JPH06189377A - Data transmitter - Google Patents

Abstract

PURPOSE:To surely send important data by setting number of data designated corresponding to priority to a transmission buffer of a terminal equipment respectively so as to reduce a transmission period of the data with higher priority. CONSTITUTION:Each local controller 3 fetches data at a prescribed fetch period and stores the data to data areas 5a-5c corresponding to the priority present in an input memory 5. A transmission optimization section 6 reads data set to the areas 8a of a transmission buffer 8 for a succeeding transmission period from the data areas 5a-5c of the memory 5 and sets the data to each of transmission data strings 6a-6c. Then a type code is added to the data and stored in each area 8a designated for each priority of the transmission buffer 8 and sent to a transmission line 2 for each prescribed transmission period. Furthermore, number of data for each priority stored in the transmission buffer 8 is revised by a revision command from a central monitor controller 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission device in which a plurality of terminal devices are connected to a center device through a transmission line and each of the terminal devices transmits a plurality of types of data to the center device.

[0002]

2. Description of the Related Art For example, in large-scale plant equipment,
A large number of on-site control devices arranged in proximity to each facility of the plant are connected to a central supervisory control device installed in a central control room or the like via a transmission line. Further, various actual devices and various detectors are connected to each field control device. Then, each on-site control device converts, for example, a large number of data (process data) detected by each detector in a constant cycle into, for example, digital data, and transmits the digital data to the central monitoring control device via the transmission path.

When data is transmitted from each site control device to the central supervisory control device, if the data output from each site control device competes with each other on the transmission path, the data output later is the first data. In many cases, a transmission protocol that waits until the transmission is completed is adopted.

The central supervisory control device classifies each data transmitted from each site control device by data type, processes the data into an expression format that can be understood by a supervisor, and displays it on a display device. Also, the received data (process data)
Perform a predetermined control calculation process to obtain the operation amount,
The operation command is sent to the corresponding field control device.

[0005]

However, the data transmission device for transmitting data from each field control device to the central supervisory control device according to the above-mentioned procedure still has the following problems to be improved.

As described above, various types of data are input to each field control device. However, among many data types, there are high priority data and low priority data. Then, it is necessary to constantly monitor the data of high priority even in the central supervisory control device. Then, when any change occurs in the data, it is necessary to immediately transmit it to the central monitoring control device. Conversely, for data that is not so important, the data transmission cycle may be lengthened.

However, in the conventional data transmission device, each field control device transmits all the data collected from each detector at a constant cycle under the same condition regardless of the importance. Therefore, the number of data included in one data transmission becomes enormous. As a result, the transmission data length output from each on-site control device to the transmission path at one time becomes long, and the probability of competing with the transmission data output from another on-site control device increases.

In this case, according to the above-mentioned transmission protocol, the data output later is kept waiting until the previous data transmission is completed. Therefore, as a result, the transmission cycle of the data transmitted from each on-site control device to the central monitoring control device is not constant, and there is a concern that the response characteristics of important data may deteriorate.

In order to solve such a problem, a data transmission device capable of transmitting a large amount of data at a high speed at a time may be adopted. However, such a data transmission device is only large in size. As a result, the manufacturing cost is significantly increased.

The present invention has been made in view of such circumstances, and sets a specified number of data corresponding to each priority in a transmission buffer provided on the terminal device side for storing only a specified number of data. By doing so, the number of data to be transmitted at one time is fixed, the transmission cycle of high priority data is shortened as a result, and important data can be reliably transmitted without significantly increasing the transmission capacity and the transmission speed. It is an object of the present invention to provide a data transmission device capable of significantly improving the reliability of data transmission and the data transmission efficiency.

[0011]

In order to solve the above problems, according to the present invention, a plurality of terminal devices are connected to a center device via a transmission line, and each terminal device transmits a plurality of types of data to the center device. In the data transmission device to

For each terminal device, a transmission buffer for temporarily storing a specified number of data items to be transmitted to the center device at a time, and data items having different priorities for each transmission cycle are designated for each priority item. Transmission data setting means for setting type information specifying the data type for each number and setting it in the transmission buffer, and all data in the transmission buffer in which a specified number of data is set by this transmission data setting means Data output means for sending to the transmission line within the time slot assigned to the data transmission number, and the number of data for each priority stored in the transmission buffer in the same cycle is changed based on the assignment change command from the center device. And means,

In response to an external command, the center device receives data output from each terminal device on the transmission path and stores and holds the data for each data type, and in response to an external command,
Change instruction means for sending an allocation change instruction to each terminal device is added.

[0014]

In the data transmission device thus constructed, each terminal device is provided with a transmission buffer for storing only a specified number of data. Then, the specified number of data stored in the transmission buffer is output to the transmission line within the time slot assigned to the corresponding terminal device. Therefore, since there is no competition with data from other terminal devices on the transmission path, the transmission cycle of each data does not change.

Next, the number of data set in the transmission buffer in one transmission cycle is specified in advance for each priority. Therefore, for example, if the number of data types with high priority and the number of data types with low priority are both N, 1
Of N high-priority data in the first transmission cycle, the first a data are set in the transmission buffer, and the low-priority N data are first b (a> b). Pieces of data are set in the transmission buffer. N with high priority
In order to transmit all of the N pieces of data, it is sufficient to transmit the data (N / a) times, but in order to transmit all of the N pieces of data with low priority, it is necessary to transmit the data (N / b) times. .
Therefore, the cycle in which the same data is transmitted indicates that the data with higher priority is shorter than the data with lower priority. Further, the number of data for each priority set in the transmission buffer in one transmission cycle can be arbitrarily changed by a change command from the center device.

Since each data transmitted to the center device is provided with type information for specifying the data type, in the center device, no matter how the data is transmitted at any set transmission cycle, These can be stored and held for each data type.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a data transmission device of an embodiment, and FIG. 2 is a diagram showing a processing operation procedure of the data transmission device.

As a center device arranged in a central control room of a large-scale plant facility, a central monitoring and control device 1 is provided, and a large number of terminal devices are provided near each facility of the plant via a transmission line 2. The site control device 3 is connected.

As shown in FIG. 1, the data output from a large number of detectors connected to the relevant site control device 3 is taken into each of the site control devices 3 at a constant acquisition cycle T _0. A transmission optimizing unit 6 for extracting necessary data at a transmission cycle T _S from the data stored in the input memory 5 and the input memory 5 for temporarily storing the data captured by the input unit 4 and the input unit 4. , A code addition unit 7 for adding a type code for identifying the type of the corresponding data to each extracted data, a transmission buffer 8 for temporarily storing the data with the type code added, and transmission of each data stored in the transmission buffer 8 A transmission section 9 that is incorporated into the format 10 and is sent to the transmission path 2 is provided in the tile slot provided to the field control device 3 of its own.

In the input memory 5, a high-speed data area 5a for storing a plurality of types of high-speed data having a high priority, a medium-speed data area 5b for storing a plurality of types of medium-speed data having an intermediate priority, and a priority A low-speed data area 5c for storing low-speed data of a plurality of types is formed.

In the transmission buffer 8, a predetermined number S of data to be transmitted to the central supervisory control device 1 at a time is stored S.
Individual regions 8a are formed. Then, in the S areas 8a to which the area numbers are assigned, how many areas 8a of the S areas 8a are set with high-speed high priority data, or how many areas of the S areas 8a are set. 8a is set to medium speed data of medium priority, or S areas 8
The number of areas 8a in a to which low-speed data with low priority is set is preset.

In the embodiment of FIG. 2, the number of areas S is 6, high-speed data is set in each of the three areas 8a of Nos. 1 to 3, and two areas of Nos. 4 and 5 are respectively set. Medium speed data is set in 8a, and low speed data is set in the last one area 8a.

Further, in the central supervisory control device 1, each data incorporated in the transmission format 10 sent from each on-site control device 3 to the transmission path 2 is received and necessary for each on-site control device 3. Transmission unit 1 for sending a command
1, a transmission management unit 12 for instructing each field control device 3 which type of data is to be preferentially transmitted, a data storage unit 1 for storing each received data in a reception data memory 13
4. A display processing unit 16 for displaying each data stored in the received data memory 13 on the CRT display device 15 is provided. Next, the operation of each unit will be described step by step.

The input unit 4 of each on-site control device 3 takes in each analog or digital data output from each measuring device under its control at a taking cycle T ₀ and is preset for each data type. Each data area 5 corresponding to the priority
It is stored in a, 5b, and 5c. Therefore, each data stored in the input memory 5 is updated to the latest data at every capture cycle T ₀ .

The transmission optimizing unit 6 sets each area 8a of the transmission buffer 8 in the next transmission cycle T _s every time the transmission cycle T _S set longer than the acquisition cycle T ₀ arrives. Data is input to each data area 5a, 5 of the input memory 5.
b. 5c, each of the transmission data strings 6a, 6b. 6
Set to c.

For example, when the Na type data is stored in the high speed data area 5a, the first transmission cycle T _S
In, for example, 3 from the beginning to 3 (3 types)
Is set in the data string 6a. In this case, since the transmission cycle T _S is longer than the acquisition cycle T ₀ , the same acquisition cycle T
Other types of high speed data read at ₀ will be discarded. Then, in the second transmission cycle T _S , the fourth to sixth data acquired in another acquisition cycle T ₀ is set in the data string 6a. Therefore, the cycle in which the same type of data is set in the data string 6a is (Na / 3) T.
It becomes _S.

Similarly, when Nb types of data are stored in the medium speed data area 5b, the first transmission cycle T _S
In, for example, two pieces of data (two types), the first and the second, are set in the data string 6b. Therefore, the cycle in which the same type of data is set in the data string 6b is (Nb /
2) T _S.

Similarly, when Nc types of data are stored in the low-speed data area 5c, the first transmission cycle T _S
In, for example, the first one (one type) data is set in the data string 6b. Therefore, the cycle in which the same type of data is set in the data string 6c is (Nc / 1) T _S
Becomes

Therefore, when the numbers of data types Na, Nb, and Nc at high speed, medium speed, and low speed are equal, the cycle in which the same data is set in the data string is 1/3 times as high as the low speed data. It becomes the cycle of.

Then, the transmission optimizing section 6 activates the code adding section 7 and assigns each data type to a total of 6 types of data for each speed set in each data string 6a, 6b, 6c. A type code to be specified is added. Then, each data to which the type code is added is stored in each area 8a in the transmission buffer 8 designated for each priority.

The transmission unit 9 incorporates each data stored in each area 8a of the transmission buffer 8 into the transmission format 10 for each transmission cycle T _S , and transmits at the timing when the time slot allocated to itself arrives. Send on road 2. Therefore, the transmission format 1 transmitted on the transmission line 2
The data length of 0 is always a constant value.

The transmission section 11 of the central supervisory control device 1 receives the transmission format 10 output from each field control device 3 on the transmission path 2 and transfers it to the data storage part 14. The data storage unit 14 retrieves each data incorporated in the transmission format 10, refers to the type code attached to each data, and stores it in the received data memory 13 in time series for each data type. . Received data memory 13
Each of the data stored in is displayed on the CRT display device 15 after being read by the display processing unit 16 and edited into a format that can be understood by the observer.

Further, the transmission management section 12 instructs each field control device 3 to have each area 8 of the transmission buffer 8 numbered 1 to 6.
A command to change the allocation state indicating the respective proportions of the number of high-speed data, the number of medium-speed data, and the number of low-speed data in a is sent.

Upon receipt of the change command from the central supervisory control device 1, the transmission optimizing section 6 of each field control device 3 operates on the basis of the change command to increase the speed of the input memory 5. How many pieces of each data stored in each of the medium-speed and low-speed data areas 5a, 5b, 5c are arranged in the same transmission cycle T _S in each of the data strings 6a, 6b, 6
Change whether to set to c.

According to the data transmission apparatus configured as described above, for example, when the number of data belonging to each priority is equal, the number of data of the same priority set in the transmission buffer 8 is increased for each transmission cycle T _S. As it is done, the transmission cycle of each data belonging to the corresponding priority becomes shorter. For example, when the number of high-speed data with high priority is set to 3 and the number of low-speed data with low priority is 1 as in the embodiment, the data with high priority is compared with the data with low priority. CR at 3 times speed
It is displayed on the T display device 15.

In this way, the CR depending on the type of data
The display speed displayed on the T display device 15 can be changed. Therefore, in controlling plant equipment, data of an important type can be displayed at high speed, so that the ability to monitor plant equipment can be greatly improved.

The length of the transmission format 10 sent from each on-site control device 3 onto the transmission path 2 is always a constant value, and is transmitted within the time slot assigned to each on-site control device 3. Therefore, the transmission cycle T of each data
_S does not change.

Furthermore, by changing the number of data of each priority assigned to each area 8a of the transmission buffer 8, for example, when the power is turned on, the ratio of the number of high-speed data is increased, and the time from the power on is increased. It is also possible to increase the number of low-speed data over time.

Further, when it is desired to intensively monitor a specific event such as when an abnormality occurs, plural kinds of data related to the relevant event are intensively extracted and set in the transmission buffer 8. This makes it possible to monitor the relevant data at high speed.

Further, in the data transmission apparatus thus constructed, only the required type of data can be observed at a high speed without significantly increasing the transmission capacity or the transmission rate. Therefore, the monitoring performance can be significantly improved without significantly increasing the manufacturing cost.

[0041]

As described above, according to the data transmission device of the present invention, the number of data designated corresponding to each priority is stored in the transmission buffer provided on the terminal device side and storing only the specified number of data. It is set. Therefore, the number of data to be transmitted at one time is fixed, and as a result, the transmission cycle of high-priority data is shortened. As a result, important data can be reliably transmitted without significantly increasing the transmission capacity and the transmission speed, and the reliability of data transmission and the data transmission efficiency can be greatly improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a data transmission device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing an operation of the apparatus of the embodiment.

[Explanation of symbols]

1 ... Central monitoring control device, 2 ... Transmission line, 3 ... Site control device, 4 ... Input unit, 5 ... Input memory, 6 ... Transmission optimization unit,
7 ... Code addition unit, 8 ... Transmission buffer, 9 ... Transmission unit, 1
0 ... Transmission format, 11 ... Transmission unit, 12 ... Transmission management unit, 13 ... Reception data memory, 14 ... Data storage unit, 1
5 ... CRT display device, 16 ... Display processing unit.

Claims (1)

[Claims] 1. A data transmission device in which a plurality of terminal devices are connected to a center device via a transmission path, and each of the terminal devices transmits a plurality of types of data to the center device, wherein each of the terminal devices is the center device. A transmission buffer that temporarily stores a specified number of data to be transmitted to the device at a time, and type information that specifies the data type for each number of data with different priority for each transmission cycle specified for each priority. Attached to the transmission buffer, and all the data in the transmission buffer in which a specified number of data has been set by the transmission data setting means are transmitted in the time slot assigned to its own terminal device. The number of data for each priority stored in the transmission buffer in the same cycle as the data output means to be sent to the route is based on the allocation change command from the center device. A data receiving / storing means for receiving data output from each of the terminal devices on the transmission path and storing and holding the data for each data type; A data transmission device, comprising: a change instructing unit that sends the allocation change command to each of the terminal devices in response to the command.