KR100976324B1 - Method for writing program of Programmable Logic Controller using Programmable And Debugging Tool - Google Patents

Abstract

According to the present invention, when a plurality of programmable and debugging tools (PADTs) capable of reading and writing a predetermined program to a programmable logic controller (PLC) are connected to a central processing unit of the PLC, all of the plurality of PADTs are selectively selected. Acquisition of write permission enables writing of a certain program to PLC.

According to the present invention, when a second PADT which wants to store a predetermined program to the PLC among the plurality of PADTs connected to the central processing unit of the PLC requests write permission, the first centralized processor of the PLC holds the write right. The write request of the PADT is requested, the central processing unit receives the write permission of the first PADT according to the request of the write permission, and provides the provided write permission to the second PADT to store a predetermined program in the PLC. do.

PADT, PLC, write permission, program, central processing unit,

Description

Method for writing program of Programmable Logic Controller using Programmable And Debugging Tool}

The present invention relates to a program writing method of a programmable logic controller (PLC) using a programmable and debugging tool (PADT).

More specifically, a plurality of PADTs capable of reading and writing a predetermined program may be connected to a PLC to a PLC that controls driving of various loads, including an electric motor, and the plurality of PADTs selectively acquire write permission. The present invention relates to a program writing method of a PLC using a PADT that enables writing of a predetermined program to the PLC.

In general, PLC is widely used to control the operation of various loads, including electric motors.

PADT is used to read and write a predetermined operation program to such a PLC. The PADT is connected to the central processing unit of the PLC through interface means such as, for example, RS-232C and Universal Serial Bus (USB), and transmits predetermined data to each other.

When a plurality of PADTs are connected to the central processing unit of the PLC, only one PADT that is connected to the central processing unit of the PLC for the first time among the plurality of PADTs is granted write permission.

The PADT granted the write right may transmit and store a predetermined program to the central processing unit of the PLC, and the remaining PADTs may be monitored only by performing a read of a predetermined program stored in the PLC because the write right is not granted. It was not possible to transmit and store a predetermined program to the central processing unit of the PLC.

In order for one PADT to which write permission is not granted, to obtain write permission and transmit and store a predetermined program to the PLC, all PADTs except the one PADT itself need to disconnect from the PLC. That is, one PADT to obtain the write right continues to be connected to the PLC, and all PADTs that do not have the write right as well as the PADT to which the write right is granted are not the PLC. The PADT that wants to acquire the write permission only needs to be disconnected so that the program can be stored in the PLC.

Therefore, an object of the present invention is to solve the problem of a plurality of second PADTs that are not given write permission and a plurality of second PADTs in which write permission is not granted in a state in which one write PADT that is granted write permission is connected to a PLC. Provided is a program writing method of a PLC using a PADT that allows a second PADT of two PADTs to obtain write permission to store a predetermined program in the PLC.

According to a method of writing a program of a PLC using a PADT of the present invention, when a second PADT having no write permission requests a write permission from a central processing unit, the central processing unit grants write permission to a second PADT requesting the write permission. To store a certain program in the PLC.

The granting of the write right provides the write right to the PADT when the CPU has the write right.

If the CPU does not have write permission, the CPU requests a write permission from the first PADT having write permission, and according to the request, writes the write permission provided by the first PADT. The processing device provides the second PADT so that the second PADT can store a predetermined program in the PLC.

Therefore, in the program writing method of the PLC using the PADT of the present invention, when the second PADT (Programmable And Debugging Tool) that wants to store a predetermined program is requested to write to the central processing unit of the programmable logic controller (PLC), the central authority is requested. Requesting, by the processor, write permission from a first PADT having write permission; receiving, by the CPU, the write permission of the first PADT according to the request of the write permission; And providing the write right to the second PADT to store a predetermined program in the PLC.

And providing the second PADT with the write right held by the CPU when the second PADT requests the write right when the CPU has the write right. .

The present invention further includes the step of connecting the first PADT and the second PADT to the CPU by requesting access to the CPU.

The connecting of the first PADT and the second PADT to the CPU may include responding to the CPU when the first PADT and the second PADT request a connection, and responding to the connection request. And when the first PADT and the second PADT request a status, the CPU responding with status information including information on read and write permissions of the first PADT and the second PADT. It is characterized by.

After responding with the status information, when the first PADT and the second PADT request a connection, the central processing unit provides a password and the first PADT and the second PADT receive a password from a user; And completing a connection when a password provided by the central processing unit and a password input from the user match.

According to the method of writing a program of a PLC using a PADT of the present invention, when a single PADT requests write permission while a plurality of PADTs are connected to a central processing unit of a PLC, the central processing unit of the PLC writes to the single PADT. By granting a plurality of PADTs can simply obtain write permission and store certain programs in the PLC.

The following detailed description is only illustrative, and merely illustrates embodiments of the present invention. In addition, the principles and concepts of the present invention are provided for the purpose of explanation and most useful.

Accordingly, various forms that can be implemented by those of ordinary skill in the art, as well as not intended to provide a detailed structure beyond the basic understanding of the present invention through the drawings.

1 is a block diagram showing the configuration of a system to which the program writing method of the present invention is applied. Here, reference numeral 100 denotes a PLC for driving a predetermined load. The PLC 100 includes a central processing unit 102, and the central processing unit 102 drives the load while operating according to a predetermined program.

Reference numeral 110 denotes a plurality of PADTs. One first PADT 110a having a write right among the plurality of PADTs 110 communicates with the central processing unit 102 of the PLC 100 to provide a predetermined program to the PLC 100. Can read and write.

In addition, the plurality of second PADTs 110b that do not acquire write permission among the plurality of PADTs 110 communicate with the central processing unit 102 of the PLC 100, and the PLC 100 operates. Can be monitored by performing a read of a predetermined program.

Figure 2 is a signal flow diagram showing the operation of the preferred embodiment of the PADT connected to the central processing unit of the PLC in the program writing method of the present invention. When the PADT 110 connects to the PLC 100, the PADT 110 first requests a connection to the central processing unit 102 of the PLC 100 (S200), and the central processing unit 102 in response to the connection request. It is determined whether the response to the access request (S202).

If the CPU 102 does not respond as a result of the determination in step S202, the PADT 110 is not connected to the CPU 102 of the PLC 100 or an error occurs. The PADT 110 ends the operation of connecting with the central processing unit 102 of the PLC 100.

When the CPU 102 of the PLC 100 responds to the connection request as a result of the determination, the PADT 110 requests a state from the CPU 102 of the PLC 100 ( In step S204, it is determined whether the central processing unit 102 of the PLC 100 makes a status response (S206).

As a result of the determination in step S206, when the central processing unit 102 does not respond to the status, the PADT 110 is not connected to the central processing unit 102 of the PLC 100 or an error occurs. The PADT 110 terminates the operation of connecting to the central processing unit 102 of the PLC 100.

When the CPU 102 makes a status response as a result of the determination in step S206, the PADT 110 analyzes the packet in response to the status and determines the status (S208). That is, the status response packet responded by the central processing unit 102 includes 'cnf_info', and the 'cnf_info' indicates whether the PADT 110 is connected to the central processing unit 102 and the connection is present. The PADT 110 includes information indicating whether a read and write permission of a program is granted to the PADT 110, and the PADT 110 is connected to the CPU 102 using 'cnf_info'. It is checked whether the PADT 110 is present and whether it is granted read permission and write permission.

In this state, the PADT 110 requests a password from the central processing unit 102 (S210), and determines whether the password is answered from the central processing unit 102 according to the password request (S212). ).

If the password is not set from the CPU 102 as a result of the determination, the password is not set, and the PADT 110 completes the connection with the CPU 102 (S218) and terminates.

When the password is answered from the CPU 102 as a result of the determination, the PADT 110 receives a password from the user (S214), and the received password is a password that the CPU 102 responds to. It is determined whether or not equal to (S216).

If the password is not the same as the determination result, the PADT 110 returns to step S214 and receives the password again, and whether the received password is the same as the password that the central processing unit 102 responds to. Repeat the operation of determining.

When the encryption result is the same, the PADT 110 completes the connection with the central processing unit 102 (S218) and terminates.

FIG. 3 is a signal flow diagram illustrating an operation of a preferred embodiment in which a PADT acquires authority to perform a write operation of a predetermined program to a PLC in the program writing method of the present invention. When the second PADT 110b which does not have the write right stores the predetermined program in the PLC 100, the second PADT 110b requests the write right to the central processing unit 102 of the PLC 100 (S300). ).

Then, the central processing unit 102 determines whether or not it has write permission (S302).

If the central processing unit 102 does not have the write right as a result of the determination, the central processing unit 102 requests the write right to the first PADT 110a having the write right (S304), and the first PADT ( It is determined whether 110a) provides write permission (S306).

If the first PADT 110a does not provide write permission, the CPU 102 returns to step S304 to request the write permission from the first PADT 110a, and the first PADT 110a. ) Repeatedly determines whether or not to provide write permission.

When the first PADT 110a provides the write right, the central processing unit 102 retains the write right (S308).

When the central processing unit 102 retains the write right as described above, the central processing unit 102 provides the retained write right to the second PADT 110b (S310).

Then, the second PADT 110b is given write permission and transmits and stores a predetermined program to the central processing unit 102.

The present invention has been described in detail with reference to exemplary embodiments, but those skilled in the art to which the present invention pertains can make various modifications without departing from the scope of the present invention. Will understand.

Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims below and equivalents thereof.

According to the present invention, when a plurality of PADTs of a PLC are connected, the plurality of PADTs selectively request write permission from the central processing unit of the PLC, and the acquired PADT obtains a predetermined program from the PLC. It can be transferred and stored.

1 is a block diagram showing the configuration of a system to which the program writing method of the present invention is applied;

Figure 2 is a signal flow diagram showing the operation of the preferred embodiment of the PADT connected to the central processing unit of the PLC in the program writing method of the present invention, and

3 is a signal flow diagram illustrating an operation of a preferred embodiment in which a PADT acquires a write right and performs a write operation of a predetermined program in a PLC in the program writing method of the present invention.

Claims (5)

When the second PADT (Programmable And Debugging Tool) wishing to store a predetermined program in the CPU of the programmable logic controller (PLC) requests write permission, the CPU writes to the first PADT that the CPU has write permission. Requesting authority; Acquiring, by the CPU, the write right provided by the first PADT according to the request of the write right; And And providing, by the central processing unit, the write right to the second PADT to allow the second PADT to store a predetermined program in the PLC. 2. The system of claim 1, wherein the central processing unit has write permission; And providing, by the second PADT, a write right held by the central processing unit to the second PADT according to a request for write permission. The method of claim 1, And requesting, by the first PADT and the second PADT, to connect to the CPU. 4. The method of claim 3, wherein connecting the first PADT and the second PADT to the central processing unit; Responding, by the central processing unit, to the connection request when the first PADT and the second PADT request a connection; And When the first PADT and the second PADT request a status after responding to the access request, the CPU responds with status information including information on read and write rights of the first PADT and the second PADT. Program writing method of a PLC using a PADT, characterized in that it comprises a step of. 5. The method of claim 4, further comprising: after responding with the status information; When the first PADT and the second PADT request a connection, the CPU providing a password and the first PADT and the second PADT receiving a password from a user; And completing a connection when a password provided by the central processing unit and a password input from the user match.

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