JPS61182345A - Priority variable type data transmission system - Google Patents

Abstract

PURPOSE:To improve the performance of supervision and control of a plant by allowing a central controller side to judge totally a transmission signal from each remote terminal device and to decide automatically the priority of the transmission data in response to the state of the plant and transmitting the data in a pattern corresponding thereto. CONSTITUTION:If a process signal among process signals P2 obtained by a sensor 23 is changed rapidly to a predetermined value or over, the signal is detected by a central processing unit 7 of a central controller 2. The central processing unit 7 detects the changing quantity not only with respect to the signal but also with respect to other input signals. As a result, the said processing signal becomes an important signal for deciding the priority in comparison with other signals. Then the central processing unit 7 decides the picture information to be transmitted with priority by the processing of priority decision architecture.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention provides a system for inputting ITV image signals, process signals, status signals of a control device, etc. and transmitting these signals. Method for determining data to be transmitted with priority [Background of the invention] In systems that transmit various types of data, as typified by intra-plant data transmission, various signals are used to strengthen monitoring and control functions. It is necessary to transmit a specific signal preferentially depending on the value or rate of change. For example, the priority transmission method disclosed in Japanese Patent Application Laid-Open No. 56-111345 is a known technique related to the above transmission method.

In this method, normally the sync word.

A transmission frame consisting of a station number word and an item word is created, and this frame signal is transmitted to the other station.

Here, one item word consists of various data items. and a sync word during priority transmission.

A transmission frame consisting of a priority transmission flag, a station number word, and a priority transmission word is created, and this frame signal is transmitted to the other station. Here, the priority transmission flag indicates that specific data is being transmitted preferentially. Furthermore, data to be transmitted preferentially is selected from among the item words that are normally transmitted, and the selected data are collected into one item word to form a priority transmission word.

That is, in this method, a priority transmission word is created at the own terminal, and this word is transmitted during priority transmission.

In intra-plant data transmission, various types of data are transmitted from each terminal device to the central control device. However, the transmitted data may not necessarily be the data that is really needed from the perspective of the entire system.

In other words, when the conventional data transmission method is applied to a target system that requires various types of data, such as a plant, there is a problem in that it is not necessarily possible to preferentially transmit specific data that is required.

As a well-known technology, there is a data transmission method disclosed in Japanese Patent Application Laid-open No. 56-87953. In this method, too, the data to be transmitted is determined and transmitted with priority at the terminal of the own station, so the above-mentioned content is I have the same problem.

[Purpose of the invention]

The purpose of the present invention is to automatically determine the priority of transmission data from each remote terminal device according to the plant situation, and to transmit high-priority data in a high-speed cycle within limited transmission capacity. The purpose is to provide a method.

[Summary of the invention]

In the present invention, the central control unit comprehensively judges all the signals transmitted from each remote terminal device to the central control unit, and selects the signals necessary for strengthening monitoring and control according to the plant situation. The importance level is determined, and from the resulting important signals and signals related to these important signals, each remote terminal device determines the signals to be transmitted preferentially, and the command information regarding these priorities is transmitted to each remote terminal device. The system is characterized in that the required high priority signals are transmitted at high-speed cycles from each remote terminal device in accordance with the plant situation.

In addition, as a modification, a data transmission method is also shown in which each remote terminal device selects and transmits a certain amount of data, and the central control device finally determines the selected data.

[Embodiments of the invention]

Hereinafter, specific implementations of the present invention will be described in detail using the drawings.

Equally numbered parts in each drawing indicate corresponding parts.

The data transmission system shown as an example in FIG. 1 is a configuration for a loop-type data transmission system.
is the central controller, and 3 and 4 are remote terminals. Central control unit 2 and each remote terminal bag [Loop transmission line 1 between 3 and 4
connected by. Here, each remote terminal device includes an ITV camera for monitoring the status of process equipment in the plant, and a sensor for capturing each process signal.

and a control device for controlling each process equipment. 21, 24, and 25 are ITv cameras, and 2
0.23 is a sensor, and 19.22 is a control device. Depending on the object to be controlled, signals from the sensors 20 and 23 may be respectively input to the control devices 19 and 22.

The remote terminal device 1 has a configuration as shown by 3, for example, and is connected to the central control device 2 by a transmission device 13. 15 is a central processing unit, which centrally controls the remote terminal device 3; The signals obtained by the ITV camera are captured by the image interface 18. sensor 20
The signal from the process signal acquisition interface 17
captured by. Regarding the control device 19, information related to maintenance such as self-diagnosis results is captured by the status information capture interface 16 as the state of the control device. Information taken in from each interface is processed by the central processing unit 15 and transmitted from the transmission device 13. Here, 14 is a memory. Note that the remote terminal device 4
It also has the same functions and configuration as 3.

The central control device 2 has a function of receiving and processing signals transmitted from each remote terminal device, and a function of transmitting control signals to each remote terminal device.

5 is a transmission device, 7 is a central processing unit, 6 is a memory, 9 is an image display interface, and 8 is a data transfer interface. An image display interface 9 is connected to each remote terminal. A signal from the ITV camera is output to each monitor 11-12. The data transfer interface 8 also displays information obtained from process signals and the status of the control devices 19 and 22 on the display device 10.

In the system having the above configuration, priority variable processing for data transmitted from each remote terminal device according to the plant situation will be described in detail below.

Normally, as shown in FIG. 2(A), signals TV, , TV2 . ...TV,
, the signal P1. obtained by each sensor. P.

...+PJt and the status signals S, S2゜...+SJ of each control device are transmitted at a uniform rate.

Here, for example, the sensor 23 connected to the remote terminal device 4
A case will be described below taking as an example a case where the signal from the ITV camera 21 suddenly changes and image information from the ITV camera 21 monitoring the related process equipment is preferentially transmitted.

In the transmission data shown in FIG. 2(A), when a certain process signal among the process signals P2 obtained by the sensor 23 suddenly changes beyond a predetermined value, this signal is transmitted to the central processing unit 7 of the central control unit 2. detected by. Here, the central processing unit 7 detects the amount of change not only in this signal but also in other input signals. As a result, the above-mentioned process signal becomes a more important signal for priority determination than other signals. Then, the central processing unit 7 determines image information to be transmitted preferentially by processing according to the priority determination structure shown in FIG. Here, the data is a signal after detecting the amount of change described above, and the priority determination mechanism determines if, th in advance from the information necessary for priority assignment stored in the database and the input data.
This is a mechanism for deriving priority information according to en-type rules6.For example, in order to shorten the time required to process this priority assignment, a database is prepared as patterns corresponding to all input data, and priority information is derived. The decision mechanism only needs to select those whose patterns match the input data. Especially if the time required for this priority assignment process is not a problem, reduce the number of information prepared as a database and select the priority decision mechanism. A method of searching for priority assignment according to the rules of , that is, reasoning using knowledge engineering can be applied. In this case, since the database capacity is small, there is an advantage that the memory capacity can be reduced. Furthermore, even if ITV cameras and sensors attached to each remote terminal device are added, it is only necessary to store related knowledge in the database, so there is an advantage that there is no need to pattern all the data again.

By the way, the priority information obtained according to the processing of this priority determination structure is: (1) Indicates that the image signal from the TV camera 21 is preferentially transmitted; Transmit to a remote terminal. Each remote terminal device decodes the transmitted priority command signal and assigns the signals to be transmitted, as shown in Figure 2 (B).
As shown in , image information T corresponding to the ITV camera 21
V, can be transmitted preferentially. Before the priority was assigned, the image information Tv1 was transmitted in the form of a still image, but after the priority was assigned, it was transmitted in the form of a moving image, and the image information Tv1 was transmitted in the form of a moving image, indicating the status of a certain process equipment 9, for example, the status of a valve (leak, etc.) can be monitored.

As described above, the data from each remote terminal/device is comprehensively judged, the priority of transmission data is automatically determined according to the plant situation, and the data is transmitted from each remote terminal device in a pattern corresponding to this. can be transmitted, allowing plant monitoring and
Control ability can be improved.

By the way, although the rate of change of the process signal was detected by the central control unit, each remote terminal device judges this, transmits only the change information, and prioritizes the signal according to the process shown in Figure 3. It is easy to understand that it is okay to decide.

Next, an example will be explained in which the preferential transmission signal is not only the image signal of ITV1 but also the image signal of ITV, which is information related thereto.

Similar to the previous example, the signal from the sensor 23 suddenly changes, and the IT monitoring the related process equipment.
Let us take as an example a case where image information of the V camera 21 and the ITV camera 25 is transmitted preferentially.

Furthermore, a case where the transmission period of image information of the ITV camera 25 is halved compared to the transmission period of image information of the ITV camera 21 will be described below.

The central control unit takes in transmission data from each remote terminal device, and based on these signals, the priority information obtained according to the process shown in FIG. This indicates that the image information of the ITV camera 25 is transmitted preferentially, the image information of the ITV camera 21 is transmitted as a moving image, and the image information of the ITV camera 25 is transmitted in a state close to that of a moving image (half the cycle of a moving image). . This thing,
When the priority command signal is transmitted to each remote terminal device via the transmission device 5, each remote terminal device allocates the signals to be transmitted according to this command signal. As a result, Figure 2 (C)
As shown in , image information TV1. corresponding to ITV cameras 21 and 25 is displayed. TV can be transmitted preferentially.

Therefore, the target device can be monitored in a moving image using the image information TV1, and furthermore, the target device can be monitored in a nearly moving state using the image information TV2.

In the above explanation, the signal to be transmitted preferentially was the image signal, but it is easy to understand that this can be processed in the same way in correspondence with the process signal and the status signal of the control device.

Further, although the above description has been made regarding a loop type data transmission system, it goes without saying that it is also effective to apply this to the multi-drop type data transmission system shown in FIG.

〔Effect of the invention〕

According to the present invention, in a system for transmitting ITV image signals, process signals, and control device status signals from each remote terminal device to a central control device, the transmission signals from each remote terminal device are integrated on the central control device side. automatically determines the priority of transmission data according to the plant situation,
Data can be transmitted in a pattern corresponding to this, improving plant monitoring and control performance. Moreover, the operating burden on the operator is significantly reduced. Therefore, the present invention is highly effective when applied to places such as plants that require monitoring and control of multiple points6.

[Brief explanation of the drawing]

FIG. 1 is a system configuration diagram of a loop-type data transmission system to which the present invention is applied, FIG. 2 is a diagram showing an example of the structure of transmission data, FIG. 3 is a diagram showing the configuration of a priority determining section, and FIG. The figure is a system configuration diagram of a multi-drop type data transmission system to which the present invention is applied. 1... Loop transmission line, 2... Central control device, 3, 4
...Remote terminal device, 5...Transmission device, 6...Memory, 7...Central processing unit, 8...Data transfer interface, 9...Image display interface, 10
...Display device, 11.12...Monitor, 13...
Transmission device, 14... Memory, 15... Central processing unit, 16, 17, 18... Interface, 19...
-Control device, 20...Sensor, 21...ITV, 2
2...Control device, 23...Sensor, 24.25.
ITV.

Claims (1)

[Claims] 1. A plurality of remote terminal devices that input ITV image signals, process signals, control device status signals, etc., and a central control that transmits and processes data between these remote terminal devices. In a data transmission system consisting of a device, a central control device determines the importance of a signal transmitted from each remote terminal device, and a means for determining the importance of a signal transmitted from each remote terminal device, and means for determining the priority of signals to be transmitted from the remote terminals to the central controller; and means for transmitting to each remote terminal a command signal for transmitting a corresponding signal from each remote terminal to the central controller; A variable priority data transmission system, characterized in that the remote terminal device includes means for transmitting high priority signals to a central control device in accordance with a command signal thereof. 2. In claim 1, the importance determining means determines whether the signal transmitted to the central controller is comprehensively determined by a signal in which the amount of change or rate of change between the previous value and the current value of the signal is greater than or equal to a predetermined value. A variable-priority data transmission method characterized by determining whether 3. In claim 1 or 2, the priority determination means selects among the signals transmitted to the central control device, a signal in which the amount of change or rate of change between the previous value and the current value is large, and this signal. A variable priority data transmission method characterized by selecting related signals. 4. In claim 3, the priority determining means sets the priority corresponding to the situation as a rule using a predetermined if and then type rule, and determines the priority by an inference mechanism of this rule. A variable priority data transmission method characterized by: 5. Data transmission consisting of multiple remote terminal devices that input ITV image signals, process signals, control device status signals, etc., and a central control device that transmits and processes data between these remote terminal devices. In the system, each remote terminal device preferentially transmits signals in which the amount of change or rate of change between the previous value and the current value of the input signal is greater than or equal to a predetermined value to the central control device, and the central control device gives priority to these signals. A variable priority data transmission system that is characterized by comprehensively determining which one to select based on the signals that are transmitted.