JP2006301846A - Retrieval apparatus for user program and program to be applied to the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a retrieval apparatus for a user program for satisfactory performing the retrieval of a virtual device on the basis of a master level even when the master label of the virtual device is changed, and a program to be applied to this. <P>SOLUTION: When a user program is displayed on a screen, a retrieval apparatus 1 for a user program performs label display on the basis of a change label table stored in a change label table storage part 27, and when a character string to be retrieved is inputted, the retrieval apparatus 1 for a user program converts the inputted character string into a virtual device on the basis of a master label table stored in a master label table storage part 26, and retrieves the user program on the basis of the virtual device after conversion. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a search apparatus for a user program and a program applied thereto, and more particularly to an improvement in a method for searching for a character string included in a user program for controlling a programmable logic controller.

  A PLC (programmable logic controller) for comprehensively controlling various control devices installed in a factory or the like is known (for example, see Patent Document 1). The PLC includes a CPU unit with a built-in CPU, and an expansion unit can be attached to and detached from the CPU unit. The user prepares an expansion unit for each function of the various control devices and attaches the expansion unit to the CPU unit, and connects each control device to the CPU unit via the expansion unit by connecting a control device corresponding to the expansion unit.

  The control device connected to the CPU unit via the expansion unit includes an input device such as a sensor and an output device such as an actuator. The CPU built in the CPU unit controls the operation of a predetermined output device via the expansion unit by executing a program based on an input signal input from the input device via the expansion unit.

  As a user program for controlling the PLC, a ladder program created using a ladder diagram is known. The ladder program is created by using a personal computer, for example, and a ladder that represents a visual relay circuit by appropriately arranging symbols of virtual devices in a plurality of cells displayed in a matrix on the display screen of the personal computer. Created by constructing a diagram.

  A ladder program created in the personal computer is converted into a mnemonic code in the personal computer. Then, when the personal computer is connected to the CPU unit of the PLC and the program converted into the mnemonic code is sent from the personal computer to the CPU unit, the program is converted into the machine code in the CPU unit, and the memory provided in the CPU unit Stored in. Thereby, the CPU of the CPU unit can control the operation of the control device based on the program converted into the machine code stored in the memory.

  Each virtual device assigned to the memory in the PLC is initially set with a label corresponding to its function as a master label. In the memory in the personal computer that creates the ladder program, a master label corresponds to each virtual device. The attached master label table is stored. When creating a ladder program using a ladder diagram, when a symbol of each virtual device is arranged in a cell, a master label corresponding to the virtual device can be displayed in the vicinity of the symbol based on the master label table. As a result, the function of each virtual device on the ladder diagram can be clearly displayed, so that a person other than the person who created the ladder program, for example, an employee of the factory where the PLC is installed, can execute the ladder program. Even when editing, the contents of the ladder program represented by the ladder diagram can be easily understood.

Some users desire to change the default master label corresponding to each virtual device. In order to respond to such a user's request, the change of the master label on the personal computer is allowed, and when the symbol of the virtual device whose master label has been changed is placed in a cell on the ladder diagram, In some cases, a changed label can be displayed in the vicinity. In this case, the master label table stored in the memory of the personal computer is rewritten so that the changed label after the change is associated with the virtual device whose master label has been changed.
JP 2005-85076 A

  While editing a ladder program, try to use the same virtual device as the virtual device used earlier in the ladder program being edited, or try to use the same virtual device as the virtual device included in the ladder program created in the past In some cases, it is desirable to search for the virtual device.

  In such a case, if the master label of the virtual device you want to search for has been changed, even if you enter the master label before the change and search the ladder program, the master label before the change will be displayed in the rewritten master label table. Since it does not exist, there has been a problem that the virtual device search cannot be performed satisfactorily based on the master label.

  The present invention has been made in view of the above circumstances, and even when a master label of a virtual device is changed, a search device for a user program that can satisfactorily search for a virtual device based on the master label, and It is an object to provide a program applicable to this.

  It is another object of the present invention to provide a user program search apparatus with improved convenience and a program applied thereto.

  A user program search device according to the present invention is a user program search device for searching for a character string included in a user program for controlling a programmable logic controller created by a user. A master label table storage unit for storing a master label table in which a master label is associated with a virtual device in the device, and when the master label is changed, the changed label is changed to the virtual device corresponding to the master label. The change label table storage unit for storing the associated change label table and the virtual device associated with the change label in the change label table when the user program is displayed on the screen are displayed in the change label table. User program display means for performing label display based on the above, input means for inputting a character string to be searched, and a virtual device for converting the character string input by the input means into a virtual device based on the master label table Device conversion means and user program search means for searching for a user program based on the virtual device converted by the virtual device conversion means are configured.

  According to such a configuration, when the master label is changed, when the user program is displayed on the screen, the changed label table in which the changed change label is associated with the virtual device corresponding to the master label is displayed. Based on this, a label is displayed. Therefore, since the changed label after the change can be displayed in association with the virtual device, the convenience for the user who desires to change the master label is improved.

  Even if the master label is changed, if the user program is searched by inputting the master label before the change, the input character string, that is, the master label is converted into a virtual device based on the master label table. The user program is searched based on the converted virtual device. Therefore, even when the master label of the virtual device is changed, the search for the virtual device can be performed satisfactorily based on the master label, and convenience for the user who performs the search is improved.

  The user program search device according to the present invention comprises search result display means for displaying the search results of the user program search means on the screen.

  According to such a configuration, even when a virtual device is searched based on the master label before the change, the virtual device associated with the changed label after the change can be displayed on the screen as a search result.

  A user program search device according to the present invention comprises a help file search means for searching for a help file based on the character string input by the input means.

  According to such a configuration, when the user program is searched by inputting the master label before the change, the virtual device can be satisfactorily searched based on the input master label, and the input master label is related to the input master label. Help information can be searched and browsed from help files. Therefore, convenience for the user who performs the search is further improved.

  In the present invention, the programmable logic controller includes a control unit, and an extension unit can be attached to and detached from the control unit, and the control unit is an extension unit attached to the control unit. Each of the allocation areas includes a memory to which a virtual device is allocated, and the master label table includes, for each expansion unit attached to the control unit, a virtual device relative to the allocation area. The virtual device converting means stores the positional information of the allocation area for each expansion unit in the memory and the virtual device in the allocation area stored in the master label table. Based on the relative position information Configured to convert the virtual device a character string input by.

  According to such a configuration, even when the extension unit attached to the control unit is different for each programmable logic controller, the location information of the allocation area for each extension unit in the memory and the allocation area stored in the master label table Based on the relative position information of the virtual device, the search for the virtual device can be performed satisfactorily.

  In addition, a program according to the present invention provides a user program search device for searching for a character string included in a user program for controlling a programmable logic controller created by a user in the programmable logic controller. Master label table storage means for storing a master label table in which a master label is associated with a virtual device, and when the master label is changed, the changed label after the change is associated with the virtual device corresponding to the master label Change label table storage means for storing the changed label table and a virtual device associated with the change label in the change label table when the user program is displayed on the screen based on the change label table. Label table A user program display means for performing, when a character string to be searched is input, a virtual device conversion means for converting the input character string into a virtual device based on the master label table, and the virtual device conversion Based on the virtual device converted by the means, it is configured to function as a user program search means for searching for a user program.

  According to such a configuration, when the master label is changed, when the user program is displayed on the screen, the changed label table in which the changed change label is associated with the virtual device corresponding to the master label is displayed. Based on this, a label is displayed. Therefore, since the changed label after the change can be displayed in association with the virtual device, the convenience for the user who desires to change the master label is improved.

  Even if the master label is changed, if the user program is searched by inputting the master label before the change, the input character string, that is, the master label is converted into a virtual device based on the master label table. The user program is searched based on the converted virtual device. Therefore, even when the master label of the virtual device is changed, the search for the virtual device can be favorably performed based on the master label, and convenience for the user who performs the search is improved.

  According to the present invention, when displaying the user program on the screen, by displaying the changed label in association with the virtual device, it is possible to improve convenience for the user who desires to change the master label, Even when the master label of a virtual device is changed, a search device for a user program that can perform a search of a virtual device satisfactorily based on the master label and can improve convenience for a user who performs the search, and the same It is possible to provide a program that is applied to.

  FIG. 1 is a conceptual diagram showing a configuration example of a ladder program search system according to an embodiment of the present invention.

  As shown in FIG. 1, this ladder program search system includes a personal computer 1 and a PLC (programmable logic controller) 2 for comprehensively controlling various control devices installed in a factory or the like. Yes.

  The PLC 2 includes a CPU unit 3 with a built-in CPU, and one or a plurality of expansion units 4 can be attached to and detached from the CPU unit 3.

  The CPU unit 3 includes a display unit 5 and an operation unit 6. The display unit 5 can display the operation status of each expansion unit 4 attached to the CPU unit 3, and the display content of the display unit 5 can be switched by operating the operation unit 6.

  The expansion unit 4 is prepared for each function in order to expand the function of the PLC 2 and is attached to the CPU unit 3 from the side. The first extension unit 4 is directly attached to the CPU unit 3 from the side. The second and subsequent expansion units 4 are sequentially attached in series from the side with respect to the already-installed expansion units 4. Thus, when the CPU unit 3 and the plurality of expansion units 4 are attached in series, each expansion unit 4 can communicate with the CPU unit 3 via the wiring provided in each expansion unit 4. Connected. Each expansion unit 4 is connected to a control device corresponding to the function of the expansion unit 4, whereby each control device is connected to the CPU unit 3 via the expansion unit 4.

  The personal computer 1 is a portable so-called notebook type personal computer, for example, and includes a display unit 7 and an operation unit 8. A ladder program for controlling the PLC 2 is created using the personal computer 1, and the created ladder program is converted into a mnemonic code in the personal computer 1. When the personal computer 1 is connected to the CPU unit 3 of the PLC 2 via a cable 9 such as a USB (Universal Serial Bus) and the program converted into the mnemonic code is sent from the personal computer 1 to the CPU unit 3, the program Is converted into a machine code in the CPU unit 3 and stored in a memory provided in the CPU unit 3.

  Although not shown in FIG. 1, the operation unit 8 of the personal computer 1 may include a mouse connected to the personal computer 1.

  FIG. 2 is a block diagram for explaining the electrical configuration of the PLC 2 of FIG.

  As shown in FIG. 2, the CPU unit 3 includes a CPU 10, a display unit 5, an operation unit 6, and a memory 11. The display unit 5, the operation unit 6 and the memory 11 are electrically connected to the CPU 10, respectively.

  The memory 11 is configured to include at least a RAM, and is conceptually attached to the program memory 12 that stores a program executed by the CPU 10, an internal memory 13 such as a flag in which data necessary for control is written, and the CPU unit 3. An allocation area 15 is allocated to each of the extended units 4, and an input / output memory 14 to which a virtual device is allocated is provided in each allocation area 15.

  The control device 16 connected to the CPU unit 3 via the expansion unit 4 includes an input device such as a sensor and an output device such as an actuator. The CPU 10 of the CPU unit 3 executes a program stored in the program memory 12 based on an input signal input from the input device 16 via the expansion unit 4, thereby causing the output device 16 via the expansion unit 4. To control the operation.

  Each expansion unit 4 is externally attached in series to the CPU unit 3 as shown in FIG. 1, but conceptually corresponds to the input / output memory 14 as shown in FIG. Each is connected to the allocation area 15. Based on the input signal from the input device 16 among the control devices 16 connected to each expansion unit 4, the virtual devices in the allocation area 15 allocated to the expansion unit 4 corresponding to the input device 16 are turned on / off. Based on this, the CPU 10 controls the operation of the output device 16 by turning on / off the virtual devices in the allocation area 15 allocated to the expansion unit 4 corresponding to the predetermined output device 16.

  In FIG. 2, the control devices 16 are connected to the respective expansion units 4 in a one-to-one correspondence. However, the configuration is not limited to such a configuration, and a plurality of control devices 16 are provided for one expansion unit 4. It may be connected.

  Further, the memory to which the virtual device is allocated is not limited to one configured by one input / output memory 14, and the input memory associated with the expansion unit 4 to which the input device 16 is connected and the output device 16 are connected. And an output memory associated with the expansion unit 4.

  FIG. 3 is a diagram showing an example of a ladder diagram 17 displayed on the display unit 7 of the personal computer 1 when a ladder program is created.

  As shown in FIG. 3, the ladder program for controlling the PLC 2 visually arranges virtual device symbols 19 in a plurality of cells 18 displayed in a matrix on the display unit 7 of the personal computer 1. It is created by constructing a ladder diagram 17 representing a simple relay circuit.

  In the ladder diagram 17, for example, cells 18 of 10 columns × N rows (N is an arbitrary natural number) are arranged. A visual relay circuit can be created by appropriately arranging the virtual device symbols 19 in time series in the cells 18 of each row from the left side to the right side shown in FIG. The relay circuit to be created may be a serial relay circuit represented by one row, or a relay circuit represented in parallel in a plurality of rows in any cell 18 (example shown in FIG. 3). Then, for example, a parallel relay circuit created by coupling in the first row of the second column may be used.

  An arbitrary character string can be displayed as a line comment without arranging the virtual device symbol 19 on any line of the ladder diagram 17.

  The ladder diagram 17 can be divided into a plurality of modules 20 composed of cells 18 of 10 columns × M rows (M is an arbitrary natural number, M <N) for each function. In this way, if the ladder diagram 17 is configured by a plurality of modules 20, the ladder program can be easily edited by appropriately replacing the modules 20 in accordance with changes in the functions executed by the PLC 2.

  4A and 4B are diagrams showing a specific example of a relay circuit created using the ladder diagram 17.

  The relay circuit shown in FIG. 4A includes symbols 19a, 19b, and 19c of three virtual devices (hereinafter referred to as “input devices”) that are turned on / off based on an input signal from the input device 16. A symbol 19d of a virtual device (hereinafter referred to as “output device”) that is turned on / off to control the operation of the output device 16 is appropriately combined.

  The characters (“R0001”, “R0002”, and “R0003”) displayed above the symbols 19a, 19b, and 19c of each input device represent the device name (address name) 21 of the input device. The characters (“flag 1”, “flag 2”, and “flag 3”) displayed below the symbols 19a, 19b, and 19c of each input device represent a device comment 22 associated with the input device. Yes. A character (“origin return”) displayed above the symbol 19d of the output device is a label 23 composed of a character string representing the function of the output device.

  As described above, the device name 21, the device comment 22, the label 23, and the like can be appropriately arranged in the vicinity of the symbol 19 of each virtual device arranged on the ladder diagram 17. If the label 23 indicating the function of the virtual device is displayed in the vicinity of the virtual device symbol 19 as in the output device symbol 19d shown in FIG. 4, the function of the virtual device can be clearly displayed. Even if a person other than the person who created the ladder program, for example, an employee of the factory where the PLC 2 is installed, edits the ladder program, the contents of the ladder program shown in FIG. 17 are easily understood. can do.

  In the example shown in FIG. 4A, two input device symbols 19a and 19b respectively corresponding to the device names “R0001” and “R0002” are coupled in series to constitute an AND circuit. In addition, an OR circuit is configured by parallelly connecting the input device symbol 19c corresponding to the device name “R0003” to the AND circuit including the symbols 19a and 19b of these two input devices. Yes. That is, in this relay circuit, the output device corresponding to the symbol 19d is turned on only when both of the input devices corresponding to the two symbols 19a and 19b are turned on or when the input device corresponding to the symbol 19c is turned on. It has come to be.

  In each virtual device, a label 23 corresponding to the function is initially set as a master label 23a by the manufacturer, and is displayed above the output device symbol 19d in the example shown in FIG. The label 23 “return to origin” indicates the master label 23a of this output device.

  Here, the virtual device of “return to origin” is a positioning device such as an XY stage for performing two-dimensional positioning of an object when the positioning device is connected to the PLC 2 as a control device (output device) 16. This is a virtual device that is turned on to return to a predetermined initial position.

  Some users desire to change the master label 23a that is initially set corresponding to each virtual device. In order to meet such a user's request, in this embodiment, the change of the master label 23a on the personal computer 1 is allowed, and the symbol 19 of the virtual device whose master label 23a has been changed is displayed on the ladder diagram 17. When arranged, the changed label 23 can be displayed as the changed label 23 b above the symbol 19. That is, in the example shown in FIG. 4A, when the user changes the master label 23a of “return to origin” to the label 23 of “position reset”, as shown in FIG. The changed label 23 (“position reset”) is displayed as the changed label 23b above the virtual device symbol 19d.

  FIG. 5 is a block diagram for explaining the electrical configuration of the personal computer 1 of FIG.

  As shown in FIG. 5, the personal computer 1 includes a CPU 24, a display unit 7, an operation unit 8, and a memory 25. The display unit 7, the operation unit 8, and the memory 25 are electrically connected to the CPU 24, respectively.

  The memory 25 includes at least a RAM, and conceptually includes a master label table storage unit 26 that stores a master label table, a change label table storage unit 27 that stores a change label table, and input / output of the CPU unit 3. An allocation position storage unit 28 that stores the position information of the allocation area 15 of each expansion unit 4 in the memory 14, an editing program storage unit 29 that stores a ladder program being edited, and a past that stores a ladder program created in the past A creation program storage unit 30, a sample program storage unit 31 for storing a sample ladder program prepared by the manufacturer, and a help file storage unit 32 for storing a help file are provided.

  The master label table stored in the master label table storage unit 26 is a table in which the master label 23a is associated with each virtual device stored in the input / output memory 14 of the CPU unit 3, and is prepared in advance by the manufacturer. Is. In the master label table, the relative position information of the virtual device in the allocation area 15 allocated to the input / output memory 14 of the CPU unit 3 is stored for each expansion unit 4. For example, the master label table corresponding to the expansion unit 4 to which the positioning device as the control device 16 is connected is relatively in the allocation area 15 of the input / output memory 14 of the CPU unit 3 corresponding to the expansion unit 4. Information indicating that the “origin return” virtual device is stored at the K-th (K is a natural number) address is stored.

  The change label table stored in the change label table storage unit 27 is created by copying the master label table in the memory 25. When the master label 23a is changed, the change label table is stored in the virtual device corresponding to the master label 23a. The change label 23b after the change is rewritten so as to be associated.

  When the CPU 24 of the personal computer 1 displays the ladder program on the display unit 7 as a ladder diagram 17, the CPU 24 performs label display based on the changed label table. Thus, for a virtual device whose master label 23a has been changed, the change label 23b stored in association with the virtual device is displayed in the change label table, and the virtual device whose master label 23a has not been changed. Is displayed, the master label 23a stored in association with the virtual device is displayed in the change label table.

  However, the label display for the virtual device in which the master label 23a has not been changed is not limited to the configuration performed based on the changed label table, but may be performed based on the master label table.

  The position information stored in the assigned position storage unit 28 may be automatically assigned by being notified (input) from the CPU unit 3 of the PLC 2 to the personal computer 1, or specified by the personal computer 1 Information may be transferred to the CPU unit 3. The expansion unit 4 is arbitrarily selected according to the user's preference and is attached to the CPU unit 3. Therefore, the number and order of the expansion units 4 attached to the CPU unit 3 are different for each PLC 2. Therefore, the position of the allocation area 15 allocated for each expansion unit 4 in the input / output memory 14 of the CPU unit 3 also differs for each PLC 2, but the position information of the allocation area 15 for each expansion unit 4 is stored in the allocation position storage. Since it is stored in the unit 28, the position information of the allocation area 15 for each expansion unit 4 stored in the allocation position storage unit 28 and the relative of the virtual device in the allocation area 15 stored in the master label table Each virtual device in the input / output memory 14 of the CPU unit 3 can be specified based on the positional information.

  For example, the expansion unit 4 to which the positioning device as the control device 16 is connected is attached to the CPU unit 3, and the expansion starts from the Lth address (L is a natural number) in the input / output memory 14 of the CPU unit 3. A case where the allocation area 15 is allocated to the unit 4 will be described. In this case, the position information (Lth address in the input / output memory 14) of the allocation area 15 of the expansion unit 4 stored in the allocation position storage unit 28 and the allocation area 15 stored in the master label table. The “origin return” virtual device in the input / output memory 14 of the CPU unit 3 is identified based on the relative position information of the “origin return” virtual device (K-th address in the allocation area 15). can do.

  The personal computer 1 is communicably connected to a server 34 via a communication line 33 such as a LAN. The server 34 is provided with a database 35 in which information related to the PLC 2 is stored, and the CPU 24 of the personal computer 1 reads information from the database 35 into the memory 25 of the personal computer 1 by communication with the server 34. it can.

  In this ladder program search system, the personal computer 1 functions as a ladder program search device, and searches the character string included in the ladder program from the search resource 36 by operating the operation unit 8 of the personal computer 1. Can do. The search resource 36 stores the ladder program being edited stored in the program storage unit 29 being edited, the ladder program created in the past stored in the past program storage unit 30, and the sample program storage unit 31. A sample ladder program, a help file stored in the help file storage unit 32, a database 35 provided in the server 34, and the like.

  FIG. 6 is a diagram illustrating an example of a search screen 37 displayed on the display unit 7 of the personal computer 1 when searching for a ladder program.

  As shown in FIG. 6, when searching for a ladder program, a search screen 37 displayed on the display unit 7 of the personal computer 1 includes a keyword input unit 38 for inputting a character string to be searched as a keyword, and a search A search target input unit 39 for selecting and inputting a search target from among the resources 36, a search start key 40 selected for starting the search, and a cancel key selected for canceling the execution of the search 41 are arranged.

  When the operation unit 8 of the personal computer 1 is operated to input a character string to be searched for into the keyword input unit 38, a search target is input into the search target input unit 39, and the search start key 40 is selected, the personal computer 1 The CPU 24 performs a search based on the character string input to the keyword input unit 38 within the search target input to the search target input unit 39.

  At this time, the CPU 24 of the personal computer 1 converts the character string input to the keyword input unit 38 into a virtual device based on the master label table stored in the master label table storage unit 26, and the converted virtual device. Search based on device. For example, as shown in FIG. 6, when a character string “return to origin” is input to the keyword input unit 38 and a search is performed, the positioning stored in the allocated position storage unit 28 as described above. Position information (Lth address in the input / output memory 14) of the allocation area 15 of the expansion unit 4 to which the apparatus is connected, and a virtual device of “origin return” in the allocation area 15 stored in the master label table Based on the relative position information (the Kth address in the allocation area 15), the virtual device of “origin return” in the input / output memory 14 of the CPU unit 3 is specified, and the input character string is Search by converting to the specified virtual device.

  FIG. 7 is a diagram illustrating a display example of the search result of the ladder program displayed on the display unit 7 of the personal computer 1.

  As shown in FIG. 7, the search result of the ladder program is displayed on the ladder diagram 17 and also displayed on the search result display unit 42 configured by a window different from the ladder diagram 17.

  For example, when a search is performed by inputting a character string of “origin return” as a keyword, as described above, the character string is converted into a virtual device of “origin return” based on the master label table, A search is performed based on the converted virtual device. The search result display unit 42 lists all search results for the search target input to the search target input unit 39 on the search screen 37. The search results listed in the search result display section 42 include the module name 44 in which the virtual device symbol 19 corresponding to the input character string exists, the position (matrix) 45 in the module 20, and the mnemonic code of the virtual device. 46 and the like are included.

  When the help file storage unit 32 is selected as a search target, the help file stored in the help file storage unit 32 is searched based on the input character string, and the search result is displayed in the search result display unit 42. Is displayed. When the database 35 of the server 34 is selected as a search target, a search is performed on the database 35 and the search result is displayed on the search result display unit 42.

  After the search, if one of the search results listed in the search result display unit 42 is selected by operating the operation unit 8 of the personal computer 1, the ladder diagram 17 displayed on the display unit 7 of the personal computer 1 is displayed. When the cursor 43 is placed on the cell 18 in which the virtual device symbol 19 corresponding to “return to origin” is placed, highlighting is performed.

  At this time, the master label 23a “return to origin” is changed to the change label 23b “position reset”, and the changed change label 23b is associated with the virtual device corresponding to the master label 23a in the change label table. 7, the virtual device symbol 19 in the cell 18 on which the cursor 43 is placed is not the master label 23 a “return to origin” corresponding to the keyword at the time of search, but “ A change label 23b “position reset” is displayed in association with it.

  In the present embodiment, when the master label 23a is changed, when the ladder program is displayed on the display unit 7 of the personal computer 1, the changed label is changed to the virtual device corresponding to the master label 23a. Label display is performed based on the changed label table associated with 23b. Therefore, since the changed label 23b after the change can be displayed in association with the virtual device, convenience is improved for a user who desires to change the master label 23a.

  Further, even when the master label 23a is changed, if the ladder label is searched by inputting the master label 23a before the change, the input character string, that is, the master label is stored in the virtual device based on the master label table. The ladder program is searched based on the converted virtual device after conversion. Therefore, even when the master label 23a of the virtual device is changed, the search for the virtual device can be favorably performed based on the master label 23a, and convenience for the user who performs the search is improved.

  Even when a virtual device is searched based on the master label 23a before the change, the virtual device associated with the changed label 23b after the change can be displayed as a search result on the ladder diagram 17.

  Further, when the ladder program is searched by inputting the master label 23a before the change, the virtual device can be satisfactorily searched based on the input master label 23a, and the help file storage unit 32 is selected as a search target. In this case, help information related to the inputted master label 23a can be searched from the help file and browsed. Therefore, convenience for the user who performs the search is further improved.

  Even when the expansion unit 4 attached to the CPU unit 3 is different for each PLC 2, the positional information of the allocation area 15 for each expansion unit 4 in the input / output memory 14 and the allocation area 15 stored in the master label table Based on the relative position information of the virtual device, the search for the virtual device can be performed satisfactorily.

  In the present embodiment, the case where the ladder program search device is configured by the notebook type personal computer 1 has been described. However, the ladder program search device is not limited to the notebook type personal computer, and for example, a desktop type personal computer. It may be a computer or another information terminal device such as a PDA (Personal Digital Assistance).

  Further, the ladder program search device is not limited to a general-purpose information terminal device such as the personal computer 1 but may be a dedicated search device for searching for a ladder program.

  Further, the program for controlling the PLC 2 is not limited to the ladder program as long as it is a user program created by the user, and may be another program. For example, a program for controlling the PLC 2 is created in a programming language such as SFC (Sequential Function Chart), FBD (Function Block Diagram), LD (Ladder Diagram), IL (Instruction List), or ST (Struction Text). May be.

  The present invention is not limited to the contents of the above-described embodiment, and various modifications can be made within the scope of the claims.

It is a conceptual diagram which shows one structural example of the search system for ladder programs by embodiment of this invention. It is a block diagram for demonstrating the electrical structure of PLC of FIG. It is a figure which shows an example of the ladder figure displayed on the display part of a personal computer at the time of creation of a ladder program. It is a figure which shows the specific example of the relay circuit created using a ladder diagram. It is a block diagram for demonstrating the electrical structure of the personal computer of FIG. It is a figure which shows an example of the search screen displayed on the display part of a personal computer, when searching a ladder program. It is a figure which shows the example of a display of the search result of the ladder program displayed on the display part of a personal computer.

Explanation of symbols

1 Personal Computer 2 PLC (Programmable Logic Controller)
3 CPU unit (control unit)
4 expansion unit 7 display unit 8 operation unit 14 input / output memory 15 allocation area 17 ladder diagram 23a master label 23b change label 26 master label table storage unit 27 change label table storage unit 32 help file storage unit

Claims (5)

In a user program search device for searching for a character string included in a user program for controlling a programmable logic controller created by a user,
Master label table storage means for storing a master label table in which a master label is associated with a virtual device in the programmable logic controller;
When the master label is changed, a changed label table storage unit that stores a changed label table in which the changed label after the change is associated with the virtual device corresponding to the master label;
User program display means for displaying a label based on the change label table for the virtual device associated with the change label in the change label table when displaying the user program on the screen;
An input means for inputting a character string to be searched;
Virtual device conversion means for converting a character string input by the input means into a virtual device based on the master label table;
A user program search device comprising user program search means for searching for a user program based on a virtual device converted by the virtual device conversion means.   2. The search apparatus for user programs according to claim 1, further comprising search result display means for displaying a search result by the user program search means on a screen.   The user program search device according to claim 1 or 2, further comprising help file search means for searching for a help file based on the character string input by the input means. The programmable logic controller includes a control unit, and an extension unit can be attached to and detached from the control unit.
The control unit includes a memory in which an allocation area is allocated for each expansion unit attached to the control unit, and a virtual device is allocated in each allocation area,
In the master label table, the relative position information of the virtual device in the allocation area is stored for each expansion unit attached to the control unit,
The virtual device conversion means is based on the location information of the allocation area for each expansion unit in the memory and the relative location information of the virtual device in the allocation area stored in the master label table. 4. The user program search device according to claim 1, wherein the character string input by the input means is converted into a virtual device. A search apparatus for a user program for searching a character string included in a user program for controlling a programmable logic controller created by a user,
Master label table storage means for storing a master label table in which a master label is associated with a virtual device in the programmable logic controller;
When the master label is changed, a changed label table storage unit that stores a changed label table in which the changed label after the change is associated with the virtual device corresponding to the master label;
User program display means for displaying a label based on the change label table for the virtual device associated with the change label in the change label table when displaying the user program on the screen;
Virtual device conversion means for converting the input character string into a virtual device based on the master label table when a character string to be searched is input;
A program that functions as a user program search unit that searches for a user program based on a virtual device that has been converted by the virtual device conversion unit.

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