JP2522401B2 - Programmable controller - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a programmable controller of a cyclic arithmetic system that controls the operation of an electronic device while repeatedly executing a sequence program.

[Conventional technology]

The programmable controller is also called a sequence controller, and is known as an apparatus that controls the operation of an electronic device by executing a sequence program.
Among the programmable controllers, in the cyclic operation type programmable controller that repeatedly executes the same sequence program, it is desired to shorten the execution time of the above sequence program, and in response to this request, the operation speed of the programmable controller is also increased. It's getting faster.

[Problems to be Solved by the Invention]

However, a control target device such as a hydraulic device having a slow operation response cannot follow the operation cycle of the programmable controller. As a result, a buffer memory for synchronization must be provided in the programmable controller in order to input / output the information signal in accordance with the operation cycle of the controlled device, and there is a problem to be solved that the device becomes expensive. It was Further, the conventional programmable controller has a drawback that a programmable controller for a controlled device having a fast operation response and a programmable controller for a controlled device having a slow operation response must be separately manufactured.

Therefore, an object of the present invention is to provide a general-purpose programmable controller that can be connected to a control target device having a fast operation response and a control target device having a slow operation response.

[Means for solving the problem]

In order to achieve such an object, the present invention provides a first mode in which the next operation of the sequence program is executed immediately after the operation of the sequence program is finished, and a second mode in which the execution time of the sequence program is set to a certain time or more. In the second mode instructed by the mode instructing means, the sequence program in the second mode instructed by the mode instructing means. Of the sequence program, which is started in synchronism with the calculation start time and measures the fixed time, and whether or not the one-time calculation execution time of the sequence program is shorter than the fixed time based on the time measurement result of the time measuring means. In the second mode, the determination result of the determination means is positive. In the case where the determination result of the determination unit in the second mode is a negative determination in the second mode, the next execution of the sequence program operation is instructed to the operation unit in synchronization with the time when the certain time is timed by the time measurement unit. Or in the first mode, the control means for instructing the calculation means to execute the next calculation of the sequence program in synchronization with the calculation end time of the sequence program.

[Action]

According to the present invention, it is possible to select the first mode similar to the conventional one in which the operation of the next sequence program is started immediately after the operation of the sequence program is finished and the second mode of the present invention in which the operation execution time of the sequence program is a fixed time. The programmable controller can be connected to both the control target device having a fast response and the control target device having a slow response.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

 FIG. 1 shows the basic configuration of the embodiment of the present invention.

In FIG. 1, reference numeral 100 is a calculation means for executing the calculation of the sequence program in response to an instruction from the outside. 20
Reference numeral 0 is a clocking means that starts in synchronization with the calculation start time of the sequence program of the calculating means 100 and measures a fixed time. Reference numeral 300 is a judging means for judging whether or not the time for which one operation of the sequence program is executed is shorter than a predetermined time, based on the time-measured result of the time-measurement means 200. When the determination result of the determination means 300 is affirmative, 400 instructs the operation means 100 to execute the next operation of the sequence program in synchronization with the time when the fixed time is measured by the time measurement means 200. When the result of the determination is negative, the control means instructs the arithmetic means to execute the next arithmetic operation of the sequence program in synchronization with the end of the arithmetic operation of the sequence program. Reference numeral 500 denotes a mode instructing means for selectively instructing a first mode in which the next operation of the sequence program is executed immediately after the operation of the sequence program is finished and a second mode in which the execution time of the sequence program is set to a predetermined time or more.

In the second mode, the control unit 400 determines the determination unit 3
When the result of the determination of 00 is affirmative, the arithmetic means 100 is instructed to execute the next arithmetic operation of the sequence program in synchronism with the time when the constant time is measured by the timer means 200.
When the determination result of the determination means 300 is negative in the mode or in the first mode, the arithmetic means 100 is instructed to execute the next operation of the sequence program in synchronization with the end time of the operation of the sequence program.

 FIG. 2 shows a concrete circuit configuration of the embodiment of the present invention.

In FIG. 2, a central processing unit (CPU) 1, a memory 2 and an input / output (I / O) interface 3 which mainly constitute the programmable controller 1000 are connected to an internal bus 4, and a mode switch 6 and a timer 5 are connected to the CPU 1. It is connected to the. The CPU 1 executes the sequence program and transmits the execution result to the control target device 500 via the I / O interface 3 so that the control target device 5
00 is controlled. The CPU1 operates as a calculation means, a judgment means and a control means. Memory 2 is control target device 500
It has a contact memory area for temporarily storing the information signal received from, and a sequence program memory area called a loader for temporarily storing the sequence program input from the program input device 8. The mode switch 6 selectively inputs the first mode in which the next sequence program is executed immediately after the completion of the sequence program and the second mode in which the sequence program is executed for a predetermined time or more in the present invention, as in the conventional case. The mode switch 6 operates as a mode instructing means. The timer 5 repeatedly counts a fixed time that determines the start timing of execution of the sequence program in the fifth mode. The timer 5 corresponds to the time measuring means.

The operation of such a circuit will be described with reference to the flowchart of FIG.

FIG. 3 shows a control procedure for one execution of the sequence program executed by the CPU 1 shown in FIG.

In FIG. 3, the CPU 1 reads a sequence program from the memory 2 and executes a sequence instruction defined in the sequence program to perform arithmetic processing (steps in FIG. 3).
S1). The execution processing of the sequence program occupies a large proportion in one calculation processing time (referred to as scan time) of the CPU1, and one processing is executed depending on the size of the sequence program and the type of the sequence instruction defined in the sequence program. Time varies slightly. When the sequence program is executed, the transmission information from the controlled device 500 stored in the contact memory area in the memory 2 is used. Information calculated as a result of execution of the sequence program and transmitted to the controlled device 500 is also stored in the contact memory area.

Next, the CPU 1 reads the above transmission information in the contact memory area and controls the device to be controlled 500 via the I / O interface 3.
Transfer to. Further, the CPU 1 writes the information signal received from the controlled device 500 in the contact memory 2 (step S2 in FIG. 3). The input / output processing and the input / output response time (speed) in step S2 also change depending on the magnitude of the scan time.

Then, the mode designated by the mode switch 6 is identified by checking the level state of the mode switch 6 in the procedure of step S3 in FIG. For example, when the mode switch 6 is on, it is determined that the execution mode of the sequence program for a certain time or more, that is, the second mode, and waits for the timer 5 started by the previous scan processing to finish measuring time (step S3 in FIG. 3). → S4 ~ S4).

In response to the timing of the timer 5 being completed, the timer 5 is restarted for the next scanning process and one scanning process is completed (steps S4 → S5 in FIG. 3).

On the other hand, the level of the mode switch 6 is off,
When the same processing mode (first mode) as in the conventional example is instructed, this control procedure is ended and one scanning process is ended. Hereinafter, the above procedure is repeatedly executed by the CPU 1.

In this way, when the second mode is instructed by the mode switch 6, the next sequence program is not executed until a certain time has elapsed, and the scan time of the substantial sequence program is increased to a specific time. Be raised. FIG. 4 shows the relationship between the capacity (size) of the sequence program and the scan time in the embodiment of the present invention. When the mode switch 6 is on, the program capacity w
The following shows that the scan time time is fixed to T. In the present embodiment, the time measured by the timer 5 is a fixed value, but the time measured by the timer 5 is variably set to adjust the operation time of the sequence program in correspondence with the response time of the controlled device. Will also be possible. In this case, it is preferable to instruct and input the time measured by the timer 5 from the loader 8.

〔The invention's effect〕

As described above, in the present invention, it is possible to select the mode between the case of connecting to the controlled device having a quick response and the case of connecting to the controlled device having a slow response. There is no need to change the design specifications of the programmable controller according to the response speed. As a result, the device can be generalized, and standardization of parts can contribute to reduction of manufacturing cost.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of the embodiment of the present invention, FIG. 2 is a block diagram showing a concrete circuit configuration of the embodiment of the present invention, and FIG. 3 is an internal process at the time of executing a scan of the embodiment of the present invention. FIG. 4 is an explanatory diagram showing the relationship between the program capacity and scan time in the embodiment of the present invention. 1 ... CPU, 2 ... memory, 3 ... I / O interface, 4 ... internal bus, 5 ... timer, 6 ... mode switch, 8 ... loader.

Claims (1)

(57) [Claims] 1. A mode for selectively instructing a first mode in which the next operation of the sequence program is executed immediately after the completion of the operation of the sequence program and a second mode in which the execution time of the sequence program is set to a predetermined time or more. Instructing means, arithmetic means for executing the arithmetic operation of the sequence program in response to an external instruction, and in the second mode instructed by the mode instructing means, in synchronization with the operation start time point of the sequence program by the arithmetic means. Started, and a clocking means for clocking the constant time, and a determination means for determining whether or not the one-time operation execution time of the sequence program is shorter than the constant time, based on the clocking result of the clocking means, In the second mode, if the determination result of the determination means is a positive determination, In the case where the operation means is instructed to execute the next operation of the sequence program in synchronism with the time when a certain period of time is measured, and the result of the determination means in the second mode is negative, the sequence program A programmable controller comprising: control means for instructing the arithmetic means to execute the next arithmetic operation of the sequence program in synchronization with the time when the arithmetic operation ends.