JP4692452B2 - Program creation method of programmable controller - Google Patents

Description

  The present invention relates to a program creation method for a programmable controller using a programming language defined in JISB3503 (IEC61131-3), and in particular, a program creation method using a range data type variable, which is one of the derived data types of variables. It is related to.

  In JISB3503 (IEC61131-3), four types shown in the following table are defined as variable data types. The explanatory text in JISB3503 is shown below. “Table 12” in the table is a table number in JISB3503.

  Currently, IEC61131-3 compliant PLCs (programmable controllers) are available from various companies. In creating the PLC program, variables individually declared in the above data form are appropriately incorporated in the program according to the purpose, and operations can be executed using these variables.

In programming using these variables, a device has been proposed that increases the validity of the program by automatically performing the type check, size check, value check, etc. of the declared variable and reduces the programming burden ( For example, see Patent Document 1).
JP-A-7-281880

  However, there is no PLC that can handle all four types of derived data types shown in the above table. In particular, in the case of a partial range data type, it cannot be determined whether the target variable is within the partial range of the variable when the program is compiled. For this reason, during the execution of the calculation, it is necessary to perform the calculation while verifying whether the calculation target data is within the defined partial range, which makes accurate programming difficult.

  For example, as shown in FIG. 3A, the partial range data type is declared as an integer “INT” and a range “−6 to +12” as the definition of the variable “VAL1”, and this variable “VAL1” is defined. When used as the operation result of the addition instruction “ADD” shown in FIG. 3B, if the value of the input data “IN1” is “−17” or less, or “3” or more, the variable “VAL1” is “ It is out of the range of “−6 to +12”. This check cannot be performed by the compiler, and can only be performed during program execution.

  Further, as a reason why the PLC corresponding to the partial range data type has not been released, it is also mentioned that the handling method when the calculation target data is out of the partial range is not clearly defined in IEC61131-3. However, in the function language, “EN flag” is defined, and there is a description that when the function is activated with EN flag = 1, if there is an operation error in the function, EN flag = 0.

  For example, in FIG. 4, if the calculation condition connected to the EN input terminal is true, the function performs the calculation. In this case, an operation is performed on input 1 and input 2, and the operation result is output. If there is no error during the calculation, true is output to the ENO terminal, but if there is an error, false is output.

  LIMIT is defined as a standard function of IEC61131-3. This function checks the upper and lower limits of the input variable and has the following form. In the LIMIT function, as shown in FIG. 5A, the numerical value given by the input “IN” is limited by the upper and lower limits by MN (lower limit value) and MX (upper limit value). For example, when MN = 0 and MX = 1000, if IN = 2000, the output is 1000. If this function is used, it is possible to perform calculations without using a subrange data type. However, since the LIMIT function limits the output to the upper and lower limits even when the input exceeds the upper limit and the lower limit, it cannot be used to check the validity of the input. That is, there is no error detection function. For example, as shown in FIG. 5B, when the output of the variable “VAL1” is limited by LIMIT, the variable “VAL1” is only limited to the range of (−6 to +12), and an error occurs during the check during calculation. It cannot be detected.

  It is an object of the present invention to provide a program creation method for a programmable controller that facilitates checking and confirming the occurrence of upper and lower limit deviations when using a partial range data type variable.

  In order to solve the above problem, the present invention automatically embeds the LIMIT function with EN and the EN flag check function when the partial range data type variable is used, and the partial range data type variable is Can be detected and confirmed, and has the following configuration.

(1) In a program creation method of a programmable controller that converts a function described in a source program into a target program by a compiler,
When the input variable of the function is a partial range data type variable, the compiler executes a LIMIT function instruction with EN for performing a partial range check on the variable, and when the variable does not fall within the partial range check. An EN flag check function instruction for storing the calculation program position at that time is automatically embedded in the conversion program.

  (2) The EN flag check function instruction obtains an output that can be confirmed by an application program when the variable does not fall within the partial range check.

  As described above, according to the present invention, when a partial range data type variable is used, the compiler automatically embeds the LIMIT function with EN and the EN flag check function, and the partial range data type variable deviates from the partial range. Therefore, it is easy to check and confirm the occurrence of deviation from the upper and lower limits when using the partial range data type variable.

(Embodiment 1)
FIG. 1 is a schematic diagram of program creation showing this embodiment, in which a partial range data type is designated for the variable X of the addition function.

  An addition function (ADD) 1 as a source program of an application program is an operation of adding a variable X and a variable Y to obtain an operation result Z (= X + Y). When described in an IL (Instruction List) language, It becomes the combination of the command shown.

  The compiler 2 obtains the conversion program 3 obtained by compiling the source program of the addition function 1 into the target program of the programmable controller. Here, if the variable X is a partial range data type and the upper limit is 1000 and the lower limit is 0, the compiler 2 sets the LIMIT function instruction with EN 3A and the EN flag check function instruction 3B for the variable X. Is automatically embedded in the conversion program to enable detection of range deviation errors. However, the instruction 3A and the instruction 3B are not shown as the source program, and only the instruction 3C which is the same as the addition function 1 is made to appear.

  In the conversion program 3 of FIG. 1, a partial range check is performed on the variable X using the LIMIT function instruction with EN 3A. The LIMIT function with EN sets ENO = 1 if the input data (variable X) is within the partial range (0 to 1000), and ENO = 0 if not. The EN flag check function instruction 3B operates only when ENO = 0, and stores the operation program position at that time. The operation program position is stored in the memory of the system program of the PLC so that it can be displayed as a source program position searched based on the error occurrence address by an apparatus such as a programming tool.

  When the variable Y is also a partial range data type variable, the compiler 2 automatically adds the EN-attached LIMIT function instruction 3A and the EN flag check function instruction 3B to the variable Y as well.

  Therefore, according to the present embodiment, when programming using the partial range data type variable, it is possible to program the application program so that the appearance is not particularly changed between the normal variable and the partial range data type variable. Then, the upper and lower limit deviation of the partial range data type variable can be notified to the system program. In addition, it is possible to display the location of a program that uses a variable that has deviated from the upper and lower limits using a programming device.

(Embodiment 2)
FIG. 2 is a schematic diagram of program creation showing this embodiment, in which a partial range data type is designated for the variable X of the addition function.

  1 is different from FIG. 1 in that the EN flag check function instruction 3B is set to output = 1 when ENO = 0. By doing so, the application program can also confirm that the partial range data has deviated from the upper and lower limits.

  In FIG. 2, when the variable X deviates from the upper and lower limits, the variable ERROR becomes true, and it can be confirmed by the application program that there has been a partial range data error. In this case, it is assumed that the EN flag check function instruction 3B can be used freely from the application program as an explicit one.

  According to this embodiment, the upper and lower limit deviation of the partial range data type variable can be confirmed by the application program.

  If the variable Y is also a partial range data type variable, the compiler 2 automatically adds an EN-attached LIMIT function instruction 3A and an EN flag check function instruction 3B for the variable Y as well.

  Further, although the first and second embodiments show the case of the partial range data type variable for the addition function instruction, the present invention can be similarly applied to other function instructions.

The schematic diagram of the program creation which shows Embodiment 1 of this invention. The schematic diagram of the program creation which shows Embodiment 2 of this invention. An example of a subrange data type. Function example. An example of a LIMIT function.

Explanation of symbols

1 Addition function 2 Compiler 3 Conversion program 3A LIMIT function instruction with EN 3B EN flag check function instruction 3C Addition instruction

Claims (2)

In the program creation method of the programmable controller that converts the function described in the source program into the target program with the compiler,
When the input variable of the function is a partial range data type variable, the compiler executes a LIMIT function instruction with EN for performing a partial range check on the variable, and when the variable does not fall within the partial range check. A program generation method for a programmable controller, comprising means for automatically embedding an EN flag check function instruction for storing a calculation program position at that time in a conversion program.   2. The program creation method of a programmable controller according to claim 1, wherein the EN flag check function instruction obtains an output that can be confirmed by an application program when the variable does not fall within the partial range check.

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