JPH02126302A - Programmable controller - Google Patents

Abstract

PURPOSE:To attain the secrecy holding and rewriting prevention and to facilitate the identification of the defined part by providing a means to input the definition of the macro instruction, a means to prohibit the reading and writing and a user program memory. CONSTITUTION:Immediately before and immediately after an arbitrary group of macro definition instructions of a user program, the instruction word of the starting and completing the macro instruction designation and serial numbers MACROS 01 and MACROE 01 are inserted, respectively. Thus, this part is macro-defined. Simultaneously, additional information is stored in the macro additional information area of a user program memory. At the area, a protecting flag is provided for the number of the instruction, at the time of designating, set to '1', further, at the time of releasing, changed to '0', and a pass-word to release the protection is registered. When the program is displayed at a tool after it is inputted to the PC, it is displayed that the defined part is MACRO 01 only. When the definition contents are developed and displayed, the pass-word is inputted, a flag is changed to '0', and thus, the contents are developed and displayed as shown in the figure.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention relates to a programmable controller (hereinafter referred to as a PC) that can restrict reading and writing of user programs.

(Summary of the Invention) This invention specifies an arbitrary part of a user program input to a PC using a macro instruction and protects the program. This makes it impossible to read or write.

(Prior art and its problems) Conventionally, a program created by a user and input into a PC is
By using read/write tools, the contents could be easily read and written. In addition, if you do not want the input program to be read or modified by an outsider, you can protect the entire program by using hardware or software protection.

However, if specific parts of a created program need to be kept secret or cannot be changed without permission, it has not been possible to prohibit reading and writing of only those specific parts.

In addition, on PCs that can use macro instructions, if a macro instruction is defined in any instruction word group in a created user program, when you disassemble and display the program contents, the macro instruction defined in the user program will be displayed. There was also the problem that it was difficult to identify which part was where.

(Purpose of the invention) This invention was made to solve the above problems, and its purpose is to maintain the confidentiality and prevent tampering of any part of the created user program, and to prevent disassembly. An object of the present invention is to provide a PC in which a macro instruction definition part can be easily identified when a macro instruction is defined.

(Structure and Effects of the Invention) In order to achieve the above object, the present invention includes means for inputting a definition of a macro instruction by specifying a start position and an end position in a user program consisting of a group of consecutive command words; A means for prohibiting reading and writing of the program contents of the part defined by the macro instruction, an area in which read and write protection is set for each defined macro instruction, and an area for setting read and write protection for each macro instruction. A user program memory having an area in which a password for canceling settings is registered;

Since this invention is configured as described above, a macro instruction is defined by specifying and inputting the start and end positions of an arbitrary part of a user program, and the macro instruction is read into the corresponding area of the user program memory provided corresponding to the macro instruction. - If write protection is set, reading and writing to the corresponding location will be prohibited. Further, these read/write prohibition settings can be canceled only when a password registered in advance in the memory area corresponding to the macro instruction is input.

As a result, it is possible to easily protect any part of the user program from reading or writing.

Also, when disassembling and displaying the input user program, start position 1 of the part defined in the macro instruction.
The end position is displayed, so you can easily identify the definition part.

(Explanation of Examples) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a diagram showing a user program input to a PC according to the present invention and its display.

As shown in the figure, the command word "MACRO3" to start macro command specification and the serial number "Ol" of the macro command are placed immediately before "ADD" at the beginning of the command group for macro definition in the input user program. It has been inserted. Furthermore, immediately after #0100° at the end of the instruction word group, the instruction word "MACROE", which ends the macro instruction specification, and the serial number "01" of the macro instruction are inserted. “ADD” to “#01
00" is defined as "MACROO1".

When specifying these macro instructions, additional information regarding the macro instructions is also stored in the macro additional information area provided at the rear end of the user program memory, as shown in FIG.

In this additional information area, a protect flag is provided for each "MACRO" instruction number, and "1" is set when protection is specified.

Furthermore, a password for changing the protect flag to "0" and canceling protection is registered in this area.

After entering these user programs into the PC and displaying them on the tool, if protection is set for the macro command, the part where the macro is defined will only be "MACROOI" as shown in the first @. Is displayed.

Here, if you try to expand and display the definition contents of the part displayed as "MACROO1'", enter the password registered in advance and change the corresponding protect flag to "O". The definition contents are expanded as shown on the right side of Figure 1.

In other words, by changing the contents of the protect flag using a password, the contents of the macro instruction can be freely expanded or stored, and this stored state is
It is also in a protected state.

As described above, in the present invention, when a macro instruction is to be defined in a user program, this can be easily done by simply inserting the start and end specifications of the macro instruction specification.

Further, by using a password registered for each macro instruction word, protection can be easily set and canceled. Furthermore, if the program is displayed in a canceled state, the portion designated by the macro can be clearly identified by the start and end designations.

As a result, a legitimate operator in possession of the password
The user program can be read and written freely, but outsiders who do not have the password can only read and write part of the program contents, which improves the confidentiality and security of the program. - Since a release password is registered for each macro command, by managing each password, it is possible to restrict the release of program contents according to the level of a large number of operators. In this case, it is more effective to configure the macro specifications in a nested manner.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a user program input to a PC according to the present invention and an example of its display, and FIG. 2 is a diagram also showing the configuration of the additional information area in the user program memory.

Claims (1)

[Claims] 1. Means for inputting the definition of a macro instruction by specifying a start position and an end position in a user program consisting of a group of consecutive instruction words, and program contents of the portion defined by the macro instruction. means for prohibiting reading and writing, an area where read/write prohibition is set for each defined macro instruction, and an area where a password is registered to cancel the read/write prohibition setting for each macro instruction. A programmable controller comprising: a user program memory having the following features;