JP4440172B2 - Programmable controller - Google Patents

Description

  The present invention relates to a programmable controller having a function of expanding and executing a compressed program.

  A programmable controller (hereinafter also referred to as PLC) includes an arithmetic processing unit (CPU), a memory, communication means, and the like. A program is stored in the memory in advance through communication means by a programming tool or the like, and the CPU executes the program at the time of executing the calculation. Arithmetic processing is performed while reading from the memory. The PLC is originally executed by making a hardware relay circuit into a software program, and may be used as a safety device such as a stop signal output for the sensor switch input. High-speed program processing that is close to the relay circuit is required.

  The PLC is used for various equipment control and complex control, and the program may be automatically converted and generated by a visual programming tool such as a function block diagram. For this reason, programs for processing the PLC have been enlarged. However, such a complicated and large-capacity program is often divided into several programs for each function.

  As described above, in the PLC, it is required to process a large-capacity program at a high speed, but on the other hand, high manufacturing cost due to an increase in memory capacity must be avoided. Therefore, it is conceivable to compress a large-capacity program and mount it in the PLC. However, if the program is stored in a memory directly accessed by the CPU, the time required for the expansion process must be taken into consideration. The program processing speed cannot be improved.

  Therefore, in Patent Document 1, when a program load instruction is issued from a CPU in a microcomputer, an execution program compressed from a ROM is sent to a processing unit in a necessary amount, and is expanded and processed by the processing unit. The execution program is stored in the RAM, and the CPU performs processing according to the program stored in the RAM. If the continuation of the program being executed continues to the processing not yet stored in the RAM, the CPU stores it in the ROM again. A command for loading the compressed execution program to the RAM is issued to the ROM and the processing unit.

Japanese Patent Laid-Open No. 10-133880 (page 3-4, FIG. 1)

  However, in the conventional technique disclosed in Patent Document 1, the CPU issues an instruction to expand the program to the machining unit after completion of the arithmetic processing of the expanded portion of the program, and waits for the completion of the program expansion by the machining unit. After that, the arithmetic processing is resumed. For this reason, Patent Document 1 has a problem that, in addition to the original program calculation processing time, a waiting time is required while the program is being developed, and the time required for executing the program as a whole is increased.

  The present invention has been made in view of the above, and an object of the present invention is to obtain a programmable controller capable of performing arithmetic processing on a compressed program without extending the arithmetic processing time as a whole.

  In order to solve the above-described problems and achieve the object, a programmable controller according to the present invention includes a decompression unit that decompresses a plurality of compressed programs, and a CPU that sequentially executes the plurality of programs decompressed by the decompression unit. The expansion means expands a program to be executed next in parallel with the program execution by the CPU.

  According to the present invention, since the processing for expanding the program by the expansion means and the processing for executing the program by the CPU are performed in parallel, there is no waiting time due to expansion on the CPU side. There is an effect that the time can be shortened.

  Embodiments of a programmable controller according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

  FIG. 1 shows a programmable controller (PLC) according to an embodiment of the present invention. The PLC includes a CPU 1 that performs arithmetic processing of a program, compression means 2 that executes compression processing of programs, data, etc., decompression means 3 that executes decompression processing of programs, data, etc., a programming tool (not shown), etc. The communication means 4 for performing the above communication and the memory (primary memory 5 and secondary memory 6) for storing the program are provided.

  A memory for storing programs and data includes a primary memory 5 and a secondary memory 6. The secondary memory 6 may include an external memory that can be expanded and replaced. A program received from the programming tool or the like via the communication means 4 is stored in the secondary memory 6. A program that can be processed by the CPU 1 is stored in the primary memory 5.

  The expansion means 3 and the compression means 2 are characterized in that they can operate independently of the CPU 1. As a result, the program can be expanded and compressed in parallel without affecting the arithmetic processing time of the CPU 1, and the program stored in the memory can be read and the program stored in the memory without going through the CPU 1. Can do.

  The name of the data is given to the program and data transmitted to the PLC from a programming tool or the like, and the type of data can be distinguished by the name. Therefore, for data that is expected to increase in data size such as text information created by a program or user, the data type is registered in advance in the PLC, and the PLC does not increase in size depending on the data type. It can be distinguished. The type of data at this time can be registered by a parameter or the like arbitrarily set by the user when creating the program, and is written in the secondary memory 6 together with the program, for example.

  When the communication unit 4 transmits / receives a program or data to / from a programming tool or other device, the communication unit 4 identifies whether the counterpart device has an expansion or compression function equivalent to the expansion unit 3 or the compression unit 2. As a result, when the communication partner device has a decompression function, the program or data that has been compressed is transmitted, and when the communication partner device has a compression function, Then, the other device is requested to transmit the compressed program and data.

  A plurality of programs and data can be stored in the memory (primary memory 5 and secondary memory 6). When there are a plurality of programs, their execution order is set as a parameter. The parameter is setting information necessary for the operation of the PLC, transmitted together with the program by a programming tool or the like, and stored in the PLC memory (primary memory 5 and / or secondary memory 6) like other programs and data. The

  First, the operation of the PLC configured as described above when the PLC transmits / receives a program or data to / from a programming tool or the like will be described.

  When the PLC receives data from a programming tool or other device via the communication unit 4, the PLC determines whether the data is a program or a kind of data to be compressed by identifying the name of the data by a parameter. If it is a program or data to be compressed, it is compressed by the compression means 2 and then stored in the secondary memory 6. Data that is not the type to be compressed is stored in the secondary memory 6 as it is. When a program or data that has already been compressed is received by a programming tool or other device having a data compression function equivalent to the compression means 2, it is stored in the secondary memory 6 as it is.

  On the other hand, when a program or data is transmitted from the PLC to a programming tool or other device, the compressed program and data are expanded by the expansion means 3 and transmitted after returning to the state before compression. Note that when the other programming tool or other device to be transmitted has a compressed data expansion function equivalent to the expansion means 3, the compressed data is transmitted.

  Next, the operation when the compressed program stored in the secondary memory 6 is expanded and executed will be described. In this case, the description will be made assuming that the primary memory 5 has a capacity for storing two programs.

  The decompressing means 3 refers to the parameters stored in the secondary memory 6 to confirm the execution order of the programs, and among the plurality of programs compressed and stored in the secondary memory 6, the first program (first program) 1 program) is read out and expanded and stored in the primary memory 5. When the expansion is completed, the expansion means 3 transmits to the CPU 1 an expansion completion notification indicating that the first program has been expanded, and receives the execution completion notification from the CPU 1 for the second program (second program). Regardless of whether or not the first program (first program) is continuously developed and stored in the primary memory 5. When the expansion process of the second program is completed, the expansion unit 3 transmits to the CPU 1 an expansion completion notification indicating that the expansion of the second program has been completed.

  When the CPU 1 receives the expansion completion notification, the CPU 1 executes arithmetic processing of the first program expanded in the primary memory 5. When the execution of the arithmetic processing of the first program is completed, the CPU 1 transmits an execution completion notification indicating that the execution of the first program is completed to the expansion means 3. Further, when the expansion completion notification indicating that the expansion of the second program has been completed is sent from the expansion means 3, the CPU 1 continues to execute the arithmetic processing of the second program expanded in the primary memory 5. To do.

  Upon receiving the first program execution completion notice, the expansion means 3 expands the next program (third program) stored in the secondary memory 6 and overwrites the first program on the primary memory 5. To do. When the expansion is completed, the expansion unit 3 transmits a expansion completion notification indicating that the expansion of the third program is completed to the CPU 1.

  When the execution of the second program is completed, the CPU 1 transmits an execution completion notification indicating that the execution of the second program is completed to the expansion unit 3. Upon receiving the notification of completion of execution of the second program, the expansion means 3 expands the program to be executed next (fourth program), overwrites the second program on the primary memory 5, and further adds the fourth program. The CPU 1 is notified of a development completion notification indicating that the program development has been completed.

  When the CPU 1 notifies the completion of the execution of the second program and then receives the notification of the completion of development from the expansion means 3, it executes the arithmetic processing of the third program, and when it completes, the CPU 1 sends an execution completion notification indicating that fact. Notify Subsequently, when a notification of expansion completion for the fourth program has been received, arithmetic processing is executed for the fourth program. Thereafter, by repeating this procedure, arithmetic processing is executed sequentially while replacing a plurality of programs within the limited capacity of the primary memory 5.

  In general, in a PLC, when a series of programs is executed to the end, the same series of programs is often repeatedly executed from the beginning. In such a case, the expansion means 3 expands the first first program while the CPU 1 is executing the last program. In such a case, in the second and subsequent rounds, when the expansion means 3 expands the second program (second program), it notifies the CPU 1 of the completion of execution of the last program and then executes the expansion processing.

  As described above, according to the present embodiment, the expansion means 3 expands the program to be executed next in parallel with the execution of the program in the CPU 1, so there is no waiting time due to expansion on the CPU 1 side. As a result, the program operation processing time as a whole can be shortened, and high-speed program processing becomes possible.

  In the field where the PLC is used, the user often changes a part of the program for adjustment after executing the program, but this PLC changes a part of the program during the execution of a series of programs. When doing so, it is only necessary to rewrite the program stored in the secondary memory 6. Therefore, after the program is rewritten, the program is expanded by the expansion means 3 and stored in the primary memory 5, whereby the program on the primary memory 5 executed by the CPU 3 is automatically replaced with the changed program. .

  As described above, the programmable controller according to the present invention is useful as a programmable controller having a function of expanding and executing a compressed program.

It is a functional block diagram which shows an example of the programmable controller concerning this invention. It is a sequence diagram for demonstrating the operation timing of CPU at the time of program execution, and an expansion | deployment means.

Explanation of symbols

1 CPU
2 Compression means 3 Expansion means 4 Communication means 5 Primary memory 6 Secondary memory

Claims (2)

A first memory for storing a plurality of compressed programs;
A second memory capable of storing N (N ≧ 2) programs after expansion;
Expansion means operable to be independent of the CPU, sequentially expanding the compressed program stored in the first memory, and storing the expanded program in the second memory ;
A CPU for sequentially executing the programs stored in the second memory ;
With
The expansion means notifies the CPU of the completion of expansion every time the expansion and storage of the program from the first memory to the second memory is completed,
When the CPU receives a notification of expansion completion from the expansion means, the CPU executes the program stored in the second memory after completion of the execution of the previous program. Inform the means,
The expansion means continuously expands the program from the first memory to the second memory from the first program to the Nth program regardless of the reception of completion of execution from the CPU. As for the program, a programmable controller that executes expansion processing by overwriting the storage area of the program that has received completion of execution of the CPU among the programs stored in the second memory . The expansion means, when expansion storage from the first memory to the second memory for the last program is completed, expands the first program again and overwrites it in the second memory. Item 12. The programmable controller according to item 1.

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