JPS62162107A - Program changing method for programmable controller - Google Patents

Abstract

PURPOSE:To attain partial changing process without interrupting execution of a user program by inserting an instruction to jump to the head of a changed program into a specified address of an existing program by single execution of service processing. CONSTITUTION:When changing a program, an [insertion mode] key on a keyboard of a programming console 4 is depressed. Then, the part of a user program to which a new program is inserted is inputted by a program address, and a [place of insertion designation] key is depressed. The process that prepared the inserted program in a buffer D is executed according to operation of a keyboard dividing it into several times of service processing instead of making all process by service processing of one time prescribed by a timer 9. Thus, a maker of the program can prepare the insertion program confirming it throughly without haste.

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to a programmable controller (hereinafter referred to as a PC), and particularly relates to a method of partially changing a user program without interrupting its execution.

<Conventional technology> In a PC, by repeatedly executing a user program,
The new logic of the control output signal group is determined according to the logic changes and history of the control input/output signal group. The shorter the repetition period of the user program execution process, the higher the responsiveness between control input and output signals, and the better control can be performed.

In addition to executing user programs, it also performs service processing such as connecting to peripheral devices such as a programming console, printer, and display device, processing given commands, and exchanging data. It also performs system monitoring processes such as resetting the watchdog timer and checking memory and buses. Furthermore, depending on the model, there are some that exchange data with other PCs.

As shown in FIG. 3, a general PC is configured to repeat user program execution processing, service processing, and other processing in order at high speed. The total one-time processing time (Ti+T2+T3) is called scan time. The execution cycle of the user program, which determines control responsiveness, is determined by this scan time. therefore,
If the service processing time T2 and other processing time T3 are shortened, the scan time will be shortened and control responsiveness will be improved.

In normal operation, the allotted time T2 for the service processing is determined by a timer to be the minimum necessary short constant time. For commands that cannot be completed in one service process, the service process is repeated several times.

In a PC with the above-mentioned prerequisites, when a user program is to be changed while it is being executed, the program in the execution area must be changed in one service process.

If a program is gradually rewritten through multiple service processes, a program that is partially rewritten (the logic does not match, or the flow of logic is interrupted) will be executed, and as a result, the control target may be This can lead to unintended operating conditions, which can be extremely dangerous.

<Problems to be Solved by the Invention> In a normal PC, rewriting of a program cannot be completed in one service process. The time it takes to rewrite a program is considerably longer than the time allotted for service processing, and generally takes more than 30 times the time allotted for service processing.

Therefore, in the past, it was not possible to change the program in parallel with the execution of the user program, and when changing the program, even if it was a simple partial fiW,
It was necessary to temporarily interrupt the execution of the user program. I had to temporarily stop running my PC.

This invention was made in view of the above-mentioned conventional problems, and its purpose is to provide a program that allows partial modification of a program without interrupting the execution of the user program.
The purpose of this invention is to provide a method for changing C programs.

Means for Solving the Problems> Accordingly, in the present invention, the above service processing is intermittently repeated within the allocated time by time-sharing processing, and while the user program is being executed, the change program is stored in the free area of the memory. At the same time, a jump instruction to a predetermined address of the existing program being executed is set at the end of the modified program, and after that, one execution of the above service processing causes the start of the modified program to be moved to the predetermined address of the existing program. The method was to insert a jump instruction to.

<Example> As shown in FIG. 1, a PC according to the present invention has a CPU (
arithmetic processing unit) 1, system program memory 2, system working memory 3, programming console 4, user program memory 5, and data memory 6
, an input circuit 7 , an output circuit 8 , and a timer 9 .

A number of control input signal sources are connected to the input circuit 7. The output circuit 8 has a large number of control output signal relays, to which devices to be controlled are connected. The control input signal group applied to the input circuit 7 is once taken into the data memory 6 and subjected to calculation, and the control output signal group generated in the data memory 6 by the calculation is outputted from the output circuit 8 to the outside. CPU
For example, by repeatedly executing the user program stored in the menu 5, new logical changes of the control output group in accordance with the logical changes of the control input/output signal group and the history are determined.

FIG. 2 shows the operation of the PC to which the present invention is applied. Steps 201 to 204 in FIG. 2 are the aforementioned user program execution processing. In step 201, the control input signal from the input circuit 7 is taken into the data memory 6. In step 202, one instruction of the user program is executed, and in step 203, each instruction is sequentially executed until the END instruction set at the end of the user program is detected. When the user program executes one error in the END command trench, the control output signal of the data memory 6 is transferred to the output circuit 8 in step 204.

When the above user program execution processing is completed once, the timer 9 is started in step 300, and the process moves to the service processing from step 301 onwards. The timer 9 is used to define the allocated time for service processing.

When this timer 9 time amplifies, a timer interrupt occurs at step 40 (shown below), and at this point step 2
01 Return to K and move to user program execution processing.

If service processing is in progress at the time the timer interrupt occurs, a continuation flag is set and the execution status (information for continuing processing) is saved (steps 401-40).
2-403). The set continuation flag is reset in step 302 at the start of the next service process.

In this way.

The user program execution process and the service process are repeated in order.

When changing a program according to this invention, first select the "insert mode" on the keyboard of the programming console 4.
Press the key. Then, the insertion mode display lamp of the console 4 lights up (steps 320→321).

Next, enter the program address in which part of the user program is to insert the new program, and press the "Specify insertion location" key. The address input is displayed on the console 4 and also stored in the insertion point pointer (A) of the system working memory 3 (steps 330, 331, 340).

Next, operate the keyboard of the console 4 to create a buffer (D) K insertion program in the system working memory 3 (steps 330, 331, 332°3).
40). At this time, buffer entry point 7/(B) and program write pointer (C) are used.

The thing to note here is that you can run the insert program into a buffer (
D) The process of creating K is not performed entirely in one service process specified by the timer 9, but is divided into many service processes and is performed in response to keyboard operations. Therefore, there is no need for the program creator to panic, just make sure that the insertion program is correct. Note that the created insertion program can also be checked by time-sharing service processing.

If you create an insertion program in the buffer (D),
Press the "Insert instruction" key. Then, steps 311-31
Process P of 6 is executed. Since the processing P with P may be slightly longer than the allotted time for the service processing specified by timer 9, timer interrupts are first prohibited in step 311, and upon completion of the processing in steps 312 to 315, the process proceeds to step 316. to disable timer interrupts.

In step 312, the address indicated by the pointer (C),
That is, at the end of the buffer (D) insertion program, a jump instruction to the address (ADR+1) obtained by adding 1 to the address ADH indicated by the pointer (A) is written. In step 313, the address AD indicated by the pointer (A) is
A jump instruction to the address indicated by pointer (B), that is, the start address of the inserted program, is written to R (insertion location of the existing program). The relationship between the jump commands described above is illustrated in FIG.

In the next step 314, the insertion indicator lamp of the console 4 is turned on, and in step 315, the insertion mode indicator lamp is turned off.

As a result of writing the jump instruction as described above, in the next user program execution process, the program jumps to the insertion program in the buffer (D) at address ADH, and then jumps back to address (ADH+1) from the end.

In other words, exactly the same control as if the insertion program were inserted at address ADH is performed.

Note that this example is a complete insertion, but if you jump to the inserted program from address X where the existing program is inserted and return to address YK of the existing program, the inserted program will replace the existing program from address X to Y. That means that.

As described above, all of the processing P must be performed in one service processing, and the processing time may exceed the set time of the timer 9. However, the excess time is so small that it hardly becomes a problem.

<Effects of the Invention> As explained in detail above, according to the present invention, the control operation can be continued without interrupting the operation of the PC.
Since the user program can be partially changed, the versatility and flexibility of the PC is further improved.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a PC according to the present invention, Fig. 2 is a flowchart showing the operation of the above-mentioned PC, Fig. 3 is a diagram showing the action of a general PC, and Fig. 4 is an explanatory diagram of an example of program change. be. ■...CPU, 3...System working memory,
4...Programming console, 5...User program memory, 9...Timer.

Claims (1)

[Claims] (1) In a programmable controller that repeats the execution process of a user program and the service process of processing commands from a programming console in sequence at high speed, the user program is executed by time-sharing processing that intermittently repeats the above service process within the allocated time. Along with preparing the program, change it to a free area of memory while running.
A jump instruction to a predetermined address of the existing program being executed is set at the end of the modified program, and then a jump instruction to the beginning of the modified program is set at the predetermined address of the existing program by one execution of the above service process. A method for changing a program in a programmable controller, characterized by inserting a.