JPS63247805A - Measurement system for program processing time of digital controller - Google Patents

Abstract

PURPOSE:To easily calculate a start cycle by obtaining the maximum processing time of a control program under the set processing conditions as soon as the processing conditions for control arithmetic are changed. CONSTITUTION:An input part 1 which reads the state of an external contact 2 and an output part 8 are connected to a digital controller 3 of a program processing time measurement system. The controller 3 consists of an arithmetic part 4, a program memory 5, a data memory 6, and an elapsed time measuring timer 7. Furthermore a programming panel 12 is added to change data and an interface part 11 set between the panel 12 and the part 3. When the processing conditions of a control program are changed, the arithmetic data is changed by an on-line system by means of the tools like the panel 12, etc. Then the count value of the timer 7 is repetitively read out and the maximum processing time is obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a program processing time measurement method for a digital control device in which the processing time of a control program is calculated based on the count value of a timer for measuring elapsed time. Regarding the method.

[Conventional technology]

FIG. 3 is a block connection diagram showing a digital control device for implementing the conventional program processing time measurement method disclosed in, for example, Japanese Patent Laid-Open No. 59-221710. In the figure, 1 is an input section, and external Read the state of contact 2. 3
is a digital control device, and has a calculation section 4. Program memory as a control content storage unit5. Each of them includes a data memory 6 as a calculation data storage section and an elapsed time measuring timer T that measures elapsed time which is the processing time of the control program. 8 is an output section, and 9 is a controlled object.

Next, the operation will be explained according to a flowchart showing the processing operation of the digital control device 3 shown in FIG.

First, the arithmetic unit 4 executes the process of outputting the start command, and then the input unit 1 outputs the necessary external data.
The operating data of the external tab contact 2 is read and stored in the data memory 6, and the address of the program memory 5 is initialized (step 5T13). Next, the calculation unit 4 executes control calculations corresponding to the contents of the control program (step 8T14). After the execution of this arithmetic processing is completed, the count value of the elapsed time measuring timer 7 is read out, and the elapsed time data T is stored in the data memory 6. Next, by reading this stored content from the data memory 6, the program processing time can be measured (step 8'l'15). Note that the above control operation is to execute a sequence program, and most of this sequence program performs logical operations and there are almost no branch instructions, so the state of the input signal input to input section 1 is There is almost no effect on control program processing time.

[Problem that the invention seeks to solve]

The conventional program processing time measurement method for digital control devices is performed as described above, so it can be applied to programs where the processing time does not fluctuate, such as sequence control programs. However, in general digital control programs, Since digital data and analog data are mixed as input signals, the contents of the control calculation will change depending on the state of these input signals, and as a result, the program processing time will also change. However, there were problems such as the need to set input signals so that the processing time for control calculations was maximized.

This invention was made to solve the above problems, and is a digital control device that can easily determine the maximum processing time of a control program within set processing conditions from calculation data such as input signals. The purpose of this study is to obtain a method for measuring program processing time.

[Means for solving problems]

The program processing time measurement method for a digital control device according to the present invention calculates the processing time of a control program from the count value of a timer for measuring elapsed time.
During the execution of the above control program, if the input data used for the above control calculations is changed, the processing conditions will be changed according to the input section and output section, and the maximum processing It was designed to ask for time.

[For production]

Changing the processing conditions of the control program in this invention is as follows:
This is done by changing calculation data online using a tool such as a programming panel, and the maximum processing time is determined by repeatedly reading the count value of a timer for measuring elapsed time.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, 10 is an analog signal such as voltage, which is one of the input signals, 12 is a programming panel for changing data, and 1) is an interface between the arithmetic control section 3 and the programming panel 12. In addition, 1 to 9
is exactly the same as that shown in Figure 3.

Friend, FIG. 2 is a flowchart of the execution processing operation of the digital i# device to which the program processing time measuring method according to the present invention is applied, and steps s 'i' 13 to 15 are exactly the same processing as shown in FIG. 4. be.

Further, steps 8T16 and 17 are processes for determining the maximum value of the program processing time, and step 5T18 is a process for changing calculation data according to instructions from the programming panel 12.

Next, the operation will be explained. For example, calculation data X1
For , If it is difficult to obtain the condition tl>tB>tB in the normal control state, use the programming panel 12 to set tl>tB.
>ts 'x Data t1+t2+t8 that satisfies
It is set in the data memory 6 as shown in step 5T19. Then run the timer start command,
The elapsed time measurement timer 70 counts are started in step 5T13). In this state, the control calculation is executed in step 5T14). Immediately after this execution, the elapsed time data T read from the elapsed time measurement timer 7 is converted into the calculated data. Maximum processing time Tm stored in data memory 6 before change
Step 5T16) to determine whether it is larger than ax.
If it is determined that the elapsed time data T is large, the elapsed time data T is updated as the maximum processing time T, max, and this is stored in the data memory 6 (step 8T17). Thereafter, in the same manner, other calculation data t41 t5, . . . tn can be set to a certain value on the programming panel 12 to determine the program processing time T.

In this way, the maximum processing time Tmax of the program under various set conditions can be determined.

In the above embodiment, the processing conditions are changed by changing the calculation data on the programming panel 12, but the input section 1. By connecting a plant simulator to the output unit 8 and changing the state of the plant simulator, it is also possible to change the processing conditions of step 5T14 of the control calculation.

〔Effect of the invention〕

As described above, according to the present invention, the maximum processing time of the control program under the set conditions can be determined at the same time as the processing conditions of the control calculation are changed. It is possible to easily determine the activation period (sampling time) that does not disturb the data, and it has the advantage of being able to respond to changes in control program processing time due to input signals containing a mixture of digital data and analog data.

[Brief explanation of drawings]

FIG. 1 is a block connection diagram of a digital control device implementing a program processing time measurement method according to an embodiment of the present invention, FIG. 2 is a 70-chart showing program processing operations in the digital control device, and FIG. 3 is a conventional one. FIG. 4 is a block connection diagram of the digital control device of FIG. 4, and a flowchart showing program processing operations in the digital control device of FIG. 3 is a digital control device, 7 is a timer for measuring elapsed time,
12 is the programming panel. In addition, in the drawings, the same reference numerals indicate the same parts, or ° indicates corresponding parts. Patent Applicant Mitsubishi Electric Corporation No. 1ryJ No. 3 Sen No. 2 Figure 4

Claims (2)

[Claims] (1) By executing the timer start command, the counter of the timer for measuring elapsed time is started, and after the execution of control calculations in the calculation section is completed, the value of the above count is read out and the processing time of the control program is calculated. In the program processing time measurement method, the processing conditions are changed by changing the input data used for the control calculations while the control program is running, and the maximum processing time is determined under the set processing conditions. A method for measuring program processing time of a digital control device, characterized by: (2) A method for measuring program processing time of a digital control device according to claim 1, wherein input data is arbitrarily changed by instructions from a programming panel.