JP2978008B2 - Memory management method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a memory management system for accessing different option transmission cards by the same instruction operand in a controller of a programmable controller to which a plurality of option transmission cards can be mounted.

[0002]

2. Description of the Related Art In a manufacturing site or the like, various information to be controlled, for example, physical information such as the number of products passing through an outlet of a belt conveyor reaching a predetermined quantity, or dangerous when a cutting machine is in operation. There is logical information such as detection of a moving object in the area. A programmable controller (hereinafter, referred to as a PC) performs predetermined output control (sequence control) according to these various information.

FIG. 6 shows a control system for controlling a production line in a factory in such a PC. In the figure, reference numeral 31 denotes a control device of a PC. The control device 31 includes a control unit 32, a T-link transmission card mounting unit 33, a P-link transmission card mounting unit 34, and a new P-link transmission card mounting unit 35. I have. Then, the sequence program created by the user is transferred from the loader 36 to the control unit 32 and stored therein, and when the command is executed, the execution result is transmitted through a transmission path called a T-link to control the production line. It is transmitted to an input / output device (I / O). The execution result is also transmitted to the control device 37 of another PC through a transmission path called a P-link.
Information of the execution result is also exchanged between them. In some cases, a new transmission path called a new P link is added. This new P link exchanges execution results with other PCs in the same way as the above P link, but the new P link has significantly improved transmission speed and transmission volume compared to the conventional P link. It was done.

A transmission card controls transmission on the transmission path of the T link, P link, and new P link. There are three types of transmission card: a T link transmission card, a P link transmission card, and a new P link transmission card. It is called a transmission card, and it is used by attaching a transmission card according to a user's request.

In a control device of a programmable controller capable of mounting a plurality of optional transmission cards, a method of accessing each of the optional transmission cards has conventionally been divided into (1) a user program for accessing the optional transmission card of the control unit 32; The control operand recognizes the address map of the currently mounted optional transmission card, determines the absolute address when executing the instruction, and accesses the optional transmission card. (2) The instruction operand of the user program accessing the option card of the control unit 32 is represented by a real address system,
The control system accesses the address value. When the option card is changed, the real address to be accessed is changed. Therefore, the user program is transferred again and reassigned to the real address corresponding to the currently mounted option transmission card. And so on.

[0006]

SUMMARY OF THE INVENTION
In the method (1), since the operation of converting the relative address to the real address is performed at the time of execution of the control unit 32, there is a problem that the execution speed of the control unit 32 is reduced.

In the above method (2), when the option transmission card is changed, the user must be requested to re-transfer the program. If the program is executed without re-transfer, it is not intended by the user. There is a problem that a location may be accessed, which causes a malfunction.

The present invention supports each option transmission card without impairing the execution speed of the control unit of the programmable controller and without giving the user any troublesome operation such as re-transferring the program. It is an object of the present invention to realize a memory management method which can provide a real address in a user program.

[0009]

According to the present invention, an identifier storage area for storing an identifier provided corresponding to each option transmission card is provided in a memory, and a previous value of the identifier stored in the identifier storage area is provided. And the current value.
From the comparison result, it is determined whether or not the installed optional transmission card has been replaced with the previous optional transmission card. If the previous value and the current value of the identifier in the identifier storage area do not match, it is recognized that the installed optional transmission card has been replaced, and the user program area is searched in order from the top address. If there is a command to access the optional transmission card, the operand address is converted to an address corresponding to the currently installed optional transmission card, that is, the newly replaced optional transmission card.

[0010]

According to the present invention, the previous value and the current value of the identifier stored in the identifier storage area are compared, and if the previous value and the current value are different, the currently installed optional transmission card is replaced with the previous transmission card. Recognize that it was done. As a result, the user program area is searched in order from the top address, and if there is an operand for accessing the option transmission card in that area, the address of the operand is converted to an address corresponding to the current option transmission card.

Therefore, the real address corresponding to each option transmission card can be stored in the user program corresponding to each option transmission card without impairing the execution speed of the control system and without bothering the user. Can be set within.

[0012]

Next, embodiments of the present invention will be described. FIG. 1 is a memory map for explaining the embodiment, in which 1 is a memory map of an optional transmission card A, 2 is a memory map of an optional transmission card B, and this memory map is the control unit described in FIG. 32 is a part of the contents of the memory. The option transmission card A is, for example, a new P-link transmission card described with reference to FIG. 6, and the option transmission card B is, for example, a P-link transmission card.

Further, in this embodiment, a user program is created when the optional transmission card A is mounted on a predetermined transmission card mounting section, and thereafter, the optional transmission card A is prepared.
Is changed to the option transmission card B.

When the optional transmission card A is the control device main body 3
When attached to 1, the control unit 32 assigns an address for accessing the optional transmission card A to the 400000H address block. Here, the head address WL0 of the transmission card address recognized by the user is set to the address 400000H in the option transmission card A and to the address 401E00H in the option transmission card B.

In the memory map shown in FIG. 1, WL indicates the name of a memory area.
“W” indicates that the area “WL” has 512 words. Similarly, W21 · 1KW, W22 ·
3KW means that the area W21 is 1K words, W
22 indicates that there are 3K words in the area 22. Here, the above WL, W21, W22, etc. are the access areas of the optional transmission cards A, B.

The user creates a user program as shown in FIG. 2A to access the optional transmission card. The contents of the user program are composed of a program start declaration statement 11, a statement 12 combining an instruction to be processed and an instruction operand, and a program end declaration statement 13.

After creating such a user program, the user transfers the program from the loader 36 shown in FIG. FIG. 2B shows an example of a program obtained by converting the user program into a format that can be understood by the processor of the control unit 32. At this time, when storing the user program, the control unit 32 converts the head address WL0 of the card address to the address 400000H and stores it, since the optional transmission card A is installed at this time.

The user program stored in this way is executed, for example, as shown in FIG. 3, by the CPU 41 in the control unit 32 reading instructions sequentially from the top of the user program stored in the user program storage area 42. You. For example, if the instruction content of the user program is “WL
0 + WL1 → WL2 ”, WL0 and WL in the access area (WL) 43 of the optional transmission card A
Read the content (value) from 1 and add them (WL
After (0 + WL1), the operation of writing it to WL2 is performed.

FIG. 4 shows an identifier storage area for storing identifiers for identifying individual cards such as the optional transmission card A and the optional transmission card B. In the figure, the content stored in a predetermined bit of the identifier storage area 21 keeps the stored content even when the power of the control unit 32 is turned off. The stored identifier of the optional transmission card is stored in a predetermined bit of the identifier storage area 21. Here, the identifier of the optional transmission card A is “0”, and the identifier of the optional transmission card B is “1”. Therefore, the example of FIG. 4 indicates that the option transmission card B is currently mounted. “1” indicating that the optional transmission card B is mounted is stored when the power is turned on.

The processing operation starts when the power is input, and the processing operation will be described below with reference to the flowchart of FIG.
First, the state of the previous transmission card stored in the identifier storage area 21 is taken out, and the optional transmission cards A and B are taken out.
Is identified (step S
1) Compare with the current installed state of the option card (step S2). As a result of the comparison, if there is no change in the option card between the previous time and the present time, the current card state is set in the storage area (step S3), and the processing is ended.

On the other hand, if there is a change in the type of the option card that has been installed last time and now, the user program area is searched from the first address to the last address, and an operand for accessing the option transmission card is obtained.
Rewrite to the address that matches the current option transmission card. Here, since the previous value is “0” and the current value is “1”, it is recognized that the option transmission card B is currently installed instead of the option transmission card A. Therefore, the operand for accessing the transmission card is rewritten to an address corresponding to the current option transmission card B.

This series of processing is performed in steps S4 to S7 of FIG. That is, after setting the start address of the user program area (step S4), it is determined whether or not the user program area has ended (step S5). Is determined (step S6). If it is a transmission card access command,
The operand for accessing the option transmission card is rewritten to an address corresponding to the current option transmission card (in this case, the option transmission card B) (step S7). An example of rewriting the address to match the current option card, that is, the option transmission card is changed from the option transmission card A to the option transmission card B
In this embodiment, as shown in FIG. 2C, the user program is rewritten from 400000H to 401E00H.

As described above, in this embodiment, the previous value and the current value of the identifier storage area for storing the identifier of each optional transmission card are compared, and for example, the previous value is “0” indicating the optional transmission card A. If the current value is “1” indicating the option transmission card B, it recognizes that the installed option transmission card has been changed from A to B. Then, the user program area is searched, and the operand for accessing the optional transmission card is converted into an address suitable for the current optional transmission card B.

[0024]

According to the present invention, in a control device of a programmable controller to which a plurality of optional transmission cards can be mounted, without impairing the execution speed of the control device,
Further, it is possible to realize a memory management system in which a real address corresponding to each transmission card can be set in the user program without bothering the user such as re-transferring the program.

[Brief description of the drawings]

FIG. 1 is a diagram showing a memory map of an optional transmission card for explaining an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a user program for explaining the embodiment.

FIG. 3 is a diagram illustrating an execution example of a user program.

FIG. 4 is a diagram showing an identifier storage area for explaining the embodiment;

FIG. 5 is a flowchart illustrating a processing procedure of the embodiment.

FIG. 6 is a diagram schematically showing a control system of a programmable controller.

[Explanation of symbols]

 1 Memory map of optional transmission card A 2 Memory map of optional transmission card B 21 Identifier storage area

Claims (2)

(57) [Claims] 1. A memory management system in a controller of a programmable controller to which a plurality of optional transmission cards can be mounted, wherein the controller of the programmable controller has an identifier storage area for storing an identifier indicating a type of the optional transmission card. By comparing the previous value and the current value of the identifier stored in the identifier storage area, it is recognized whether or not the type of the installed optional transmission card is changed, and the type of the optional transmission card is changed. In this case, a memory management method for retrieving a user program area and, if there is an operand for accessing the optional transmission card in the area, converting the operand address to the address of the corresponding optional transmission card. 2. The method according to claim 1, wherein the identifier storage area stores the identifier even after power-off.
2. The memory management method according to claim 1, wherein an identifier already stored is held as a previous value, and at the time of power-on or reset, an identifier of an optional transmission card installed at that time is stored as a current value. .