JP2007280214A - Programmable controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a programmable controller capable of simplifying a monitor device to be connected to perform a monitoring operation and accelerating the monitoring operation a in speed. <P>SOLUTION: The programmable controller 300 downloads a performance code and a table generated by using a hash function generation system 120 on a different programming device 100 which are performance codes (variable name hash function (103)) of a predetermined function program for deriving a hash value from a variable name and a table (allocation destination address arrangement 104) for deriving an allocation destination address of a monitor value from the hash value in a storing part, determines an allocation destination address for a variable name inputted from the outside by referring to an evaluation result by a function program and the table and outputs a corresponding monitor value. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a programmable controller, and more particularly to a programmable controller that outputs a monitor value corresponding to a variable name input from the outside.

  FIG. 4 is a schematic diagram showing the configuration of a conventional programmable controller and its peripheral devices. In FIG. 4, a programmable controller (PLC: Programmable Logic Controller) 1300 stores a PLC execution code 102 in a storage unit (not shown). The PLC execution code 102 is compiled by the programming device 1100 into an execution code (load module) and downloaded to the programmable controller 1300. The programmable controller 1300 outputs the monitor value corresponding to the variable name input from the monitor device 1200 to the monitor device 1200 by executing the PLC execution code 102.

  The programming device 1100 stores a PLC source code 101 described in a high-level programming language such as a structured text language (ST language) defined in the international standard ICE61131-3. Is compiled using a PLC execution code generation system (compiler) 110 to generate a PLC execution code 102. In this specification, “compiling” means converting a design drawing (source code) of software created by a human using a programming language into a format (executable code) executable on a computer. .

  The PLC execution code generation system 110 generates a variable allocation table 130 that is an intermediate product in the process of compiling the PLC execution code 102. In the variable allocation table 130, variable names found on the PLC source code 101 during compilation are sequentially registered. Further, necessary areas are sequentially assigned from the empty areas in the data memory of the programmable controller to the registered variable names, and the memory addresses are recorded. Conventionally, the variable allocation table 130 is filed and copied to a monitor device 1200 that monitors the programmable controller 1300. When the monitor device 1200 performs a monitoring operation, the variable allocation table 130 is a correspondence table for deriving an allocation destination address of a monitor value from a variable name It was used.

  The variable assignment table search system 1220 of the monitor device 1200 uses this variable assignment table 130 to derive the monitor value assignment destination address 1203 from the variable name 201 to be monitored input by the operator. Then, the PLC communication system 210 inquires of the peripheral service processing system 1330 of the programmable controller 1300 about the monitor value at the allocation destination address 1203. The peripheral service processing system 1330 of the programmable controller 1300 acquires the monitor value stored in the assignment destination address 1203 via the PLC execution control system 310, and outputs this monitor value to the monitor device 1200. Conventionally, the monitoring operation of the monitor device 1200 with respect to the programmable controller 1300 has been performed in this manner.

  Here, the difference between a computer general-purpose device such as a personal computer and a programmable controller will be mentioned. Programmable controller refers to a programmable logic control device that performs so-called sequence control applicable to a wide range of applications including factory automation (FA) field, and simulates logical interconnection of signals according to a ladder diagram or a function chart, for example. This refers to a dedicated device, and generally has more input / output functions than a general-purpose device such as a personal computer, but the capacity of the storage device is small.

  Conventionally, problems related to the storage capacity of a storage device have existed over a wide technical field for a long time. Conventionally, it has been proposed to use a hash function for the purpose of reducing the storage area and for the purpose of reducing the search time. For example, in a search operation of an electronic dictionary in a word processor or the like, it has been proposed to shorten the time required for spell check using a hash function (see, for example, Patent Document 1).

JP-A-62-74153

  In the prior art shown in FIG. 4, the variable allocation table 130 generated as an intermediate product during the compilation process has the variable name itself inside. Therefore, a very large storage area is consumed by the variable allocation table 130 in the technical field of programmable controllers that register many relatively long variable names. On the other hand, the storage unit of the programmable controller 1300 has a smaller storage area than the storage unit of a general-purpose device such as a personal computer as described above. Therefore, it is not easy to store the variable allocation table 130 in the storage unit of the programmable controller 1300. Conventionally, as shown in FIG. 4, the variable allocation table 130 is provided on the monitor device 1200 side that performs the monitoring operation of the programmable controller 1300. It was held.

  Further, conventionally, the monitor device 1200 has a variable assignment table search system 1220. In this variable assignment table search system 1220, the assignment destination address must be searched from the variable name using the variable assignment table 130. In addition to not being able to perform the operation speedily, it is necessary to use, for example, a personal computer having a large storage area and high performance as the monitor device 1200, resulting in an increase in cost.

  On the other hand, in the method proposed in Patent Document 1, when the word groups are grouped and registered in the dictionary, the number of words per group is adjusted by increasing or decreasing the number of digits of the index of the hash value. Therefore, by setting the number of digits in the index sufficiently large, the number of groups is increased compared to the case of grouping by initial and number of characters, and the number of words per group is decreased accordingly, thereby reducing the time required for spell check. Shorten. However, this technique is effective when the search elements are grouped, and the variable assignment table of the above problem is not particularly applicable because the search elements are not grouped.

  The present invention has been made to solve the above-described problem, and the conversion means for deriving the allocation destination address from the variable name to be given to the programmable controller can be made small. It can be easily stored in the storage unit. On the other hand, there is no need to have a variable allocation table on the monitor device side, the monitor device can be simplified, and the monitoring operation performed by the monitor device can be performed at high speed. It is an object of the present invention to provide a programmable controller that can do the above.

  In order to solve the above problems, a programmable controller according to the present invention is an execution code and a table generated using a hash function generation system on another programming device, and has a predetermined value for deriving a hash value from a variable name. The execution code of the function program (variable name hash function) and the table (assignment destination address array) for deriving the assignment destination address of the monitor value from the hash value are downloaded to the storage unit, and the variable name input from the outside Then, the allocation destination address is determined by referring to the evaluation result by the function program and the table, and the corresponding monitor value is output to the outside.

  According to the conventional programmable controller, as described above, since the variable allocation table has the variable name itself, a very large storage area is consumed in a situation where many variable names having a long name are registered. Therefore, it could not be easily stored in the storage unit of the programmable controller. However, according to the programmable controller of the present invention, as a conversion means for deriving the monitor value assignment destination address from the variable name, the function program execution code (variable name hash function) for deriving the hash value from the variable name and the hash value are used. A table (assignment destination address array) for deriving the assignment destination address of the monitor value is downloaded to the storage unit. And since the hash function for deriving the hash value does not have the variable name itself and is merely an arithmetic program that maps the character string given as the input argument of the function to a specific value, the execution code of the program is Compared with the variable allocation table generated as an intermediate product during the compilation process, it can be made very small. Therefore, it can be easily stored in the storage unit of the programmable controller.

  Further, according to the programmable controller according to the present invention, the hash function for deriving the hash value is composed of a relatively simple arithmetic program, and a linear search conventionally used for the purpose of finding the target variable name from the variable allocation table. Compared to a search program using an algorithm or a binary tree search algorithm, the program can be executed at high speed. As a result, the monitoring operation performed by the monitoring device can be performed at high speed.

  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.

Embodiment FIG. 1 is a schematic diagram showing the configuration of a programmable controller and its peripheral devices according to an embodiment of the present invention. In FIG. 1, the programmable controller 300 allocates a PLC execution code 102, a variable name hash function 103 which is an execution code of a function program as claimed in a claim, and a table which is also a claim as a claim in a storage unit (not shown). The destination address array 104 is stored. The PLC execution code 102, the variable name hash function 103, and the allocation destination address array 104 are generated by another programming device 100 such as a personal computer and downloaded to the programmable controller 300, for example. The programmable controller 300 outputs a monitor value corresponding to the variable name input from the monitor device 200 by executing these execution codes (load modules).

  The programming device 100 according to the present embodiment stores a PLC source code 101 described in a high-level programming language such as a structured text language (ST language) defined in the international standard ICE61131-3, for example. . Then, the PLC execution code 102 is generated by compiling the PLC source code 101 using a PLC execution code generation system (compiler) 110.

  The variable allocation table 130 is a table generated by the compiler as an intermediate product in the process of compiling the PLC source code 101, and newly found while picking up the variable names on the PLC source code 101 during compilation. The Then, necessary areas are sequentially assigned from the empty areas in the data memory of the programmable controller 300 to the registered variable names, and the memory addresses are recorded. This variable allocation table 130 is a correspondence table for deriving the allocation destination address of the monitor value from the variable name. In the variable assignment table 130, for example, variable names and assignment destination addresses are described as follows.

Variable name Allocation address
VAR1 D0020
PUMP_STATUS D1234
::

  The minimum complete hash function generation system 120 generates a minimum complete hash function 103 (hereinafter referred to as a variable name hash function 103) that receives a variable name registered in the variable assignment table 130 as an input. The variable name hash function 103 derives a value (hash value) of 0 to N−1 that does not collide with the keys of the total N variable names. In the present embodiment, “GNU gperf” which is a table generation utility for the minimum complete hash function is used as the minimum complete hash function generation system 120. The minimum complete hash function generation system 120 also generates an allocation destination address array 104 from the variable allocation table 130 and the variable name hash function 103. This allocation destination address array 104 is an allocation destination address array of monitor values using the hash value of the variable name hash function 103 as an array index.

  The programmable controller 300 includes a hash function evaluation system 320 in addition to the PLC execution control system 310 and the peripheral service processing system 330 that are also included in the prior art. As described above, the programmable controller 300 is downloaded from the programming device 100 to the storage unit (not shown) as a set of the PLC execution code 102, the variable name hash function 103, and the allocation destination address array 104.

  The monitor device 200 that monitors the programmable controller 300 can be connected to the programmable controller 300 by, for example, serial (RS232, RS422, USB) or Ethernet (registered trademark). The monitor device 200 has a PLC communication system 210. The PLC communication system 210 takes in the variable name 201 to be monitored input by the operator, and outputs the variable name 201 as it is. The service processing system 330 is inquired about the monitor value. For example, an inquiry is made as follows.

“VAR1”?
“PUMP_STATUS”?

  Then, the corresponding variable monitor value 202 is obtained from the peripheral service processing system 330 of the programmable controller 300. On the other hand, the peripheral service processing system 330 first passes the received variable name to the hash function evaluation system 320. Next, the hash function evaluation system 320 uses the variable name hash function 103 to derive a hash value from the variable name, and further assigns it. The allocation address of the monitor value is derived from the hash value using the destination address array 104. Then, the peripheral service processing system 330 reads the data stored in the allocation destination address and outputs the data to the monitor device 200 as a variable monitor value.

  FIG. 2 is a flowchart showing the operation of the generation process of the variable name hash function 103 and the allocation destination address array 104 performed by the minimum complete hash function generation system 120 of the programming device 100. A process of generating the variable name hash function 103 and the allocation destination address array 104 will be described with reference to FIG. When the generation of the variable name hash function 103 and the allocation destination address array 104 is started, first, a variable name list is extracted from the variable allocation table 130, and this is given to the minimum complete hash function generation system 120, so that the variable name hash function 103 is generated (step S1).

  Next, an allocation destination address array 104 having the same number of elements as the number of variable names is prepared (step S2). Next, variable names and their allocation destination addresses are sequentially stored in the allocation destination address array 104 from the variable allocation table 130. Are enumerated (step S3). Further, the enumerated variable names are given to the variable name hash function 103 and evaluated (execution of the function), and a hash value is obtained (step S4). Then, the allocation destination address is stored in the array element of the variable allocation destination address array using the obtained hash value as the array index position (step S5).

  Next, it is confirmed whether or not all the variables in the variable allocation table 130 are enumerated (step S6). If not all the variables are enumerated yet, the process returns to step S3. On the other hand, if all the variables are enumerated, the generation is performed. End.

  FIG. 3 is a flowchart showing an operation of a monitor response based on variable names performed mainly by the hash function evaluation system 320 of the programmable controller 300. The operation of the monitor response by the variable name will be described with reference to FIG. In operation, first, the peripheral service processing system 330 receives the monitoring target variable name from the monitoring device 200 (step S11). Next, the received variable name is given to the variable name hash function and evaluated (the function is executed), and a hash value is obtained (step S12). Then, an allocation destination address is acquired from the array element of the variable allocation destination address array using the obtained hash value as the array index position (step S13).

  Next, the PLC execution control system 310 refers to the value located at the allocation destination address (step S14), and the obtained value is transmitted in response to the monitor device 200 as a monitored variable value (step S15). Become.

  In the programmable controller 300 having such a configuration, for example, an execution code and a table generated using the hash function generation system 120 in an environment of another programming device 100 such as a personal computer, and a hash value is obtained from a variable name. A variable name hash function 103 to be derived and an allocation destination address array 104 to derive an allocation destination address of the monitor value from the hash value are downloaded to the storage unit, and the variable name hash function 103 is obtained for the variable name input from the outside. The assignment destination address is determined by referring to the evaluation result and the assignment destination address array 104, and the corresponding monitor value is output.

  According to the programmable controller 300 of this embodiment, the hash function for deriving the hash value does not have a variable name itself, and an arithmetic program that maps a character string given as an input argument of the function to a specific value Therefore, the execution code of the program can be made very small as compared with the conventional variable allocation table, and can be easily stored in the storage unit of the programmable controller 300.

  Furthermore, according to the programmable controller 300 of this embodiment, the hash function for deriving the hash value is a relatively simple arithmetic program, and a linear search algorithm conventionally used to find the target variable name from the variable allocation table. It can be executed faster than a search program using a binary tree search algorithm, and the monitoring operation can be made faster.

  Further, since the hash function to be used is the minimum complete hash function, the corresponding hash value is uniquely determined, and the conversion table can be greatly reduced.

  In this embodiment, a high-level programming language such as a structured text language (ST language) defined in the international standard ICE61131-3 is used as a programming language. However, the present invention is not limited to this. There may be. In this embodiment, “GNU gperf” is used as the table generation utility for the minimum complete hash function, but other utilities may be used.

  Further, for example, a checksum may be added as error detection data to the allocation destination address array 104 of the present embodiment. Thereby, the reliability of data acquisition can be improved by an easy method.

  The present invention is optimally applied to a programmable controller used in the field of factory automation (FA).

It is a schematic diagram which shows the structure of the programmable controller of embodiment which concerns on this invention, and its peripheral device. It is a flowchart which shows the process of the production | generation of a variable name hash function and an allocation destination address array. It is a flowchart which shows the operation | movement of the monitor response by a variable name. It is a schematic diagram which shows the structure of the conventional programmable controller and its peripheral device.

Explanation of symbols

100 Programming Equipment 101 PLC Source Code 102 PLC Execution Code 103 Variable Name Hash Function (Function Program Execution Code)
104 Allocation destination address array (table)
110 PLC execution code generation system (compiler)
120 Minimum complete hash function generation system (hash function generation system)
DESCRIPTION OF SYMBOLS 130 Variable allocation table 200 Monitor apparatus 201 Monitor object variable name 202 Variable monitor value 210 PLC communication system 300 Programmable controller 310 PLC execution control system 320 Hash function evaluation system 330 Peripheral service processing system

Claims (4)

Execution code and table generated using a hash function generation system on another programming device, and an execution code of a predetermined function program for deriving a hash value from the variable name, and assignment of a monitor value from the hash value A table for deriving the destination address is downloaded to the storage unit,
A programmable controller, wherein an assignment destination address is determined by referring to an evaluation result of the function program and a reference to the table for a variable name input from the outside, and a corresponding monitor value is output. The programmable controller according to claim 1, wherein the hash function is a minimum complete hash function. The programmable controller according to claim 1, wherein error detection data is added to the table. The programmable controller according to claim 3, wherein the error detection data is a checksum.

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