KR100234982B1 - Automatic execution-order decision method for function blocks in a logic diagram - Google Patents

Abstract

The present invention can enhance the convenience of the author by allowing the execution order of each functional block made by the functional block diagram technique, an international standard language for writing control logic, to be accurately determined irrespective of the position and size on their graphic screen. A method for determining the execution order of an arbitrarily created functional block diagram. According to an aspect of the present invention, there is provided a method of determining an execution order of an arbitrary functional block diagram, the method comprising: (a) parsing a graphic screen on which an arbitrary functional block diagram is created to check input / output connection relations of respective functional blocks; (b) dividing the entire functional block into an unconstrained functional block group that can be executed immediately and another limited functional block group only prior to executing the entire functional block based on the connection relationship identified in step (a); (c) determining and storing an execution order of functional blocks belonging to the unrestricted functional block group according to a predetermined rule; (d) repeating step (b) or below for the functional blocks belonging to the restricted functional block group on the premise of executing the unrestricted functional blocks until the execution order of all functional blocks is determined.

Description

How to Determine Execution Order of Arbitrarily Created Functional Block Diagrams

The present invention relates to a method of determining an execution order of an arbitrarily written functional block diagram. In particular, the execution order of each functional block created by the functional block diagram technique, which is an international standard language for writing control logic, is independent of their position on a graphic screen. It relates to a method of determining the execution order of an arbitrarily written functional block diagram that can be accurately determined.

Function Block Diagram (hereinafter simply referred to as FBD) is an international standard for creating control logic for control and monitoring systems, such as a programmable logic controller or a distribution control system. It is a kind of language defined by IEC (International Electrotechnical Commission) 1131-3. IEC 1131-3 provides standards for two textual languages and three graphical languages. FBD is the most representative graphical language. The FBD is arranged to perform various operations by arranging various types of functional blocks having specific functions and connecting their input / output signals.

On the other hand, the FBD has a standard convention that the function block can be placed anywhere on the screen provided by the FBD writing tool within the extent easily understood by the author and the related parties, and the input / output of these can be freely connected. Have. Therefore, in order to comply with the above-described standard rules of FBD, the processing order of the functional blocks must be fully automatically processed for the arbitrarily written FBD. However, most of the existing methods have some degree of the FBD creation process as in the following example. It requires a constraint of. For example, suppose that one output of an arbitrary function block (called "FBa") is connected to one of the inputs of another function block (called "FBb"). Of course, should be preceded by the processing of "FBb". In this case, the existing FBD writing tools are generally restricted that the position of "FBa" on the graphic screen should be located on the left side and the top of the position of "FBb". This is because most FBD writing tools process the function blocks located at the top left according to their position on the graphic screen before the function blocks located at the bottom right. Therefore, the technician or end user who writes the control logic should execute it first in the execution of the entire control logic considering the order in which each function block is executed according to the scenario to connect the input / output signals. It must be located.

1 is a view for explaining a method of determining the execution order of functional blocks in a conventional functional block diagram creation tool. For convenience, the connection between input and output signals of each functional block is not displayed. In the creation tool shown in Fig. 1, the canvas for creating an FBD is divided into eight horizontal and eight vertical cells, and each cell is numbered 1 to 64. In addition, one cell can select and locate one arbitrary function block. In this process, the function block to be executed first is placed on the upper left side in consideration of the input / output of each function block. Therefore, in the FBD in which 12 functional blocks are drawn as shown in the example of FIG. 1, the execution order of each functional block is 1-> 2-> 3-> 4- > 5-> 6-> 7-> 8-> 9-> 10-> 11-> 12. On the other hand, assuming that the leftmost column is executed from the top row to the bottom row, 1-> 4-> 12-> 8-> 3-> 5-> 9-> 7-> 6-> 11-> 2-> 10 Will be executed in order.

However, in the process of writing control logic in the actual FBD language, when the output of a function block is connected to the input of a function block located at the left or upper side according to the convenience or preference of the author, that is, the function block located at the right or the bottom is There are many cases where it needs to be executed first.

2 is a diagram illustrating a functional block diagram for explaining a problem of a method for determining an execution order of functional blocks in a conventional functional block diagram preparation tool. In the example shown in Fig. 2, on the screen of the control logic, it is easy to see that the execution order of the function blocks should be FB1-> FB7-> FB2-> FB3-> FB5-> FB4-> FB6-> FB8. And the performer of doing this has a problem of performing an operation in an undesired manner by misinterpreting the control logic. That is, FB1-> FB2-> FB3-> FB4-> FB5-> FB6-> FB7-> FB8 or FB1-> FB7-> FB2-> FB5-> FB3-> FB4-> FB6-> There was a problem running in the order of FB8. In particular, when a feedback loop is created using the FBD, there is a problem that the plant or the processor to be controlled becomes unstable due to the above operation.

In addition, the conventional FBD writing tool for placing functional blocks one by one in a predetermined cell is not only in violation of the IEC 1131-3 standard that the functional blocks should be located at a desired location, but also for each function depending on the number of inputs and outputs of the functional blocks. Given that the blocks all have different sizes, the problem is that they are actually very inefficient.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is possible to accurately determine the execution order of each functional block made by the functional block diagram technique, an international standard language for writing control logic, irrespective of the position and size on their graphic screen. The purpose of the present invention is to provide a method of determining an execution order of an arbitrarily written functional block diagram, which facilitates the convenience of the author.

Another object of the present invention is to provide a randomly written method that automatically determines the correct order of execution of a large number of functional blocks placed on a graphic screen provided by the FBD during the parsing or compilation process of the FBD writing tool program. The present invention provides a method for determining an execution order of a functional block diagram.

According to an aspect of the present invention, a method for determining an execution order of an arbitrarily created functional block diagram includes: (a) parsing a graphic screen on which an arbitrary functional block diagram is created to check input / output connection relations of respective functional blocks; step; (b) dividing the entire functional block into an unconstrained functional block group that can be executed immediately and another limited functional block group only prior to executing the entire functional block based on the connection relationship identified in step (a); (c) determining and storing an execution order of functional blocks belonging to the unrestricted functional block group according to a predetermined rule; (d) repeating step (b) or below for the functional blocks belonging to the restricted functional block group on the premise of executing the unrestricted functional blocks until the execution order of all functional blocks is determined.

On the other hand, the execution order determination method of the arbitrarily created functional block diagram according to another aspect of the present invention is a flag indicating whether or not the execution order of each functional block is determined, the function block of the functional block of which the identification number of each functional block is k One-dimensional array space (i_count) to store the number of inputs connected to the output, one-dimensional array space (ready) to store identification numbers of the functional blocks having a value of the one-dimensional array space (i_count) and a function block of identification number i Allocating a two-dimensional array link in order to store identification numbers of functional blocks using the output of the input as an input; (b) filling the one-dimensional array space (i_count) and the two-dimensional array space (link) after parsing a graphic screen on which a functional block diagram has been prepared and checking the input / output connection relationship of each functional block; (c) storing identification numbers of the functional blocks having a value of the one-dimensional array space (i_count) equal to zero in the one-dimensional array space (ready); (d) checking the flag to determine whether there is a flag whose execution order is already determined in the one-dimensional array space; (e) If there is a function block whose execution order has not yet been determined as a result of the determination in the step (d), the execution order of the execution block is determined and stored, and the corresponding flag is set by indicating that the execution order has already been determined. Reducing the one-dimensional array space (i_count) value by one and (f) repeating step (c) or below until all flags are set. In the above configuration, the identification number of each functional block may be arbitrarily assigned in the order of serial number during the parsing process of step (b).

1 is a view for explaining a method of determining the execution order of functional blocks in a conventional functional block diagram creation tool;

2 is a view for explaining a problem of a method for determining an execution order of functional blocks in a conventional functional block diagram preparation tool;

3 is a flowchart for explaining a method of determining execution order of an arbitrarily created functional block diagram of the present invention;

4 is an exemplary diagram of a functional block diagram arbitrarily created to illustrate the method of the present invention.

Hereinafter, a method of determining an execution order of an arbitrarily written functional block diagram according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings, and the present invention basically includes a parser and a compiler software. Since it is related to the basic algorithm for implementation, description will be made based on the basic flowchart of the algorithm instead of the hardware drawing.

First, in order to determine the execution order of the respective functional blocks as described above, each functional block is given a random number from 1 to N completely randomly, and these are parsed into the serial number by parsing the graphic screen FBD in the algorithm. The precondition that random assignment is to be satisfied. In addition, for each functional block, as shown in Table 1, a space for storing related information should be secured.

Definition of various variable names Variable name Characteristics Explanation flag [k] Boolean variable Indicates whether or not the function block with identification number k is performed; initial value is 0; i_count [k] One-dimensional array Number of inputs connected to the outputs of other function blocks in the function block with identification number k ready [N] One-dimensional array Array space in which the identification numbers of the function blocks with i_count variable value of 0 are stored link [i, j] 2-dimensional array (0≤j≥N-1) An array space in which the identification numbers of elements that use the output of the function block with the identification number i as inputs are stored in order starting from j = 1 and the rest are zeros.

3 is a flowchart for explaining a method of determining an execution order of an arbitrarily written functional block diagram of the present invention. In FIG. 3, only the algorithm for determining the execution order is used. Therefore, the meaning of the term “execution” should be implemented. It is assumed that the identification number of the function block to be printed is printed in the order table indicating the execution order.

First, since the output of another function block and a function block whose input is not connected, that is, a function block having a value of ＂i_count＂ of 0, can be executed first, in step S10, a graphic screen in which an arbitrary FBD is created is parsed. These identification numbers are stored in order in "ready", which is the one-dimensional array space described above. Next, in step S20, it is determined whether the function flag stored in the ready table has a value of "flag" of 0, that is, a function block that has not yet been executed. If at least one function block having a value of "flag" is 0 in step S20, the flow advances to step S30 to convert the value of i-count value of the function block to which the output of the function block is connected. Use to decrease by 1. Next, in step S40, the function block is executed, that is, the identification number is printed in the execution order table of contents, and in step S50, ＂flag＂ of the function block is set so that the function block is executed. , That is, to 1 Next, in step S60, it is determined whether "flag" of all function blocks is set. If there is a function block in which "flag" is not set in step S60, "flag" of all function blocks is set. The program is terminated after repeating steps S60 and below.

This algorithm can be expressed by borrowing the form of "C language".

1. INITIONALIZATION

k1 <-0

FOR i = 1 TO N FOR j = 0 TO (N-I) link [i, j] <-0

2.for id = 1 TO N

IF (i_count [id] = 0) THEN {ready [k1] <-id, k1 <-k1 + 1}

3. FOR k2 = 0 TO (k1-1) {

id <-ready [k2];

IF (flag [id] = 0) THEN {

FOR k3 = 0 TO (o_count [id] -1)

IF (link [id, k3] ＞ 0) THEN

i_count [link [id, k3]] <-i_count [link [id, k3] -1;

PRINT (＂id＂);

flag [id] <-1; }

}

4. IF All flag [id] = 0, id = 1,2, ..., N THEN ends.

ELSE repeat step 2-3.

Hereinafter, the operation of the execution order determination method of the arbitrary functional block diagram of the present invention will be described in detail.

4 is an exemplary diagram of a functional block diagram arbitrarily created to explain the method of the present invention, wherein BK1 to BK6 represent functional blocks arbitrarily created by a user. Graphical parsing of the functional block diagram illustrated in FIG. 4 generates variables with initial values set forth in Tables 2 and 3 below, as in the foregoing preconditions.

link [i, j] variable link [i, j] i = 1 i = 2 i = 3 i = 4 i = 5 i = 6 j = 0 6 4 0 0 One 4 j = 1 0 0 ; ; 3 0 j = 2 ; ; : ; 0 ; j = 3 : : ; : ; : : ; ; ; ; : ;

i_count [k] value i = 1 i = 2 i = 3 i = 4 i = 5 i = 6 i_count [k] One 0 One 2 0 One

As can be seen in Table 3 above, the function blocks having the value of i-count 0 are BK2 and BK5. In step S10, the functional blocks to be executed in the order of BK2 and BK5 in the one-dimensional array space ＂ready＂ Will be saved. Next, in step S20, since these functional blocks have not yet been executed, the process proceeds to step S30 to identify the function blocks to which the outputs of the function blocks are connected, that is, BK4 and BK1 using the variable ＂link＂. Later, the value of &quot; i_count &quot; of this functional block is decreased by one. Thus, at this point the value of i_count of function block BK4 will be the first two to one, and the value of i_count of the function block BK1 will be first one to zero. Next, in step S40, the function blocks BK2 and BK5 are executed sequentially, that is, printed. In step S50, the corresponding 'flag' is set so that the function blocks BK2 and BK5 are executed.

On the other hand, in step S60, only the functional blocks BK2 and BK5 have been executed at this point in time, so the program returns to step S10.

As a result of the return to step S10, at this point in time, the functional blocks to be executed in the order of the functional blocks BK1, BK2, BK3 and BK5 are stored in the array space "ready". Next, in step S20, a function block that has already been executed is determined by checking through the corresponding 'flag'. Thus, execution of the identified function blocks BK2 and BK5 is omitted in step S50. Next, for the function blocks BK1 and BK3 that have not yet been executed, the function block to which the output of the function block is connected using the variable link in step S30, that is, the BK6 (in this example, the function block connected to BK3) Ignore this function and ignore it, and then decrease the i_count value of this function block by one. Therefore, the value of i_count &quot; of the function block BK6 at this point will be from 1 to 0 in the first place. Next, in step S40, the function blocks BK1 and BK3 are executed sequentially, that is, printed. In step S50, the corresponding 'flag' is set so that the function blocks BK1 and BK3 are executed.

On the other hand, in step S60, only the functional blocks BK1, BK2, BK3 and BK5 have been executed at this point in time, so the program returns to step S10. As a result of the return to step S10 At this point in time, the functional blocks to be executed in the order of the functional blocks BK1, BK2, BK3, BK5 and BK6 are stored in the array space "ready". Next, in step S20, the function blocks BK1, BK2, BK3, and BK5, which have already been executed, are checked through the corresponding 'flag', and the function blocks thus confirmed are omitted in the subsequent step S50. Next, for BK6, which has not yet been executed, after checking the function block to which the output of the function block is connected, that is, BK4, using the variable ＂link 변수 in step S30, the value of＂ i_count ＂of this function block is determined. Decreases by 1. Thus, the value of &quot; i_count &quot; of the function block BK4 at this point will decrease from 1 back to zero. Next, in step S40, the function block BK6 is executed, i.e., printed, and in step S50, the corresponding &quot; flag &quot; is set so that the function block BK6 is executed.

On the other hand, in step S50, since there exists a function block BK4 that has not yet been executed at this point in time, the program returns to step S10. As a result of the return to step S10 At this time, the functional blocks to be executed in the order of the functional blocks BK1, BK2, BK3, BK4, BK5 and BK6 are stored in the one-dimensional array space "ready". Next, in step S20, these already executed functional blocks BK1, BK2, BK3, BK5, and BK6 are identified through corresponding 'flag', and the thus confirmed functional blocks are omitted from the subsequent step S50. do. Next, for BK4, which has not yet been executed, the function block to which the output of the function block is connected is checked using the variable ＂link＂ in step S30. Proceed to step S40. Next, in step S40, the function block BK4 is executed, i.e., printed. In step S50, the corresponding flag is set so that the function block BK4 is executed.

On the other hand, in step 60, the program returns to step S10 because it is not yet possible to confirm whether function block BK4 has been executed at this time. As a result of the return to step S10 At this time, the functional blocks to be executed in the order of the functional blocks BK1, BK2, BK3, BK4, BK5 and BK6 are stored in the one-dimensional array space "ready". Next, in step S20, the program is terminated because no functional block exists.

Therefore, the order in which the respective functional blocks are performed in the given FBD at the end of the algorithm is precisely ＂2-> 5-> 1-> 3-> 6-> 4＂.

Meanwhile, as can be seen from the above description, it can be seen that the number of repetitions of steps S10 to S60 is determined depending on the identification number assigned to each functional block. In other words, as the identification numbers of the initially assigned functional blocks are similar to the order in which they are to be actually performed, the number of iterations of the algorithm according to the method of the present invention is reduced, so that a more efficient algorithm can be created.

On the other hand, in general, since the identification number assigned to the functional block in the FBD is usually determined by the creation order during the user's writing, it may be considered to be inefficient because the number of iterations of the algorithm is increased in some cases. However, since the algorithm according to the present invention is performed only once as a step of the compiler before the control logic is written and downloaded, the inefficiency of the algorithm as described above is very small.

The execution order determination method of the arbitrarily created functional block diagram of the present invention is not limited to the above-described embodiments, and can be modified in various ways within the scope of the technical idea of the present invention. For example, the method of the present invention can be applied without being bound by specific markers representing functional blocks or input / output relationships on any specific writing tool.

According to the execution order determination method of the arbitrarily created functional block diagram of the present invention as described above, since the execution order is determined based on the input / output relationship of each functional block in the arbitrarily created functional block diagram, the position of the functional block on the graphic screen. And the convenience of arbitrarily setting the size.

Claims (3)

(a) parsing a graphic screen on which a function block diagram has been created and confirming an input / output connection relationship of each function block; (b) dividing the entire functional block into an unconstrained functional block group that can be executed immediately and another limited functional block group only prior to executing the entire functional block based on the connection relationship identified in step (a); (c) determining and storing an execution order of functional blocks belonging to the unrestricted functional block group according to a predetermined rule; and (d) repeating step (b) or below for the functional blocks belonging to the restricted functional block group on the premise of the execution of the unrestricted functional blocks until the execution order of all the functional blocks is determined. How to determine the execution order of the created functional block diagram. (a) a flag indicating whether the execution order of each functional block is determined, a one-dimensional array space (i_count) for storing the number of inputs connected to the outputs of other functional blocks for a functional block whose identification number of each functional block is k, Stores identification numbers of functional blocks that use the one-dimensional array space (ready) for storing the identification numbers of the functional blocks having the value of the one-dimensional array space (i_count) and outputs of the functional blocks having the identification number as input, in order. Allocating a two-dimensional array link; (b) filling the one-dimensional array space (i_count) and the two-dimensional array space (link) after parsing a graphic screen on which a functional block diagram has been prepared and checking the input / output connection relationship of each functional block; (c) storing identification numbers of the functional blocks having a value of the one-dimensional array space (i_count) equal to zero in the one-dimensional array space (ready); (d) checking the flag to determine whether there is a flag whose execution order is already determined in the one-dimensional array space; (e) If there is a function block whose execution order has not yet been determined as a result of the determination in the step (d), the execution order of the execution block is determined and stored, and the corresponding flag is set by indicating that the execution order has already been determined. Reducing the one-dimensional array space (i_count) value by one; and and (f) repeating step (c) or below until all flags are set. The method of claim 2, wherein the identification number of each functional block is randomly assigned in the order of serial number during the parsing of step (b).

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