JPH087611B2 - How to check sequential function chart of programmable controller - Google Patents

Description

The present invention relates to a method for checking a sequential function chart (hereinafter referred to as SFC) which is a program used by a programmable controller.

[Prior Art] FIG. 8 is a diagram showing a configuration example of an SFC. The blocks in the figure indicate steps, and the symbol "-" in the figure indicates a transition condition. The types of connectors that transfer control to the next step include simultaneous branch 81 (connection in which control transfers from one step to all multiple steps) and simultaneous merging 84 (control from multiple steps to one step Connection to migrate)
There are four types: a branch 82 (a connection in which control shifts from one step to a step in which a transition condition is satisfied) and a merge 83 (a connection in which control is returned to one flow again from the step selected by the branch). In each case, when the respective transition conditions are satisfied, the step advances from the preceding step to the next step (control shift to the next step). In addition, simultaneous branching and simultaneous merging, and branching and merging are always used in pairs. Therefore, FIGS. 9 (a), (b),
Referring to (c), steps 004, 005, 006 are performed for simultaneous branching from step 001 to step 002 and step 003.
The operation in the case where the simultaneous merging to step 007 creates a wrong program that does not form a pair will be described below.

First, step 001 is activated (indicated by a shaded line in the figure) (FIG. 9 (a)), and if the transition condition 100 is satisfied, the process simultaneously branches to steps 002 and 003 (FIG. 9 (b)).
Next, the activated steps 002 and 003 respectively advance to steps 004 and 006 when the transition conditions 101 and 103 are satisfied (FIG. 9 (c)). In this case, step 005 is not activated, so simultaneous merging to the next step 007 is not possible.

Conventionally, a method for checking the presence or absence of such an SFC error has not been particularly proposed, and the user has read each step and checked the operation each time.

[Problems to be Solved by the Invention] In the above-described conventional check method, the user has to check the operation at each step, so that there is a drawback in that the user takes a lot of time and effort to debug the SFC. is there.

[Means for Solving the Problem] In the method for checking the SFC of the programmable controller of the present invention, the numerical value 1 is assigned to the first step of the SFC to set the level of that step, and each time the step advances according to the flow of the program. , If one step is connected only to the next one step, the level of the previous step is moved as it is to the level of the next step, and one step is simultaneously branched and connected to the next multiple steps. In the case of a step, the value of the previous step level is multiplied by the number of the next multiple steps connected at the same time to be the level of each of the multiple simultaneous branch destinations, and one step is connected to the next multiple steps. If so, the level of the preceding step is transferred as it is and set as the level of each step that is branched and connected. If multiple steps are connected to the next one by merging, it is checked whether the levels of the respective merging and connecting steps are all the same. If it is determined that there is an error in the confluent connection, and multiple steps are simultaneously joined to the next one step, the reciprocal of the sum of the reciprocals of the levels of the steps that are jointly joined is calculated as the reciprocal of the next step. Level, and if the level is less than 1, it is determined as an error of the simultaneous merging connection, and when the level of the last step matches the level of the first step, the connection relationship between the steps of the SFC is It is determined to be correct.

[Operation] FIG. 4, FIG. 5, FIG. 6, and FIG. 7 are explanatory diagrams when the present invention is applied to the respective connection examples of simultaneous branching, branching, merging, and simultaneous merging. According to the present invention, the connection information from the previous step to the next step in the SFC program is given to each step according to a predetermined standard. In the following description, this connection information is called a level. Thus, each step can carry the connection information from the first step, conveyed in order by level. In the case of the simultaneous branch connection (FIG. 4), if the level of step 001 is 1, the level of the next steps 002, 003, 004 is multiplied by the number of steps 3, and all are set to 3. In the case of branch connection (FIG. 5), the level of step 001 is directly transferred to the next steps 002 and 003. In the case of the merge connection (FIG. 6), steps 001 and 002 shift the level as it is only when the levels are equal. At this time step 001
If the levels of Step 002 and Step 002 are different, an SFC error occurs. In case of simultaneous merging connection (lower two steps in Fig. 7), sum of reciprocals of level 3 of steps 005, 006 and 007 respectively The reciprocal of 1 is used as the level of the next step 008. Since the level is always 1 or more, if the calculation result in this case is less than 1, it is an SFC error.

Since SFC uses simultaneous branching, simultaneous merging, and branching and merging in pairs, if there is no contradiction in the description of SFC, as shown in the example of FIG. Since the level of the SFC is the same as that of the step of SFC, it is possible to determine whether or not the connection relationship between the steps of the SFC is correct by performing the tracking check of the level of the step.

[Embodiment] Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows the SFC of the programmable controller of the present invention.
FIG. 6 is a diagram showing a configuration of an SFC to which an embodiment of the check method of FIG.

The first step 001 is step 00 via transition condition 100
Simultaneous branch connection to 2,003, step 002 is transition condition 101
Is connected to step 004 through step 003, and step 003 is branched and connected to steps 005 and 006 through transition conditions 102 and 103, respectively. In addition, steps 004, 005, and 006 are transition conditions 104
Connected at the same time to the final step 007 via.

Therefore, when applying this embodiment to this SFC, first,
The level of step 001 is set to an initial value of 1. Step 00
Since 2,003 is simultaneously branched and connected to step 001, the level is 2, and the level of step 004 is 2, because the level of step 002 is 2, and the level of steps 005 and 006 is branched and connected to step 003. , 2 respectively. Here, since steps 004, 005, 006 and step 007 are connected at the same time, the level of step 007 is The reciprocal of the calculation result of is 2/3, which is less than 1, so this SFC is judged as an error. This is an error because there is no merging connection for the branch connection.

FIG. 2 is a diagram showing another configuration of the SFC to which this embodiment is applied.

The first step 001 is branched and connected to steps 002 and 003 via transition conditions 200 and 201, and step 002 is a transition condition 202.
Is connected to the step 004 via the transition condition 203, and the step 003 is connected to the steps 005 and 006 via the transition condition 203 at the same time. In addition, steps 004, 005, and 006 are the transition conditions 2
It is connected to the final step 007 via 04,205,206.

Therefore, when applying this embodiment to this SFC, first,
The level of step 001 is set to an initial value of 1. Step 00
Since 2,003 is branched and connected to step 001, the level is 1, and the level of step 004 is step 002.
The level of Steps 005 and 006 becomes 2 due to the simultaneous branch connection with Step 003.
Here, since step 004, 005, 006 and step 007 are merged and connected, the level matching check is executed, but since the level of step 004 and the level of step 005, 006 do not match, this SFC is judged as an error. . This is an error because there is no simultaneous merging connection for simultaneous branching connections.

FIG. 3 is a diagram showing still another configuration of the SFC to which this embodiment is applied.

The first step 001 is step 00 via transition condition 300
Connected to 2,003 at the same time, step 002 is transition condition 301
Is connected to step 004 through step 003, and step 003 is simultaneously branched and connected to steps 005 and 006 through transition condition 302. Further, steps 004, 005, and 006 are simultaneously merged and connected to the last step 007 via the transition condition 303.

Therefore, when the present embodiment is applied to this SFC, first, the level of step 001 is set to 1 which is the initial value. Step 002,0
The level of 03 becomes 2 by simultaneous branch connection with step 001, the level of step 004 receives the level of step 002, and the levels of step 005 and 006 are step 003.
It becomes 4 each by simultaneous branch connection with. here,
Since steps 004, 005, 006 and step 007 are connected at the same time, the level of the last step 007 is Since this is the reciprocal of the calculation result of 1 and matches the level of the first step 001, this SFC can be judged to be valid.

[Effects of the Invention] As described above, according to the present invention, level 1 is assigned to the first step of the SFC, the level of the next step is sequentially determined according to the flow of the sequence, and all the points are joined when the join connection is made. If the levels of the steps in
In the case of simultaneous merging connection, the sum of the reciprocals of the levels of the merging steps is taken. If the reciprocal of the calculation result is less than 1, it is judged as an error of this SFC and the level of the last step is When this SFC is judged to be valid when it matches the level of the first step, it is a basic grammatical error, but it is difficult for the user to detect a branch / merge, simultaneous branch / simultaneous merge mutual error. Since the check can be performed easily without omission, there is an effect that the burden on the user for debugging the program can be significantly reduced.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an SFC to which an embodiment of the SFC check method of a programmable controller of the present invention is applied,
FIG. 3 is a configuration diagram of another SFC to which the same embodiment is applied, FIG. 3 is a configuration diagram of yet another SFC to which the same embodiment is applied, and FIG. 4, FIG. 5, FIG. 6, FIG. FIG. 8 is an explanatory diagram when the check method of the present invention is applied to each of the simultaneous branching, branching, merging, and simultaneous merging connection examples, FIG. 8 is a diagram showing a configuration example of a conventional SFC, FIG. (B), (c) is explanatory drawing of the step operation of a step when SFC is performed. 001, ~, 008 ... Step, 100 ~ 104,200 ~ 206,300 ~ 303 ...
Transition condition, 81 ... Simultaneous branch, 82 ... Branch, 83 ... Merge, 84 ... Simultaneous merge.

Claims (1)

[Claims] 1. A method of checking a sequential function chart used by a programmable controller, wherein a numerical value 1 is assigned to the first step of the sequential function chart to set the level of the step, and each step of the step according to the flow of the program is performed. , If one step is connected only to the next one step, the level of the previous step is moved as it is to the level of the next step, and one step is simultaneously branched and connected to the next multiple steps. In the case of a step, the value of the previous step level is multiplied by the number of the next multiple steps connected at the same time to be the level of each of the multiple simultaneous branch destinations, and one step is connected to the next multiple steps. If yes, leave the level of the previous step as it is The level of each step that is branched and connected in a row, and if multiple steps are connected to the next one step by merge, check whether the levels of each of the connected steps are the same. If all the levels do not match, it is judged that there is an error in the confluent connection, and if multiple steps are simultaneously confluent in the next step, each of the converging connections is The reciprocal of the sum of the reciprocals of the step levels is taken as the level of the next step. If the level is less than 1, it is determined that the simultaneous merging connection has an error, and the level of the last step matches the level of the first step. Then, the programmable controller that determines that the connection relationship between each step of the sequential function chart is correct How to check the sequential function chart.