JPH1027007A - Process controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process controller which can control a process without deteriorating its control ability nor receiving any restriction from the number or kind of functional blocks. SOLUTION: After a process controller is started, the controller reads the functional block information (the kind, input, and output of arithmetic operation) of an application program (ST22), then performs compilation for removing undefined input-output or functional blocks (ST23). The controller stores the compiled results in a memory (ST24) and, when the controller enters periodic operations, the controller reads out the compiled results stored in the memory (ST26) and successively execute the compiled results (ST27).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a process control device used for continuous control of a plant.

[0002]

2. Description of the Related Art Generally, a heart control system of a process control device for controlling a plant has a CPU board including a microprocessor and a memory, and an analog input signal which is an electric signal of 4 to 20 mA and 1 to 5 V. An I / O board including a multiplexer and an A / D converter, and a multiplexer that outputs an analog output signal to the outside;
An I / O board including an / A converter, an I / O board including a port for receiving a digital input signal from the outside, an I / O board including a port for outputting a digital output signal to the outside, and the like.

An application program for constructing a system of the process control apparatus is stored in a part of a memory in the form of information of the operation of each functional block and information of signal connection between the blocks. Are sequentially read, interpreted and processed. This is a processing method like a so-called interpreter.

An example of storing blocks and an example of storing the information in the process control device will be described. FIG. 3 is a block diagram showing a storage example. Here, block 1, block 2, and block 4 are used, and block 3 is not used. A process input is taken from the input terminal AI ₁ , taken into the SQ block 1, and the SQ block 1 outputs a process amount and inputs it to the PID block 4. Also, the input terminal DI ₁ and the input terminal DI ₂ are increased in setting, respectively.
Take in the input of setting decrease, input it to SET block 2,
The set amount is output from the ET block 2 and input to the PID block 4. PID block 4 takes in the signals of the automatic / manual switch as further input from the input terminal DI _3,
Performs PID calculation, and outputs the calculated manipulated variable to the output terminal AO _1.

[0005] Information on the operation contents of each block and the connection between the blocks in the above example are stored in the order of blocks as shown in FIG. In each block, a defined “code representing the type of operation” and “code representing input to the block” are stored. Opcode block 1 code indicating the SQ (No.) is also input 1 is AI _1, input 2 is no. Block 2 is the opcode SET (set), the input 1, input 2 is DI ₁ and DI _2. In an unused block such as the block 3, a "code indicating unused" is stored in the operation code.

In the above-mentioned conventional process control device, in the part for performing the periodic operation processing, first, as shown in FIG. 5, after the initialization processing is performed (ST1), every time the sampling time arrives (ST2), the entire processing is performed. External input processing is performed, and all input values are temporarily stored in an external input value area (ST3).
Next, in the block processing part, the block number N is set to 1 (ST4), and the operation code of the block N is read (S4).
T5), and further read the input code of block N (ST
6) With reference to the block N and the input value of the read input code (ST7), an arithmetic subroutine is called, and the arithmetic defined by the block N is performed. For example, in the above example,
In block 1, SQ (square root) operation is performed on the input value of the input AI ₁ (ST8). The calculation result is written as the output value of block N (ST9). With this, block N
Is completed, and then N is incremented by 1 (S
T10) Until all blocks are completed (ST11), S
Returning to T4, the processing of ST4 to ST11 is repeated, and processing is performed for all blocks.

The processing of all blocks is completed (ST11).
With reference to the output value area of the block N corresponding to the code defined as the external output, and performs all external output processing (ST
13) Return to ST2 and wait for the next sampling time to arrive. This type of process control device has the advantage that, when an application program is created externally and downloaded to the CPU board or uploaded from the CPU load and changes are made to the application program, the process program can be handled in the form of a functional block (image). is there.

[0008]

The above-described conventional process control device is an interpreted processing method.
All external input processing is performed in order, and the operation code,
Since the input and output are read, the input values are referred to, an arithmetic subroutine is executed, and all the external output processing is performed by referring to the output values of the defined blocks, the execution speed is low. For this reason, the number and types of functional blocks that can be executed at regular intervals are greatly restricted. On the contrary, if many functional blocks are to be processed, it is necessary to terminate the processing without leaving the processing of these many blocks, and the execution cycle must be extended. However, if the execution cycle (sampling cycle) is made longer, there is a problem that the control performance is reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a process control apparatus which does not reduce control performance and is not restricted by the number and types of functional blocks. I have.

[0010]

A process control apparatus according to the present invention comprises a CPU board including a microprocessor and a memory, an analog signal as an electric signal such as 4 to 20 mA, 1 to 5 V, or a digital signal such as a contact ON / OFF. In an I / O board for inputting and outputting signals to and from an external device, a process for performing process control is performed by storing an application program in a part of a memory of the CPU board in the form of a combination of functional blocks. At the start, the program has a function of compiling and optimizing an application program, and thereafter executing the compiled application program at regular intervals.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to embodiments. FIG. 1 is a block diagram showing a hardware configuration of a process control device according to an embodiment of the present invention. The process control device includes a CPU board 11 including a microprocessor 12 and a memory 13;
A multiplexer 2 which receives analog input signals AI ₁ ,..., AI ₁₆ which are electric signals of 20 mA and ₁ to 5 V from outside.
2, an I / O board 21 including an A / D converter 23, a multiplexer 32 for outputting analog output signals AO ₁ ,..., AO ₁₆ to the outside, and an I / O board 31 including a D / A converter 33. , D ₁ ,..., D
And I / O board 41 includes a port 42 for taking in I _16, the digital output signal DO ₁ to external, ..., and an I / O board 51 includes a port 52 for issuing a DO _16.

However, the hardware configuration of the process control apparatus according to the embodiment is an ordinary well-known one, and does not have a characteristic. The most characteristic feature of this embodiment lies in an application program stored in a memory. That is, the process control apparatus of this embodiment reads the functional block information and executes the compilation before starting the periodic operation, writes the compilation result in the storage area, and stores the compiled result during the periodic operation. Is read and executed. The execution of the compilation result is performed only for the necessary processing. Therefore, processing of undefined input / output and functional blocks is not performed. Since there is no reference processing for searching for the address of the actual value from the code, the time required for processing in the fixed-period operation portion is shorter than in the conventional method.

FIG. 2 is a flowchart for explaining the operation of the process control apparatus according to this embodiment. When activated, first, initialization processing and the like are performed (ST21), functional block information is read (ST22), and compilation is performed (ST23). As a result, as described above, undefined input / output and unused blocks are removed. After compiling, the result is stored in the storage area (ST24). FIG. 4 shows an example in which the compilation result is stored in the storage area. In this example, the application program illustrated in FIG. 3 is compiled, and AI ₁ input processing, square root SQ processing based on input AI ₁ , DI ₁ input processing, DI ₂ input processing, and input DI ₁ are input. Setting SET processing based on DI ₂ , DI ₃ input processing,
PID processing based on the SQ output, SET output, and DI ₃ , AO ₁ output processing based on the PID output, and processing are sequentially arranged. The above-mentioned execution of compilation and storage of the compilation result are executed at the beginning of the startup.

In the fixed-period operation section, the compile result is sequentially read from the storage area every time the sampling time comes (ST25) (ST26), and each process of the compile result is sequentially executed (ST27). When processing is completed, S
The process returns to T25 and waits for the next sampling time.

[0015]

According to the present invention, the information of the functional blocks is stored in a part of the memory of the CPU board.
From an external perspective, application programs are easy to handle (upload, download, external creation,
The processing of the functional blocks in the fixed-period block can be sped up while taking advantage of the advantage that the color change is easily performed. The period from the start to the start of the fixed-cycle operation is longer than that of the conventional method, but does not affect the control performance and is not a problem.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a hardware configuration of a process control device according to an embodiment of the present invention.

FIG. 2 is a flowchart for explaining a processing operation of the process control device of the embodiment.

FIG. 3 is a diagram showing a storage example of an application program applied to the process control device of the embodiment.

FIG. 4 is a diagram showing a state in which the application program of FIG. 3 is compiled and stored in a storage area.

FIG. 5 is a flowchart illustrating a processing operation of a conventional process control device.

6 is a diagram showing an example of information storage of blocks of the application program of FIG. 3 in a conventional process control device.

[Explanation of symbols]

 Reference Signs List 11 CPU board 12 Microprocessor 13 Memory 21 Analog input signal I / O board 31 Analog output signal I / O board 41 Digital input signal I / O board 51 Digital output signal I / O board

Claims (1)

[Claims] 1. A CPU including a microprocessor and a memory.
In a process control device including a board and an I / O board for inputting / outputting an analog signal which is an electric signal such as 4 to 20 mA, 1 to 5 V or a digital signal such as a contact ON / OFF to / from the outside, a process for performing process control is performed. Storing the application program in a part of the memory of the CPU board in the form of a combination of functional blocks, compiling and optimizing the application program at the start of the operation of the CPU board, and then executing the compiled application program at a fixed interval. A process control device, characterized in that the process control device is provided with a function to be executed on a computer.