JP2838588B2 - Process data processing system - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process data processing system, and more particularly, to a communication system in which a plurality of communication control devices are connected by a transmission line to exchange data between the communication control devices. The present invention relates to a process data processing system employing a method.

[Conventional technology]

In the conventional cyclic communication system, a transmitting communication control device transmits information in a memory at fixed time intervals, and each receiving communication control device receives the information with a fixed delay time. The computer connected to each receiving communication control device always uses the received data in the memory, so it can be used freely when the data is needed. Can be received by all the receiving communication control devices, the computer connected to the transmitting communication control device does not need to transmit data to each receiving station one by one. There is an advantage that processing can be reduced.

The data subject to cyclic communication is disclosed in
For example, as shown in 258534 and JP-A-57-206924, this is process data for process control.

Japanese Patent Application Laid-Open No. 62-258534 employs a cyclic communication system in which a computer transmits or receives process data at regular intervals. The collection of process data is executed by a computer connected to each communication control device in the network.

On the other hand, Japanese Patent Laying-Open No. 57-206924 employs a configuration in which a dedicated control device is installed for each process monitoring and control target, the control devices are connected via a communication network, and the load is distributed. The process control target is connected to a communication network via a plurality of process input / output devices, and each control device takes in necessary process control data from a subordinate process input / output device to perform arithmetic processing, but is not under its own control When data of a process input / output device is required, zeta communication is performed with a control device that controls the process input / output device to obtain necessary data.

[Problems to be solved by the invention]

In a conventional process control method using cyclic communication, a computer connected to a communication control device constituting a network performs data input / output with a process input / output device, so that the computer and the process input / output device are far apart. In such a case, another computer is required for data input / output with the process input / output device, resulting in high cost.

On the other hand, in the conventional distributed processing type process control device, each control device is configured to hold only data on the process input / output devices under its control, so data held by other control devices is required. In this case, it is necessary to perform data communication with a computer having the data at a required timing. During this data communication process, there has been a problem that the responsiveness of the system is reduced and control performance is impaired.

Further, in the conventional process control system, when the process input / output device is changed, for example, when the process input / output device is removed, the control device directly performs data input / output. There is a problem that a non-mounting error or the like indicating that the device is not mounted is caused, which is a fatal obstacle for the computer of the control device.

An object of the present invention is to provide an inexpensive process control system that does not require a dedicated computer for inputting and outputting data to and from various control targets.

Another object of the present invention is to provide high responsiveness and a flexible operation mode and system structurability even when updating a process input / output device or the like without causing a failure such as an unmounted error on the control device side. It is to provide a process control system.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a process input / output device for inputting / outputting process data, a computer for controlling a process via the process input / output device, and a process input / output device and a computer installed in correspondence with the computer. A communication control device connected by a communication path, and a process data memory respectively connected between the computer and the communication control device;
A memory control device that manages the input / output of the process data memory and the cycle of the cyclic communication, respectively, cyclically transmits process data from at least one communication control device, and a communication control device other than the transmission side communication control device In a cyclic communication type process data processing system for receiving process data, the control computer includes means for defining a control command / response area in an area of a process data memory used as process data. A process data processing system in which a scanning device is installed between a data memory and a memory control device and a process input / output device is proposed.

More specifically, the scanning device receives the address data of the process data memory in accordance with a command from the computer, stores the address data in order, the address of the process input / output device and the input / output direction in accordance with the command from the computer. And a direction memory for receiving data indicating the above and storing the data in order.

The scanning device simultaneously accesses the address memory and the direction memory, and when the input / output direction of the direction memory is the input side, indicates the data read from the address of the process input / output device indicated in the direction memory to the address memory. To the specified process data memory address. On the other hand, when the input / output direction of the direction memory is the output side, the process data is read from the address of the process data memory indicated by the address memory and written to the address of the process input / output device indicated by the direction memory.

[Action]

In the present invention, since each computer has all the data to be controlled of the process input / output device, it can obtain necessary data by referring to its own memory. Therefore, data communication between computers for data acquisition becomes unnecessary, and the responsiveness and control performance of the system are improved.

The mounting information of the process input / output device is set in the scanning device by a command from the computer. When the process input / output device is changed, the mounting information is changed.
Then, if the command is reissued, the unmounted error does not occur. Since the computer takes in the data sent from the scanning device via its own communication control device and process data memory, no unmounted error occurs on the computer side.

When acquiring data from a process control target, the computer simultaneously accesses the address of the acquired data on the process input / output control device and the address of the memory for storing the data in order, and performs cyclic communication at predetermined intervals. Send. If the period is sufficiently shorter than the changing speed of the process, the latest data can be obtained with the required accuracy.

The computer is not directly connected to the process control device, but is connected indirectly via the process data memory, so that the system construction is improved, the process control device can be separated for maintenance, and the maintainability is good. Becomes

〔Example〕

Next, an embodiment of a process control system according to the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of an embodiment of a process control system including a command control device according to the present invention.

The process control system includes a plurality of computers 1 and 2 for controlling the processes of the process control target 60 in a distributed manner, and a communication path 70.
Thus, for example, the communication control devices 30, 31,
32, 33, the process data memories 10, 11 connected between the computers 1, 2 and the communication control devices 30, 31, respectively, and the input / output and cyclic communication cycles of the process data memories 10, 11 And memory control devices 20 and 21 for managing the respective devices.

The process control system also includes communication control devices 32, 33
Process input / output devices 50, 51 provided between the control input and the control target 60, scanning devices 40, 41 for scanning the process input / output devices 50, 51, respectively, the scanning devices 40, 41 and the communication control device 32 , 33, respectively, and memory control devices 22, 23 for managing the input / output of the process data memories 12, 13 and the cycle of the cyclic communication, respectively.

FIG. 2 is a block diagram showing the connection between the computer 1, the process data memory 10, and the communication control device 30 in more detail.

The computer 1 includes a central processing unit (CPU) 80, a data memory 81, a program memory 82, and an address bus 83 and a data bus 84 connecting these. The address bus 83 and the data bus 84 are connected to the process data memory 10
Are also connected to the memory controller 20. The process data memory 10 and the memory control device 20 are connected to the communication control device 30 by another set of address bus and data bus, respectively.

The configuration of the computer 2, the process data memory 11, and the communication control device 31 is the same as that of the computer 1, the process data memory 1,
0, the same as the communication control device 30.

The CPU 80 executes a necessary operation using the process data of the control target 60 stored in the data memory 81 according to the program stored in the program memory 82,
The process of the process control target 60 is controlled via the communication control device 30. To realize this control, it is necessary to determine the transmission area and the reception area in the process data memory 10 and the transfer cycle.

The CPU 80 follows the program in the program memory 82,
As shown in FIG. 4, the process data memory 10 is divided into areas. A, shown in the process data memory 10,
Uppercase letters such as E indicate transmission areas, and lowercase letters such as b, c, and d indicate reception areas. This notation system using uppercase and lowercase letters is the same for the other process data memories 11, 12, and 13. The uppercase letter indicates a transmission area, and the lowercase letter indicates a reception area. The CPU 80 writes the control data for dividing the area and the transfer cycle into the memory control device 20.

The communication control device 30 extracts data from the process data memory 10 according to the setting information written in the memory control device 20, and transmits the data. Further, it takes in the data in the received frame sent through the communication path 70 and writes this data into the process data memory 10.

Therefore, the computer 1 has the process data memory 10
By writing data to or reading data from the process data memory 10 at a predetermined timing, process data can be transmitted and received, and the process control target 60 can be controlled.

FIG. 3 is a block diagram showing the connection between the process input / output device 50, the scanning device 40, the process data memory 12, the memory control device 22, and the communication control device 32 in more detail.

In the scanning device 40, a processing device 42, a program data memory 43, an address memory 44, and a direction memory 45 are connected by an address bus 83 and a data bus 84.
The address bus 83 and the data bus 84 are connected to the external process data memory 12 and the memory controller 22.
The external process data memory 12 and the memory control device 22 are connected to a transfer control device 47. Transfer control device 47
Is further connected to a counter 46 to know the transmission timing. The transfer control device 47 controls reading and writing of data between the process data memory 12 and the process input / output device 50.

When the scanning device 40 is turned on,
As shown in a, b, C, and d shown in FIG. For example, the area a is determined in advance as a command reception area from the computer 1 and the area C is determined in advance as a response transmission area for a command. The other e, f, g, and h areas are to be separated from each other by a command. The section information of the command response area is set in the memory control device 22 connected to the scanning device 40 so that the command from the computer 1 can be received.

FIG. 5 shows an example of a command format. In this embodiment, the partner device number A is included in the command format.
It has 1, a command A2, a command identification number A3, and data A4, and communicates a command issuing partner A1, command processing contents A2, A3, and data A4 accompanying the command.

The scanning device 40 processes the command by referring to the command format in the procedure shown in FIG. In the flowchart of FIG. 6, the scanning device 40 determines whether or not the command is addressed to itself.
It is determined whether the command identification number is different from the previous command identification number. This process prevents the same command from being processed multiple times. If the command identification number is different from the previous one, the command is processed, and the processing result is written to area G in FIG. 4 as a response. The contents to be written are information indicating whether the processing of the command has been completed normally, whether there has been an error, or whether there has been an error in the command parameters.

 The control contents by the command will be described below.

First, data is set in the address memory 44 and the direction memory 45. Data for associating the address X of the process data memory 12 with the address Y of the process input / output device 50 is set in the address memory 44. Also, direction data indicating whether the access direction is from address X to address Y or from address Y to address X is set in the direction memory 45. Then, with another command,
Set the division data of the e, f, g, h areas and the transfer cycle. The scanning device 40, according to the command, e, f, g, h
Data for determining the area and period of transmission and reception of the area is written in the memory control device 22. The communication control device 32 determines the area from this point based on the written data of the division and the cycle.
The operation of transmitting and receiving e, f, g, and h is started. First, a command is issued to the scanning device 40 to start the data transfer between the process data memory 12 and the process input / output device 50, and the process is executed between the process data memory 12 and the process input / output device 50. The process data of the control target 60 is exchanged.

When the above processing is performed on all the computers 1 and 2 and the scanning devices 40 and 41, the process data memories 10 and 1
1, 12, and 13 are classified as shown in FIG. Further, each of the scanning devices 40 and 41 can execute data transfer between the process control target 60 and the process data memories 12 and 13, respectively.

In this state, for example, if the computer 1 sets data in the transmission area E, each of the scanning devices 40 and 41 transfers the data set in the transmission area E. Therefore, the transfer control device 47 in each of the scanning devices 40 and 41 transfers a control signal to the process control target 60 via the process input / output devices 50 and 51.

For the transfer in the reverse direction, the transfer control device 47 stores the process data of the process control target 60 in the process data memory.
Since the data is written into the transmission areas G and H of the areas 12 and 13 and transmitted to the areas g and h of the computers 1 and 2, the computer can freely use the process data. Process data memory 10, 11, 1
When 2, 13 are set as shown in FIG. 4, each of the computers 1 and 2 has all the process data, and the data communication between the computers becomes unnecessary, so that the processing load on the computers is reduced.

〔The invention's effect〕

According to the present invention, since each computer has all the data to be controlled of the process input / output device, it is possible to acquire necessary data by referring to its own memory. Therefore, data communication between computers for data acquisition becomes unnecessary, and the responsiveness and control performance of the system are improved.

To acquire data from the process control target, the address of the acquired data on the process input / output control device and the address of the memory for storing the data are simultaneously accessed in order, and transmitted at a predetermined cycle by cyclic communication. If the period is sufficiently shorter than the changing speed of the process, the latest data can be obtained with the required accuracy.

Since the computer is not directly connected to the process control device, the system construction is improved, the process control device can be separated for maintenance, and the maintainability is also improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of an embodiment of a process control system according to the present invention, and FIG. 2 shows a more detailed configuration of a computer, a process data memory, and a memory control device of the embodiment of FIG. FIG. 3 is a block diagram showing a detailed configuration of the scanning apparatus of the embodiment shown in FIG. 1, FIG. 4 is a view for explaining a method of transferring a command of cyclic communication and a method of transferring process data, FIG. FIG. 6 is a diagram showing an embodiment of the configuration of command data according to the present invention, and FIG. 6 is a flowchart showing a processing procedure for command fetching and command execution of the scanning device of the embodiment of FIG. 1,2 Computer, 10-13 Process data memory, 20-23 Memory control device, 30-33 Communication control device, 40,41 Scan device, 42 Processing device, 43 ... Program data memory, 44 ... Address memory, 45 ... Direction memory, 46 ... Counter, 47 ... Transfer control device, 50,51 ... Process input / output device, 60 ... Process control object, 70 ... Communication Road, 83 ... address bus, 84 ... data bus.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G05B 15/02 G06F 13/00

Claims (2)

(57) [Claims] 1. A process input / output device for inputting / outputting process data, a computer for controlling the process via the process input / output device, and a communication channel installed corresponding to the process input / output device and the computer Communication control device, a process data memory respectively connected between the computer and the communication control device, and a memory control device for managing the input / output of the process data memory and the cycle of cyclic communication, respectively. And
In a process data processing system of a cyclic communication system in which process data is cyclically transmitted from at least one of the communication control devices and a communication control device other than the transmission side communication control device receives the process data, the control computer Has a means for defining a control command / response area in an area of a process data memory used as process data, and writes data read from the process input / output device at the time of input to an address of the process data memory. ,
A scanning device having means for writing process data read from the process data memory to the process input / output device at the time of output is provided between the process input / output device and the memory control device and the process input / output device, respectively. Characterized process data processing system. 2. The process data processing system according to claim 1, wherein when the identification number of the control command included in the data in the control command / response area is the same as the previous time, the scanning device performs the control. A process data processing system comprising means for ignoring commands.