JPH1185223A - Programmable controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily modify the substantial contents of a program to be executed by providing a means which selects a microinstruction read out of a microprogram memory and a microinstruction read out of a user program memory in pre-stage of an instruction execution part for microinstructions. SOLUTION: In the microprogram memory 20, microinstructions for executing respective sequence instructions stored in the user program 3 are stored. An instruction selecting circuit 17 selects microinstructions read out of the memory 20 in order and sends them out to an arithmetic circuit 18 while a selection command for the memory 20 is applied from an execution control circuit 15. Further, an instruction selecting circuit 17 selects and sends microinstructions read out of an instruction register 14 in order to the arithmetic circuit 18 while a selection command for the instruction register 14 is applied from the execution control circuit 15. The arithmetic circuit 18 after temporarily writing a specific arithmetic process result in an internal register 13 outputs it as operation data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is incorporated in various plants, such as steel, paper and other manufacturing plants, chemical plants, electric power plants, and water and sewage plants, and controls the operation and state of various controlled objects to optimal conditions. The present invention relates to a programmable controller, and more particularly to a programmable controller capable of easily changing and adding a program to be executed.

[0002]

2. Description of the Related Art Programmable controllers incorporated in the above-mentioned various plants execute various control processes on control targets. A control program for executing each control process is usually composed of a plurality of sequence instructions. Further, the control program is generally configured such that the execution of the program is executed by hardware or a microprogram written with a plurality of microinstructions.

However, when the execution control portion of the control program is entirely constituted by hardware, it is impossible to change or add a sequence instruction. Therefore, in recent years, the execution contents of the sequence instructions are often stored in a rewritable microprogram memory.

[0004]

In the case where the control operation of the programmable controller is controlled by a microprogram, a microprogram memory in which microinstructions indicating the actual contents of each sequence instruction in each control program are written, for example, If it is composed of rewritable independent storage elements such as HDD and RAM,
The specific execution contents of the control program can be freely changed by rewriting each microinstruction constituting each sequence instruction.

However, when this microprogram memory is built together with other circuit elements in an LSI (Large Scale Integrated Circuit), the contents of the sequence instruction are executed in the same manner as when the execution of this program is realized by hardware from the beginning. Is impossible to change.

In order to reduce the number of components of the entire programmable controller, it is desirable to implement an LSI including the above-mentioned microprogram memory. However, if there is a possibility that the specific contents of the sequence instructions may change, the LSI is implemented. It is impossible.

The present invention has been made in view of such circumstances, and means for switching between a microinstruction read from a microprogram memory and a microinstruction read from a user program memory at a stage preceding an instruction execution unit of a microinstruction. To provide a programmable controller that can easily change and add substantial contents of a program executed by the controller even if the microprogram memory is configured by substantial hardware such as an LSI. Aim.

[0008]

According to a first aspect of the present invention, there is provided a programmable controller for storing a microinstruction of a program to be executed, and an instruction for executing an input microinstruction. Execution means, execution mode instructing means for instructing an execution mode of the program, and instruction selection means for providing the microinstruction read from the microprogram memory or the user program memory to the instruction execution means based on the instructed execution mode. Have.

In the programmable controller configured as described above, when a microinstruction different from each microinstruction of the program stored in the microprogram memory is executed, the different microinstruction is set in the user program memory and executed. What is necessary is just to give an instruction for selecting the microinstruction read from the user program memory to the instruction selection means by the mode instruction means.

As a result, instead of the microinstruction read from the microprogram memory, the instruction execution means has
The microinstruction read from the user program memory is input. Therefore, for example, instead of the microinstruction stored in the microprogram memory, a microinstruction specified by an operator or a user is executed.

That is, even if LS together with other potential members
Even if the microprogram memory is built in the I, the microinstructions stored in the microprogram memory can be replaced with different external microinstructions and executed, and the versatility of the programmable controller can be greatly improved.

According to a second aspect of the present invention, in the programmable controller of the first aspect, a micro-instruction writing for writing a defective micro-instruction written in the micro-program memory or a correct micro-instruction for a micro-instruction to be changed in the user program memory. Means. Further, the execution mode instructing means instructs an execution mode for selecting a microinstruction read from the user program memory.

In the programmable controller configured as described above, when there is a defect in a microinstruction constituting the program stored in the microprogram memory, or when it is desired to change the contents indicated by the microinstruction of the sequence instruction of the program In addition, by writing the micro-instruction whose contents have been changed into the user program memory, it is possible to easily substantially correct or change a specific micro-instruction.

According to a third aspect of the present invention, in the programmable controller of the first aspect, another program writing means for writing a microinstruction of another program different from the program stored in the microprogram memory in the user program memory is provided. Further, the execution mode instruction means includes:
An execution mode for selecting a microinstruction read from the user program memory is forcibly instructed based on an externally input electric signal.

With this configuration, when executing a completely different control program different from the control program preset in the programmable controller, the microinstruction of the completely different control program is written into the user program memory. The operation mode may be forcibly set to a mode for selecting a microinstruction read from the user program memory by using an external electric signal.

In this case, the program stored in the microprogram memory is not used at all, and another program written in the user program memory is executed exclusively.

Further, in this case, if necessary, the microprogram memory can be removed. According to a fourth aspect of the present invention, in the programmable controller of the first aspect, an additional program writing means for writing a micro instruction of an additional program to the program stored in the micro program memory in the user program memory is provided. Further, in response to the start of reading of the additional program stored in the user program memory, the execution mode instructing means instructs an execution mode of selecting a microinstruction read from the user program memory, and the execution mode is stored in the user program memory. In accordance with the end of reading of the additional program, an execution mode for selecting a microinstruction read from the microprogram memory is designated.

In the programmable controller configured as described above, when it is necessary to add another program later to the program set in the existing microprogram memory, each microinstruction of the additional program is required. May be written in the user program memory.

As a result, an additional program stored in the user program memory is executed in addition to the program already set in the existing micro program memory. That is, the number of programs to be easily executed can be increased.

According to a fifth aspect of the present invention, in the programmable controller of the fourth aspect, the additional program writing means writes start information and end information before and after the microinstruction when writing the microinstruction of the additional program in the user program memory. Write. The execution mode instructing unit detects the start and end of reading of the additional program based on the start information and the end information.

In the programmable controller configured as described above, the start and end of reading of the additional program are easily detected, and the processing load on the execution mode instruction means is reduced.

According to a sixth aspect of the present invention, in the programmable controller according to the fourth aspect, the additional program writing means, when writing micro instructions of the additional program into the user program memory, comprises a plurality of micro instructions constituting the additional program. For the microinstruction already stored in the microprogram memory, the corresponding microinstruction is written in a form called from the microprogram memory by a subroutine.

By writing the additional program into the user program memory using the subroutine in this way, the microinstructions already stored in the microprogram memory can be used, so that the resources of the entire programmable controller can be more effectively used. Can be used.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram illustrating a schematic configuration of the programmable controller according to the embodiment. In this programmable controller, a sequence operation CPU 2 which is a central part of the programmable controller, a user program memory 3 in which a user-specific control program of the programmable controller is stored, and an external bus 1 are incorporated in a plant. Input / output port 4 for taking in process data from various control targets such as equipment and sending operation data to various control targets
And the operator inputs various operation commands and user program memory 3
An operation section 5 for inputting program data of a sequence command or microinstruction constituting a control program to be set in the control program is connected.

As shown in FIG. 2, in the user program memory 3, a plurality of sequence instructions 6 constituting a control program set by a user who is an installer of the plant where the programmable controller is installed are stored in the order of execution. ing.

In this user program memory 3, as shown in FIG. 3, an extended mode instruction instruction 7 as start information of the micro instruction and a normal mode instruction instruction as end information of the micro instruction are provided as necessary. 8 and a plurality of microinstructions 9 interposed between the extended mode instruction instruction 7 and the normal mode instruction instruction 89 may be written by a write operation via the operation unit 5 of the operator.

Further, as shown in FIG. 4, only a plurality of microinstructions 9 constituting one control program may be written in the user program memory 3 as necessary.

Further, as shown in FIG. 5, if necessary, the user program memory 3 is extended not only to the predetermined number of sequence instructions 6 shown in FIG. An additional program consisting of a mode instruction instruction 7, a plurality of micro instructions 9 and a normal mode instruction instruction 8 may be written.

In a sequence operation CPU 2 constituting a central portion of the programmable controller shown in FIG. 1, an address counter 11 for specifying an address of a user program memory 3 and an input / output port 4 for an internal bus 10, a user program memory A data input / output circuit 12 for inputting / outputting various information to / from the input / output port 4 and the operation unit 5; an internal data buffer 13 for temporarily storing data input / output to / from the input / output port 4; An instruction register 14 for temporarily storing various instructions such as a sequence instruction 6, an extended mode instruction instruction 7, a micro instruction 9, and a normal mode instruction instruction 8 read from the user program memory 3 is connected.

When the micro instruction 9 is input from the user program memory 3, the instruction register 14 sends the input micro instruction 9 to the instruction selection circuit 17. Further, the instruction register 14 is connected to the internal bus 10.
The instruction decoder 16 decodes the extended mode instruction instruction 7 and the normal mode instruction instruction 8 fetched into the instruction control circuit 15 and sends the instruction to the execution control circuit 15, and the operation as instruction execution means for executing the microinstruction selected by the instruction selection circuit 17. The circuit 18 is connected.

Further, the instruction decoder 16 sends the address contained in the sequence instruction 6 fetched into the instruction register 14 to the microprogram address counter 21 as an initial address value.

When the micro-instruction is input, the arithmetic circuit 18 performs a control operation instructed by the micro-instruction on the process data input from the control target taken into the internal data register 13 and obtains the operation result. Is written into the internal data register 13.

Upon receiving the decoded normal mode instruction command 8 from the instruction decoder 16, the execution control circuit 15 sets the operation mode of the operation mode register 19 to the "normal operation mode", and When the extension mode instruction command 7 is input, the operation mode of the operation mode register 19 is set to “extended operation mode”.

Further, when the operation mode set in the operation mode register 19 is the "normal operation mode", the execution control circuit 15 sends an instruction to select the microprogram memory 20 to the instruction selection circuit 17, and executes the operation mode. When the operation mode set in the register 19 is the “extended operation mode”, the instruction register 1
4 is transmitted.

Further, when the operation mode set in the operation mode register 19 is the “normal operation mode”, the execution control circuit 15 outputs one operation result for the microinstruction from the operation circuit 18, Each time one microinstruction is executed, a count up signal is sent to the microprogram address counter 21.

When the operation mode set in the operation mode register 19 is the “extended operation mode”, the execution control circuit 15 outputs an operation result for the microinstruction 9 from the operation circuit 18, that is, Each time one microinstruction 9 is executed, a count-up signal is sent to the address counter 21.

Microprogram address counter 21
Each time a count-up signal is input from the execution control circuit 15, the microprogram memory 20 stores the address value counted up from the previously input initial address value.
Apply to

In the micro program memory 20, a plurality of micro instructions for executing each sequence instruction 6 stored in the user program memory 3 are stored. Then, the address at which the head microinstruction in each sequence instruction 6 is stored, that is, the head address is specified by each sequence instruction 6.

As a result, the microprogram memory 20
From the sequence instruction 6 stored in the instruction register 14
Are sequentially read out and sent to the instruction selection circuit 17.

The instruction selection circuit 17 selects micro instructions sequentially read from the micro program memory 20 during the period when the selection instruction of the micro program memory 20 is applied from the execution control circuit 15 and the instruction selection circuit 17
8

The instruction selection circuit 17 selects the macro instructions 9 sequentially read from the instruction register 14 during the period when the instruction for selecting the instruction register 14 is applied from the execution control circuit 15 and sends the instruction to the arithmetic circuit 18. Send out.

Next, the operation of the thus configured programmable controller will be described. 1) Normal operation In this case, in the user program memory 3, as shown in FIG. 2, each sequence instruction 6 of the control program indicating the control to be executed by the programmable controller is sequentially stored.

In this case, the "normal operation mode" is set in the execution mode register 19. When the operator inputs a start command via the operation unit 5, the start command is taken into the command register 14 via the data input / output circuit 12. Then, the address counter 11 is activated, and the user program memory 3 designated by the address counter 11 is activated.
Is read and taken into the instruction register 14.

When the first sequence instruction 6 is fetched into the instruction register 14, this sequence instruction 6 is decoded by the instruction decoder 16, and the operation of the execution control circuit 15 is determined according to the result, thereby constituting the sequence instruction 6. The microinstruction is read from the microprogram memory 20 and sent to the arithmetic circuit 18 via the instruction selection circuit 17.

The arithmetic circuit 18 executes a predetermined control arithmetic processing on the process data to be controlled, which is read by the internal data register 13, and temporarily writes the arithmetic processing result into the internal data register 13. Internal data register 1
The operation processing result once written in the data input / output circuit 3
The operation data is transmitted to the control object via the input / output port 4 via the input / output port 4.

The execution control circuit 15 sends a count-up signal to the microprogram address counter 21 every time one microinstruction is executed by the arithmetic circuit 18 to update the address output to the microprogram memory 20.

Accordingly, each microinstruction constituting the corresponding sequence instruction 6 stored in the microprogram memory 20 is sequentially read out and executed by the arithmetic circuit 18. When the control processing for one sequence instruction 6 is completed, the next sequence instruction 6 is read from the user program memory 3, and each micro instruction constituting the corresponding sequence instruction 6 is read from the micro program memory 20 and sequentially executed. .

As described above, during the normal operation, the control program is sequentially executed only by each microinstruction stored in the microprogram memory 20 of the sequence operation CPU 2.

2) At the time of malfunction of microinstruction or at the time of change of microinstruction Next, a malfunction occurred in each microinstruction constituting each sequence instruction stored in microprogram memory 20, or a specific microinstruction was changed. In this case, the operator operates the operation unit 5 to replace the sequence instruction to which the corresponding microinstruction in the user program memory 3 belongs with, as shown in FIG. The micro instruction 9 and the normal mode instruction instruction 8 are written.

In this case, when the programmable controller is started, the “normal operation mode” is set in the execution mode register 19. Therefore, since the first sequence instruction 6 to the fourth sequence instruction 6 in the user program memory 3 of FIG. 3 are in the normal operation mode setting, as described above, each of the instructions stored in the micro program memory 20 is stored. Microinstructions are executed in order.

When the extended mode instruction instruction 7 is fetched into the instruction register 14 instead of the fifth sequence instruction 6, the operation mode of the operation mode register 19 is changed to the "extended operation mode". A selection command for the instruction register 14 is applied from the circuit 15 to the instruction selection circuit 17.

When the address counter 11 designates the microinstruction 9 at the address next to the extension mode instruction instruction 7 in the user program memory 3, the microinstruction 9 is sent to the arithmetic circuit via the instruction register 14 and the instruction selection circuit 17. 18 is input. Therefore, the arithmetic circuit 18 executes the microinstruction 9 read from the user program memory 3.

When the execution of one microinstruction 9 is completed, the execution control circuit 15 sends a count-up signal to the address counter 11, so that the address counter 11 specifies the next microinstruction 9. In this way, each microinstruction 9 in the user program memory 3 is sequentially executed.

When the address counter 11 specifies the normal mode instruction command 8, the normal mode instruction command 8
Is taken into the instruction register 14. As a result, the operation mode of the operation mode register 19 is changed from the “extended operation mode” to the “normal operation mode”. Then, a selection command for the microprogram memory 20 is applied from the execution control circuit 15 to the instruction selection circuit 17.

Therefore, thereafter, each microinstruction read from the microprogram memory 20 is input to the arithmetic circuit 18 via the instruction selection circuit 17. That is, each of the sixth and subsequent sequence instructions 6 in the user program memory 3 is executed by each micro instruction stored in the micro program memory 20.

As described above, for example, the microprogram memory 20 formed of virtual hardware such as an LSI is used.
If the micro-instruction stored in the micro-instruction becomes defective or a part of the micro-instruction needs to be changed, the modified or changed micro-instruction 9 is stored in the external user program memory 3 in the extended mode instruction. By inserting and setting between the instruction 7 and the normal mode instruction instruction 8, the modified or changed micro instruction 9 can be automatically executed.

3) When a completely different control program is executed. A completely different control program is used without using a control program consisting of a plurality of microinstructions stored in the microprogram memory 20 in the sequence operation CPU 2. Therefore, it may be necessary to operate this programmable controller.

In this case, as shown in FIG.
A plurality of microinstructions 9 constituting another control program to be executed are written into the user program memory 3 via the operation unit 5.

Further, an external setting signal which is an electric signal is applied to the execution mode register 19 to forcibly set the operation mode to the "extended operation mode". Therefore, the operation mode of the execution mode register 19 maintains the "extended operation mode" regardless of what mode designation instruction is taken into the instruction register 14. Therefore, the instruction selecting circuit 17 always selects each microinstruction 9 taken into the instruction register 14 from the user program memory 3 and sends it to the arithmetic circuit 18.

When the programmable controller set in this way is started, a start command is taken from the operation unit 5 into the command register 14, and the address counter 11 is started and stored in the user program memory 3 shown in FIG. Are designated in order. Each microinstruction 9 specified in order by the address counter 11 is sequentially input to the arithmetic circuit 18 via the instruction register 14 and the instruction selection circuit 17.

The arithmetic circuit 18 sequentially executes the input microinstructions 9 read from the user program memory 3. Thus, for example, in a small programmable controller, the microprogram memory 2
To omit 0 itself, the execution mode register 19
The operation mode can be forcibly set to the "extended operation mode" by an external setting signal consisting of a fixed electric signal instead of a software instruction for the extended mode instruction.

Therefore, it is possible to read each microinstruction 9 from the user program memory 3 from the start of the program controller. Therefore, when there are few types of sequence instructions 6 and the circuit of the sequence operation CPU 2 This is effective for applications where you do not want to increase the scale.

4) When an Additional Program is Executed (Part 1) Even if each microinstruction constituting the control program stored in the microprogram memory 20 incorporated in the sequence operation CPU 2 is normal. In some cases, it is desired to execute another control program using this programmable controller.

In such a case, as shown in FIG. 5, after each of the sequence instructions 6 from 1 to 9 of the already written control program in the user program memory 3, the control program to be added this time is An extended mode instruction instruction 7 and a normal mode instruction instruction 8 before and after each micro instruction 9
Write across.

As described above, when the programmable controller is started in a state where each micro instruction 9 of the additional control program is written in the user program memory 3,
After the first to ninth sequence instructions 6 are executed in the same procedure as when the micro instruction is defective or the micro instruction is changed, each micro instruction 9 of the control program added this time is executed. .

When each microinstruction 9 of the additional control program is written at the head of the user program memory 3, after the additional control program is executed,
The already set control program is executed.

As described above, by adjusting the write position of the additional control program in the user program memory 3, the additional control program can be executed at an arbitrary timing.

In the conventional programmable controller, if there is no problem in the contents of the control program and a new control program is to be added, or if it is desired to extend the sequence instruction, the sequence operation CPU 2 must be redesigned or the sequence instruction 6 Had to be combined to realize new functions.

However, in the programmable controller of this embodiment, the necessary control program and the microinstruction 9 of the required sequence instruction 6 are newly written at the timing position to be executed in the user program memory 3 so that the programmable controller can be easily programmed. It is possible to extend the function of the controller.

5) When Executing Additional Program (No. 2) In this case, the manufacturer of this programmable controller previously discloses each microinstruction of the microprogram memory 20 and each sequence instruction of the user program memory 3 to the user. Keep it.

When the user of this programmable controller executes an additional control program in the same manner as the above-described method of executing a new program, the user can freely create a new control program on the user program 3. At the same time, if there is a sequence instruction 6 created by the manufacturer and set in the user program memory 3 among the plurality of sequence instructions constituting the new control program, each of the sequence instructions 6 It is also possible to write a microinstruction to be called from the microprogram memory 20 in a subroutine format.

As described above, since each microinstruction already stored in the microprogram memory 20 can be used in the form of a subroutine, there is no need to write the microinstruction in the user program memory 3 redundantly. Can be used more effectively.

[0073]

As described above, according to the programmable controller of the present invention, the microinstruction read from the microprogram memory and the microinstruction read from the user program memory are provided before the instruction execution unit of the microinstruction. A means for selecting is provided.

Therefore, even if the microprogram memory is constituted by substantial hardware such as an LSI, the substantial contents of the program executed by the programmable controller can be easily changed and added.

Further, when there is a defect in the microinstruction stored in the microprogram memory or when it is desired to change the content of the microinstruction, the execution content of the microinstruction can be easily changed.

Further, by changing the operation mode with an external electric signal, the microprogram memory can be deleted by always reading the microinstruction from the external user program memory.

When an additional program is required for the program stored in the microprogram memory, each microinstruction of the additional program is written in the user program memory.

Therefore, the number of programs executed by the programmable controller can be easily increased. Further, by writing the program in the user program memory in a subroutine format, there is no need to write the microinstruction in the user program memory 3 in duplicate, and the resources of the programmable controller can be more effectively utilized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a programmable controller according to an embodiment of the present invention.

FIG. 2 is a diagram showing contents stored in a user program memory of the programmable controller;

FIG. 3 is a diagram showing storage contents of a user program memory of the same programmable controller.

FIG. 4 is a diagram showing storage contents of a user program memory of the same programmable controller.

FIG. 5 is a diagram showing storage contents of a user program memory of the same programmable controller.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... External bus 2 ... Sequence calculation CPU 3 ... User program memory 4 ... I / O port 5 ... Operation unit 6 ... Sequence instruction 7 ... Extended mode instruction instruction 8 ... Normal mode instruction instruction 9 ... Micro instruction 10 ... Internal bus 11 ... Address Counter 12 Data input / output circuit 13 Internal data register 14 Instruction register 15 Execution control circuit 16 Instruction decoder 17 Instruction selection circuit 18 Operation circuit 19 Execution mode register 20 Micro program memory 21 Micro program address counter

Claims (6)

[Claims] 1. A microprogram memory for storing a microinstruction of a program to be executed, an instruction execution unit for executing an input microinstruction, an execution mode instructing unit for instructing an execution mode of a program, An instruction selecting means for providing a microinstruction read from the microprogram memory or the user program memory to the instruction executing means based on an execution mode. 2. An execution mode instructing means, comprising: micro instruction writing means for writing a defective micro instruction written in the micro program memory or a correct micro instruction for a micro instruction to be changed in the user program memory. 2. The programmable controller according to claim 1, wherein said instruction indicates an execution mode for selecting a microinstruction read from a user program memory. 3. A separate program writing means for writing a microinstruction of another program different from the program stored in the microprogram memory into the user program memory, wherein the execution mode instruction means is externally input. 2. The programmable controller according to claim 1, wherein an execution mode for selecting a microinstruction read from the user program memory is forcibly instructed based on the electric signal. 4. An additional program writing means for writing a micro instruction of an additional program to a program stored in the micro program memory in the user program memory, wherein the execution mode instruction means is stored in the user program memory. In response to the start of reading of the additional program, an execution mode for selecting a microinstruction read from the user program memory is designated, and in response to completion of reading of the additional program stored in the user program memory, the execution mode is selected. 2. The programmable controller according to claim 1, wherein an execution mode for selecting the read microinstruction is indicated. 5. The method according to claim 1, wherein the additional program writing means writes start information and end information before and after the microinstruction when writing the microinstruction of the additional program in the user program memory. 5. The programmable controller according to claim 4, wherein the start information and the read end of the additional program are detected based on the start information and the end information. 6. The additional program writing means, when writing a micro instruction of the additional program in the user program memory, has already been stored in the micro program memory among a plurality of micro instructions constituting the additional program. 5. The programmable controller according to claim 4, wherein said microinstruction is written in a form called from a microprogram memory in a subroutine by a subroutine.