JP2648827B2 - Sequence control method - Google Patents

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 operation steps by an SFC performed using a programmable sequence controller.

[0002]

2. Description of the Related Art Sequence control of a plurality of operating steps performed by using a programmable sequence controller includes:
In addition to the advantage that the operation process can be easily changed,
It is well known that due to its many advantages, it has been widely implemented in production plants in various technical fields. In recent years, graphs developed in France have recently been developed because it is difficult to repair or modify the relay ladder processing method known as a sequence control method for a plurality of operation steps performed using a programmable sequence controller. Various programmable sequence controllers using a language of a graphic expression format have been proposed, including a programmable sequence controller of a set processing method.

[0003] SFC (Sequentiai Function Chart), which is one of the above-mentioned languages of the graphic representation format, is represented by three description elements of steps, transitions, and links, and each step has a corresponding operation circuit. Each transition has a corresponding transition condition circuit. The above-mentioned steps have an active logic state and an inactive logic state, and are one-to-one only when in the active state (condition satisfied).
Executing the content of the action corresponding to the above, and the above-mentioned transition defines an execution process transition condition from a step of an active logical state to an adjacent step of an inactive logical state via a link, and The transition condition corresponding to 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 a logical value “0” or a logical condition “1” (transition condition satisfied). The SFC has the advantages that the execution order of the sequence and the contents of the processing can be visually represented, and that the control status can be easily monitored.

[0004] As a conventional example of a sequence control method of a plurality of operation steps by SFC performed using a programmable sequence control device, an automatic article transport system will be described with reference to Figs. In FIG. 2, reference numeral 35 denotes an article to be conveyed. Operation panel 2
When the start button 7 provided on the controller 4 is pressed, the programmable sequence controller starts a predetermined control operation. First, the indicator lamp 17 for the automatic operation is turned on. The rotation of the motor 14 is started by supplying power. By moving the conveyor belt 27 wound between the driving pulley 26 and the driven pulley 28 fixed to the rotating shaft 25 of the motor 14 in the direction of arrow X in the drawing, the articles 35 are When the limit switch 10 is transported to a predetermined position and the limit switch 10 operates, the programmable sequence controller controls the motor 14 to stop according to the information from the limit switch 10, and the article 35 is stopped by stopping the motor 14. The vehicle is stopped at the predetermined position. Next, 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 by the operating body 31 fixed to the tip of the operating rod 30. From the belt 27 to the side. Pusher 29 described above
With the information from the limit switch 11 which is operated when the operating body 31 which has advanced by the operation of FIG. 3 reaches the advance limit position, the programmable sequence controller controls the operating rod 30 of the pusher 29 to retract, and When the limit switch 13 in the backward limit is turned on, control is performed to turn off the indicator lamp 17 of the automatic operation operation, and one cycle is completed.

In one cycle of the operation of the automatic article transport system described above, which is performed using the programmable sequence controller, the display screen of the display 4 (see FIG. 5) of the programmable sequence controller is displayed on the display screen. 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 unit S1d on the display surface of the display 4 is bright corresponding to the execution of step S1 by the on state of the system power switch. The display is made. In FIG. 5, the figure shown in the two-dot chain line frame 36 shown on the left of the display 4 is a drawing symbol T1 on the display surface of the display 4.
Although the step transition condition circuits of the transitions T1 to T6 indicated by T6 to T6 are shown, the display contents as shown by the two-dot chain line frame 36 are displayed on a display different from the display 4. In addition, in FIG. 5, figures shown in a two-dot chain line frame 37 shown on the right of the display 4 are display units indicated by drawing symbols S1d to S7d on the display surface of the display 4. Are the operation circuits in the respective steps S1 to S7 to be displayed. The display contents as shown by the two-dot chain line frame 37 are displayed on a display different from the display 4. It is. Next, transition T1
When the start button 7 is operated by the step transition condition circuit, the information is given to the programmable sequence controller, and the steps shift from step S1 to step S2, and the display 4 in the programmable sequence controller is changed. The display of the display unit S1d corresponding to the step of the SFC flowchart corresponding to the sequence control on the display surface (see FIG. 5) returns to a dark display state, and at the same time, the display unit S2d changes from a dark state to a bright state.

The step proceeds to step S2, and the display of 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 programmable sequence controller described above is bright. When the interlock between the emergency stop button 9 and the overload protection means (thermal switch) 12 is off, the indicator lamp 17 for the automatic operation is turned on. Is 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 in which the automatic article transport system is operating, even if it is considered from the purpose of displaying the indicator light of the automatic driving operation. Is desired. However, since the basic operation mode of the SFC is a state in which only the operation circuit of one step in the sequential steps is operating, according to the operation in the basic operation mode of the SFC, Step S
The indicator 17 of the automatic driving operation which is turned on by the operation of the operation circuit 2 is turned off when the step moves from step S2 to step S3. The lighting state does not match the original display purpose. So conventionally, step S
In step S2, the automatic operation operation indicator lamp 17 illuminated in step 2 is continuously turned on throughout the entire operation period of the automatic article transport system.
The indicator 17 of the automatic operation, which is turned on by the operation of the operation circuit, is also turned on after step S3 by a set command.

The above-mentioned step S2 is executed and the indicator lamp 17 of the automatic driving operation is turned on, and the S corresponding to the sequence control on the display surface of the display 4 (see FIG. 5) in the programmable sequence controller described above is performed.
When the display on the display unit 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. When the time set in the timer elapses, the transition T
The contact point of the timer (the contact point of the timer provided in the operation circuit of step S2) in the step transition condition circuit of step 2 is turned on, and the step shifts from step S2 to step S3 to perform programmable sequence control. The display on the display unit S2d corresponding to the steps 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 unit S3d changes from the dark state to the bright state. Changes and the timer value is reset. However, step S
The indicator lamp 17 of the automatic driving operation, which is turned on in 2, continues to be turned on by the set command as described above.

The process proceeds to step S3, and the display of the display section S3d 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 described above 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 turned off.
Is started, the article 35 is conveyed by the belt 27, and the limit switch 1 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, where the display 4 in the programmable sequence controller is displayed.
A display unit S3d corresponding to the steps in the SFC flowchart corresponding to the sequence control on the display surface of (see FIG. 5).
Is returned to the dark display state, the display section S4d changes from the dark state to the bright state, and the conveyor belt 27 stops moving.

As described above, the step proceeds to step S4, and 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 (see FIG. 5) in the programmable sequence controller described above. When the display changes to a bright state, the operation circuit of step S4 is executed and the timer is set. When the time set in the timer elapses, the contact point of the timer in the step transition condition circuit of transition T4 (step The contact point of the timer provided in the operation circuit of S4 is turned on, and the step shifts from step S4 to step S5 to display the display screen 4 (see FIG. 5) of the programmable sequence controller. S corresponding to the sequence control in
At the same time, the display on the display unit S4d corresponding to the step in the FC flowchart returns to the dark display state, and at the same time, the display unit S5d changes from the dark state to the bright state, and the timer value is reset.

The step proceeds to step S5, and the display of the display section S5d 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 described above is bright. When the interlock between the emergency stop button 9 and the overload protection means (thermal switch) 12 is off, the operation body is operated by the operation rod 30 of the pusher 29. 31 advances, and discharges the articles 35 on the belt 27 from the belt 27. And the aforementioned pusher 2
When the operating body 31 of No. 9 turns on the forward limit switch 11 in the step transition condition circuit of the transition T5, the steps are changed from step S5 to step S6.
At the same time, the display on the display unit S5d 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 returns to the dark display state, The display section S6d changes from a dark state to a bright state.

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

As described above, the step proceeds to step S7, and the display section S7d corresponding to the step in the SFC flowchart corresponding to the sequence control on the display surface of the display 4 (see FIG. 5) in the programmable sequence controller described above. When the display changes to a bright state, the operation circuit of step S7 changes the indicator lamp 1 of the automatic operation operation.
A reset command for turning off 7 is executed to turn off the indicator lamp 17 of the automatic operation, and one cycle ends.

[0013]

As described above, the basic operation mode of the SFC is such that an operation circuit of one step in a plurality of steps is put into an operating state, and one step is performed. Since the operation of the operation circuit of the above does not continue over a plurality of steps, it is desired that the automatic transportation system for articles be continuously turned on throughout the period in which the operation is continued. In the case where it is desired that the operation of the operation circuit of one step is continuously performed 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-described conventional example. As a solution, conventionally, the operation of the operation circuit of one step is continued over a plurality of step periods by using a set instruction. 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 of the step in which the operation is continued by the set instruction is performed even if the interlock condition is not satisfied in the subsequent step. The inconvenience of staying there may also occur, and measures to improve it have been sought.

[0014]

According to the present invention, in a sequence control of a plurality of operation steps by an SFC performed by using a programmable sequence controller, a predetermined step among a plurality of steps of the SFC is determined. Unless the interlock condition in the step is not satisfied, the operation of the operation circuit of the step continues during the period up to the step set to execute the interlock reset instruction for the step. And a sequence control method to be executed by the computer.

[0015]

The operation of the operation circuit of the predetermined step in the plurality of steps of the SFC can be continued to be executed even during the period of the step following the step. The operation of the operation circuit is inoperative when the interlock condition in the step is not satisfied, and when the step set to execute the interlock reset instruction with respect to the predetermined step is executed. Done.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the specific contents of the sequence control method of the present invention will be described in detail. FIG. 1 is a block diagram showing a schematic configuration of a programmable sequence control device used to carry out the sequence control method, and FIG. 2 shows the sequence control method of the present invention applied to an automatic article transport system. FIG. 3 is a perspective view schematically showing a part of an article conveying device in the case, FIG. 3 is a plan view illustrating a display surface of a display, and FIG. 4 is an explanatory diagram of a memory map of a RAM table.

In FIG. 1, reference numeral 1 denotes a CPU (Central Processing Unit), and 2 denotes a read-only memory (ROM). The ROM 2 stores a program. Also, 3
Is a random access memory (RAM); 4 is a display;
PU, and connected to the display 4 by a signal transmission line 22.
M3 is connected to the CPU by a signal transmission path 21 and to the display 4 by a signal transmission path 23. The display 4 may be, for example, a cathode ray tube display device using a fluorescent screen of a cathode ray tube as a display surface, a liquid crystal display device, or a display panel using a large 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. However, in the following description, a fluorescent screen of a cathode ray tube is used as a display surface. It is assumed that a cathode ray tube display is used as the display 4. On the display surface of the display 4, a pattern (S1d to S7d or T1 to T7d in FIG. The display of a figure and an END as exemplified in T6) is displayed. The input unit (interface) 5 is connected to the CPU 1 via a signal transmission line 18, and the output unit (interface) 6 is connected via a signal transmission line 19. The input unit 5 includes a start button 7, a stop button 8, an emergency stop button 9, limit switches 10, 11, 13 provided on an operation panel 24 shown in FIG. Switch) 12 and the like, and the output unit 6 supplies the driving power to the motor 14, supplies the operating power to the pusher 29 at the time of the forward operation 15 and the reverse operation 16 of the pusher 29, and performs the automatic operation. Operation power is supplied to the operation indicator lamp 17. It should be noted that reference numerals 32 and 33 in the figure indicate power sources, respectively.

Referring to FIG. 2, which schematically shows a portion of a device for transporting articles constituted by various push buttons 7 to 9 and switches 10 to 13 shown in FIG. When the power switch (not shown) in the system including the display device is turned on, the display unit S1d on the display surface of the display shown in FIG. 3 turns on the power switch of the system (not shown) in step S1. Is performed, the display state is changed from the low-brightness (dark) display state to the high-brightness (bright) display state to 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 input section 5 can program the information that the start button 7 is operated in a programmable sequence control. Given to CPU1 in the device, CPU1
Processes the information that the start button 7 has been operated in accordance with the program stored in the ROM 2 and shifts the step from step S1 to step S2.
A display unit S1d corresponding to the steps of the SFC flowchart corresponding to the sequence control on the display surface (see FIG. 3).
From the high-brightness state to the low-brightness state
(Dark state) and the display of the display section S2d of the display 4 from a low luminance state to a high luminance state. When the start button 7 provided on the operation panel 24 is pressed, the programmable sequence controller starts a predetermined control operation, and controls the operation circuits in steps S1 to S7 in order. In addition to performing the operation, the sequential steps of the SFC flowchart corresponding to the sequence control are performed on the display screen of FIG. 3 in which a part of the display screen of the display 4 shown in FIG. 1 is enlarged. Display is performed on the display units S1d to S7d corresponding to S1 to S7.

In FIG. 3, the figures shown in the two-dot chain line frame 36 shown on the left of the display 4 are transitions T1 to T4 indicated by reference numerals T1 to T4 on the display surface of the display 4. The step transition condition circuit shown in FIG. 3 is shown, but 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 of the display 4 is a drawing symbol S1d on the display surface of the display 4.
5 shows operation circuits in steps S1 to S5 which are to be displayed on the respective display units indicated by S5d. The display contents as shown by the two-dot chain line frame 37 are different from those of the display 4. Are displayed on the display.

FIG. 4 shows an example of the configuration of a memory map of a RAM table used for storing information for determining the display state of the display unit in the display 4. In FIG.
m, S1m, S2m... correspond to the sequential steps S1, S2, S3... of the SFC flowchart corresponding to the sequence control, and the display modes of the respective steps set on the display 4 in the display sections S1d, S2d, S3d. It shows a storage area in which information for designation is written and read. In the following description, the information for designating the display mode stored in S1m of the storage area in the RAM table described above corresponds to the step S of the SFC flowchart corresponding to the sequence control.
1 is information for specifying the display mode in the display unit S1d of the step set in the display 4 corresponding to 1, and information for specifying the display mode stored in S2m of the storage area in the RAM table. Corresponds to step S2 of the SFC flowchart corresponding to the sequence control.
The steps and steps of the SFC flowchart corresponding to the storage area and sequence control in the RAM table described above are information for designating the display mode on the display unit S2d of the steps set in the display 4 corresponding to When the subscript numbers 1, 2, 3,... Used in the reference numerals indicating the display unit of, etc. are represented by i (i is a natural number) by a general expression, Sim in the storage area of the RAM table is used. Is stored in the display 4 in correspondence with step S i of the SFC flowchart corresponding to the sequence control.
Are used as information for specifying the display mode of the step set in the display unit Sid.

In the following description, the display units S1d and S1d of the respective steps set in the display 4 described above will be described.
When S2d, S3d... Are displayed in a continuous display mode with a constant low luminance, “00” is stored in the storage area of the RAM table corresponding to the display unit of the step to be set to such a display mode. Is written, and the display unit S of each step set in the display 4 is set.
When 1d, S2d, S3d... Are displayed in a continuous display mode with a constant high brightness, the storage area of the RAM table corresponding to the display unit of the step to be set to such a display mode is stored in the storage area. "11" is written, and the display mode of the display units S1d, S2d, S3d... Of each step set in the display 4 is changed between a display in a constant high luminance state and a constant low luminance state. In the case where the display according to the state is alternately displayed on the time axis, "1" is stored in the storage area of the RAM table corresponding to the display unit of the step to be displayed in such a manner.
"0" is written.

As described above, S corresponding to the sequence control
Steps S1, S2, S3 ... of the FC flowchart
.. In the display units S1d, S2d, S3d,... Of the respective steps set in the display 4 in correspondence with the display area S0m, S1m, S2m,. The information is read from the RAM table and is used to determine the display mode on the display units S1d, S2d, S3d... Of each step set in the display 4, and is stored in the RAM table as described above. The displayed information for designating the display mode is C
Needless to say, it can be effectively used for other operation control by the PU1.

Now, when the start button 7 is operated by the step transition condition circuit of the transition T1 and the information is given to the programmable sequence control device, the step shifts from step S1 to step S2, and the program becomes programmable. The display of the display unit S1d 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 simple sequence control device is changed from a display state in a constant high luminance state (bright state) to a constant state. At the same time when the display section S2d returns to the display state in the low luminance state (dark state), the display section S2d changes from the display state in the constant low luminance state (dark state) to the constant high luminance state.
The display changes to (bright state).

When the step proceeds from step S1 to step S2, the emergency stop button 9 and the overload protection means (thermal switch) 12 are both off, 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 lamp 17 of the automatic operation is turned on, and the display 4 (see FIG. 3) in the programmable sequence controller described above is used. The display of the display unit S2d corresponding to the step of the SFC flowchart corresponding to the sequence control on the display surface changes from a low-luminance display state to a continuous high-luminance display state. And
The execution of the above-described interlock set command is performed in a state where the interlock condition of step S2 is satisfied and held even if the steps of the SFC flowchart corresponding to the sequence control are advanced. Since the operation circuit of S2 also keeps its execution state, the lighting operation of the indicator lamp 17 of the automatic operation operation is continued throughout the period when the automatic article transport system is operating.

When the step proceeds from step S2 to step S3, the emergency stop button 9 and the overload protection means (thermal switch) 12 are both off, that is, the interlock condition of step S3 is satisfied. If there is, the operation circuit of step S3 in the programmable sequence control device is executed, the conveyor is started and the movement of the belt 27 is started, and the display 4 in the programmable sequence control device is controlled.
A display unit S3d corresponding to the steps of the SFC flowchart corresponding to the sequence control on the display surface of FIG. 3 (see FIG. 3).
Changes from the low brightness state to the high brightness state. SF corresponding to sequence control as described above
When the steps of the flowchart C go from step S2 to step S3, if the interlock condition in step S2 in which the above-described interlock set command is executed is satisfied, the operation circuit of step S2 also continues execution. Therefore, the lighting operation of the indicator lamp 17 in the automatic driving operation is continued during the period of step S3.

The movement of the belt 27 causes the article 3
When 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 provided to the CPU 1 in the programmable sequence controller via an input 5 in the programmable sequence controller. In the above CPU 1, RO
According to the program stored in M2, the above-mentioned information on the turning-on of the limit switch 10 is processed, and the step shifts from step S3 to step S4. When the step advances from step S3 to step S4, the emergency stop button 9
Is off, that is, if the interlock condition at step S4 is off, the operation of the operation circuit at step S4 in the programmable sequence controller described above causes the output unit to stop the movement of the conveyor belt 27. From 6, the supply of drive power to the motor 14 is cut off. SFC corresponding to sequence control as described above
When the steps of the flowchart proceed from step S3 to step S4, if the interlock condition in step S2 where the above-described interlock set command is executed is satisfied, the operation circuit of step S2 also continues execution. Therefore, the lighting operation of the indicator lamp 17 in the automatic driving operation is continued during the period of step S4.

The above description corresponds to the sequence control and the corresponding S
When the steps of the FC flowchart proceed 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 relates to the case where the interlock condition of step S3 is satisfied, but when the step of the SFC flowchart corresponding to the sequence control proceeds from step S2 to step S3, step S3 is executed.
When one or both of the emergency stop button 9 and the overload protection means (thermal switch) 12 in the execution circuit of the above is ON, that is, if the interlock condition in step S3 is not satisfied, the CPU 1 executes the above-described RAM. The storage content of the storage area S3m corresponding to step S3 in the table is changed from the storage content “00” up to that point to the storage content “1”.
0, and the storage contents of all the 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 sequence control device which can be programmed with reference to the RAM table. Display unit S corresponding to the steps of the SFC flowchart corresponding to the sequence control on the display surface of
The display state of 3d is such that the display state of the display unit S3d is alternately changed to a high-brightness state and a low-brightness state on the time axis from the continuous constant low-brightness state up to that point. Change to In this state, if the interlock condition is satisfied in step S2 where the above-described interlock set command is executed, the operation circuit in step S2 also continues to execute, and the lighting operation of the indicator lamp 17 of the automatic operation operation is performed. Is being continued.

At the time when the steps of the SFC flowchart shift 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 turned off and the interface is turned off. Although the lock condition has been satisfied, 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, and the interlock condition is established. Is not satisfied, 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 storage content of the storage area S3m corresponding to step S3 in the above-described RAM table with the storage content up to that time. 0
From "0" to the storage content "11", the storage content of all storage areas other than the storage area S3m corresponding to step S3 in the RAM table is rewritten to "00", and the RAM table can be programmed with reference to the RAM table. The display of 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 changed from the continuous low brightness state to the display state of the display unit S3d on the time axis. Above, the state is continuously changed to the high luminance state, but 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. At the point in time when the interlock condition is not satisfied, the CPU 1 stores the storage area corresponding to step S3 in the above-described RAM table. 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
0 ”and an SFC corresponding to the sequence control on the display surface of the display 4 in the programmable sequence controller with reference to the RAM table.
The display state of the display unit S3d corresponding to step S3 of the flowchart is sequentially changed from the continuous high-brightness state to the high-brightness state and the low-brightness state on the time axis. To a display state that changes to In this state, if the interlock condition in step S2 where the interlock set command is executed is satisfied, the operation circuit of step S2 also continues to execute, and the lighting operation of the indicator lamp 17 of the automatic driving operation is performed. Is being 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 such that the display state changes alternately between a high luminance state and a low luminance state on a time axis. In 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 whether the cause of the failure exists in the step transition condition circuit of the transition This is convenient because the distinction can be easily and clearly understood. 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 unit corresponding to the specific step continues a continuous display state in a state of high luminance.

Next, the steps of the SFC flowchart corresponding to the sequence control are performed from step S3 to step S4.
If the emergency stop button 9 is off when the process proceeds to step S4, that is, if the interlock condition in step S4 is off, the motor 14 is stopped by executing the operation circuit in step S4 in the programmable sequence controller described above. To stop the movement of 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 previous low brightness state to the high brightness state. Change to a state. When the step of the SFC flowchart corresponding to the sequence control proceeds from step S3 to step S4 as described above, if the interlock condition is satisfied in step S2 in which the above-described interlock set command is executed, The operation circuit of step S2 also continues to execute, and the lighting operation of the indicator lamp 17 in the automatic driving operation is continued during the period of step S4. The above step S
When the display on the display unit S4d corresponding to 4 changes from the previously low brightness state to the high brightness state, step S4
The operation circuit is executed and the timer is set. When the time set in the timer elapses, the contact of the timer in the step transition condition circuit of the transition T4 (the contact of the timer of the operation circuit in step S4) is turned on. In the state, the step shifts 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 controller is performed.
The 4d display is changed from the high brightness state to the low brightness state
(Dark state) and the display on the display unit S5d of the display 4 is changed from a low-brightness state to a high-brightness state, and at the same time, the display unit S5d is changed from a dark state to a bright state and the timer value is reset. Is 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, and 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
0, the operating body 31 advances, and the articles 35 on the belt 27
From the belt 27, and the display on the display unit S5d corresponding to the steps of the SFC flowchart corresponding to the sequence control on the display surface of the display 4 in the programmable sequence controller described above is changed from the previous low brightness state to the high level. Simultaneously with the change to the brightness state, the display of 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 to the low brightness state. When the step of the SFC flowchart corresponding to the sequence control proceeds from step S4 to step S5 as described above, if the interlock condition is satisfied in step S2 in which the above-described interlock set command is executed, The operation circuit of step S2 also continues to execute, and the automatic operation operation indicator 1
The lighting operation of No. 7 is continuously performed during the period of step S5.

The operating body 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 of the programmable sequence control device via the input section 5 of the programmable sequence control device, the CPU 1 turns on the limit switch 11 according to the program stored in the ROM 2. And the process moves from step S5 to step S6. When the step of the SFC flowchart corresponding to the sequence control proceeds from step S5 to step S6 as described above, 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 so, 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 aforementioned programmable sequence controller
A display unit S6d corresponding to the steps of the SFC flowchart corresponding to the sequence control on the display surface of FIG. 4 (see FIG. 4).
Changes from a low-luminance state to a high-luminance state. When the step of the SFC flowchart corresponding to the sequence control proceeds from step S5 to step S6 as described above, if the interlock condition in step S2 in which the interlock set command is executed is satisfied, The operation circuit of step S2 also continues to execute, and the lighting operation of the indicator lamp 17 in the automatic driving operation is continued during the period of step S6.

The operating body 31 of the pusher 29 turns on the limit switch 13 of the backward limit in the step transition condition circuit of the transition T6, and the information is programmed via the input unit 5 in the programmable sequence controller. When given to the CPU 1 in a possible sequence controller, the CPU 1
According to the program stored in M2, the above-described information on the ON state of the limit switch 13 is processed, and the process proceeds from step S6 to step S7. Step S
In step 7, the interlock reset command is executed, the execution of the operation circuit in step S2 is stopped, the indicator lamp 17 for the automatic operation is turned off, and the one-cycle operation is completed.

[0034]

As is apparent from the above description, the sequence control method of the present invention, when performing a sequence control of a plurality of operation steps using a programmable sequence control device, requires a plurality of SFCs. The operation of the operation circuit of a predetermined step during the step,
The execution of the operation circuit of the predetermined step is such that the interlock condition in the predetermined step is not satisfied during the period of the step subsequent to the step. Case and a step set for executing the interlock reset command with respect to the predetermined step is made inoperative, so that, for example, an automatic In the case where it is desired that the automatic transportation system for articles is continuously turned on throughout the period of operation, such as an indicator light for driving operation, even in view of the display purpose, it is necessary to perform sequential steps. Is the operation in the basic operation form 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 of the operation circuit of the predetermined step is allowed to continue over the required period of a plurality of steps, and the interlock condition of the operation circuit of the predetermined step is satisfied. During this period, the operation of the operation circuit is continuously performed, the interlock condition of the operation circuit in the above-mentioned predetermined step is not satisfied, and the interlock set instruction is released by the interlock reset instruction. And
The operation of the predetermined step is stopped when the interlock set instruction is released by executing 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, the above-mentioned conventional problems can be satisfactorily solved.

[Brief description of the drawings]

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

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

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 Unit 6 Output Unit 7 Start Button 8 Stop Button 9 Emergency Stop Button 10, 11, 13 Limit Switch 12 Overload Protection means (thermal switch) 14 Motor 24 Operation panel 26 Drive roller 27 Belt 28 Follower roller 29 Pusher 30 Operating rod 31 Operating body 32, 33 Power supply

Claims (1)

(57) [Claims] 1. In a sequence control of a plurality of operation steps by an SFC performed by using a programmable sequence controller, an interlock condition in a predetermined step among a plurality of steps of the SFC is not satisfied. Unless it becomes
A sequence control method in which the operation of the operation circuit of the step is continuously executed during a period up to a step set to execute the interlock reset instruction in the step.