operation step stored in the operation step map, TS _xi −τ _si > δ _0. If (2), it is determined that there is a failure ("step time over") in the execution of the operation step. Here, δ ₀ is a constant.

Step hang-up Further, in this failure diagnosis system, the operation step which has not been executed is periodically scanned, and the elapsed time TP-TS _Si up to the present is TP-TS _Si > δ ₁ .... If (3), it is determined that the operation step is in a loop or hung up. Here, TP is the current time, and δ ₁ is a constant. δ ₁ is usually the maximum allowable time within the time required to execute the operation steps of the production line. Such a failure is "step hangup". Block hang-up "Block hang-up" will be described with reference to Figs. 18 and 19 to 23.

As shown in FIG. 18, there are a plurality of blocks operating in parallel with each other. Considering such a plurality of blocks as a group, a certain group (18th
In the example of the figure, all the step operations of BL1 form one group are completed, and another group (GR1 consisting of BL2, BL3 and BL4 in the example of FIG. 18) following that group is executed. It is necessary to monitor the passage of time until it reaches the end. The block time register TBi described above is the elapsed time until the block group is activated. For each group, by monitoring the measurement operation time while comparing it with the reference time, the abnormality of each group,
In other words, it is possible to diagnose a failure that has occurred in the process of transitioning from one block to another block. Such a failure is a “block hangup”. In the system of this embodiment, when the block hang-up occurs, the operation step that caused the hang-up is further specified.

A method for identifying the operation step that causes the "block hang-up" will be described with reference to FIGS. 19 to 23. These drawings are simplified operation block maps of a certain production line consisting of four operation blocks in order to facilitate the description of the “block hang-up”. The production line in FIG. 19 is simply composed of four operation blocks. The motion block map for these motion blocks is simplified to the fourth
It is shown as in FIG.

In FIG. 20, block 1 to block 2
Γ is the time required to start ₁₂From block 1
Γ is the time required to activate block 3₁₃Etc. and table
It has been forgotten. These transition times Γ can be set in advance
That's why. For example, block 4 is a parallel block
It is activated by the end of steps 2 and 3. With reference to FIG.
As explained, the block time register TBi is
It is zero until the block can be activated. That
Then, when it becomes possible to start, the time is stored. Obey
The value of register TBi is not zero,
If the time is sufficiently larger than Γ above, the block
It can be judged that a guppy is occurring. Therefore,
Times Γ24 and Γ34 have passed since the end of locks 2 and 3
Even if block 4 is not started, block hang
Failure is recognized as up.

When the block hangup is detected because the block 4 is not activated, the operation step causing the block hangup must be in any one of the blocks 2 and 3. FIG. 21 shows an operation step map of the operation block 2, and FIG. 22 shows an operation step map of the block 3. According to FIG. 21, four operation steps are set in the block 2, and the output at each step is Y
, Y2, ... Y4, and the confirmation switches of those output actuators are X1, X2, ... X4. Further, according to FIG. 22, three operation steps are set in the block 3, and the output at each step is Y5, Y.
6 and Y7, and the confirmation switches of those output actuators are X5, X6, and X7. Check switch X above
The states of 1 to X7 are unique for each block and can be known in advance when the blocks 2 and 3 are finished. The activation condition map of FIG. 23 shows the conditions for activating each of the four operation blocks shown in the example of FIG. 19, that is, the state logic of the operation confirmation switch. Referring to the block 4 in the figure, in the block 2, the outputs Y1 to Y4 are turned on, and the confirmation switches X1 to X4 are turned on. Also, block 3
Then, the outputs Y4 to Y7 are turned on, and the confirmation switch X4
To X7 are turned on. Therefore, when block 4 is started normally, it must be X ₁ * X ₂ * ... * X ₇ . Blocks 2 and 3 are activated by the end of block 1. Therefore, the activation conditions of blocks 2 and 3 are the logical product of the states of the confirmation switches of all the operation steps of block 1. Incidentally, in FIG. 23,
<N> means that the confirmation switch is in a state of confirming that the output Y is in the “out” state, and <I> indicates that the confirmation switch confirms that the output Y is in the “return” state. Means to be in a state.

As described above, if the activation condition of each operation block is combined with the state of the device for confirming the output of all the operation steps of the preceding block of the block as a logical product, the operation block of the operation block can be programmed. The activation is not performed unless it is confirmed that all the operation steps of the operation block in the previous stage are normally completed. In other words, if the starting condition is not satisfied, the block hang-up described above occurs and the failure is correctly detected. Moreover, if the block in which the failure is detected is recognized, the start condition map is compared with the state of the actual confirmation switch to determine which switch is abnormal, and the input / output map and the operation step map. By referring, it is possible to quickly know which output actuator of which operation step was wrong. <Failure Recovery> Next, a method of recovering the system from the detected failure and restarting the system will be described.

As described above, the characteristic of the recovery in this system is that the ladder program of an unexpected operation step is prevented from being executed. Prevention of parallel execution For this purpose, the ladder program in this system is
A "default" program element S _xhold as shown in FIG. 24 is put in the ladder program element for activating the next operation step. That is, in order to turn on step S _xhold , the interlock condition must be satisfied and S _xhold / must be satisfied. If S _xhold is off, then S _x is on. However, if S _xhold is on, S _x does not turn on even if the interlock condition is satisfied.

Here, S _xhold is controlled by the failure diagnosis program. That is, if a failure is found in a certain operation step S _i , and the operation step that may possibly operate in parallel with this S _i is S _x , the failure diagnosis program (recovery program) uses the S _{xhold of} this step S _x . Mark on. Then, this step S _x is not started together with S _i when restarting.

In this system, as shown in FIG.
Ladder program element S of symbol _xholdThe program
System generation system 104 has as a fixed symbol
It is a thing. This will activate the operation step
During a simple ladder program, the symbol S
_xholdIs inserted. I do not have it as a symbol
Even if the programmer inserts it in the ladder program
You may promise to do so.Step jump detection at recovery Next, there is a high risk of damage to equipment during restoration,
The detection of the operation step for performing the column operation will be described.
Such an operation step for performing parallel operation occurs.
Is called a step "fly".

For convenience of explanation, as shown in FIG.
Consider two equipments, B and B. In each facility,
There are cylinders Y _A1 and Y _A2 and Y _B1 and Y _B2 , and these cylinders have operation confirmation switch signals X _A1 and X _A2 ,
It shall be confirmed by X _B1 and X _B2 . FIG. 26 shows
The ladder program of the block on the equipment A side is shown. In this program, the steps assume S _A1 and S _A2 . The above-mentioned hold symbol is inserted in the start condition of S _A1 and S _A2 . It should be noted here that the starting condition of step S _A1 includes the monitoring condition S _A2 / of the next step which is not operating, but the starting condition of step S _A2 is: This is that the monitoring condition S _A3 / indicating that the next step is not operating is not inserted due to a program error. Therefore, the starting condition of S _A2 is that the cylinder Y _{B1 of the} equipment B is turned on. During normal operation, it is assumed that step S _A2 was operating without being accidentally started depending on the operating state of the cylinder Y _B1 of the equipment B.

When the failure monitoring system 106 finds a failure in any operation step, it stops the entire system. Therefore, in each block, the counter CS for each block indicates at which step the program is stopped. Is held. Therefore, the operator first removes the true cause of the failure in the step of the block in which the failure has occurred, and then, in each block,
Work to set the equipment that is currently stopped so that it can be restarted. This work is, for example, that it is necessary to return a certain work to the original position, or switching the switch from the on state to the off state.

It is assumed that the equipment A is stopped in step S _A0 . In the above restoration work, the operator mistakenly
_Suppose that cylinder Y _{B1 of} equipment B is set to ON. Then, when the entire system is restarted, in the equipment A, although the start point is the step S _A1 , the step S _A2 is also started together.

Therefore, in order to prevent such parallel restart, that is, step skipping, the recovery program of this system has the step number held in the counter CS of this block before actually starting the restart. In steps other than (which should only be restarted from this number originally),
We will check for the existence of a step in the logic that is invoked.

FIG. 27 shows the fault diagnosis / recovery system 106.
3 is a flowchart showing a partial control procedure of the above. In step S2, it is confirmed whether all the above-mentioned manual operations for restoration by the operator have been completed (switch 40 in FIG. 28).
0). If the operator makes the confirmation, step S
Go to 4. In step S4, the operator presses the restart button 40.
Make sure you press 1. Then the system 106
The contents of the register CS for each block are fetched.
This register CS holds the step number of each block that should be restarted originally.

Next, in step S8, it is checked for each block whether or not there is a step that is in a startable condition among steps other than the value held in the counter CS. In this check, the system 106 captures the values of the switch signals of all the equipment, and substitutes the captured switch signal values into the activation conditions of each step to determine whether the step is activated. By doing.

When such a step that may cause step skipping is found, S _xhold of that step is turned on in step S14. Then, step S16
In, the operator is made to know that there is a risk of step jump. Usually, this alert will tell the operator if there were any mistakes in the work they were doing. In step S18, the restart is awaited until the operator presses the "forced restart switch" 402. When the switch 402 is pressed, the execution of the ladder program is restarted in step S20.
In this case, step S _x is not executed because its execution is suppressed by the signal S _xhold . However, after the restart, the steps are executed one after another, and when it is confirmed in step S22 that the step _Sx is reached, the signal S
_Turn off _{xho ld} and allow the step to execute. Thus, while preventing step jumps, and
It is possible to reliably and automatically execute a step that is suitable for jumping. <Modification> The present invention can be variously modified without departing from the spirit thereof.

For example, in the above-described embodiment, the existence of a step that may cause a parallel operation is performed when the recovery from the failure is resumed. However, this check may be performed when the ordinary ladder program is executed. Good. Because,
This is because, in order to prevent a malfunction, it is usually preferable that only one step be executed in the block at all times.

Further, in the above embodiment, only the steps after the step number stored in the CS register are checked, but the steps before that may be checked together. This is because step jumps can occur between previous steps.

[0061]

As described above, the verification method of the present invention is a method for verifying the sequence operation of equipment that operates according to the sequence operation defined in the order of step numbers, and the steps for the sequence operation to be executed are performed. Holds the number and one of the sequence operations related to the step number different from the held step number,
It is characterized in that it is checked whether or not a condition to be started at the same time as the sequence operation to be executed is satisfied, and a warning is issued when a sequence operation to be simultaneously started is found.

Therefore, by checking whether or not two or more sequence operations for a plurality of step numbers are executed in parallel, it is possible to prevent damage to the equipment.

[Brief description of drawings]

[Figure 1]

[Fig. 2]

FIG. 3 is a diagram illustrating a production line of an automobile to which the present invention is applied.

[Fig. 4]

[Figure 5],

FIG. 6 is a flow chart showing an operation block flow chart by dividing the operation in the production line in FIG.

FIG. 7 represents the operation in one block of FIG.
A flow chart diagram called a motion step flow chart.

[FIG. 8]

[Figure 9]

10 is a ladder program diagram showing a partial operation of the step of FIG. 7,

FIG. 11 is a symbolic view of equipment on a production line.

FIG. 12

FIG. 13 is a pattern diagram of a ladder element used in the example system.

FIG. 14 is a diagram illustrating a hardware configuration of an example system.

[FIG. 15]

FIG. 16 is a diagram showing an overall software relationship in the embodiment system.

FIG. 17:

FIG. 18

FIG. 19:

FIG. 20:

FIG. 21

FIG. 22:

FIG. 23 is a diagram illustrating a principle of detecting a failure such as block hang-up.

FIG. 24 is a diagram for explaining the principle for preventing step jump in the present embodiment.

FIG. 25 is a diagram showing an example of equipment in which step skip prevention can occur.

FIG. 26 is a ladder program diagram showing the operation of the equipment of FIG. 25.

FIG. 27 is a flow chart showing a control procedure for preventing step jump.

FIG. 28 is a view showing an operation switch.

[Procedure amendment]

[Submission date] July 20, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a diagram illustrating a production line of an automobile to which the present invention is applied.

FIG. 2 is a diagram illustrating a production line of an automobile to which the present invention is applied.

FIG. 3 is a diagram illustrating a production line of an automobile to which the present invention is applied.

FIG. 4 is a flow chart showing an operation block flow chart by dividing the operation in the production line in FIG.

FIG. 5 is a flow chart which is called an operation block flow chart, in which the operation in the production line of FIG. 1 is divided into blocks.

FIG. 6 is a flow chart showing an operation block flow chart by dividing the operation in the production line in FIG.

FIG. 7 represents the operation in one block of FIG.
A flow chart diagram called a motion step flow chart.

8 is a ladder program diagram showing a partial operation of the step of FIG. 7. FIG.

9 is a ladder program diagram showing a partial operation of the step of FIG. 7. FIG.

10 is a ladder program diagram showing a partial operation of the step of FIG. 7. FIG.

FIG. 11 is a symbolic view of equipment on a production line.

FIG. 12 is a pattern diagram of a ladder element used in the example system.

FIG. 13 is a pattern diagram of a ladder element used in the example system.

FIG. 14 is a diagram illustrating a hardware configuration of an example system.

FIG. 15 is a diagram showing an overall software relationship in an example system.

FIG. 16 is a diagram showing an overall software relationship in the embodiment system.

FIG. 17 is a diagram illustrating a principle of detecting a failure such as block hang-up.

FIG. 18 is a diagram illustrating a principle of detecting a failure such as block hang-up.

FIG. 19 is a diagram illustrating a principle of detecting a failure such as block hang-up.

FIG. 20 is a diagram illustrating a principle of detecting a failure such as block hang-up.

FIG. 21 is a diagram illustrating a principle of detecting a failure such as block hang-up.

FIG. 22 is a diagram illustrating a principle of detecting a failure such as block hang-up.

FIG. 23 is a diagram illustrating a principle of detecting a failure such as block hang-up.

FIG. 24 is a diagram for explaining the principle for preventing step jump in the present embodiment.

FIG. 25 is a diagram showing an example of equipment in which step skip prevention can occur.

FIG. 26 is a ladder program diagram showing the operation of the equipment of FIG. 25.

FIG. 27 is a flow chart showing a control procedure for preventing step jump.

FIG. 28 is a view showing an operation switch.

Claims (5)

[Claims] 1. A method for verifying a sequence operation of equipment that operates according to a sequence operation defined in the order of step numbers, the method holding a step number for a sequence operation to be executed and different from the held step number. If any of the sequence operations related to the step number is checked for the condition to start at the same time as the sequence operation to be executed, and if the sequence operation for which the condition to start at the same time is satisfied is found, , A method for verifying sequence operation of equipment, which is characterized by issuing a warning. 2. The equipment sequence operation verification method according to claim 1, further comprising the step of stopping the equipment when the sequence operations satisfying the conditions to be started simultaneously are found. Sequence operation verification method. 3. The method for verifying a sequence operation of equipment according to claim 1, wherein the existence of a sequence operation with a condition to be started at the same time exists only for a sequence operation of a step number preceding the held step number. A method for verifying sequence operation of equipment, which is characterized by checking. 4. The method for verifying the sequence operation of equipment according to claim 3, wherein the sequence operations that satisfy the conditions to be started simultaneously are:
When the sequence operation of the step number before the held step number is found, the sequence operation of the held sequence number is executed while suppressing the activation of the sequence operation of the found sequence number. Then, if the discovered sequence number is reached, the sequence operation verification method of the facility is characterized by executing the sequence operation of the sequence number. 5. The method of verifying the sequence operation of equipment according to claim 1, wherein the check is performed in a restart operation after restoration after an abnormality is found in the sequence operation. Method of verification.