JPH07111643B2 - Sequence control method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a sequence control method for controlling a system including various mechanical devices, and more particularly to a control method using a plurality of control terms in parallel.

[Conventional technology]

In addition to the ladder diagram which is a scanning type program which has been widely used as a language for automatic machine control, in recent years, as described in JP-A-61-110204, FORTRA
Sequential execution type programs based on high-level languages such as N and BASIC tend to be used. On the other hand, the development of a sequence control device that can selectively use a ladder diagram, which is a scanning type program, and command words, flow charts, BASIC, etc., which are sequential execution type programs, is a technically This is a trend.

[Problems to be solved by the invention]

The above-mentioned prior art does not consider using a scanning type program and a sequential execution type program together in a single sequence control device, and has the following problems. That is,
In general, if the target is a system with strong logic, it is easier to describe it with a ladder diagram, but on the contrary, if the system has a strong order, BASIC is easier to describe.
There is a demand to properly use the languages to be used depending on the control target and to execute them by appropriately linking them during control. However, in the prior art, when the system is controlled by a single sequence controller, the user must write a consistent program in one language selected first, for example, a BASIC program to a ladder diagram routine. When I started up, it was impossible to write a mixture of multiple languages. Further, when various users share the program and describe the program, the above-mentioned point becomes a constraint, which may hinder the efficiency of creating the control program. It is only necessary to be able to input in different languages using multiple sequence controls, but it becomes a problem that the price increases due to the complexity of the device configuration and the linkage such as data exchange between control devices takes time and effort. . Further, when continuous control such as servo control is required, a dedicated control device such as a positioning unit must be additionally connected and executed, which also causes a problem of high price.

An object of the present invention is to perform a scan-type control, a sequential-execution-type control, and a continuous-system control in parallel by appropriately time-dividing the processing of a single control device, thereby providing an inexpensive and highly functional sequence. In addition to providing a control device, multiple input languages (ladder diagram, sequential execution language such as BASIC, N
It is intended to improve the usability by allowing mixed use according to the controlled object (C language etc.).

[Means for solving problems]

In order to achieve the above object, the present invention comprises a program input means for inputting a desired program, a storage means for storing the program input to the program input means, and an arithmetic means for executing the stored contents of the storage means. In the sequence control system having the above, the arithmetic means is provided with a timing means for transmitting an interrupt signal at a predetermined cycle, and one of the sequential execution type program, the continuous system control program and the scanning type program inputted from the program input means is selected. The arithmetic unit that is executing the program sequentially executes another program of the plurality of programs by the interrupt signal, executes a predetermined unit amount of arithmetic operation, and then executes the first program again, and then executes the next interrupt signal. Sequence to execute another program in sequence and repeat this operation, the sequence program to execute the scanning program next to the continuous control program. To propose a scan control method.

In order to achieve the above object, the present invention also provides a program input means for inputting a desired program, a storage means for storing the program input to the program input means, and an arithmetic means for executing the stored contents of the storage means. In a sequence control system having: a first clock means for transmitting an interrupt signal to the arithmetic means at a predetermined cycle; and a second clock means for simultaneously starting the interrupt signal and measuring a predetermined period shorter than the predetermined cycle.
The arithmetic means, which is provided with a time measuring means and is executing one of the plurality of programs input from the program inputting means, sequentially executes the other programs of the plurality of programs in response to an interrupt signal to measure a predetermined period. Then, the program 1 is executed again, another program is sequentially executed again by the next interrupt signal, and this operation is repeated to propose a sequence control method.

The one program is a sequential execution type program, and one of the other programs is a continuous control program,
When another one of the other programs is a scanning type program, the scanning type program is executed next to the continuous control program.

When the one program is a sequential execution type program and the other programs are scanning type programs, after starting the acquisition of an input signal necessary for an operation for determining one output during execution of the scanning type program, If a predetermined period of time elapses before the end of the input signal acquisition, the execution of the scanning program can be continued until the end of the input signal acquisition.

[Action]

In the present invention, since the scanning type program is executed after the continuous system control program, the timer is saved.

Both the continuous system control program and the scanning program are periodically executed, but the continuous system control program must always set the starting point of the execution start to the fixed cycle. For example,
If it is a speed control calculation of a servo system, it is necessary to execute it every 3 ms at regular intervals. On the other hand, it is not necessary that the execution start time of the scanning program is a fixed cycle. Therefore, if the scanning type program is executed after the continuous control program, the start point of the execution of these programs can be managed by one timer.

If the end of execution of the scanning program is managed by time, another timer will be required as described later. This is the same when the starting point is managed by two timers.

Further, since the end of the scanning type program is managed by the timer 2 synchronized with the timer 1, it is possible to avoid the execution delay and the congestion of the scanning type program and the sequential type program.

If you want to execute three programs with different execution requirements and scanning programs, execution programs, and continuous control programs on a single device, you must give due consideration to the priority relationships of each program, and the programs with lower priorities. There is a delay in processing. Normally, the continuous control program is given the highest priority, but the scanning type program and the sequential type program have no particular priority relationship. Therefore, there is a problem in a method of appropriately terminating the execution of each program and shifting the processing. After scanning the scanning program once, it is common to move to the sequential program and vice versa, but the allocation time of the program to be executed later varies depending on the length of the program to be executed first. It was a problem to do.

The present invention allocates the processing time without prioritizing between the two programs by providing the timer interrupt with the subordinate relationship. Therefore, the processing can be equally assigned without delaying the specific processing.

Further, even when the timer 2 indicates the end timing of the scanning type program, if the scanning type control is continued until the timing at which the scanning type program is to be ended, it is possible to prevent an erroneous output due to a non-uniform input time.

In the scanning program, the output signal is determined based on the result of the logical operation such as AND and OR of the plurality of input signals. Therefore, if the input timings of a plurality of input signals are different, the logical operation becomes abnormal and there is a risk of erroneous output. Therefore, while a part of the input is being taken in, even if the timer 2 finishes the execution time allotted to the scan type program, the execution of the scan type control is continued until all the inputs are taken in. It should be noted that it may be continued until the logical operation and output are completed.

〔Example〕

Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS. FIG. 1 shows the configuration of a control device to which the present invention is applied. In the constituent elements of the control device 101 of FIG. 1,
The system memory 111 stores the processing procedure to be executed by the arithmetic unit 109, and the program memory 112 stores the object data corresponding to the program described by the user. Further, the data memory 113 stores data necessary for calculation and is rewritten by the calculation device 109 as necessary. The arithmetic unit 109 operates according to the procedure shown in the system memory 111, and executes arithmetic according to the contents of the program memory 112. Arithmetic unit 109, system memory
111, program memory 112, data memory 113 includes an input circuit 114, an output circuit 115, a servo control circuit 116, a time division circuit 108,
Together with the communication circuit 110, they are connected by a bus 117. The output of the switch 102 is input to the input circuit 114 through the input contact X1. This signal is transmitted to the arithmetic unit 109 via the bus 117. Arithmetic unit 109 to relay 103,10
The signal for turning on and off 4,105 is output through the output circuit 115.
Output from output contacts Y1, Y2, Y3 respectively. On the other hand, the control amount given by the arithmetic unit 109 to the servo device 106 is transmitted to the servo control circuit 116. The servo control circuit 116 performs necessary calculation between the information and the physical quantity (current position, current speed, etc.) returned from the servo device 106 through F1, and then outputs a control signal to the servo device 106 through H1. .
A program for operating the arithmetic device 109 is input from the program input device 107. The program input device 107 is
The input program is edited as needed so that it can be executed by the arithmetic unit 109, and sent to the communication circuit 110. This content is transferred to the program memory 112. Time division circuit 108
Is composed of a first timer 121, a second timer 120, and an interrupt controller 122. All of them are connected to the arithmetic unit 109 via the bus 117, and operate in a programmable manner in accordance with a command from the arithmetic unit 109. First timer 121
Sends a signal directly through the signal line 118 to the interrupt controller 122 every period determined by the arithmetic unit 109. The interrupt controller 122 directly transmits this signal as an interrupt signal to the arithmetic unit 109 through the signal line 119. Second timer
The storage unit 120 stores a predetermined period of time predetermined by the arithmetic unit 109, and starts clocking according to a command from the arithmetic unit 109. Then, the arithmetic unit 109 is notified of the elapse of the predetermined time. In FIG. 1, as devices controlled by the controller 101, a switch 102, a relay 103, a relay 104, a relay 105,
I connected the servo device 106, but as a whole system,
Other switches, relays, and servo equipment may be provided. Further, the program input device 107 and the control device 101 may be integrated.

FIG. 2 is an example of a control program input by the user from the program input device 107 in order to cause the control device of FIG. 1 to perform a desired operation. FIG. 2 is composed of (a) sequential execution type program and (b) scanning type program (ladder diagram). For the sequential execution type program, the contents shown in the comment sentence are sequentially calculated for each line, and for the scanning type program, the unit block showing the input / output relation surrounded by the broken line in FIG. Repeatedly calculate up to. The unit block has one output (Y3 in the case of FIG. 2).
0) and some signals (X21 and Y15 in the case of FIG. 2) necessary to calculate the output. “START $ 01” on line 120 in (a) is an instruction to start execution of the program in (b), and line 170 is an instruction to terminate its execution. If the execution of the program is partially delayed, the maximum delay time in system control increases, which causes a problem. Therefore, it is necessary to execute lines 130 to 170 and (b) in (a) in parallel. Therefore, the arithmetic unit 109
Will be time-shared and both will be executed at an appropriate ratio.

FIG. 3 shows an algorithm executed by the arithmetic unit 109 at this time. First, in S1, the scanning type control start cycle T1 is set in the first timer 121, and then this timer is started.
In S2, the execution time of scanning control is set as the time-up time T2,
Set second timer 120. At this time, needless to say, T1> T2. After this, the arithmetic unit 10
The interrupt of 9 is enabled, and the sequential execution type program is sequentially executed from line 100 in S3. First timer 1
21 sends a signal to the interrupt controller 122 in every cycle T1, and the interrupt controller 122 sends it to the arithmetic unit 109 as an interrupt signal. Upon receiving the interrupt signal, the arithmetic unit 109 starts the interrupt process as shown in FIG. First, in S4, the second timer is started, and in S5, it is determined whether or not there is a scanning program to be executed, that is, whether or not scanning control is performed. In the example of FIG. 2, when the lines 130 to 170 of (a) are being executed, the scanning type program of (b) indicated by $ 01 is executed in parallel. In this case, one unit block of the scanning program described above is executed in S6, and the value of the second timer 120 is read in S7. S
In 8 it is judged whether or not the time is up based on that value, and if it is not in time up, the next unit block is executed in S6. After that, until the time is up, S6
~ Repeat S8. Since the minimum unit of execution of the scanning type program is the unit block, the execution of the scanning type control does not end in the middle of inputting a plurality of signals for obtaining the output of each unit block. Therefore, as the time lag of each unit block calculation, a value equal to that when the calculation device is dedicated to the execution of the scanning program is guaranteed, and the operation delay caused by the time division is controlled by the control device. There is no malfunction. When the lines other than the lines 120 to 170 are executed in (a), it is determined in S5 that the scanning control need not be executed, and the process returns to S3 without waiting for the time-up. The algorithm of FIG.
The process of 109 is eventually time-divided as shown in FIG. 4, and two types of control are executed in parallel. 4 in FIG. 4 corresponds to that in FIG. 3 and shows the timing at which each control is switched.

In this embodiment, the scanning program started from the sequential execution program is only "$ 01", but even when a plurality of scanning programs are started in parallel, they are sequentially scanned. As a result, the algorithm shown in FIG. 3 can be used. Although the unit block is defined as shown in FIG. 2 in this embodiment, it may be defined in another form convenient for calculation. Further, in FIG. 2, the start and end of the scanning type program is managed from the sequential execution type program, but conversely, the execution of the sequential execution type program from the scanning type program can be managed by the same idea. Furthermore, although the arithmetic device 109 receives the signal of the first timer 121 as an interrupt, a polling method in which the arithmetic device 109 periodically detects the signal of the first timer 121 may be used. Further, in this embodiment, as shown in FIG. 1, the time division is configured by the two hard timers 121 and 120 and the interrupt controller 122. However, when the arithmetic unit 109 has the soft timer function, It is also possible to realize some or all of them by software.
When the function of the first timer 121 is executed by software, the interrupt controller 122 is not necessary, and software interrupt processing may be performed.

Next, a second embodiment relating to the present invention will be shown. Figure 5 shows
3 is an example of a control program input by a user from the program input device 107. FIG. 5 shows the same (a) as FIG.
In addition to the sequential execution type program (2) and the scanning type program (ladder diagram) (b), the servo control program (c) requires positioning calculation for the servo system. (C) shown at $ 02 is line 140 of (a)
It is started by "START $ 01" of, the servo X axis is positioned at 100 on the line 1000, and the servo Y axis is positioned at 50 on the 1100. In order to guarantee a stable response to the servo system, it is necessary to continuously execute the sampling with a fixed period. In addition, the time required for one sampling calculation depends on whether the control content is PTP (Point to Point) or CP (Con
tinuous path) or the number of axes to be controlled varies considerably, but one sampling operation must be executed continuously until the end in order not to deteriorate control accuracy and responsiveness. . As in the case of FIG. 2, in (b), the execution is started at "START $ 01" on the line 120 in (a), and the execution is ended at "STOP $ 01" on the line 170. Therefore, line 140 to line 170 in (a)
In addition to (b) at the time of execution, it is necessary to execute the program of (c) in parallel. The processing of the arithmetic device 109 must be time-divided into these three processings while satisfying the above-mentioned requirements regarding the control of the servo system.

FIG. 6 shows an algorithm executed by the arithmetic unit 109. The difference from FIG. 3 is that T5 determines whether or not there is a continuous program to be executed prior to the execution of the scanning type program in the interrupt processing, that is, whether to execute continuous system control. If it exists, T6 that executes the control operation is added. The stepping from T6 to T7 is performed when all the calculations per sampling in the continuous system control are completed. By the algorithm of FIG. 6, the processing of the arithmetic unit 109 is time-divided as shown in FIG. 7, and three types of control are executed in parallel.

In this embodiment, the servo control program is described separately from the other two programs, but the same applies to the case where the contents and the continuous control such as servo control are included in the sequential execution type program or the ladder diagram. Can be implemented in the following manner.

According to this embodiment, it is possible to execute the sequential execution type program and the scanning type program in parallel with a single sequence control device. Therefore, the user can use different input languages according to his / her preference and the characteristics of the system, and a hierarchical system in which languages with different control methods such as activating a scanning program from a sequential execution type program are linked hierarchically. A description is also possible. Also, when continuous system control such as positioning of the servo system is required, this can be incorporated in time division and similarly executed in parallel. At this time, a constant sampling period is guaranteed for control of the continuous system, and the response of the continuous system can be kept stable. Further, in executing the scanning type program, the time lag that occurs in a plurality of input signals of the unit block is guaranteed to be the same value as when the sequence controller is dedicated to executing the scanning type program. The operation delay does not cause the sequence controller to malfunction.

〔The invention's effect〕

According to the present invention, after inputting a plurality of programs, one of the plurality of programs is executed by the calculating means, another program is executed after a predetermined time has elapsed, and a predetermined unit amount of calculation is executed, Alternatively, after a lapse of a certain time, the above-mentioned program 1 is executed again, and the above-mentioned work is repeatedly executed, so that the scanning type control, the sequential execution type control, and the continuous system control can be executed in parallel. In addition, since a plurality of control objects having different input languages can be mixedly used, the usability can be diversified.

[Brief description of drawings]

FIG. 1 is a device configuration diagram of an embodiment of the present invention, FIG. 2 is a diagram showing a program input by a user, FIG. 3 is a diagram showing an algorithm executed by an arithmetic unit, and FIG. FIG. 5, FIG. 5 is a diagram showing a program input by the user, FIG. 6 is a diagram showing an algorithm executed by the arithmetic unit, and FIG.
The figure is a diagram showing time division. 101 ... Control device, 107 ... Program input device, 108 ...
… Time division circuit, 109 …… Calculator.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-59-79311 (JP, A) JP-A-60-48503 (JP, A) JP-A 61-6704 (JP, A) JP-A 61- 156307 (JP, A)

Claims (4)

[Claims] 1. A sequence control system having a program input means for inputting a desired program, a storage means for storing the program input to the program input means, and a calculation means for executing the stored contents of the storage means. The computing means is provided with a clocking means for transmitting an interrupt signal at a predetermined cycle, and executes one program of a sequential execution type program, a continuous system control program, and a scanning type program input from the program input means. The arithmetic means in the sequence sequentially executes another program of the plurality of programs in response to the interrupt signal, executes a predetermined unit amount of arithmetic operation, and then executes the first program again to execute the next interrupt. The other program is sequentially executed again by the input signal, and when this operation is repeated, the scanning is performed next to the control program of the continuous system. Sequence control system and executes the program. 2. A sequence control system having a program input means for inputting a desired program, a storage means for storing the program input to the program input means, and a calculation means for executing the stored contents of the storage means. A first clock means for transmitting an interrupt signal to the arithmetic means at a predetermined cycle, and a second clock means for simultaneously starting the interrupt signal and measuring a predetermined period shorter than the predetermined cycle, the program input The arithmetic means, which is executing one program of the plurality of programs input from the means, sequentially executes another program of the plurality of programs by the interrupt signal, measures the predetermined period, and again 1 program is executed, the other program is sequentially executed again by the next interrupt signal, and this operation is repeated. Sequence control system. 3. The sequence control method according to claim 2, wherein the one program is a sequential execution type program, one of the other programs is a continuous system control program, and the other program is Another one of the programs is a scanning type program, and the scanning type program is executed next to the continuous system control program. 4. The sequence control method according to claim 2, wherein the one program is a sequential execution type program, the other program is a scanning type program, and the scanning type program is being executed. If the predetermined period of time elapses after the acquisition of the input signal necessary for the operation for determining one output is started and before the acquisition of the input signal is completed, the scanning type is continued until the acquisition of the input signal is completed. A sequence control method characterized by continuing program execution.