JP2970142B2 - Programmable controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an SFC (Sequencial Fun
ctiont Chart) relates to a programmable controller that can be programmed in both description and mnemonic representation.

[0002]

2. Description of the Related Art Programmable controllers (hereinafter referred to as P
For example, at the work site, various physical information (for example, information that the number of products that have passed through the outlet of the belt conveyor has reached a predetermined amount) or logical information (for example, when the cutting machine is operating) , It can be programmed to perform output control (sequence control) in response to information such as that a sensor that scans a dangerous area has detected a moving object). .

Recently, as a method of describing a program for a PC, an international standard called SFC (IEC SC65) has been proposed.
A / WG6) is known. FIG. 3A is a conceptual diagram of the structure of the SFC program description. As shown in FIG. 3A, a description portion called “STEP” and a description portion called “TRANSITION” are connected by a link (LINK). , Alternately S
20, TN21, S21, TN22,... If the transition is on and the transition is on, the PC selects the next step. If the transition is off, the PC determines that the subsequent step is not selected.

FIG. 3 (b) shows an example of a conventional program in the SFC description. This program uses a so-called mnemonic expression that expresses an operation state, the nature of an instruction, and the like using appropriate abbreviations. This is shown in the program description example used. The program described in this manner is translated into a machine language, converted into word-based bit information, and sequentially written into a program storage memory such as a RAM in the order of addresses.

The program shown in FIG. 3B executes an action program (outputs the contents of input X10 to Y110) when step S20 is activated, and then turns on transition TN21 of the transition condition (turns on input X1). If the TN 21 is turned on / off), the process proceeds to the next step S21. Then, the action program of this step 21 (the content of the input X11 is changed to Y1
11), if the transition of the transition condition is on (the TN 22 is also turned on / off by turning on / off the input X2), the operation proceeds to the next step.

That is, first, the activation / inactivation of the step is checked, then the action program is executed, and then the program for turning on the transition condition is executed. And
In the next step, programs similar to the above are sequentially executed.

As described above, conventionally, an entire program is constituted by alternately programming an action program and a transition program.

[0008]

However, in the conventional program configuration as described above, if step S20 is in an active state and X1 of the parallel condition program is turned on, the process proceeds to step S21. Then, only at the moment of shifting to step S21 (one operation cycle), step S20 and step S21 are simultaneously activated. This problem occurs because the contents of the action are programmed before the transition condition is turned on, the transition is completed, and the step before the transition is deactivated.

As described above, as a method for not simultaneously turning on the outputs (in this case, Y110 and Y111) based on the action contents of two consecutive steps (in this case, S20 and S21), two steps S20 and S21 are conventionally used.
As shown in FIG. 4, the output of each other's actions, that is, in step S20, an interlock is applied by the action output Y111 of step S21,
21, the action output Y1 of step S20
The method of adding an interlocking circuit according to No. 10 was used. However, such a method of adding a circuit is not preferable because the hardware configuration becomes complicated.

According to the present invention, the program is not expanded according to the SFC description, but the entire program is converted into all transition groups,
By separating the program into all the link groups and all the action groups and developing the programs in the order of these programs, the step transition is completed before the next step action is executed, and two consecutive actions are performed. The purpose of this is to prevent the contents from being executed simultaneously.

[0011]

FIG. 1 is a block diagram for explaining the principle of the present invention. The present invention is applied to a programmable controller 10 which can be programmed in both SFC description and mnemonic expression.

The entire transition group program 1 is composed of only a program indicating a transition condition in the entire program. In addition, the all link group program 2 is composed of only a program indicating a connection relationship of which step is connected to which step in the entire program. Further, the entire action group program 3 is composed of only a program indicating an actual movement (action) in each step in the entire program.

[0013]

As described above, according to the present invention, the SF shown in FIG.
Instead of developing the programs in order from top to bottom in accordance with the C description, first, the transition condition program is executed by all the transition group programs 1, and when the execution of all the transition group programs 1 is completed, the next all links are executed. The group program 2 executes a program indicating a connection relationship between adjacent steps, which steps are connected to each other. When all the programs indicating the connection relationship have been executed, an all action group program is executed. Move to 3. Then, the program of the action group of only the steps that are in the active state is executed in accordance with the program contents of the all action group program 3.

As described above, the transition is completed before executing the content of the action, and the program is set so that only one step is active. The content will not be executed simultaneously.

[0015]

Next, embodiments of the present invention will be described. FIG. 2 shows an example of the program of the embodiment. As in FIG. 1, a transition group program 1 consisting of only a program indicating a transition condition in the whole program. An all link group program 2 composed of only a program indicating a connection relation of which steps are connected, and a total action group program 3 composed of only a program indicating an action of each step in the entire program. Have been.

The specific contents of these programs 1, 2 and 3 are as follows. First, in the entire transition group program 1, the transition condition (transition) TN21 is also turned on / off by turning on / off the input X1, and the transition condition TN22 is also turned on / off by turning on / off the input X2. For example, if the input X1 is on, the transition condition TN
21 is also on, and steps S20 to S21
It is determined that the condition for shifting to (1) is satisfied (see FIG. 3 (a) for the relationship between these steps S20 and the shifting condition TN21).

Further, the all link group program 2 has a SIN
GLE instruction to E The steps up to the TRA instruction indicate what steps are connected to each other. In this case, if the transition condition TN21 is on,
The process proceeds from step S20 to step S21, and indicates that the process proceeds from step S21 to step S22 if the transition condition TN22 is on. In addition, SINGL
The E instruction means that it is connected to the step immediately below, and another instruction is prepared for branching / merging. Also E The TRA command means that one connection has been completed, and is used every time the connection between steps is completed.

Next, all the action group programs 3
From the EXE instruction to E The contents up to the ACT instruction are the contents of the actual action, and the S number (S2
0, S21,...) Means the content of which step. In this case, in step S20, the content of the input X10 is output to Y110, and in step S21, the content of the input X11 is output to Y110.

By adopting such a program configuration, first, when the all transition group program 1 is executed, the on / off of the transition conditions TN21 and TN22 is determined. You are ready to take the next step. Next, when the all link group program 2 is executed, the active / inactive state of each step can be determined, and if the transition is completed, the step before the transition can be deactivated.

Finally, all action group programs 3
Is executed, the action content of only the active step is executed, and the action content of the inactive step is not executed.

As a result, the programs for the respective actions in the successive steps are not executed simultaneously.

[0022]

According to the present invention, instead of developing the program according to the SFC description, the program is developed in the order of all transition group programs, all link group programs, and all action group programs, and the contents of the action in the next step Before executing the process, by completing the transition so that only one step is active,
The two actions are not executed at the same time, and a circuit for interlocking with each other by the action output of each of two successive steps is unnecessary, and the hardware configuration can be simplified. In addition, since the entire program is divided into a transition group, a link group, and an action group, the program can be very easy for the user to maintain.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the principle of the present invention.

FIG. 2 is a diagram showing an example of a program configuration for explaining an embodiment of the present invention.

FIG. 3 is a configuration diagram illustrating an SFC description and a diagram illustrating a conventional program example.

FIG. 4 is a diagram showing an example in which an interlock is added to an action program in the related art.

[Explanation of symbols]

 1 All transition group programs 2 All link group programs 3 All action group programs 10 Programmable controller

Claims (1)

(57) [Claims] In a programmable controller (10) that can be programmed in both SFC (Sequencial Functiont Chart) description and mnemonic expression, the entire program is connected to all transition group programs (1) indicating transition conditions and steps. The structure is separated into an all-link group program (2) indicating the relationship and an all-action group program (3) indicating the operation of the step. All transition group programs (1), all link group programs (2), and all action programs ( A programmable controller characterized in that the program is developed in the order of 3).