JPH075804A - Sequence control method - Google Patents

Abstract

PURPOSE:To provide a sequence control method by an SFC having a step operatable in plural steps. CONSTITUTION:Separately from such a basic operational form of the SFC that only one step among sequential steps is made an operating state, in the prescribed step executing an interlock set command, the operation of the operating circuit of the prescribed step is made continue at the intervals of required plural steps. The operation of the operating circuit is continued while the interval when the interlock condition of the operating circuit of the prescribed step is realized, and the operation of the prescribed step is stopped in the case when no interlock condition of the operating circuit in the step is realized, and when the interlock set command is released by the execution of the interlock set command in the step set for executing an interlock reset command related to the prescribed step.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sequence control method, and more particularly to a sequence control method for a plurality of operating steps by SFC performed using a programmable sequence control device.

[0002]

2. Description of the Related Art Sequential control of a plurality of operating steps performed using a programmable sequence controller is
Besides having the advantage that the operating process can be changed easily,
It is well known that due to its many advantages, it has become widely implemented in production plants of various technical fields. The relay ladder system, which is known as a sequence control system for a plurality of operation steps performed by using a programmable sequence controller, is difficult to repair or modify. Various programmable sequence controllers using a graphic expression format language have been proposed, including a programmable sequence controller of a set processing system.

SFC (Sequentiai Function Chart), which is one of the languages of the graphic representation format described above, is represented by three descriptive elements of steps, transitions, and links, and each step has a corresponding operation circuit. Each transition has a corresponding transition condition circuit. The above steps have an active logic state and an inactive logic state, and have a one-to-one correspondence only when the active state (condition is satisfied).
And executes the contents of the action corresponding to, and the transition defines the execution process transition condition from an active logic state step to an adjacent inactive logic state step via a link. The transition condition corresponding to the pair 1 is executed only when the step connected above is in the active state, and the processing result of the transition condition is indicated by the logical value "0" or the logical condition "1" (transition condition satisfied). The SFC has advantages that it can visually represent the sequence execution order and the processing content, and that the control status can be easily monitored.

As a conventional example of a sequence control method of a plurality of operating steps by SFC performed using a programmable sequence control device, an automatic article conveyance system will be described with reference to FIGS. 2 and 5. In FIG. 2, reference numeral 35 is an article to be conveyed. Control panel 2
The programmable sequence control device starts a predetermined control operation by pressing the start button 7 provided on the No. 4, firstly, the indicator light 17 of the automatic operation operation is turned on, and then the motor 14 is operated. The rotation of the motor 14 is started so that the electric power is supplied. The belt 27 of the conveyor, which is wound between the drive pulley 26 and the driven pulley 28 fixed to the rotating shaft 25 of the motor 14, moves in the direction of arrow X in the figure, so that the article 35 is moved by the belt 27. When the limit switch 10 is moved to a predetermined position and operated, the programmable sequence control device controls the motor 14 to stop according to the information from the limit switch 10 described above, and the stop of the motor 14 causes the article 35 to move. It is stopped at the predetermined position. Then, the pusher 29 is operated to advance the operating rod 30 thereof toward the article 35 on the belt 27, and the article on the belt 27 is moved to the belt 27 by the operating body 31 fixed to the tip of the operating rod 30. To the side of the belt 27. Pusher 29 described above
According to the information from the limit switch 11 that operates when the forward moving actuator 31 reaches the forward limit position, the programmable sequence controller controls the operating rod 30 of the pusher 29 to retract, and The control for turning off the indicator light 17 of the automatic driving operation is performed by turning on the limit switch 13 for the backward movement limit to complete one cycle.

In the one-cycle operation of the above-described automatic article transport system performed using the programmable sequence controller, the sequence on the display surface of the display 4 (see FIG. 5) of the programmable sequence controller is The display is performed on the display unit corresponding to the step of the SFC flowchart corresponding to the control. That is, when the power switch of the system including the programmable sequence controller is turned on, the display portion S1d on the display surface of the display 4 is bright corresponding to the execution of step S1 due to the on state of the power switch of the system. Displayed. In FIG. 5, the graphic shown in the two-dot chain line frame 36 shown on the left side of the display 4 is indicated by the drawing symbol T1 on the display surface of the display 4.
The step transition condition circuits of the transitions T1 to T6 shown by ~ T6 are shown. The display contents as shown by the two-dot chain line frame 36 are those displayed on a display different from the display 4. Also, the figures shown in the two-dot chain line frame 37 shown on the right side of the display 4 in FIG. 5 are the display portions indicated by the drawing symbols S1d to S7d on the display surface of the display 4. The operation contents in each of the steps S1 to S7 which are the objects of display are shown, and the display contents as shown by the two-dot chain line frame 37 are displayed on a display different from the display 4. Is. Next, transition T1
By providing information to the programmable sequence controller by operating the start button 7 in the step transition condition circuit, the step moves from step S1 to step S2, and the display 4 in the programmable sequence controller is changed. The display on the display S1d corresponding to the step of the SFC flowchart corresponding to the sequence control on the display surface (see FIG. 5) returns to the dark display state, and at the same time, the display S2d changes from the dark state to the bright state.

When the step advances to step S2, the display of the display section S2d corresponding to the step of the SFC flow chart corresponding to the sequence control on the display surface of the display 4 (see FIG. 5) in the programmable sequence controller described above is in a bright state. When the interlock between the emergency stop button 9 and the overload protection means (thermal switch) 12 is off, the operation lamp of the automatic driving operation is turned on when the operation circuit of step S2 is executed. To be done. By the way, the indicator light 17 of the automatic driving operation which is turned on in step S2 is continuously turned on throughout the period during which the automatic article conveying system is in operation, considering the display purpose of the indicator lamp of the automatic driving operation. Is desired. However, since the basic operation mode of SFC is such that only the operation circuit of one step in the sequential steps is in operation, the operation in the basic operation mode of SFC is as follows. Step S
The indicator light 17 of the automatic driving operation which is turned on by the operation of the operation circuit of 2 is turned off when the step moves from step S2 to step S3. The lighting state does not meet the original display purpose. So conventionally, step S
In order to ensure that the automatic operation indicator light 17 that is turned on in 2 is continuously turned on during the entire operation period of the automatic article transport system, step S2
The indicator light 17 of the automatic driving operation, which is turned on by the operation of the operation circuit of (3), is kept on by the set command even after step S3.

The step S2 is executed to turn on the indicator light 17 for the automatic driving operation, and the step S2 corresponding to the sequence control on the display surface of the display 4 (see FIG. 5) in the programmable sequence control device is performed.
When the display of the display section S2d corresponding to the step of the FC flowchart changes to a bright state, the operation circuit of step S2 is executed and the timer is set, and the transition T occurs when the time set in the timer has elapsed.
In the step transition condition circuit of step 2, the contact of the timer (the contact of the timer provided in the operation circuit of step S2) is turned on, and the step moves from step S2 to step S3, and programmable sequence control is performed. The display section S2d corresponding to the step of the SFC flowchart corresponding to the sequence control on the display surface of the display 4 (see FIG. 5) in the device returns to the dark display state, and at the same time, the display section S3d changes from the dark state to the bright state. Changes and resets the timer value. But step S
The indicator light 17 of the automatic driving operation turned on in 2 continues to be turned on by the set command as described above.

In step S3, the display of the display portion S3d corresponding to the step of the SFC flow chart corresponding to the sequence control on the display surface of the display 4 (see FIG. 5) in the programmable sequence control device is bright. When the interlock between the emergency stop button 9 and the overload protection means (thermal switch) 12 is off, the conveyor is started and the belt 27 is operated.
Is started, the article 35 is conveyed by the belt 27, and the limit switch 1 is set at a predetermined position in the step transition condition circuit of the transition T3.
When 0 is turned on, the information is given to the programmable sequence controller, and the step shifts from step S3 to step S4 to display 4 in the programmable sequence controller.
The display unit S3d corresponding to the steps of the SFC flowchart corresponding to the sequence control on the display surface (see FIG. 5)
At the same time as the display returns to the dark display state, the display portion S4d changes from the dark state to the bright state, and the conveyor belt 27 stops moving.

As described above, the step advances to step S4, and the sequence control on the display surface of the display 4 (see FIG. 5) in the programmable sequence controller described above corresponds to the step of the SFC flow chart corresponding to the step of the SFC flowchart. When the display changes to a bright state, the operation circuit of step S4 is executed and the timer is set, and when the time set in the timer elapses, the contact of the timer in the step transition condition circuit of transition T4 (step The contact of the timer provided in the operation circuit of S4) is turned on, and the step moves from step S4 to step S5, and the display surface of the display 4 (see FIG. 5) of the programmable sequence controller is displayed. Corresponding to sequence control in S
At the same time as the display on the display S4d corresponding to the step of the FC flowchart returns to the dark display, the display S5d changes from the dark to the light and the timer value is reset.

When the step advances to step S5, the display of the display section S5d corresponding to the step of the SFC flow chart corresponding to the sequence control on the display surface of the display 4 (see FIG. 5) in the programmable sequence controller described above is in a bright state. When the interlock between the emergency stop button 9 and the overload protection means (thermal switch) 12 is off, the operating rod 30 of the pusher 29 operates the operating body. 31 moves forward, and the article 35 on the belt 27 is discharged from the belt 27. And the pusher 2 mentioned above
When the actuating body 31 of 9 turns on the limit switch 11 of the forward limit in the step transition condition circuit of the transition T5, the steps are from step S5 to step S6.
Then, the display of the display section S5d corresponding to the step of the SFC flow chart corresponding to the sequence control on the display surface of the display 4 (see FIG. 5) in the programmable sequence control device returns to the dark display state, and at the same time, The display portion S6d changes from a dark state to a bright state.

As described above, the process proceeds to step S6, and the sequence control on the display surface of the display 4 (see FIG. 5) in the programmable sequence controller described above corresponds to the step of the SFC flow chart corresponding to the step of the SFC flowchart. When the display changes to a bright state, the operation circuit of step S6 is executed and pusher 2
The actuating rod 30 and the actuating body 31 of 9 are retracted, and the actuating body 31 of the pusher 29 is the limit switch 13 of the backward limit in the step transition condition circuit of the transition T6.
When the switch is turned on, the step shifts from step S6 to step S7, and the display corresponding to the step of the SFC flowchart corresponding to the sequence control on the display surface of the display 4 (see FIG. 5) in the programmable sequence controller. At the same time as the display of the portion S6d returns to the dark display state, the display portion S7d changes from the dark state to the bright state.

As described above, the step proceeds to step S7, and the sequence control on the display surface of the display 4 (see FIG. 5) in the programmable sequence controller described above corresponds to the step of the SFC flow chart corresponding to the step of the SFC flowchart. When the display changes to a bright state, the operation circuit of step S7 indicates that the automatic operation indicator lamp 1
A reset command for extinguishing 7 is executed to extinguish indicator light 17 of the automatic driving operation, and one cycle is completed.

[0013]

By the way, as described above, the basic operation mode of the SFC is such that the operation circuit of one step in a plurality of steps is brought into an operating state. Since the operation circuit of the above does not continue the operation over a plurality of steps, it is desirable that the automatic article conveying system is continuously turned on during the continuous operation. In the case where it is desired that the operation of the operation circuit of a certain step is continuously executed over a plurality of step periods, as in the example of turning on the indicator light of the automatic driving operation described in the above-mentioned conventional example. As a solution, the operation of the operation circuit of one step is conventionally continued by using a set instruction for a plurality of step periods. DOO but has been performed, the operation state of the operation circuit of a step operation is continued over a plurality of step period by the so set instruction as is
Since it will not be released unless a reset command is issued,
For example, as described above, the operation of the operation circuit in the step in which the operation is continued by the set instruction is continued by the set instruction described above even if the interlock condition is not satisfied in the subsequent step. Since the inconvenience of staying in the same state may occur, improvement measures for it have been sought.

[0014]

According to the present invention, in a sequence control of a plurality of operating steps by SFC performed by using a programmable sequence controller, a predetermined step among a plurality of steps of SFC is Except when the interlock condition in the step is not satisfied, the operation circuit of the step continues to operate during the period until the step set to execute the interlock reset command for the above step is reached. A sequence control method for performing the above is provided.

[0015]

The operation of the operation circuit of the predetermined step in the plurality of steps of the SFC is designed so that the execution can be continued during the step following the step, and the operation of the predetermined step is performed. The operation of the operation circuit becomes inoperable when the interlock condition in the step is not satisfied and when the step set to execute the interlock reset command is executed with respect to the predetermined step. Done.

[0016]

The concrete contents of the sequence control method of the present invention will be described in detail below. FIG. 1 is a block diagram showing a schematic configuration of a programmable sequence control device used to implement the sequence control method, and FIG. 2 applies the sequence control method of the present invention to an automatic article transfer system. FIG. 3 is a perspective view showing an outline of the article transporting device portion, FIG. 3 is a plan view illustrating a display surface of the display, and FIG. 4 is an explanatory diagram of a memory map of a RAM table.

In FIG. 1, reference numeral 1 is a CPU (central processing unit), 2 is a read only memory (ROM), and a program is stored in the ROM 2. Also, 3
Is a random access memory (RAM), 4 is a display, and the ROM 2 described above is C by a signal transmission line 20.
It is connected to the PU and is also connected to the display 4 by the signal transmission line 22.
The M3 is connected to the CPU by the signal transmission line 21, and is also connected to the display 4 by the signal transmission line 23. The display 4 may be, for example, a cathode ray tube display device having a fluorescent surface of a cathode ray tube as a display surface, a liquid crystal display device, or a display plate using a number of lamps as light sources. A display device or the like configured to illuminate a predetermined pattern provided can be used regardless of its configuration mode, but in the following description, the fluorescent surface of the cathode ray tube is used as the display surface. A cathode ray tube display device is used as the display 4, and a pattern showing an SFC flow chart corresponding to the sequence control is displayed on the display surface of the display 4 (reference numerals S1d to S7d and T1 to S1d in FIG. 3). A graphic such as T6 and an END display) are displayed. An input section (interface) 5 is connected to the CPU 1 through a signal transmission path 18, and an output section (interface) 6 is connected through a signal transmission path 19. The above-mentioned input unit 5 includes a start button 7, a stop button 8, an emergency stop button 9, limit switches 10, 11, 13 provided on the operation panel 24 shown in FIG. Information from the switch) 12, etc. is input, drive power is supplied from the output unit 6 to the motor 14, operation power is supplied to the pusher 29 during forward operation 15 and during reverse operation 16, and automatic operation is performed. The operation power is supplied to the operation indicator lamp 17. Note that reference numerals 32 and 33 in the figure respectively denote power sources.

A programmable sequence control device is shown in FIG. 2 which is a schematic view of an article conveying device portion which is constituted by various push buttons 7 to 9 and switches 10 to 13 shown in FIG. When a power switch (not shown) in the system including the switch is turned on, the display unit S1d on the display surface of the display of FIG. 3 is turned on by the power switch of the system (not shown) being turned on. In response to the execution of, the display state of the low brightness (dark) is changed from the display state of high brightness (bright) to the display that the system is operable. In this state, when the operator operates the start button 7 of the operation panel 24, that is, the start button 7 in the step transition condition circuit of the transition T1, the sequence control which can program the information that the start button 7 is operated in the input section 5 is programmable. CPU1 in the device, CPU1
Then, the information that the activation button 7 is operated according to the program stored in the ROM 2 is processed, and the step moves from the step S1 to the step S2, and the display 4 in the programmable sequence controller is processed.
The display unit S1d corresponding to the steps of the SFC flowchart corresponding to the sequence control on the display surface (see FIG. 3)
Is displayed from the state of high brightness until then to the state of low brightness
While changing to the (dark state), the display of the display portion S2d of the display 4 is changed from the low luminance state to the high luminance state. The programmable sequence control device starts a predetermined control operation when the start button 7 provided on the operation panel 24 is pressed, and the operation circuit is sequentially operated in steps S1 to S7. While performing the operation, on the display surface of the display of FIG. 3 showing a part of the display surface of the display 4 shown in FIG. 1 in an enlarged manner, sequence control and corresponding sequential steps of the SFC flowchart corresponding to the sequence control. The display is made to be displayed on the display portions S1d to S7d corresponding to S1 to S7.

In FIG. 3, the figure shown in the two-dot chain line frame 36 shown on the left side of the display 4 is the transitions T1 to T4 indicated by the reference symbols T1 to T4 on the display surface of the display 4. Although the step transition condition circuit of No. 2 is shown, the display contents as shown by the two-dot chain line frame 36 are displayed on a display different from the display 4. Further, in FIG. 3, the figure shown in the two-dot chain line frame 37 shown on the right side of the display 4 is indicated by the drawing symbol S1d on the display surface of the display 4.
~ S5d shows the operation circuit in each step S1 ~ S5 to be displayed on each display section, and the display contents as shown by the two-dot chain line frame 37 are different from the display 4. It is what is displayed on the display.

FIG. 4 shows a configuration example of a memory map of a RAM table used for storing information that determines the display state of the display unit in the display 4, and S0 in the figure is shown.
m, S1m, S2m ... Corresponding to the sequential steps S1, S2, S3 ... Of the SFC flow chart corresponding to the sequence control, the display modes on the display sections S1d, S2d, S3d ... of the respective steps set in the display 4 are shown. The storage area in which the information for designating is written and read is shown. In the following description, the display mode specifying information stored in S1m of the storage area in the RAM table described above is the step S of the SFC flowchart corresponding to the sequence control.
Information for designating the display mode on the display section S1d of the step set in the display 4 corresponding to 1 and information for designating the display mode stored in S2m of the storage area in the RAM table described above. Is the step S2 of the SFC flowchart corresponding to the sequence control.
The step and step of the SFC flowchart corresponding to the storage area in the RAM table and the sequence control such as the information for designating the display mode on the display section S2d of the step set in the display 4 corresponding to When the subscripted numbers 1, 2, 3, ... Used in the reference numerals indicating the display part of etc. are represented by i (i is a natural number) by a general expression method, Sim in the storage area of the RAM table is represented. The display mode designation information stored in the display 4 corresponds to the step S i of the SFC flowchart corresponding to the sequence control.
It is supposed to be used as information for designating the display mode on the display section Sid of the step set to.

Then, in the following description, the display portion S1d of each step set in the display 4 described above,
When S2d, S3d ... Are made to be in a continuous display mode in a constant low luminance state, "00" is stored in the storage area of the RAM table corresponding to the display section of the steps to be in such a display mode. Is displayed, and the display portion S of each step set in the above-mentioned display 4 is written.
When 1d, S2d, S3d ... Are made to be in a continuous display mode in a constant high-intensity state, the storage area of the RAM table corresponding to the display unit of the steps to be in such a display mode is It is assumed that "11" is written, and further, the display mode in the display sections S1d, S2d, S3d, ... Of each step set in the display 4 is the display in a constant high brightness state and the constant low brightness state. In the case where the display according to the state of 1 appears alternately on the time axis, "1" is stored in the storage area of the RAM table corresponding to the display portion of the step to be displayed in such a manner.
It is said that "0" is written.

As described above, S corresponding to the sequence control
Sequential steps S1, S2, S3 of the FC flowchart ...
Corresponding to the above, the display table S1d, S2d, S3d of each step set in the display 4 is stored with the RAM table in which the information for specifying the display mode is written in each of the storage areas S0m, S1m, S2m. The information is read from the RAM table and used to determine the display mode on the display portions S1d, S2d, S3d, ... Of each step set in the display 4, and is stored in the RAM table as described above. The information for designating the display mode is C
It goes without saying that it can be effectively used for other operation control by the PU1.

Now, by providing information to the programmable sequence controller by the operation of the start button 7 in the step transition condition circuit of the transition T1, the step shifts from step S1 to step S2, and the programmable The sequence control on the display surface of the display 4 (see FIG. 3) in the simple sequence control device corresponds to the step of the SFC flowchart corresponding to the display of the display portion S1d from the display state in the high brightness state (bright state) to the constant display state. At the same time as returning to the display state in the low brightness state (dark state), the display section S2d is changed from the display state in the constant low brightness state (dark state) to the constant high brightness state
The display changes to (bright).

When the step advances from step S1 to step S2, both the emergency stop button 9 and the overload protection means (thermal switch) 12 are in the off state and the interlock condition of step S2 is satisfied. For example, when the operation circuit of step S2 is executed and the interlock set command is executed, the indicator light 17 of the automatic operation operation is turned on, and the display 4 in the programmable sequence controller described above (see FIG. 3). The display of the display unit S2d corresponding to the step of the SFC flowchart corresponding to the sequence control on the display surface is changed from the low-luminance display state to the continuous high-luminance display state. And
Execution of the interlock set instruction described above is carried out in the state where the interlock condition of step S2 is satisfied, even if the step of the SFC flowchart corresponding to the sequence control is carried out, and the step is held. Since the operation circuit of S2 also continues its execution state, the lighting operation of the indicator light 17 of the automatic driving operation is continued throughout the period during which the automatic article conveying system is operating.

When the step proceeds from step S2 to step S3, both the emergency stop button 9 and the overload protection means (thermal switch) 12 are off, that is, the interlock condition of step S3 is satisfied. If so, the operation circuit of step S3 in the programmable sequence controller executes to start the conveyor to start the movement of the belt 27, and display 4 in the programmable sequence controller described above.
The display portion S3d corresponding to the step of the SFC flowchart corresponding to the sequence control on the display surface (see FIG. 3)
Display changes from the low-luminance state until then to the high-luminance state. SF corresponding to sequence control as described above
When the step of the flowchart C proceeds from step S2 to step S3, if the interlock condition in step S2 in which the interlock set instruction is executed is satisfied, the operation circuit of step S2 also continues execution. However, the lighting operation of the indicator light 17 of the automatic driving operation is continuously continued during the period of step S3.

By moving the belt 27 described above, the article 3
5 is conveyed and the limit switch 10 set at a predetermined position in the step transition condition circuit of the transition T3 is turned on by the article 35,
The information is given to the CPU 1 in the programmable sequence controller via the input unit 5 in the programmable sequence controller. In the above CPU1, RO
According to the program stored in M2, the information on the ON state of the limit switch 10 is processed to shift the step from step S3 to step S4. When the step proceeds from step S3 to step S4, the emergency stop button 9
Is off, that is, if the interlock condition of step S4 is off, the operation of the operation circuit of step S4 in the programmable sequence controller described above is executed so that the movement of the conveyor belt 27 is stopped. The supply of drive power from 6 to the motor 14 is cut off. SFC corresponding to sequence control as described above
When the step in the flowchart proceeds from step S3 to step S4, if the interlock condition in step S2 in which the interlock set instruction is executed is satisfied, the operation circuit in step S2 also continues to execute. However, the lighting operation of the indicator lamp 17 of the automatic driving operation is continuously continued during the period of step S4.

The above description corresponds to S for sequence control.
When the step of the FC flowchart proceeds from step S2 to step S3, the emergency stop button 9 and the overload protection means (thermal switch) 1 in the execution circuit of step S3
2 was related to the case where the interlock condition of step S3 according to 2 is satisfied, but when the step of the SFC flowchart corresponding to the sequence control advances from step S2 to step S3, step S3
When either one or both of the emergency stop button 9 and the overload protection means (thermal switch) 12 in the execution circuit of step S3 are ON, that is, when the interlock condition of step S3 is not satisfied, the CPU 1 causes the RAM described above. The stored contents of the storage area S3m corresponding to step S3 in the table are changed from the stored contents "00" up to the stored contents "1".
0 ", and the stored contents of all storage areas other than the storage area S3m corresponding to step S3 in the RAM table are rewritten to" 00 "and the display 4 in the programmable sequence control device is referred to by referring to the RAM table. S corresponding to the steps of the SFC flowchart corresponding to the sequence control on the display surface of S
The display state of 3d is such that the display state of the display section S3d is sequentially and alternately changed to a high luminance state and a low luminance state on the time axis from the continuous constant low luminance state until then. Change to. In this state, if the interlock condition in step S2 in which the interlock set command is executed is satisfied, the operation circuit in step S2 continues to execute and the operation of turning on the indicator light 17 of the automatic driving operation is continued. Has been continued.

At the time when the step of the SFC flow chart shifts from step S2 to step S3, both the emergency stop button 9 and the overload protection means (thermal switch) 12 in the execution circuit of step S3 are in the OFF state. Although the lock condition is satisfied, either or both of the emergency stop button 9 and the overload protection means (thermal switch) 12 are turned on while the execution circuit of step S3 is operating, and the interlock condition is satisfied. When is not established, the following operation is performed. That is, when the step of the SFC flowchart corresponding to the sequence control proceeds from step S2 to step S3, the CPU 1 replaces the stored content of the storage area S3m corresponding to step S3 in the RAM table described above with the stored content up to that point. 0
The memory content is rewritten from "0" to the memory content "11", and the memory content of all memory areas other than the memory area S3m corresponding to step S3 in the RAM table is rewritten to "00", and the RAM table can be referred to for programming. The display on the display unit S3d corresponding to the steps of the SFC flowchart corresponding to the sequence control on the display surface of the display 4 in the sequence control device is displayed from the continuous low-brightness state until then to the display state of the display unit S3d on the time axis. Although the above is continuously changed to the high brightness state, one or both of the emergency stop button 9 and the overload protection means (thermal switch) 12 are turned on while the execution circuit of step S3 is operating. When the interlock condition is not satisfied by the CPU, the CPU 1 stores the storage area corresponding to step S3 in the RAM table described above. The stored contents of S3m, rewriting the storage contents "10" then to the memory contents "11", also "0 the contents stored in the entire storage area other than the storage area S3m corresponding to step S3 in RAM table
SFC corresponding to the sequence control on the display surface of the display 4 in the programmable sequence control device by rewriting to "0" and referring to the RAM table.
The display state of the display unit S3d corresponding to step S3 of the flowchart is sequentially alternated from the continuous high-luminance state until then to the high-luminance state and the low-luminance state on the time axis. Change to a display state that changes to. In this state, if the interlock condition in step S2 in which the interlock set command is executed is satisfied, the operation circuit in step S2 continues to execute and the operation of turning on the indicator light 17 of the automatic operation operation is continued. Has been continued.

As described above, S corresponding to the sequence control
In the case of a failure in the execution circuit of the step of the FC flowchart, the display mode of the display unit corresponding to the step is changed such that the display state is alternately changed to the high brightness state and the low brightness state on the time axis. In the case of the display state, whether the cause of the failure exists in the execution circuit of the step of the SFC flowchart corresponding to the sequence control or the cause of the failure exists in the step transition condition circuit of the transition. This is convenient because the distinction is easy and clear. That is, if the cause of the failure exists in the step transition condition circuit of the transition, the step transition condition in the step transition condition circuit of the transition in which the failure exists is not satisfied. This is because there is no transition of the steps in the flowchart, and the display section corresponding to the specific step continues the continuous display state in the high brightness state.

Next, the steps of the SFC flowchart corresponding to the sequence control are steps S3 to S4.
If the emergency stop button 9 is in the off state when proceeding to step 4, that is, if the interlock condition in the step S4 is in the off state, the motor 14 is stopped by executing the operation circuit in the step S4 in the programmable sequence controller described above. Stop moving the conveyor belt 27,
The display on the display unit S4d corresponding to the steps of the SFC flowchart corresponding to the sequence control on the display surface of the display 4 (see FIG. 3) in the programmable sequence controller described above is changed from the low brightness state up to the high brightness state. Change to a state. As described above, when the step of the SFC flowchart corresponding to the sequence control proceeds from step S3 to step S4, if the interlock condition in step S2 in which the interlock set command is executed is satisfied, The operation circuit of step S2 is also continuing to execute, and the lighting operation of the indicator lamp 17 of the automatic driving operation is continuously continued during the period of step S4. Step S above
When the display of the display section S4d corresponding to 4 changes from the low brightness state up to that time to the high brightness state, step S4
When the operation circuit of is executed and the timer is set and the time set in the timer elapses, the contact of the timer in the step transition condition circuit of transition T4 (the contact of the timer of the operation circuit in step S4) is turned on. When the state is changed, the step moves from step S4 to step S5, and the display section S corresponding to the step of the SFC flowchart corresponding to the sequence control on the display surface of the display 4 in the programmable sequence control device.
4d display, from high brightness state until then to low brightness state
The display value of the display unit S5d of the display 4 is changed from the low-luminance state to the high-luminance state while the display unit S5d is changed from the dark state to the bright state, and the timer value is reset. To be done.

When the step of the SFC flowchart corresponding to the sequence control proceeds from step S4 to step S5, the emergency stop button 9 in the execution circuit of step S5 is turned off, that is, the interlock condition of step S5 is satisfied. If it is in the state, the operation circuit of step S5 is executed, the output 15 from the output unit 6 of the CPU 1 is supplied to the pusher 29, and the operating rod 3 of the pusher 29 is operated.
The actuating member 31 moves forward by 0, and the article 35 on the belt 27
From the belt 27, and the sequence control on the display surface of the display 4 in the programmable sequence controller described above corresponds to the step of the SFC flow chart corresponding to the step of the SFC flowchart. At the same time as changing to the brightness state, the display on the display unit S4d corresponding to the step of the SFC flowchart corresponding to the sequence control on the display surface of the display 4 is changed from the high brightness state up to that time to the low brightness state. As described above, when the step of the SFC flowchart corresponding to the sequence control proceeds from step S4 to step S5, if the interlock condition in step S2 in which the interlock set instruction is executed is satisfied, The operation circuit of step S2 is still executing and the indicator light 1 of the automatic driving operation
The lighting operation of 7 is continuously continued during the period of step S5.

Then, the actuator 3 of the pusher 29 described above.
1 turns on the limit switch 11 of the forward limit in the step transition condition circuit of the transition T5,
When the information is given to the CPU 1 in the programmable sequence control device via the input unit 5 in the programmable sequence control device, the CPU 1 in the above-mentioned CPU 1 outputs information on the ON state of the limit switch 11 according to the program stored in the ROM 2. Is processed to shift the step from step S5 to step S6. As described above, when the step of the SFC flowchart corresponding to the sequence control proceeds from step S5 to step S6, the emergency stop button 9 in the execution circuit of step S6 is turned off, that is, the interlock condition of step S6 is satisfied. If it is, the operation circuit of step S6 is executed, and the output 16 from the output unit 6 of the CPU 1 is supplied to the pusher 29, whereby the operating rod 30 and the operating body 31 of the pusher 29 are retracted, and Display 4 in the programmable sequence controller described above.
The display section S6d corresponding to the step of the SFC flowchart corresponding to the sequence control on the display surface (see FIG. 4)
Display changes from a low brightness state to a high brightness state. As described above, when the step of the SFC flowchart corresponding to the sequence control proceeds from step S5 to step S6, if the interlock condition in step S2 in which the interlock set instruction is executed is satisfied, The operation circuit of step S2 is also continuing to execute, and the lighting operation of the indicator light 17 of the automatic driving operation is continuously continued during the period of step S6.

The actuating member 31 of the pusher 29 causes the limit switch 13 in the backward limit of the step transition condition circuit of the transition T6 to be turned on, and the information thereof is programmed through the input unit 5 of the programmable sequence controller. When given to the CPU1 in a possible sequence control device, the
According to the program stored in M2, the above-mentioned information on the ON state of the limit switch 13 is processed, and the step moves from step S6 to step S7. Step S
In 7, the interlock reset command is executed, the execution of the operation circuit in step S2 is stopped, the indicator light 17 for the automatic driving operation is turned off, and the operation for one cycle is completed.

[0034]

As will be apparent from the above detailed description, the sequence control method of the present invention enables the sequence control of a plurality of operating steps to be performed using a programmable sequence control device. The operation of the operation circuit of a predetermined step in the step is
Execution can be continued even during the period of the step subsequent to that step, and the operation of the operation circuit of the above-mentioned predetermined step is such that the interlock condition is not satisfied in the predetermined step. In this case, when the steps set for executing the interlock reset command with respect to the above-mentioned predetermined steps are executed, the operation is disabled. If it is desired to keep the automatic transport system for articles continuously lit during the period of operation even if it is considered from the display purpose, such as the indicator light for driving operation, in the sequential steps Is it the operation in the basic operation mode of SFC in which only the operation circuit of one step is operated? Apart about said predetermined step of executing the interlock set instruction,
The operation circuit of the predetermined step is allowed to continue operating for a required period of a plurality of steps, and the interlock condition of the operation circuit of the predetermined step is satisfied. During that period, the operation circuit continues to operate, the interlock condition of the operation circuit in the predetermined step is not satisfied, and the interlock set command is released by the interlock reset command. And if
The operation of the predetermined step is stopped when the interlock set instruction is released by the execution of the interlock set instruction in the step set to execute the interlock reset instruction with respect to the predetermined step. According to the sequence control method of the present invention which is performed, the above-mentioned conventional problems can be solved well.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a programmable sequence control device used for implementing a sequence control method of the present invention.

FIG. 2 is a perspective view showing an outline of an article conveying device portion when the sequence control method of the present invention is applied to an article automatic conveying system.

FIG. 3 is a plan view illustrating a display surface of a display.

FIG. 4 is an explanatory diagram of a memory map of a RAM table.

FIG. 5 is a plan view illustrating a display surface of a display.

[Explanation of symbols]

 1 CPU (Central Processing Unit) 2 Read Only Memory (ROM) 3 Random Access Memory (RAM) 4 Display 5 Input Section 6 Output Section 7 Start Button 8 Stop Button 9 Emergency Stop Button 10, 11, 13 Limit Switch 12 Overload Protective means (thermal switch) 14 motor 24 operation panel 26 drive roller 27 belt 28 driven roller 29 pusher 30 actuating rod 31 actuating body 32, 33 power supply

Claims (1)

[Claims] 1. In the sequence control of a plurality of operating processes by SFC performed by using a programmable sequence controller, for a predetermined step among a plurality of steps of SFC, an interlock condition in that step is not satisfied. Except when
A sequence control method in which the operation of the operation circuit of the step is continuously executed during the period until the step set to execute the interlock reset command is reached with respect to the above step.