JPS60241104A - Arithmetic method of digital controller - Google Patents

Abstract

PURPOSE:To perform both the sequence processing and the numerical processing at a high speed and with high efficiency by executing the sequence processing only when a sequence data input signal has a change and otherwise carrying out the numerical processing. CONSTITUTION:In an arithmetic method of the digital controller for both the sequence processing and the numerical processing, the ON/OFF signals I1-In are supplied to a signal change discriminating circuit 1 for a switch, etc. supplied for the sequence processing. Then the changes of these signals are detected, and this detection output is supplied to an instruction switch circuit 2. The circuit 2 decide to start a sequence instruction circuit 3 or a numerical processing instruction circuit 4. The result of this decision is supplied to the corresponding circuit. The output signals of both circuits 3 and 4 are supplied to an arithmetic circuit 5 for execution of an operation. The sequence processing is carried out only when a sequance data input signal has a change. Thus it is possible to perform both sequence and numerical processings at a high speed through the same arithmetic circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a calculation method for a digital control device having both sequence processing and numerical processing processing functions.

[Background of the invention]

A programmable controller (hereinafter abbreviated as PC) is a control device that performs sequence processing by program.
There is. Since PCs perform sequence processing through programs, they have the advantage of being easier to handle than conventional relay circuits, and have come to be widely used. As the field of application of PCs expands, it becomes necessary not only to have a sequence processing function that simply handles on and off signals, but also to have a device that can simultaneously perform both sequence processing and numerical processing that handles arithmetic operations. Since these processes are described as two separate flows, in order to execute them with the same processing device, it is necessary to execute the sequence processing and the numerical processing in a time-sharing manner. For this purpose, for example, conventionally, a method has been considered in which numerical processing is performed after a series of sequence processing is performed, and when the numerical processing is completed, the sequence processing is performed again. Alternatively, you can insert an instruction to move from sequence processing to numerical processing, or vice versa, somewhere in a program that executes sequence processing or numerical processing, and each time this command is issued, the sequence processing changes to numerical processing, and vice versa. A method has been considered in which processing is executed in sequence, and sequence processing and numerical processing are performed alternately.

However, these methods have the following problems. In other words, in the former method, when there is a lot of numerical processing, the execution time of numerical processing becomes long, so it takes time until the next sequence processing is executed, and there is a problem that the actual execution time of sequence processing becomes longer. . On the other hand, the latter method not only makes the program complicated because it changes the processing from sequence processing to numerical processing or vice versa, but also, for example, if there is a timer operation in the sequence processing, When attempting to perform numerical processing, it is necessary to manage timers separately from this processing, which poses a problem in that the apparatus becomes complicated.

[Purpose of the invention]

The present invention has been made to address the above-mentioned drawbacks, and its purpose is to provide a calculation method for a digital control device that can perform sequence processing and numerical processing efficiently and at high speed.

[Summary of the invention]

A feature of the present invention is that sequence processing is executed only when the sequence data input signal changes, and numerical processing operations for performing arithmetic operations including logical operations are executed at other times. The purpose is to substantially reduce the number of processing times and to be able to execute sequence processing and numerical processing at high speed.

[Embodiments of the invention]

FIG. 1 shows an embodiment of the present invention.

In FIG. 1, reference numerals II to D indicate on/off signals of switches, etc., input for sequence processing, which are input to the data processing device. In addition, signals 11 to ■ are not only signals from outside the digital control device, but also perform a certain sequence operation, that is, a logical operation from the on/off state, and if necessary for the operation that outputs the result, the signal is calculated within the digital control device. It may be a signal that Signals 11-I are input to the signal change determination circuit 1, and changes in signals 11-I are detected. The output of the signal change discrimination circuit 1 is sent to the command switching circuit 2.
is input. The instruction switching circuit 2 is the sequence instruction circuit 3.
The first step is to decide which one of the numerical processing command circuits 4 to start. The result is input to the sequence instruction circuit 3 or the numerical processing instruction circuit 4. The output signals of the sequence instruction circuit 3 and the numerical processing instruction circuit 4 are input to the arithmetic circuit 5.
The operation is executed. Note that the numerical processing referred to here includes not only simple numerical calculations but also accompanying logical calculations and conditional judgments, if necessary.

This operation will be explained using the operation waveforms shown in FIG.

Signal 11-1. If any one of them changes, it is detected by the signal change determination circuit I. The signal change discrimination circuit is shown in Figure 2 (
A pulse-like signal as shown in a) is output. On, off signals 11-1. When a pulse signal as shown in FIG. 2(a) is input to the command switching circuit 2 due to a change in the sequence data input state, that is, a change in the sequence data input state, the command switching circuit 2 issues an activation command to the sequence command circuit 3. When the sequence command circuit 3 is activated and a sequence command signal is input to the arithmetic circuit 5, the arithmetic circuit 5 stops executing numerical processing, stores the current data, etc. in the built-in memory, and executes the sequence command. When a series of sequence processing is completed, an end signal is sent to the command switching circuit 2 from the sequence command port #63. The instruction switching circuit 2 issues a start instruction to the numerical processing instruction circuit 4. 'When a numerical processing command is input to the arithmetic circuit 5, numerical processing is started from the state immediately before executing the previous sequence process, and the arithmetic circuit 5 operates according to the numerical processing command.

FIGS. 2(b) and 2(C) show the instruction execution status in the arithmetic circuit 5. FIG. FIG. 2(b) shows how sequence processing is performed, and FIG. 2(C) shows how numerical processing is performed. From Figure 2, the same figure (a
It can be seen that the sequence processing is executed every time the pulse signal obtained when the on/off signal changes as shown in ) is output. At this time, sequence processing may start from the beginning of the sequence processing instruction, or if it is known which part of the sequence instruction should be executed from the current status of sequence processing, only that part may be executed. You may also do so. In the latter case, there is no need to read all of the sequence data input signals II to II required for sequence processing, and there is an advantage that the time required for sequence processing can be shortened.

FIG. 3 is an explanatory diagram of the operation in the case where there is a process in which calculations need to be performed at regular intervals in order to perform feedback control or the like in the numerical processing. FIG. 3 (a) shows the output signal of the signal change discrimination circuit 1, (b) shows the state where sequence processing is being performed, (C) shows the state where numerical processing is performed in a constant cycle, and (ψ is This shows a state in which numerical processing other than the above is being executed. When a pulse signal as shown in Fig. 3(a) is output, sequence processing is executed as shown in Fig. 3(b). If the numerical processing in C) that is processed at a constant cycle also exists during sequence processing, the sequence processing is interrupted and priority is given to the numerical processing at a constant cycle.

The activation of the constant period numerical processing is managed by a timer within the arithmetic circuit 5. If neither sequence processing nor fixed period numerical processing is being executed, other numerical processing is executed as shown in FIG. 3(d).

Calculations are performed as described above, but since sequence processing is executed only when the sequence data input signal changes, the number of sequence processing executions is reduced, making it possible to efficiently and quickly perform sequence processing and numerical processing in the same operation. It can be implemented by a circuit.

FIG. 4 shows a detailed circuit example for concretely implementing the embodiment shown in FIG. Monostable multivibrators 11 to 15 are input signal components 1 to I on the sequence.

is input, and outputs a pulse-like signal when the input signal changes. The outputs of the monostable multivibrators 11 to 15 are input to the OR circuit 16, and further to the OR circuit 1.
The output of 6 is input to the interrupt terminal of microprocessor 17. The input/output signals of the microprocessor 17 are connected to the bus 23.
A sequence input circuit 18, a sequence output circuit 19, and an input/output circuit 2 for inputting and outputting numerical signals through the
0, connected to memory 21.22.

- In the configuration shown in Figure 4, sequence data input signal 1
When any one of 1 to 1 changes, the change is detected by the monostable multivibrators 11 to 15, and is input to the interrupt terminal of the microprocessor 17 via the OR circuit 16.

When the microprocessor 17 receives an interrupt signal, it executes sequence processing, so it stops numerical processing and inputs the current state into the memory 21. Next, the sequence instructions are read from memory 22 and sequence processing is executed. The sequence data signals 1 to 1 are read through the input circuit 18, and the result of sequence processing is sent to the output circuit 19.
Output signals 01~0. is output as When the sequence processing is completed, the state returns to the state before the sequence processing was performed, and numerical processing is performed according to instructions from the memory 22. Numerical values necessary for calculation are output to external equipment through the input/output circuit 20.

FIG. 5 shows a flowchart for performing the above processing. FIG. 5(a) is a flowchart for executing numerical processing. Although not shown in FIG. 5A, the data is input/output to the data line memory 21 or the input/output circuit 20 necessary for calculation. No. 511(b) shows a flowchart when an interrupt signal is input to the interrupt terminal of the microprocessor 17 and sequence processing is executed. In this case, as explained earlier, from the results of the sequence operations so far,
If you know which part of a sequence instruction should be executed, you can execute only that part. At this time, the sequence data input signal ■! It is not necessary to include all of ~, but only the necessary parts. Furthermore, it is only necessary to change only the necessary signals without outputting all the calculation results as outputs 01 to 01.

〔Effect of the invention〕

As described above, according to the present invention, the input signal of sequence data changes and sequence processing is executed only where sequence processing is necessary, so the number of sequence processings is reduced. As a result, the time required for sequence calculations can be shortened, and more time can be devoted to numerical processing.As a result, numerical processing and sequence processing can be performed efficiently and at high speed on the same arithmetic circuit. moreover,
Since a high-speed data processing device can be configured with one arithmetic circuit, there is also an economical effect that the device becomes cheaper.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 and 5 are diagrams explaining the operation of the circuit shown in FIG. 4. 1... Signal change determination circuit, 2... Command switching circuit, 3
...Sequence instruction circuit, 4...Numerical processing instruction circuit, 52m +l#M- 1st page (t)

Claims (1)

[Scope of Claims] 1. A first storage means for storing an instruction group of numerical processing instructions for performing arithmetic operations including logical operations and sequence processing instructions for performing logical operations for processing on and off signals; a first output means for exchanging numerical data with an external device; a second output means for exchanging sequence data with the external device; and a numerical processing operation or a sequence processing operation according to instructions from the first storage circuit. arithmetic means to execute;
and second storage means for storing data calculated by the calculation means, wherein the calculation means has an interrupt processing function for changing the processing order of instructions from the first storage means. , when the on/off state change signal of the signal input as sequence data is input as an interrupt signal, the numerical processing operation is stopped and the sequence processing operation is executed, and after the sequence processing is completed, the data before the sequence processing starts is A calculation method for a digital control device, characterized by performing numerical processing calculations from a state. 2. In claim 1, when there is a numerical processing instruction that performs calculations at a constant cycle, the calculation means executes the numerical processing instruction with priority at a constant cycle even during sequence processing calculations. A calculation method for a digital control device characterized by: