JP3207333B2 - Programmable controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a programmable controller capable of changing a user program during execution of the user program.

[0002]

2. Description of the Related Art In a programmable controller having a user program built in a rewritable memory,
When writing a program to the user program memory,
Since the program is temporarily stopped, it is necessary to restore the change in the condition caused by stopping the program other than the program writing time, and it takes a lot of time to change the program.

[0003]

When the user program is changed during the execution of the programmable controller, the rewritable memory is sequentially written from the programming console. Everything up to the address is written and meaningful. Therefore, if the CPU does not change the instruction at the last address of the user program immediately after the execution, the program execution may be hindered. Thus, an object of the present invention is to execute a user program while executing the user program.
A programmable controller capable of performing a change is provided.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has the following structure. That is, in the programmable controller, first, the memory is divided into a program execution portion that requires instantaneous switching of the user program and a non-execution portion, that is, a modification portion that plays an auxiliary role of the program.

Second, when a user program is rewritten, a program to be newly written is replaced by a program executing section and a program modifying section in which the program is originally written.
The program is written alternately, and the program execution section is written first, and then the program modification section is written. As a specific configuration, a user program execution unit storage unit that stores an execution unit of a user program, a user program modification unit storage unit that stores a modification unit of the user program, and an execution unit start address of the user program are stored. User program execution section start address storage means, user program execution section last address storage means for storing the execution section address of the user program, and program instruction execution for repeating the operation of sequentially executing instructions at each address up to the last address of the user program Means.

[0006]

According to the above solution, the following operation can be achieved. (A) When rewriting a user program, a new program execution unit is sequentially written into the currently executing program modification unit, and writing to the last address is completed. (B) After the writing is completed, the programming console notifies the CPU of the programmable controller that the execution unit is to be switched, and upon receiving the notification, the CPU executes the last address of the old program execution unit and then switches to the new program. (C) After the switching is completed, the CPU notifies the console that the switching has been performed to the program execution unit, and thereafter executes the new program. As a result, while the CPU is executing the new program execution unit, the console writes the new program modification unit to the execution unit of the old program that is no longer needed, and ends the console. Further, the present invention will be described in detail with reference to the drawings.

[0007]

FIG. 1 shows a programmable controller system shown to facilitate understanding of the present invention, wherein 1 is a programmable controller, 2 is an input / output unit, 3 is a connection cable, and 4 is a programming console. is there. That is, the programmable controller 1
Is a ROM 12 in which a system program is written, a user program memory 16 in which a user program is written, a CPU 11 which processes the user program in accordance with the system program, a system memory 14 used for the processing, and the transfer of input data and output data to an external device. And an input / output unit 2 and the like. They are C
It is connected by the bus 13 of the PU 11. An interface 15 is connected to the bus 13, and the interface 1
The programming console 4 is connected to the connection console 3 via the connection cable 5.

FIG. 2 shows the contents of the user program memory and the system memory according to the present invention separately before and after writing the user program. 141 and 142 are system memories, 161 and 162 are user program memories, and D is a division line. is there. In FIG. 2, the user program memory 1
Prior to writing, the content of 61 is divided into an execution part and a decoration part by a division line D. Here, A1 indicates a pre-writing execution section, B1 indicates a pre-writing modification section, and C11 and C12 indicate unused areas before writing.

An instruction code to be executed by the CPU is written in the execution unit A1 before writing, and the CPU executes processing according to the instruction code. Information for monitoring the user program on the programming console is written in the pre-writing modification unit B1, and the screen address of the instruction code necessary for displaying the user program on the screen, the name of the operation parameter, and a comment for explaining the program Information is included. Further, between the division line D, unused areas C11 and C12 before writing of the memory are provided so as to be able to cope with an increase in programs. Further, it is apparent that the system memory 141 stores the user program execution unit start address and the user program execution unit end address, and can be referred to when the system program processes the user program.

Here, when the power is turned on in the programmable controller, the system program refers to the contents of the system memory 141 and executes the pre-write execution section A1 sequentially from the user program execution section start address,
An input signal 211 from the outside is read into the programmable controller 1 via the input / output circuit 21 of the input / output unit 2, and an internal operation is performed based on this information. Further, the result is output to the output signal 212 via the input / output circuit 21. C
When the execution address of the PU reaches the final address, the system program terminates the processing of the user program, executes processing required for maintaining the system other than the user program, and then executes the user program again from the beginning. Execute repeatedly. When the user program is checked, the programmable controller 1 operates the programming console 4 to read the information of the pre-writing modification section B1 of the user program through the connection cable 3. Then, based on this information, a programming information screen that is easy for the user to understand is created on the programming console 4, and the execution result can be confirmed.

When a user program is changed according to a user's request, the programming console 4
And starts writing the user program. At this time, the information of the pre-writing decoration part B1 drawn on the programming console 4 is no longer necessary, and the execution A2 after writing of the new program starts writing from the address of the pre-writing decoration part B1 of the old program. . At that time, the CPU 11
Although the execution unit A1 before writing of the old program is executed, writing of the new program uses an interrupt procedure (in this example), and it is necessary to prevent interruption of control to the external circuit. .

When the writing of the new program to the end is completed, the start address of the user program execution unit in the system memory 142 is changed by the interrupt request of the program console. After executing the old user program up to the final address, the system program reads the above-mentioned user program execution section address, finds out that the user program has changed, and starts execution of the new write execution section A2. At that time, the system program notifies the programming console that the execution section start address of the program has been changed,
It can be seen that the pre-write execution unit A1 of the old program has become unused. Thereafter, the programming console starts to write the new user program post-writing modification section B2 to the old program pre-writing execution section A1. In this case, the system program executes writing by an interrupt from the programming console while executing the new program. However, there is no control over the external circuit other than that generated by a change in the user program. After the writing of all the new programs is completed, the user program is checked again. In this case, a request from the programming console is generated, and after writing, a new screen which is drawn on the programming console based on the information of the modification unit B2 and is easy for the user to understand. Is created, and the result of the program execution can be confirmed again.

[0013]

As described above, according to the present invention, the user program can be exchanged during execution of the user program without increasing the user program area, and the start period of the program can be greatly reduced. Equipment can be provided.

[Brief description of the drawings]

FIG. 1 is a system block diagram of a programmable controller.

FIG. 2 is an explanatory diagram showing before and after writing in a user program memory according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Programmable controller 11 CPU 12 ROM 13 Bus 14 System memory 15 Interface 16 User program memory 161 User program memory 162 User program memory 2 I / O unit 3 Connection cable 4 Programming console Part B2 Modified part after writing C11 Unused area before writing C12 Unused area before writing C21 Unused area after writing C22 Unused area after writing D Divided line

Claims (1)

(57) [Claims] 1. A programmable controllerIncorporate
User program can be converted during execution of user program
An execution unit in which the CPU performs real-time processing of the user program.
In addition to dividing into decoration parts that are not executed in real time,
Each time the program is written,, Said repair
A new method to write the execution part to the area where the decoration part was stored
User program that is actually stored in the storage unit as the row unit
Execution unit storage means; Modification part Storage means for storing a user program modifying unit
And a user for storing an execution unit start address of the user program.
User program execution section start address storage means and execution
User program execution section last that stores the section final address
Address storage means and instructions for each address up to the last address of the user program
Instruction execution means that repeats the operation in which
And a step.
Trolla.