JPH0418605A - Method and device for preparing ladder sequence program - Google Patents

Abstract

PURPOSE:To grasp the control specification of a machine with high readability by dividing the operational specification of the machine into operation flow and operation specification, expressing the operation flow by using a Petri net, and expressing the operation specification by using a sequence table. CONSTITUTION:In this device, a means 1 inputs the Petri net composed of place showing the operational state of the machine and transition showing the transition state of the operation of the said machine. A means 2 detects the above-mentioned place from said inputted Petri net. A first converting means 3 converts the said detected place to the ladder sequence program. A means 5 detects the above-mentioned transition from the above-mentioned inputted Petri net. A second converting means 6 converts the said detected transition to the ladder sequence program. A means 4 synthesizes the ladder sequence programs converted by the above-mentioned means 6 and 3. Thus, the control specification of the machine can be grasped, maintainability is improved and the conversion of the operation specification is made easy.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method and apparatus for creating a ladder sequence program that is input to a sequencer or the like for controlling a machine.

(Prior Art) The operation of many machines is controlled by programmable controllers. This programmable controller is generally called a sequencer, and inputs a sequence program expressing the operation of the machine to the sequencer. The machine is then controlled according to the input sequence program.

The program input to the programmable controller is generally a computer program.

Relay sequence is a description language for machine control specifications that has been widely used by engineers since the days of old "contact" relays.

This language uses (complex) combinations of ON and OFF information to operate a machine's actuator and set operating conditions, and has expressions that correspond to traditional "contact" relays. Because it is possible, it has been widely used.

This relay sequence is generally called a ladder sequence because it looks like a ladder when depicted in a drawing.

Since the ladder sequence is an expression corresponding to a conventional "contact" relay, when the system becomes complicated, readability becomes low, making it difficult to maintain or change the operating specifications.

In addition, since machine control know-how is written directly in the sequence, it is difficult to apply it to other machines.
Productivity as a software was low.

Therefore, as a sequence control program for a programmable controller, a technology has been proposed that automatically creates a sequence program directly from operation specifications without using a ladder sequence program (for example, JP-A-63
(Refer to Publication No.-106004).

The conventional automatic program creation device for a programmable controller has an input processing unit that identifies the operating unit to be controlled, control conditions, and operating instructions from the input operation specification description, and a system that eliminates the occurrence of conflicting actions with respect to each action in the input statement. an ink clock condition automatic generation processing section that adds the ink clock condition to the control condition of the operation; a program synthesis processing section that converts the statement to which the ink clock condition has been added into an existing programming language; and an input/output signal used to control each operation. an input/output automatic assignment processing section that automatically assigns to each contact of the input/output device of the programmable controller; and a post-processor section that replaces the input/output signal of the processing result by the program synthesis processing section based on the processing result of the processing section. It was characterized by the following:

(Problems to be Solved by the Invention) The conventional automatic program creation device for programmable controllers is superior to devices that input ladder sequence programs in that it can directly create sequence control programs by inputting operating specifications. It is something.

However, since the driving specification description is not visual and has low readability, it is extremely difficult to modify it. That is, as the system becomes more complex, it becomes difficult to perform maintenance or change the operating specifications, similar to the ladder sequence described above.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a ladder sequence program creation method and creation device that allows a sequence control program to be created directly from a visual Petri net in order to facilitate maintenance and changes in operation specifications. shall be.

(Means for Solving the Problems) In order to achieve the above object, the present invention takes the following measures.

That is, the ladder sequence creation method of the present invention divides the operating specifications of a machine into an operation flow and an operation specification, expresses the operation flow with a Petri net, expresses the operation specification with a sequence table, and divides the operation specification of the machine into an operation flow and an operation specification, expresses the operation flow with a Petri net, expresses the operation specification with a sequence table, The present invention is characterized in that a sequence table is input into a computer by an input means, and the input Petri net and sequence table are converted into a ladder sequence program by the computer.

Further, as shown in FIG. 1, the ladder sequence creation device of the present invention includes means 1 for inputting a Petri net consisting of a place indicating an operating state of a machine and a transition indicating a transition state of the operating state of the machine; means 2 for detecting the place from the input Petri net; first conversion means 3 for converting the detected place into a ladder sequence program; means 5 for detecting the transition from the input Petri net; a second conversion means 6 for converting a transition into a ladder sequence program; and the second conversion means 6.
and means 4 for synthesizing the ladder sequence program converted by the first converting means 3.

Furthermore, as shown in FIG. 2, according to the present invention, the first converting means 3 detects a transition on the input side in a place to be converted, and converts the detected transition into A.
an eleventh conversion means 11 for converting into a ladder sequence connected in parallel as a contact; and a twelfth conversion means for detecting a transition on the output side at a place to be converted and converting the detected transition into a ladder sequence connected in series as a B contact. 12, a thirteenth converting means 13 for serially connecting the ladder sequence converted by the twelfth converting means 12 to the ladder sequence converted by the eleventh converting means 11; a fourteenth converting means 14 that connects in series an output relay indicating the operating state of the place to the ladder sequence that has been converted, and a fifteenth converting means 14 that connects the A contact of the output relay in parallel to the ladder sequence portion converted by the eleventh converting means 11 The second converting means 6 is a second converting means 6 that detects a place on the input side in a transition to be converted and converts the detected place into a ladder sequence connected in series.
1 converting means 21, and a 22nd converting means 22 which connects in series a pulse output relay indicating the operation progress of the transition to the ladder sequence connected in series by the 21st converting means 21.

Further, as shown in FIG. 3, another ladder sequence creation device according to the present invention includes a means 1 for inputting a Petri net consisting of a place indicating an operating state of a machine and a transition indicating a transition state of the operating state of the machine. , means 2 for detecting the place from the input Petri net; first conversion means 3 for converting the detected place into a ladder sequence program; and means 5 for detecting the transition from the input Petri net. a second conversion means 6 for converting the detected transition into a ladder sequence program; a means 7 for inputting a sequence table representing interlock conditions for the operation of the machine; and a second conversion means 6 for converting the detected transition into a ladder sequence program; It is characterized by comprising a third converting means 8 for converting, and a means 4 for synthesizing the ladder sequence programs converted by the first to third converting means 3, 6.8.

(Operations and Examples) According to the present invention, the operating specifications of a single machine or mechanical equipment are described separately into an operating flow and an operating specification.

The operation flow is expressed as a Petri net (for more information on "Petri net", see, for example, "Software Engineering Handbook", published by Ohmsha, June 20, 1986, pp. 314-315).

That is, by associating the operating state of the machine with a place and associating the progress of the motion with a transition, the operating flow is expressed using a Petri net graph (see FIG. 4). Thereby, the Petri net representation can be uniquely converted into a sequence program.

That is, as shown in FIG. 6, the Petri net has a place P
, a transition t, and an arc connecting them.

Place P is marked with a circle, and transition 1. is represented by a mark.

The place P can have 1.-kun, and the place PI with a token is represented by a .

Tokens change according to the following rules.

■ Transition 1. If the place pi at the starting point of the arc whose destination is all has tokens, then
That transition, t, "fires". (In Figure 6, places P+ and Pt have tokens, and transition t is fired.) ■ When transition also "fires", the token is taken away, and the arrival point of the arc that fires from transition t8. Tokens are supplied to place P+ at . (In FIG. 6, places P1 and P2 change from * to O, and places P3 and P4 become * and have tokens.

) A place P+ of a Petri net with the above properties is
Corresponding to representing the operating state of the machine, transition t,
corresponds to representing the transition state of the machine's operation.

That is, when extracting the operating state and the transition of the operation from the operating specifications of the machine and creating the operation flow, the operating state is made to correspond to the place P, and the transition of the operation is set to the transition t.
, the operational flow is expressed as a Petri net.

The operation of the machine expressed by the Petri net shown in Figure 6 is
Can be uniquely converted into a ladder sequence. The method is shown below.

First, conversion of the place part will be explained.

As shown in FIG. 7, the places P are t, , t2...
...has m input transitions of t□, and tff
l+l t mat...t ma, n of l
Assume that there are output transitions.

At this time, it is converted into a ladder sequence according to the following conversion rules. (However, the order of conversion is not limited to the following cases.) Conversion rule 1; Input transition (tl - tffi
) are connected in parallel as A contacts.

Conversion rule 2; Output transitions (t□1 to ti+n) are connected in series with the B contact to the parallel connection portion. However, if there is one in t m+1 ''=L man that is the same as t, to t7, it will not be connected.

Conversion rule 3: Connect the output relay P representing the place P to the configured ladder sequence.

Conversion rule 4; A of the output relay P is connected to the parallel connection part.
Connect the contacts in parallel for self-holding.

FIG. 8 shows the result of converting the place portion of FIG. 7 into a ladder sequence using the above conversion rules.

Next, conversion of the transition section will be explained.

As shown in FIG. 9, the transition t is Pl, P2・
...Assume that it is the output light of four places of Pi. At this time, it is converted into a ladder sequence according to the following conversion rules.

Conversion rule 5; Relay P representing place (p, ~Pj)
, ~Pj are all connected in series.

Conversion rule 6: Connect a pulse relay t that represents transition t (A pulse relay is a relay that outputs an output that is ON for one cycle of the sequencer and then OFF (ON for only one scan).) FIG. 10 shows the result of converting the transition portion shown in FIG. 9 into a ladder sequence using the conversion rules.

By converting all place parts and transition parts into ladder sequences and composing the ladder sequences according to the conversion rules for place parts and transition parts described above, the expression by Petri net is converted into an executable ladder sequence. be able to.

On the other hand, conversion of operational specifications is performed using a sequence table. An example of this sequence table and its conversion method will be described below.

FIG. 5 is a display screen showing an example of this sequence table, and shows the specifications of the forward motion of the main ram of the placing machine (the motion name is m-A shown at the upper left corner of FIG. 5). The sequence table in Figure 5 consists of a part that represents the activation signal (the upper right part (A) in Figure 5) and a part that represents the interlock conditions for the entire operation (the lower part (A) in Figure 5). , and a portion (the upper left portion in FIG. 5) representing the control conditions of the actuator necessary for performing the operation. Note that the upper left corner of FIG. 5 is a display for a screen editor that creates a sequence table, and is not directly related to the creation of a ladder sequence.

Next, a method for converting the sequence table shown in FIG. 5 into a ladder program will be explained by dividing each part of the sequence table.

First, a method of converting the portion representing the activation signal (the upper right portion (A) in FIG. 5) will be explained. In Figure 5, “
There are three starting modes: manual, inching, and automatic, and the most common machine operation is stopping by pressing "stop." That is, "manual" mode and "jog" mode are rPBL-MNI J (this is Pu5h B
otLan with Light-MaNual
1 may be arbitrarily named. ), and also indicates that there is an "auto" mode (indicated by the symbol * in FIG. 5). The following rules are used to convert this into a ladder program.

Conversion rule 7: If there is a name written in the manual mode column, connect the A contact of rMANUALJ indicating manual in series to the A contact of that name (rPBL-M'NI J in FIG. 5), and further,
The A contact (r tbl , dev'' in FIG. 5), which indicates that this operation is being performed, is connected in parallel to the A contact rPBL MNI J for self-holding.

Conversion rule 8: If there is a name written in the column of inching mode, indicate inching at the A contact of that name (rPBL-MNI J in Figure 5) [Connect A contact of NCHING J in series] , are connected in parallel to the ladder program created according to conversion rule 7 above.

Conversion rule 9; Convert A contact with the name written in the stop column (rPBL-MNI J in Figure 5) to conversion rule 8
Connect in series to the ladder program created in .

Conversion Rule 10 Check that there is a description (* in Figure 5) indicating that there is an automatic mode in the automatic mode column, and if there is, enter the name of this operation created using the Petri net described above (Figure 5). In this case, the automatic operation start condition related to m-A) is connected in parallel with the A contact, and the A contact of rAUTOJ, which indicates automatic, is connected in series, and then connected in parallel with the ladder program created in Conversion Rule 9.

Conversion Rule 11: A relay (SRC: 5Tart Condition in FIG. 5) is connected in series to the ladder program created in Conversion Rule 10 to indicate that the conditions for starting the operation have been met.

The ladder program created using the above conversion rules is
Shown in Figure 1.

Note that in this example, a case has been described in which there are three types of modes, but not all modes are always present. In other words, if there is no entry in a predetermined column, it is assumed that the mode does not exist, and the sequence program for that part will not be created.

Also, the activation signal for each mode is not limited to one, for example,
There may be more than one, such as when starting with a limit switch in addition to a push button. In this case, these multiple conditions are A
They will be connected in parallel using contacts.

Here, to explain how to efficiently detect from the Petri net the automatic driving start condition regarding the name of this operation (m-A in Figure 5) created with the Petri net of conversion rule 9, for example, Figure 12 When converting the Petri net shown in FIG. Each time a conversion is performed, the output relay of that place is tied to this operation m-A as a tag.

(In Fig. 12, P2 and P7 are the output relays, and in Fig. 11, these are the A contact relays written with blank names before the rAUTOJ contact.) Next, the interface for the entire operation is A method of converting the part representing the lock condition (the lower part (A) in FIG. 5) will be explained. In FIG. 5, the description r+J indicates that the connection relationship of the interlock condition is OR, and the description of "," indicates that the connection relationship of the intercock condition is AND.

The following rules are used to convert this into a ladder program.

Conversion rule 12: The OR condition is a parallel mechanism, and the AND condition is a series connection, and the indications written in the interface column are connected with an A contact.

Conversion rule 13: A relay (TTR: abbreviation of InTerRock in FIG. 14) indicating the interlock condition of operation is connected in series to the ladder program created in conversion rule 12.

The ladder program created using the above conversion rules is
Shown in Figure 4.

In addition, in this example, OR and AND are "+" and ", J
It goes without saying that other expressions may be used.

Next, a method of converting a portion (upper left portion in FIG. 5) representing the actuator control conditions necessary for performing an operation into a ladder sequence will be described.

First, the meaning of the part representing the control conditions of the actuator necessary for performing the operation will be explained. In Figure 5,
This part consists of a part that describes the operation process (the part marked by the dotted line box (1) in the upper left corner of Figure 5), and a part that shows the interlock conditions unique to each process (the part marked by the dotted line box (1) in the upper center part of Fig. 5). ○N10 F
5), and a portion showing the state of the analog-controlled actuator at each step (the part surrounded by a dotted line (g) in the center left of FIG. 5), It consists of a part showing interlock conditions specific to these actuators (the part surrounded by a dotted line in the center of FIG. 5).

The part (1) that describes the action process shows that the action process consists of four steps (A-D), and each step progresses in sequence <(A-B→C-D). . Specifically, this figure shows that the main ram of the place advances at four speeds from low speed to high speed.

Part (e) showing interlock conditions unique to each step
indicates an interlock condition specific to that step, such as a stroke limit switch, a proximity switch, etc.

The part (force) indicating the state of the actuator in each step indicates how each actuator should be used to perform each step.

For example, in Figure 5, to perform step A,
5-This indicates that the actuator indicated by AI and the actuator indicated by SP1 are ONL, and the actuator indicated by Ql needs to be opened 100%. In this example, 5-A1 etc. indicate solenoids and Ql
etc. show variable flow rate control valves, but it goes without saying that the invention is not limited to these.

The part showing the interlock conditions of the actuator hard sheath (
5) shows interlocks specific to each actuator. For example, in FIG. 5, LSSTO4 is used as the interlock to operate the 5-AI actuator. LS-3TO4 is, for example, a sensor that does not indicate the status of a hydraulic pump.

Next, a method of converting this portion into a ladder sequence will be explained. This conversion consists of a conversion related to the transition of each process, a conversion related to the ON10FF-controlled actuator, and a conversion related to the analog-controlled actuator.

Among these, the conversion of the parts related to the transition of each process is based on the following rules.

Conversion rule 14; Relay ST created with conversion rule 11
The A contact of C is connected in series with the A contact of the relay ITR created in conversion rule 13.

Conversion rule 15: Detect the number of steps from the part (1) in FIG.
) : Abbreviation for TaBLe DEVice) and an output relay (tbl, dev) that indicates that this operation is being performed are connected in parallel, and connected in series to the ladder program created in conversion rule 14.

Note that the A contact of the output relay (tbl, dev) created in conversion rule 15 is used in conversion rule 7.

Conversion rule 16: Detect the interlock condition specific to each process from the part (e) in Figure 5, and apply that condition as an A contact between the output relay of each step and the ladder program created in conversion rule 14. Connect in series.

Conversion rule 17; Between the output relay of each step and the ladder program created in conversion rule 14, the output relay of the step proceeding after the step is connected in series as a B contact.

This means that the progress of the process is reversed. This is to prevent people from doing so.

The ladder program created using the above conversion rules is
It is shown in Figure 5.

Although FIG. 15 shows the case where there are four steps, it goes without saying that there may be only two steps. For example, if there are three steps, the 15th
All you have to do is remove the part surrounded by the dotted line in the figure.

Next, a method of converting the part related to the 0N10FF controlled actuator will be explained. The conversion of this part is based on the following rules.

Conversion rule 18: Detect the valve that turns on the corresponding actuator from the (force) part in FIG. 5, and connect all A contacts of the output relays of the 8th step in parallel.

Conversion rule 19: Detect the interlock condition specific to each actuator from the part (ri) in FIG. 5, and connect the condition in series to the ladder program created in conversion rule 18 as the A contact.

Conversion rule 20: A relay indicating the actuator is connected in series to the ladder program created in conversion rule 19.

Conversion Rule 21: Connect the A contact of the relay representing the actuator in parallel to the part of the ladder program created in Conversion Rule 18 for self-holding purposes.

FIG. 16 shows the part related to 5-AI of the ladder program created using the conversion rules listed in (2) below.

Although FIG. 16 shows a case where there is only one interlock condition, there may be a plurality of interlock conditions. In this case, these interlock conditions may be connected in series.

Finally, a method of converting parts related to analog-controlled actuators will be explained. The conversion of this part follows the rules in F.

Conversion rule 22: Detect the step that turns on the corresponding actuator from the part (g) in FIG. 5, and connect all A contacts of the output relays of the three steps in parallel.

Conversion rule 23: Detect the interlock condition specific to each actuator from the part (ri) in FIG. 5, and connect the condition in series to the ladder program created in conversion rule 22 as an A contact.

Conversion rule 24: Detect the analog amount to be output to the corresponding actuator from the part (g) in FIG. 5, and connect the command to output this to the corresponding analog device in series to the ladder program created in conversion rule 23.

Of the ladder program created according to the above conversion rules, the portion related to Ql is shown in FIG.

FIG. 17 shows that there is no interlock condition and 100% analog quantity is output to the analog device Q1. (In Figure 17, this is referred to as rMOV K100O1
Shown with ko. This instruction is provided in most commonly used sequencers. ) In the sequence program using the conversion mentioned above, each actuator has self-holding, so
When it becomes N, it continues to be ON. Therefore, it is necessary to add a ladder program that turns off at the beginning of the sequence program. That is, the control conditions for the actuator are determined and output for each cycle of the sequence.

A ladder sequence program for the machine is created by combining the ladder program created by converting from the Petri net and the ladder program created by converting from the sequence table.

After this, in order to operate the machine, the created ladder sequence program is transferred to the sequencer, and the machine is operated according to this program.

All parts of the ladder sequence program may be created using the method according to the present invention, but additional parts such as lamp displays may be created by using a screen editor etc. on the ladder program created using the method according to the present invention. The configuration may be such that the data is written additionally, or the data may be written additionally after being transferred to the sequencer.

Embodiments of the present invention will be described below based on the drawings.

What is shown in FIG. 18 is an explanatory diagram of the operation of a virtual machine composed of two actuators.

In the figure, operation A means moving the truck forward or backward, and operation B means clamping or unclamping the clamper.

The operation flow of the virtual machine is such that when the cart carries a workpiece, it is clamped, and after the cart moves backward, it is unclamped and dropped. That is, action A, (
Forward) → Movement Bl (Clamp) - Movement A, (Backwards)
- Perform operation B2 (unclamp).

The operation specifications of the virtual machine are that in operation A, the on-load valve P1 opens, the virtual machine moves forward when the logic valve P-^8 opens, the on-load valve P+ opens, and the logic valve P
Back up when A2 opens.

In operation B, clamping occurs when on-load valve P2 opens and logic valve P B+ opens, and unclamping occurs when on-load valve P2 opens and logic valve P-82 opens.

Also, as an interlock, when a workpiece is placed on the trolley (LS-^0 is ON), it must not move forward with operation B clamped.

Also, if a workpiece is placed on the cart (LS-80 is ON) or the cart is at the forward limit, do not unclamp it.

The 19th Petri net representation of the above operation flow is
A sequence table representation of the operational specifications is shown in FIG.

That is, in the Petri net of FIG. 19, actions (e.g., action A1, action B1, etc.) and sensor 0N10FF states (e.g., LS A+l, S B+, etc.) correspond to places, and the transition of the action (e.g., t2, etc., which indicates whether or not the action A1 has been completed, corresponds to a transition.

The Petri net is then input into the computer by the Petri net input means 1 shown in FIG. This Petri net input means 1 includes a means for creating and inputting a Petri net on a CRT screen using a screen editor using a CRT monitor and keyboard or a mind, and a means for inputting a Petri net drawn on paper as image information using an image league. Possible methods include means for analyzing input image information.

Places in the input Petri net are detected by place detection means 2, as shown in FIG. The detected place is then converted into a ladder sequence by the first conversion means 3. This first conversion means 3 is
As shown in FIG. 2, the 11th to 15th conversion means LL12,1
It is composed of 3, 14, and 15.

For example, the place detection means 2 performs operation A.

When the first place is detected, as shown in Figure 2, the first place is detected.
1 conversion means detects the transition t1 on the input side of the place of action A, and converts the transition t1 on the input side of the place of action A. Convert to a ladder sequence connected in parallel with A contact. Eleventh conversion means 1
1, for example, detects a Q mark representing a place from the display on the CRT screen, and sequentially traces the arcs represented by - that come out from the ○ display, which have the ○ mark as the arrival point, and detects the CRT at the end point.
There is a method of detecting whether or not there is a display indicating a transition at the position. The detected object is thereby connected as an A contact.

Next, the twelfth converting means 12 detects the transition on the output side of the place of the action A1, and converts the detected transition t2 into a ladder sequence connected in series with the B contact. The twelfth converting means 12 detects, for example, an O mark representing a place from the display on the CRT screen, and sequentially traces arcs represented by - that come out from the O display, which have the O mark as the arrival point, and converts the CRT at the end point. There is a method of detecting whether or not there is a display indicating a transition at the position.

Note that it does not matter which one of the conversion by the eleventh conversion means and the conversion by the twelfth conversion means is performed first.

Then, the thirteenth converting means 13 converts the ladder sequence converted by the eleventh converting means 11 and the twelfth converting means 1.
Connect in series to the ladder sequence converted in step 2.

Then, the fourteenth converting means 14 connects in series an output relay indicating "operation A+J" to the ladder sequence.

Further, the fifteenth converting means 15 connects the A contacts of operations A and J in parallel to the ladder sequence part converted by the eleventh converting means 11.

In the above steps, as shown in FIG. 21, the ladder sequence of "Operation A" in the flowchart 1-J is created.

Similarly, the input Petri net is subjected to transition detection by the transition detection means 5, as shown in FIG. The detected transition is then converted into a ladder sequence by the second conversion means 6.

As shown in FIG. 2, the second converting means 6 is composed of a 21st and a 22nd converting means 21 and 22.

For example, when the transition detection means 5 detects the transition t2, the 21st conversion means 21
The place "A+J and rLS-8" on the input side is detected, and the detected places are converted into a ladder sequence connected in series.

Then, the 22nd converting means 22 converts the ladder sequence converted by the 21st converting means 2I into a pulse output relay (PLS) indicating the operation progress of the transition.
tz) are connected in series.

With the above, rPLSt shown in the flowchart part of FIG.
A ladder sequence of zJ is created.

Then, the ladder sequences converted by the first converting means 3 and the second converting means 6 are combined by the combining means 4, and the ladder sequence of the "flowchart" part shown in FIG. 21 is created.

The sequence table shown in FIG. 20 is input into the computer by the sequence table input means 7 shown in FIG. The input ladder sequence is then converted into a ladder sequence by the third conversion means 8. Then, the synthesis means 4 synthesizes the ladder sequence converted from the Petri net.

The results are shown in FIG.

In FIG. 21, the pulse marked with * is an output that is momentarily ORed (only for one scan) and immediately turned off. Also, **marked S PI-? )S p2 (7) For actuators that are used multiple times, by resetting them at the start of one scan, parallel (OR)
Evaluate.

Figure 21: Interlocked (AIJTO), Independent (MAR)
) movement and the 0N10FF of the actuator are described separately. Here, ITR, STC, and MTN represent interlocks of respective operations, operation commands, and operation signals as the logical product thereof.

Note that the present invention is not limited to the above embodiments.

(Effects of the Invention) According to the present invention, the operational specifications of a machine are divided into an operation flow and an operation specification, and the operation flow is expressed using a Petri net, and the operation specification is expressed as a sequence table.
It is highly readable and easy to read, and it also makes it possible to understand the control specifications of the machine, improving maintainability and making it easy to convert operational specifications.

In addition, since control know-how can be expressed explicitly, it is easier to pass down software among software engineers.

Furthermore, since Petri nets and sequence tables can be uniquely converted into ladder sequences, document management of sequence programs becomes easier.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the invention according to claim 2,
FIG. 2 is a block diagram showing the invention as claimed in claim 3, FIG. 3 is a block diagram showing the invention as claimed in claim 4, FIG. 4 is a display screen diagram showing a Petri net, and FIG. 5 is a sequence table. Display screen diagram, FIG. 6 is an explanatory diagram showing the Petri net, FIG. 7 is an explanatory diagram of the place detection means, FIG. 8 is an explanatory diagram of the conversion means 11 to 15, and FIG. 9 is an explanatory diagram of the transition detection means. , Figure 10 is 21~
22 is an explanatory diagram of the conversion means, FIG. 11 is an explanatory diagram for converting the activation signal of the sequence table into a ladder sequence, and FIGS. 12 and 13 are explanatory diagrams for registering the operation name of the Petri net in the internal memory of the computer. Explanatory diagram, 1st
Figure 4 is a ladder sequence diagram showing the results of converting interlocks into ladder sequences, Figure 15 is a ladder sequence diagram showing the results of converting transition conditions, and Figure 16 is a diagram showing the conversion to ladder sequences when the actuator is a discrete output. FIG. 17 is a diagram showing conversion to a ladder sequence when the actuator has an analog output, FIG. 18 is an explanatory diagram of operating specifications of a virtual machine showing an embodiment of the present invention, and FIG. 19 is an operation flow diagram. Petri net diagram,
Figure 20 is a sequence table diagram showing the operation specifications;
Figure 1 is a ladder sequence diagram. DESCRIPTION OF SYMBOLS 1... Petri net input means, 2... Place detection means, 3... First conversion means, 4... Synthesis means, 5.
... transition detection means, 6... second conversion means,
7... Sequence table input means, 8... Third conversion means, 11... Eleventh conversion means, 12... Twelfth conversion means
Conversion means, 13... 13th conversion means, 14... 1st
4 conversion means, 15...15th conversion means, 21...21st conversion means, 22...22nd conversion means. Patent applicant: Kobe Steel, Ltd. Representative: Patent attorney Yasu 1) Yui Toshi I'z. q Shaft

Claims (4)

[Claims] (1) Divide the operating specifications of the machine into an operation flow and an operation specification, express the operation flow with a Petri net, express the operation specification with a sequence table, and input the Petri net and sequence table into the computer by input means. A method for creating a ladder sequence program, comprising converting an input Petri net and a sequence table into a ladder sequence program using the computer. (2) means (1) for inputting a Petri net consisting of a place indicating an operating state of a machine and a transition indicating a transition state of the machine's operation; and means (2) for detecting the place from the input Petri net a first converting means (3) for converting the detected place into a ladder sequence program; a means (5) for detecting the transition from the input Petri net; and converting the detected transition into a ladder sequence program. and means (4) for synthesizing the ladder sequence program converted by the second converting means (6) and the first converting means (3). Features: Ladder sequence program creation device. (3) The first conversion means (3) is an eleventh conversion means (11) that detects a transition on the input side in the place to be converted and converts the detected transition into a ladder sequence connected in parallel as an A contact. and a twelfth conversion means (12) that detects a transition on the output side of the place to be converted and converts the detected transition into a ladder sequence connected in series as a B contact.
12), a thirteenth converting means (13) for serially connecting the ladder sequence converted by the twelfth converting means (12) to the ladder sequence converted by the eleventh converting means (11); 14th converting means (14) that connects in series an output relay indicating the operating state of the place to the ladder sequence connected in series by the 13th converting means (13); )
a fifteenth conversion means (15) connected in parallel to the ladder sequence portion converted by the second conversion means (6), the second conversion means (6) detects a place on the input side in the transition to be converted and converts the detected place. 21st conversion means (21) for converting into a ladder sequence connected in series
and a 22nd conversion means (22) which connects in series a pulse output relay indicating the operation progress of the transition to the ladder sequence connected in series by the 21st conversion means (21).
5. The ladder sequence program creation device according to claim 4, comprising: (4) means (1) for inputting a Petri net consisting of a place indicating an operating state of a machine and a transition indicating a transition state of the machine's operation; and means (2) for detecting the place from the input Petri net a first converting means (3) for converting the detected place into a ladder sequence program; a means (5) for detecting the transition from the input Petri net; and converting the detected transition into a ladder sequence program. means (7) for inputting a sequence table representing interlock conditions for the operation of the machine; and third conversion means (7) for converting the input sequence table into a ladder sequence program.
8), and means (4) for synthesizing the ladder sequence programs converted by the first to third conversion means (3), (6), and (8).
) A sequence program creation device comprising: