JP5503980B2 - SEQUENCE PROGRAM, RECORDING MEDIUM RECORDING SEQUENCE PROGRAM, PROGRAMMABLE CONTROLLER STORING SEQUENCE PROGRAM, SEQUENCE PROGRAM PROTECTION SUPPORT METHOD AND DEVICE IN PROGRAMMABLE CONTROLLER - Google Patents

Description

  The present invention relates to a sequence program that writes a control sequence of a device to be controlled, a recording medium that records such a sequence program, a programmable controller that stores the sequence program, and a sequence program protection support method and apparatus in the programmable controller.

  FIG. 3 shows a configuration of a general programmable controller (PLC) and peripheral devices. The programmable controller 1 temporarily stores the MPU 2 that performs logical operations and arithmetic operations, the system program memory 3 that stores the contents and procedures controlled by the MPU 2, the sequence program memory 4 that stores the sequence programs, and the operation results of the sequence programs. And a peripheral device interface 6 mainly for changing the contents of the sequence program memory.

  The peripheral device 7 is used not only for the purpose of programming a sequence program that is processed by the programmable controller 1, but also for writing the sequence program to the programmable controller 1, reading the sequence program from the programmable controller 1, and checking the operation of the sequence program. The

  FIG. 4 shows a general form of a sequence program displayed on the peripheral device 7. In the peripheral device 7, the sequence program is generally displayed in a ladder symbol format 8 or an instruction word format 9, and the control content is obvious. The peripheral device 7 itself is provided in the form of personal computer application software, and has good availability in terms of price and delivery date.

  It has been proposed to prevent unauthorized duplication of a sequence program stored in a ROM by encryption using an encryption key and decryption using a decryption key (Patent Document 1). A programmable controller having a function of preventing unauthorized stealing of a user program by permitting reading of the user program from the user memory by collating the input keyword with a registered keyword has been proposed (Patent Document 2). ). Further, it has been proposed that a sequence program stored in the program memory is prohibited from being read by providing a read prohibition processing unit that prohibits reading from the service interface to an external device (Patent Document 3). . Furthermore, it has been proposed to protect the flash memory by making it part of the user program as a library and storing it in the flash memory by utilizing the fact that the flash memory cannot be accessed by a tool (Patent Document 4).

  In a programmable controller that is installed in an end user's factory in a state of being incorporated into various industrial machines by a vendor, or that is installed in an end user's factory equipment by an end user, input / output of a program to be protected in the user program When executed, it has been proposed to replace display data with predetermined hardware-specific data and apply display protection (Patent Document 5). It is disclosed that a specific program part in a user program cannot be operated except for a specific PLC, and a protection target program part at a predetermined address of an input / output memory is replaced with a function block and display protection is applied. Has been. Also, when there is a part to be protected by the execution program, the protection program is read out to the user terminal, and after the invalid instruction program is embedded, the execution program is distributed to the user terminal or distributed in a recording medium It has been proposed to protect a confidential program from unauthorized analysis (Patent Document 6). Furthermore, it has been proposed that when a program output prohibition instruction is included in the control procedure program, the program output prohibition procedure protects the control procedure program by prohibiting the program output operation (Patent Document 7).

JP-A-6-110512 JP-A-62-100805 JP 2006-331130 A JP 2004-5389 A JP 2009-070144 A JP 2003-271255 A Japanese Patent Laid-Open No. 5-233036

  As described above, since the programmable controller has a peripheral device interface and the peripheral device itself is highly available, a third party other than the program creator can download the sequence program stored in the programmable controller. It can be read easily.

  The sequence program stored in the programmable controller often includes know-how related to the controlled equipment and techniques for program description, and such important information is leaked and used without permission. There is a risk.

  The present invention has been made in view of the above-mentioned reasons, and an object thereof is to provide a programmable controller that protects a sequence program by preventing the support program from reading the sequence program stored in the program memory. There is.

  In order to solve the above problems, a sequence program according to the present invention is a sequence program that can be stored in a sequence program memory of a programmable controller and writes a control sequence of a device to be controlled. It is characterized in that some programs are rewritten for the purpose of not displaying them. Further, the present invention is a recording medium in which the sequence program is recorded and can be used in a computer.

  The programmable controller according to the present invention performs arithmetic processing based on a rewritable sequence program memory for storing a sequence program for writing a control sequence of a device to be controlled, and the sequence program stored in the sequence program memory. A programmable controller comprising a microprocessor unit and a peripheral device interface connectable to a peripheral device for rewriting the sequence program stored in the sequence program memory, the sequence program stored in the sequence program memory Is the above-mentioned sequence program in which a part of the program is rewritten for the purpose not to be displayed on the peripheral device.

  The dummy data written at the head of the sequence program stored in the sequence program memory of the programmable controller is defined as an instruction that does not process anything on the programmable controller side. For this reason, whether or not dummy data is written at the beginning of the sequence program stored in the sequence program memory of the programmable controller does not affect the control contents. On the other hand, on the peripheral device side, dummy data written at the head of the sequence program stored in the sequence program memory of the programmable controller is defined as an illegal instruction.

  When reading the contents of the sequence program memory of the programmable controller from the peripheral device, if dummy data is included at the beginning of the sequence program, the peripheral device determines that it contains illegal data and By preventing the sequence program from being displayed on the screen, the sequence program is protected. On the other hand, if dummy data is not included in the first step of the sequence program of the programmable controller read by the peripheral device, the sequence program is displayed on the peripheral device.

  Another object of the present invention is to prevent the sequence program stored in the programmable controller from being displayed on the peripheral device without affecting the control content of the controlled object controlled by the control sequence written in the sequence program. The sequence program protection support method in the programmable controller is characterized in that a part is rewritten.

  Furthermore, the present invention is a sequence program protection support apparatus in a programmable controller, wherein a part of the sequence program stored in or to be stored in the sequence program memory of the programmable controller is rewritten.

  Specifically, a support device for writing one-step dummy data at the head of the sequence program stored in the sequence program memory of the programmable controller is used. This support device is provided as a personal computer application in a form different from that of the peripheral device.

  According to the configuration of the present invention, in order not to display the sequence program stored in the peripheral device on the peripheral device, a part of the sequence program stored in the sequence program memory of the programmable controller is rewritten and protected. If the sequence program memory of the programmable controller is protected, the third party who owns the peripheral device cannot view the sequence program without permission, so the sequence program know-how leaks, the sequence program is stolen, the sequence program Tampering can be prevented. Furthermore, there is an advantage that the sequence program can be protected without implementing complicated means such as encryption processing in the programmable controller or the peripheral device.

It is a figure which shows embodiment of this invention, and is explanatory drawing of the programmable controller which arithmetically processes the sequence program in the protection state stored in the sequence program memory. It is explanatory drawing of the intermediate language format and NOOP opcode corresponding to the ladder symbol and instruction word which show embodiment of this invention. It is explanatory drawing which shows the structure of a general programmable controller. It is explanatory drawing of the ladder symbol and command which are displayed on a peripheral device. It is explanatory drawing of the intermediate language format corresponding to a ladder symbol and an instruction word. It is explanatory drawing of the sequence program stored in the sequence program memory. It is explanatory drawing of the assistance apparatus and programmable controller which show embodiment of this invention. It is a flowchart of the program protection process which shows embodiment of this invention. It is a flowchart of the program protection cancellation | release process which shows embodiment of this invention.

  Before describing a mode for implementing a programmable controller according to the present invention, a general programmable controller and a support device will be described with reference to FIGS. 5 and 6.

  FIG. 5 is an example of an intermediate language corresponding to the ladder symbol format 8 or the instruction word format 9 displayed on the peripheral device 7. The intermediate language is a code in an intermediate state between the ladder symbol format 8 or the instruction word format 9 and the machine language that can be processed by the MPU 2. In this description, a set of these codes is expressed as a sequence program.

  The sequence program programmed by the programmer in the ladder symbol format 8 or the instruction word format 9 is converted into an intermediate language format by the peripheral device 7. The code in the intermediate language format is stored in the sequence program memory 4 via the peripheral device interface 6 and the MPU 2. This series of operations is expressed as writing a sequence program.

  On the other hand, the operation of loading the sequence program stored in the sequence program memory 4 into the peripheral device 7 via the MPU 2 and the peripheral device interface 6 is expressed as reading the sequence program. The read sequence program in the intermediate language state is reversely converted by the peripheral device 7 and displayed in the ladder symbol format 8 or the instruction word format 9.

  FIG. 6 shows the state of the sequence program stored in the sequence program memory 4. The programmable controller 1 sequentially processes the sequence program stored in the sequence program memory 4 from step 1, and when the END instruction in step 7 is processed, the process is repeated again from the code in step 1 again.

  FIG. 7 is a connection diagram of a sequence program protection support apparatus and a programmable controller according to an embodiment of the present invention, and an operation screen of the sequence program protection support apparatus. The sequence program protection support apparatus 10 is used by being connected to the programmable controller 1, is implemented in the form of application software of a personal computer, and is displayed on the screen of the protection support apparatus 10 like an operation window 11. In the operation window 11, a protect button 12 and an unprotect button 13 are arranged.

FIG. 8 is a processing flowchart when the Protect button 12 of the operation window 11 of the protection support apparatus 10 is pressed.
When protecting the sequence program memory of the programmable controller, the user depresses the Protect button 12 of the operation window 11 of the protection support apparatus 10 (step 11; abbreviated as “S11”, the same applies hereinafter).
When the protection support device 10 detects that the Protect 12 button has been pressed in S11, the sequence program in the programmable controller is taken into the protection support device by communication (S12). The sequence program fetched into the protection support apparatus 10 at S12 is analyzed at S13, and whether or not the operation code at the first step is NOOP (NOn-OPeration, an instruction to do nothing; dummy data). Is checked.

  In the check in S13, when the operation code of the first step is not NOOP, the protection support apparatus 10 determines that the sequence program in the programmable controller is not in the protection state, and proceeds to the process of S14. On the other hand, when the operation code of the first step is NOOP, the protection support apparatus 10 determines that the sequence program in the programmable controller is in the protection state, and proceeds to the process of S16, and “already protected” in S16. Is displayed after the message is displayed.

  In S14, a NOOP opcode is added to the first step of the sequence program fetched in S12 to reconstruct the step numbers of the entire sequence program. The sequence program reconfigured in S14 is written back to the programmable controller 1 in S15.

FIG. 9 is a processing flowchart when the Unprotect button 13 of the operation window 11 of the protection support apparatus 10 is pressed.
When canceling the protection of the sequence program memory of the programmable controller, the user depresses the Unprotect button 13 of the operation window 9 of the protection support apparatus 10 (S21). When the protection support device 10 detects that the Unprotect button 13 is pressed, the sequence program in the programmable controller is read into the protection support device by reading the sequence program, that is, by communication (S22).

  The sequence program fetched into the protection support apparatus 10 at S22 is analyzed at S23, and it is checked whether or not the first step opcode is NOOP. In the check of S22, when the operation code of the first step is NOOP, the protection support apparatus 10 determines that the sequence program in the programmable controller is in the protection state, and proceeds to the process of S24. On the other hand, if the operation code at the first step is not NOOP, the protection support device 10 determines that the sequence program in the programmable controller is not in the protection state, and proceeds to the processing of S26. Is displayed, the process is terminated.

  In S24, the NOOP opcode at the first step of the sequence program fetched in S22 is deleted, and the step numbers of the entire sequence program are reconfigured. The sequence program reconfigured in S24 is written back to the programmable controller 1 in S25.

  FIG. 2 shows an intermediate language corresponding to a ladder symbol or instruction word displayed on the peripheral device 7 according to an embodiment of the present invention, and is characterized in that an intermediate language “NOOP” opcode is added. On the programmable controller side, the NOOP instruction is interpreted as an instruction that does nothing. On the other hand, the peripheral device is characterized in that the NOOP opcode is interpreted as an undefined illegal instruction.

  FIG. 1 shows a state of a protected sequence program stored in a sequence program memory 4 according to an embodiment of the present invention. On the programmable controller 1 side, the NOOP opcode is stored in the first step, but the MPU 2 is processed as an instruction that does not process the NOOP opcode based on the intermediate language instruction stored in the system program memory 3. Therefore, the sequence program stored in the sequence program memory 4 is sequentially processed from step 1, and when the END instruction in step 8 is processed, the processing is repeated again from the NOOP opcode in step 1 again. That is, even if the sequence program is in the protected state, the processing content on the programmable controller side is not affected at all. The data memory 5 is a memory for temporarily storing values used for calculation in the calculation process of the sequence program in the microprocessor unit 2, and the peripheral device interface 6 is a sequence program as described above. This interface is connectable to the peripheral device 7 in order to rewrite the sequence program stored in the memory 4.

1 Programmable controller 2 MPU
3 System Program Memory 4 Sequence Program Memory 5 Data Memory 6 Peripheral Device Interface 7 Peripheral Device 8 Ladder Symbol Format Sequence Program 9 Command Word Format Sequence Program 10 Sequence Program Protection Support Device 11 Sequence Program Protection Support Device Operation Window 12 Sequence Program Sequence program protection button 13 of the protection support device Sequence program protection release button of the sequence program protection support device

Claims (16)

A sequence program that can be stored in the sequence program memory of the programmable controller and indicates the control sequence of the device to be controlled, and is executed by the programmable controller,
The sequence program stored in the sequence program memory is
Incorporated into the sequence program protection support device outside the programmable controller, in the sequence program protection support device,
It is checked whether the operation code of the sequence program is dummy data, and the dummy data is an instruction that does not process anything on the programmable controller side and does not affect the control content of the device. It is data defined as an illegal instruction on the peripheral device side for rewriting,
As a result of the check, if it is determined that the operation code is not dummy data and is not in a protected state, a dummy data operation code is added to the sequence program, and the processing step number of the entire sequence program is reconfigured.
The reconstructed sequence program is written back to the programmable controller,
Executed by the programmable controller ;
When the operation code is dummy data, the sequence program is protected from being rewritten by the peripheral device of the programmable controller by preventing the sequence program from being displayed on the peripheral device displaying the sequence program.   2. The sequence program according to claim 1, wherein the dummy data opcode added to the sequence program is dummy data of the first step written at the head of the sequence program. The dummy data is an instruction that does not process anything on the programmable controller side and does not affect the control content of the device, and is defined as an illegal instruction on the peripheral device side of the programmable controller. The sequence program according to claim 2.   The computer-readable recording medium which recorded the said sequence program as described in any one of Claims 1-3. A rewritable sequence program memory for storing a sequence program for writing a control sequence of a device to be controlled;
A microprocessor unit executed based on the sequence program;
A programmable controller comprising a peripheral device interface connectable to a peripheral device for rewriting the sequence program, and connected to a sequence program protection device for protecting the sequence program;
The microprocessor unit is
The sequence program stored in the sequence program memory is taken into the sequence program protection support device outside the programmable controller, and in the sequence program protection support device,
It is an instruction that checks whether the operation code of the sequence program is dummy data, and the dummy data does not process anything on the programmable controller side and does not affect the control content of the device. It is data defined as an illegal instruction on the peripheral device side for rewriting,
As a result of the check, if it is determined that the operation code is not dummy data and is not in a protected state, a dummy data operation code is added to the sequence program, and the processing step number of the entire sequence program is reconfigured.
Based on the sequence program written back to the programmable controller, the reconstructed sequence program is executed ,
When the operation code is dummy data, rewriting of the program by the peripheral device of the programmable controller is protected by not displaying the sequence program on the peripheral device displaying the sequence program. Programmable controller.   6. The programmable controller according to claim 5, further comprising a data memory connected to the microprocessor unit and temporarily storing a value used for an operation in an operation process of the sequence program. . Program for the purpose of not displaying the sequence program on the peripheral device without affecting the control contents of the control target controlled by the control sequence written in the sequence program, and storing the sequence program stored in the programmable controller A protection support method for protecting a sequence program in the programmable controller with a sequence program protection support device for rewriting a part of
The sequence program in the programmable controller is taken into the sequence program protection support device outside the programmable controller,
In the sequence program protection support device, analyze the sequence program,
It is an instruction that checks whether the operation code of the sequence program is dummy data, and the dummy data does not process anything on the programmable controller side and does not affect the control content of the device. It is data defined as an illegal instruction on the peripheral device side for rewriting,
If it is not dummy data, it is determined that it is not in a protected state,
Add dummy data opcode to the sequence program, reconfigure the step number of the whole sequence program,
Write the reconfigured sequence program back to the programmable controller,
When the operation code is dummy data, the sequence program is protected from being rewritten by the peripheral device of the programmable controller so that the sequence program is not displayed on the peripheral device that displays the sequence program. Method. A sequence program protection support apparatus in a programmable controller capable of rewriting a part of an operation code of a sequence program stored or to be stored in a sequence program memory of a programmable controller,
The sequence program protection support device includes:
The capture sequence program in the programmable controller, analyzes the captured sequence program, the opcode of the sequence program checks whether the dummy data, if not the dummy data, determined not to protection state, the The dummy data is an instruction that does not process anything on the programmable controller side and does not affect the control content of the device, and is defined as an illegal instruction on the peripheral device side for rewriting the sequence program,
Add a dummy data opcode to the sequence program, to reconstruct the step number of the entire sequence program to back write sequence program the reconstituted to the programmable controller,
When the operation code is dummy data, rewriting of the program by the peripheral device of the programmable controller is protected by not displaying the sequence program on the peripheral device displaying the sequence program. A sequence program protection support device in a programmable controller.   9. The sequence program protection support apparatus in a programmable controller according to claim 8, wherein the sequence program protection support apparatus is used in connection with a programmable controller. In the sequence program protection support device, the protection button that is an operation to rewrite a part of the operation code of the sequence program and a protection release button that is an operation to release the rewrite of the sequence program are arranged. A sequence program protection support apparatus in a programmable controller according to claim 8 or 9, further comprising a display unit that displays the operation window displayed on the screen. In the sequence program that can be stored in the sequence program memory of the programmable controller and write the control sequence of the device to be controlled,
The sequence program is taken into a protection support device that has received an operation to protect the sequence program memory, and is determined whether or not it is in a protected state.
The sequence program determined not to be in the protected state is added with dummy data, which is an instruction that causes the programmable controller to perform no processing, and the dummy data does not process anything on the programmable controller side and affects the control contents of the device. Is a data that is defined as an illegal instruction on the peripheral device side for rewriting the sequence program,
The sequence program to which the dummy data is added is reconfigured with the entire step number,
The sequence program in which the whole step number is reconfigured is written back to the programmable controller and processed by the programmable controller .
When the operation code is dummy data, rewriting of the program by the peripheral device of the programmable controller is protected by not displaying the sequence program on the peripheral device displaying the sequence program. A sequence program. The sequence program according to claim 11,
The added dummy data is added as an operation code of the first step of the sequence program. A programmable controller in which the sequence program according to claim 11 or 12 is stored,
A programmable controller, wherein the programmable controller is controlled as a process that does not perform any dummy data included in the sequence program written back to the programmable controller. In the sequence program that can be stored in the sequence program memory of the programmable controller and write the control sequence of the device to be controlled,
The sequence program is taken into a protection support device that has received an operation to protect the sequence program memory, and is determined whether or not it is in a protected state.
In the sequence program determined to be in the protected state, the dummy data, which is an instruction that does not cause the programmable controller to process anything, is deleted, and the dummy data does not process anything on the programmable controller side and affects the control contents of the device. Is a data that is defined as an illegal instruction on the peripheral device side for rewriting the sequence program,
The sequence program from which the dummy data has been deleted is reconfigured with the entire step number,
The sequence program in which the whole step number is reconfigured is written back to the programmable controller and processed by the programmable controller,
When the operation code is dummy data, rewriting of the program by the peripheral device of the programmable controller is protected by not displaying the sequence program on the peripheral device displaying the sequence program. A sequence program. A sequence program according to claim 14,
The deleted dummy data is deleted as an operation code of the first step of the sequence program. A programmable controller in which the sequence program according to claim 14 or 15 is stored,
A programmable controller, wherein the programmable controller is controlled with a sequence program from which the dummy data written back to the programmable controller is deleted.

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