JPH0410081B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a programmable controller,
In particular, it relates to a programmable controller that allows programs to be changed during operation.

[Technical background and problems of the invention]

Programmable controllers (hereinafter simply referred to as controllers) are classified into many types, from simple types to highly functional types, based on the number of process input/output points, calculation functions, system configuration scale, etc., and are often applied to plant control. In particular, high-performance models are required to be highly reliable, and enable online program monitoring, data monitoring, data modification, etc.

Ladder diagrams are commonly used as a programming language for controllers.

FIG. 1 is a diagram showing an example of a program using a ladder diagram.

FIG. 2 is a program diagram converted into processor command words by a compile program corresponding to the ladder diagram of FIG. 1. The ladder diagram uses a program method that is converted into machine language by a compiler and executed by a processor.

Figure 3 shows the format of the machine language. The machine language varies depending on the processor, such as 8 bits or 16 bits, but it consists of an opcode 1 and an operand 2.

In the above programming method, changing operand 2 only requires rewriting one word of data. i.e. shift the entire program,
No insertion work is required. Furthermore, changing an instruction word to another instruction word having the same number of words can be done by rewriting memory data without shifting the entire program. Currently, online program changes are performed in units of operands or instruction words as described above.

Recently, with the increasing functionality of controllers, there is an IF that controls the program in the ladder diagram.
Syntax commands such as statements and DO statements, and special function operations such as sinx and e ^x can be programmed.

Changing these programs necessarily requires shifting or relocation of the entire program, which poses a problem in that it is impossible to execute it online.

[Purpose of the invention]

The present invention has been made based on the above circumstances, and it is possible to change a program without interrupting process control, and if the new program that has been changed has a defect or inconsistency in control, it is possible to immediately change the program from the previous program. The purpose of the present invention is to provide a programmable controller that provides continuity of plant control and higher reliability by making it possible to restore plant control.

[Summary of the invention]

The present invention includes a program memory for storing a sequence program, a data memory for storing intermediate results of calculations, data, etc., an input section for taking in information input from the outside, and an input section for taking in information from the input section or the data memory. an interface unit that exchanges information between a calculation control unit that performs calculations using the computer, an output unit that outputs the calculation results of the calculation control unit, and a program loader that inputs or displays programs, data, etc. In a programmable controller, a first memory (program area) stores a sequence program consisting of a plurality of function programs, and a second memory stores management information such as a start address and program size for each function program. (function program management area), a sequence program execution means for executing the function program based on the management information, and a sequence program execution means for executing the function program based on the management information; means for writing into the first memory; a third memory (changed function program management information area) for storing management information of the changed function program; and a third memory (changed function program management information area) for storing management information of the changed function program. A fourth memory (function program management information storage area), and management information of the function program to be changed in the second memory is saved in the fourth memory while online, and is stored in the third memory. It replaces the management information, enables the function program to be changed, and also
This programmable controller is provided with means for returning management information stored in the second memory to the second memory and returning to the original function program, thereby making it possible to change the function program during operation.

[Embodiments of the invention]

FIG. 4 is a block diagram of the programmable controller of the present invention. Reference numeral 3 denotes an arithmetic control unit which processes sequence arithmetic commands specific to the controller, arithmetic operations added to the high-function type, and syntax command processing, and at the same time executes commands necessary to control the controller. A ROM 4 stores an execution management program (hereinafter abbreviated as OS) that controls the mode of the controller, manages program execution, and controls the loader interface. A RAM 5 stores programs, a function management table, a save table, etc., which will be described later. This RAM
5 is normally non-volatile and the power is turned off.
However, the contents will be saved. 6 is a process input/output module that inputs signals from external processes;
and output signals to external processes. Reference numeral 7 denotes a program loader interface for data transmission such as program loading and monitoring of program execution status. Although there are various data transmission methods, serial transmission is generally used, and a command and text are contained in one frame. The CPU interprets the command and processes the text. Sometimes there is no text, just a command. This is mainly used to give commands when changing the control mode of the controller.

8 is a program loader. The program loader consists of a CRT display, a dedicated keyboard, an external storage device, etc. The external storage device allows it to be separated from the controller and programmed using the program loader alone.

FIG. 5 is a memory map diagram showing the memory area of the RAM 5 of the programmable controller of the present invention by function, and shows the structure of the program.

5-1 indicates a program area in the RAM 5 in which a program is stored, and the program is divided into a plurality of function programs 5-11 to 5-1n and stored according to the process control function.

5-2 is each function program 5-11
The function program management area in the RAM 5 stores management information such as the start address of 5-1n and program size, and manages where the function programs 5-11 to 5-1n exist in the program space. It is for.

5-3 is a function program management information storage area in the RAM 5, which stores the function management information of the changed function program when a given function program is changed to a new function program. It is something to preserve.

Function programs include interrupt processing functions executed in response to external interrupts, scan functions executed in synchronization with sequential scanning, and execution of interrupt processing functions and scan functions within sequential scanning time. It is classified as a batch processing function, etc., which is processed during the remaining time.

FIG. 6 is a time chart showing the execution status of functions within the sequential scanning time.

The execution of the function program is managed by the OS 4-1 stored in the ROM 4.
When a function program execution factor (interrupt, sequential scan) occurs, the OS 4-1 retrieves the registered address of the corresponding function program from the function program management area 5-2 and starts the function program. .

When the started function program finishes running, it returns to OS4-1, searches for the next function program to start, retrieves the registered address of the found function program from the function program management area, and executes the next function program. Execution of the function program begins. Thereafter, function programs are executed one after another under the control of the OS 4-1 in the same manner.
FIG. 7 is a state diagram showing the starting order of the OS 4-1 and the function programs 5-11 to 5-1n.

When an interrupt occurs in an arbitrary function program and the priority of the interrupt is high, the function program being executed is temporarily suspended and the interrupt processing function program is activated.

Similarly to interrupt processing, the processing program of the program loader also interrupts the currently executing function program and processes it preferentially.

FIGS. 8-11 are state diagrams illustrating the online change process.

FIG. 8 is a state diagram in which the program loader 8 searches for a function program registration area. The program loader 8 reads the start address and program size of each function program from the function program management area 5-2 in response to an interrupt command from the program loader 8.
Program area 5- that can be transmitted to and newly registered
1. Calculate the registration start address and registration space. If there is insufficient registration space, online changes will not be possible.

FIG. 9 shows a state in which the modified function program 5-1x is loaded from the registered start address of the program area 5-1 by interrupt processing by the program loader 8. Note that loading is performed little by little during a short period of time within the sequential scanning time so as not to affect process control while online.

Figure 10 shows modified function program 5.
-1y and change function program 5-1x
FIG. 4 is a state diagram showing management information registration changes in the function program management area 5-2 of FIG. After the loading is completed as described above, the management information 5-1 of the modified function program 5-1x is
XC is registered in the changed function program management information area 5-4.

When the program loader 8 gives a command to register the modified function program 5-1x, the management information 5 of the modified function program in the function program management area 5-2
-1YC is stored in the function program management information storage area 5-3, and the management information 5-1YC of the modified function program 5-1y in the function program management area 5-2 is changed.Function program management Rewrite the information area 5-4 to management information 5-1XC. Through this processing, management information such as the start address and program size of the modified function program 5-1x is registered while online, but this series of processing is performed at the start of sequential scanning as shown in Figure 6. OS in advance
Executed by

Figure 12 shows the function program Fn2.
This is a time chart showing the execution status before and after changing to Fn2A. In this way, it is possible to change the function program without interrupting the execution of plant control.

FIG. 11 is a state diagram showing the restoration of the modified function program. Program loader 8
When a restoration command is given from , the management information 5-1YC of the restoration function program is read out from the function program management information storage area 5-3 before starting the sequential scanning shown in FIG. The program management area 5-2 is stored at the appropriate location. As a result, the restoration to the old function program 5-1Y is executed at the end of the scan, and can be performed without interrupting the execution of plant control.

〔Effect of the invention〕

As described above, according to the programmable controller of the present invention, it is possible to change programs in function program units while control is being executed, and control optimization can be achieved online in a short time, making it possible to perform test runs. Therefore, it is possible to provide a programmable controller with good adjustment efficiency even when the time comes.

[Brief explanation of drawings]

Fig. 1 is a program diagram using a ladder diagram, Fig. 2 is a program diagram converted into processor command words, Fig. 3 is a configuration diagram of machine language, Fig. 4 is a block diagram of the programmable controller of the present invention, and Fig. 5 is a memory map diagram of RAM 5, Figure 6 is a time chart showing the execution state of functions within the sequential scanning time, Figure 7 is a state diagram showing the startup order by the execution management program OS, and Figures 8 to 11. 12 is a state diagram of each memory area showing online change, and FIG. 12 is a time chart showing the execution state before and after the program change. 3...CPU, 4...ROM, 4-1...Execution management program, 5...RAM, 5-1...Program area, 5-2...Function program management area, 5-3...Fan Function program management information storage area, 5-4...Change function program management information area.

Claims (1)

[Claims] 1. A program memory that stores a sequence program, a data memory that stores intermediate results of calculations, data, etc., an input section that takes in information input from the outside, and an operation that uses information from the input section or the data memory. an arithmetic control unit that performs
A programmable controller equipped with an interface unit that exchanges information between an output unit that outputs the calculation results of the calculation control unit and a program loader that inputs or displays programs and data, etc. a first memory (program area) that stores a sequence program consisting of a sequence program; a second memory (function program management area) that stores management information such as the start address and program size for each function program; sequence program execution means for executing the function program based on the management information; means for writing the modified function program from the program loader into the first memory little by little during online sequential scanning time; a third memory (changed function program management information area) for storing management information of the changed function program;
A fourth memory (function program management information storage area) that stores management information of the function program to be changed;
The management information of the function program to be changed in the memory is saved in the fourth memory and replaced with the management information in the third memory, making it possible to change the function program, and A programmable controller characterized in that a programmable controller is provided with means for returning management information stored in the second memory to the second memory and returning to the original function program.