JP3318863B2 - Synchronous data transmission method and synchronous data transmission device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for transmitting synchronous data in a plant control and monitoring system for nuclear power, thermal power, gas, chemical, etc., which requires high reliability. The present invention relates to a method of transmitting synchronous data of a system using a combination of data such as a control command signal and a digital signal indicating validity / invalidity of the data.

[0002]

[Prior art]

1. As a data transmission method between CPUs in a control system or the like, there is a packet switching method in which data is synchronized in units of transmission and editing performed by the CPU. In the packet switching transmission, transmission data is divided into packets of a fixed length and then transmitted to the network as packet data. The receiving side reads and edits the packet data, and then executes its own control operation.

[0003] 2. As shown in Japanese Patent Application Laid-Open No. 7-50661, the memory transfer method ensures synchronization between the control operation of the CPU and data transmission in a section of a certain length of the memory and data reception. There is also a method of ensuring synchronization between the control operation and the control operation.

[0004]

In the prior art 1 described above,
Synchronization of transmission data is guaranteed, but transmission / reception processing takes time, and it is difficult to increase the transmission speed. This time-consuming point is due to the speed of control, which is the main task of the CPU.
This is an obstacle to increasing capacity. Further, if data synchronization is secured over a plurality of packets, transmission / reception processing takes more time, and it becomes more difficult to increase the transmission speed. Further, in the prior art 1, it is necessary to select data requiring synchronization and arrange the data in a transmission packet that can guarantee the synchronization, which complicates the design and increases the room for mixing errors.

[0005] In the above-mentioned prior art 2, the synchronization of transmission data is guaranteed, and the load on transmission and reception processing is reduced as compared with the prior art 1. However, since the processing is complicated and a lot of asynchronous data is discarded, there is a limit to speeding up. Also,
Data for synchronization processing must be present in the transfer memory, and if there are many CPUs with a small amount of transmission data, the amount of data used for synchronization will be larger than actual data, thus improving transmission efficiency. Even had limitations.

SUMMARY OF THE INVENTION An object of the present invention is to provide a highly efficient method for transmitting synchronous data, in which the load on the control device is small, the synchronization of transmission data can be ensured.

Another object of the present invention is to provide a transmission apparatus for synchronous data, which has a small load on the control device and includes transmission means capable of ensuring synchronization of transmission data.

[0008]

In order to achieve the above object, according to the present invention, when a control program incorporated in a transmitting apparatus edits and transmits a plurality of data obtained by performing control operations, the transmitting program transmits the edited data. In a method for transmitting synchronous data in a control system having a control program having a control program that operates on the premise of guaranteeing synchronization, it is ensured that at least a part of the data is only a synchronization output signal as a result of one operation execution. , The output signal of the transmitting device consists of a pair of analog data and digital data whose synchronization is guaranteed, and synchronization is required.
Word is the minimum unit of memory transfer
Alternatively, the present invention proposes a synchronous data transmission method in which digital data is embedded in a bit string such as a long word and digital data is embedded as specific bits of a signal obtained by digitizing analog data.

A set of analog data and digital data whose synchronization is guaranteed is one of the bit strings of analog data represented by a bit string such as a word or a long word.
The bits are used as this set of digital data.

When the format of a bit string such as a word or a long word representing analog data represents a floating point value, the digital data is stored in a bit position representing the least significant part of the mantissa in the bit string representing the floating point value. Embedded.

According to another aspect of the present invention, there is provided a control apparatus comprising a plurality of control units for exchanging data with each other. When editing and transmitting the data, it is ensured that at least a part of the transmission data is only a synchronous output signal of a single operation execution result, and a control circuit built in the receiving side device guarantees synchronization. In a transmission device for synchronous data in a control system having a control program that operates as a premise, at least a transmission side device includes a control circuit in which the control program is represented by a combination of symbolic elements such as a control function block diagram and a ladder, The output signal of the device consists of a pair of analog data and digital data whose synchronization is guaranteed, and the control circuit requires synchronization.
Is the smallest unit of memory transfer, word
Alternatively, there is proposed a synchronous data transmission device including means for embedding digital data as specific bits of a signal obtained by digitizing analog data by embedding the data in a bit string such as a long word .

The control circuit on the transmitting side includes a synchronization assurance transmitting element having an analog data input terminal and a digital data input terminal to assure synchronization of a set of analog data and digital data, and a set of digital signals of which synchronization is guaranteed. Means for embedding data in specific bits of digitized analog data.

On the other hand, the control circuit on the receiving side has means for extracting a set of digital data whose synchronization is guaranteed from specific bits of the digitized analog data, and an analog data output terminal and a digital data output terminal. A synchronization assurance receiving element for outputting the separated analog data and the extracted digital data as control signals whose synchronization is guaranteed.

The present invention is applicable not only to an output signal consisting of a set of analog data and digital data whose synchronization is guaranteed, but also to an output signal consisting of a set of first digital data and second digital data whose synchronization is guaranteed. Is also effective, in which case the data that needs to be synchronized
Word or long word, which is the minimum unit of transcription
The second digital data embedded in the bit string is
Embedded as specific bits of digital data.

According to the present invention, in order to reduce the transmission / reception processing, when transfer memory communication is performed, a plurality of data requiring synchronization are embedded in a bit string such as a word or a long word which is the minimum unit of memory transfer. , So that they can be sent and received together.

To solve the problem that the amount of data used for synchronization becomes larger than the actual data, the transmission area that cannot be transmitted is allocated to the data required for ensuring the synchronization with the data capacity. The reduction may be sufficient or substantially negligible.

It is necessary to select data requiring synchronization and arrange the data in a transmission packet capable of guaranteeing synchronization.
Regarding the concern that the design becomes complicated and that there is a large room for error, synchronization can be assured by designating a set of data that requires synchronization, even if the designer is not aware of the transmission packet.

Among the control device, the computer, and the control / monitoring data periodically updated between them, the data that needs to be synchronized among a plurality of data include, for example, 1. Control command data and the validity of the command. 2. Monitoring data and data indicating the validity of the monitoring data 3. Process input data and data indicating the validity of the process input data, that is, each data and data indicating validity / invalidity of the data It is a pair with.

Generally, data is transmitted and received using a bit string such as a word or a long word as a minimum unit, and data synchronization within this minimum unit is guaranteed.

Since analog data is generally expressed as a bit string such as a word or a long word, it is not possible to further combine analog data and other data and arrange a plurality of data in this minimum unit. ing. Therefore, when it is necessary to assemble a minimum unit in which the synchronization of a plurality of data is guaranteed and to secure synchronization between them, conventionally, complicated processing is required.

Of the data updated periodically, attention is paid to control devices that require synchronization between a plurality of data and control / monitoring data exchanged between computers.
It is a set of data and data indicating whether the data is valid. The data indicating whether the data is valid can be represented by digital data. Therefore, of the data updated periodically, the control device and the control / monitoring data exchanged between the computers which need to be synchronized among a plurality of data are either analog data and digital data or digital data. It is one of a pair with digital data.

In general, since digital data is represented by bits, a plurality of digital data can be arranged as a set within this minimum unit, and it is relatively easy to ensure synchronization between the plurality of digital data. It is.

In the present invention, a set of analog data and digital data is also expressed in a minimum unit in which synchronization is ensured by embedding digital data in one bit of a bit string expressing analog data.

Therefore, the transmitting side has a processing function of overwriting the least significant bit of the mantissa of the bit string indicating the floating-point analog data with the set of digital data, and the receiving side has the processing function of overwriting the least significant bit of the mantissa of the bit string. Has a processing function of extracting the data as digital data.

When a control program is created, it is necessary for a designer to clearly specify a data set requiring synchronization. The process control circuit built in the control device is a control function block diagram, a combination of symbolic elements such as a ladder, and a control program for producing the symbolic elements by connecting them with signal lines. On the transmitting side, signal lines representing analog data and digital data specified from the outputs of the respective arithmetic elements described in the program are connected, and elements of the control program for combining the data are defined. On the receiving side, an element indicating a receiving section of the synchronous data is defined, a signal line representing analog data and digital data is connected from this element to an input of each arithmetic element described in the program, and each data is extracted.

When one bit of a bit string expressing digital data is handled as digital data, a set of digital data and one-bit digital data can be expressed in the minimum unit for ensuring the synchronization. Similarly, when one bit of a bit string representing analog data is treated as digital data, a set of analog data and one-bit digital data can be represented within the minimum unit for ensuring this synchronization.

Generally, analog data used as process data is limited to a resolution of 12 bits from the precision of a high response type A / D converter, and the precision is about ± 0.25%. Even a high-precision A / D converter applied to a very limited use has a resolution of 16 bits and an accuracy of about ± 0.0015%.

Therefore, if the minimum unit for ensuring synchronization is a bit string representing a floating point value, the error caused by using the least significant bit of the mantissa as digital data is extremely small, so that there is no problem.

When a plurality of data requiring synchronization are arranged in a bit string such as a word or a long word, which is the minimum unit of transfer of the memory performed by the transfer memory communication, and data is transmitted / received, the load on the transmission / reception processing is reduced. Therefore, there is no need to exchange work data for ensuring synchronization between the transmission side and the reception side by communication, and the data transmission efficiency is increased.

Further, since a plurality of data requiring synchronization are arranged in a bit string such as a word or a long word which is the minimum unit of the memory transfer, the synchronization of the data within the minimum unit is guaranteed. On the transmitting side, connecting the analog data specified from the output of each processing element described in this program and the signal line representing digital data respectively defines the elements of the control program that combines the data, A set of data that guarantees synchronism during the production of software for this device is defined, and can be reliably arranged in a bit string such as a word or a long word, which is the minimum unit that can guarantee synchronization. On the receiving side, define an element indicating the receiver of the synchronous data, and connect a signal line representing analog data and digital data to the input of each arithmetic element described in the program from this element, and extract each data Therefore, the data can be reliably and easily extracted from a bit string such as a word or a long word, which is the minimum unit capable of guaranteeing the synchronization, and data requiring synchronization can be handled without the designer being aware of the transmission packet.

In the exchange between control devices as mere data, there are cases where values and character strings are exchanged as a set of character codes such as ASCII codes. When data is handled as a set of character codes such as ASCII codes, a bit string such as a word or a long word is required for each character in order to represent the data. In this case, it is necessary to guarantee the data synchronization for the number of characters representing the required data, but the data amount increases compared to the case where the value is represented as a bit or a bit string as described above, When high-speed data exchange for monitoring is required, it is not applied, so there is no particular problem.

According to the present invention, the load on the control device and the computer is small, a highly efficient transmission method can be obtained, and synchronization of transmission data can be ensured. In addition, it is possible to easily design a set of transmission data that requires synchronization, reduce the possibility of errors, improve the quality of the control system, and increase the reliability.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a synchronous data transmission method and a synchronous data transmission apparatus according to the present invention will be described with reference to FIGS.

FIG. 1 is a block diagram showing a schematic configuration of an example of a plant control system employing a synchronous data transmission device according to the present invention. In this embodiment, a control command transmitted from the computer 2 to the controller 1 will be described as an example of synchronous data. The operator of the plant monitors and confirms the status through the display 21 which is connected to the computer 2 and presents process information such as the process amount (PV) and the control set value (SV) and the operation status. The process is operated using the 23 and the decrease command button 24. The inputs of the increase command button 23 and the decrease command button 24 of the process are taken into the computer 2 via the digital input device 22. The control command creation processing means in the computer 2 is represented as a control command circuit block diagram 25. An increase / decrease command input from the process increase command button 23 or the process decrease command button 24 via the digital input device 22 is input to the analog memory 251, added to the current command value 252, and output as the control command value 252. The fact that the operator is operating is taken as "button operation", and this is used as the effective signal 253 of the control command value. Control command value 252
And the valid signal 253 of the control command value are connected to the synchronization assurance transmission element 254 and transmitted to the network 3 as data whose synchronization is guaranteed.

The control means in the controller 1 is represented as a control command circuit block diagram 11. The received data from the computer 2 whose synchronization is guaranteed is received by the synchronization guarantee receiving element 1.
The control command value 111 and a valid signal 112 of the control command value are output. Analog switch 114
Outputs the control command value 111 received from the computer as its own control command value 113 only when the control command value valid signal 112 indicates valid, and when the control command value valid signal 112 indicates invalid, It outputs its own control command value 113 as its own control command value 113. The control command value 113 from the controller 1 is
Is output to the process operation terminal 4 via

FIG. 2 is a timing chart showing the relationship between the control command value (analog data) and the effective signal (digital data) of the control command value. The control command 252 and the control command value effective signal 253 transmitted from the computer 2 are delayed by the time required for communication via the network 3, and are transmitted to the controller 1 by the control command value 111 and the control command value valid signal 112. As received. That is, even if the operator starts the operation at the computer 2 at the timing 51, the control command of the result is transmitted and the controller 1 receives the operation at the timing 52. Similarly, even if the operator finishes the operation in the computer 2 at the timing 53, the control command of the result is transmitted and the controller 1
Is received at the timing 54.

Control command 252 and control command effective signal 2
When transmitted in combination with 53, it is possible to reliably transmit only the change in the control command during the operation by the operator. For example, even if the control command 252 changes due to some trouble, if the operator is not operating, the signal of “button operation” is not taken in, the valid signal 253 of the control command is lost, and the controller 1 Does not occur.
This is an advantage of exchanging the valid signal of the control command value as synchronous data.

FIG. 3 is a block diagram showing an outline of a part related to data transmission processing of the computer 2 in the embodiment of FIG. In the transmission data area 26 of this embodiment, the minimum unit 261 for storing data that can guarantee synchronization is a 32-bit bit string representing a floating-point value. Calculator 2
In the control operation 271 of the flowchart 27 of the software in the above, the control operation including the control operation represented by the control command circuit block diagram 25 is executed. In the synchronous data editing process 272, data 252 and data 253 which need to be synchronized and are input to the synchronization assurance transmitting element 254 are extracted, the analog data value is stored in a 32-bit bit string 261 representing a floating point value, and the digital data is converted. The least significant bit 2611 of the mantissa of the 32-bit bit string 261 representing the floating point value is overwritten. Transmission editing process 273
Sets a bit string 261 which is the minimum unit that can guarantee synchronization in which synchronization data is stored, at a predetermined location in the transmission data area 26. When all the data to be transmitted is set in the transmission data area 26 in this manner, the transmission processing 2
At 74, the data is sent out onto the network 3.

FIG. 4 is a block diagram showing an outline of a portion related to the data receiving process of the controller 1 in the embodiment of FIG. Receive data area 1 in controller 1
6, the smallest unit 161 for storing one piece of data that can guarantee synchronization is a 32-bit bit string representing a floating-point value. The reception processing 171 of the flowchart 17 of the software in the controller 1 causes the data received from the network 3 to be set in the reception data area 16. The reception editing processing 172 is performed in the reception data area 1
6 is extracted and extracted as a bit string 161 that is the minimum unit that can guarantee synchronization. The synchronous data editing process 173 extracts an analog data value from the bit string 161 as a 32-bit bit string representing a floating-point value, extracts digital data from the least significant bit 1611 of the mantissa of the 32-bit bit string 161 representing the floating-point value, Synchronization assurance receiving element 115
Are set to the data 111 and 112 that need to be output. In the control operation 174, in the control operation including the control operation shown in the control command circuit block diagram 11, the signal is output from the synchronization assurance receiving element 115 in a state where it is guaranteed to be output as a result of the same operation on the transmission side. Control signal 1
11 and a control command valid signal 112 can be used.

In this embodiment, the case where the transmitting side is a computer and the receiving side is a control device is described, but the transmitting side may be a control device and the receiving side may be a control device.

Also, the transmitting device and the receiving device are
One device may be used. That is, in the present embodiment, an example was described in which the data transmission means between the transmission-side device and the reception-side device was a network. When a certain data is shared and used between a plurality of programs that operate asynchronously, a computer system that can reliably and synchronously exchange an analog signal and a digital signal between the plurality of programs is provided.

Furthermore, the present invention is effective not only for the combination of analog data and digital data whose synchronization is guaranteed, but also for the combination of digital data whose synchronization is guaranteed.

[0043]

According to the present invention, the load on the control device and the computer is small, and the transmission data can be synchronized by a highly efficient transmission method. In addition, it is possible to easily design a set of transmission data that requires synchronization, reduce the possibility of errors, improve the quality of the control system, and increase the reliability.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of an example of a plant control system employing a synchronous data transmission device according to the present invention.

FIG. 2 is a timing chart showing a relationship between a control command value (analog data) and an effective signal (digital data) of the control command value.

FIG. 3 is a block diagram illustrating an outline of a portion related to a data transmission process of a computer in the embodiment of FIG. 1;

FIG. 4 is a block diagram illustrating an outline of a portion related to a data reception process of a controller in the embodiment of FIG. 1;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Controller 2 Computer 3 Network 4 Process operation terminal 11 Control command circuit block diagram built in controller 1 12 Analog output device 16 Receive data area of controller 1 17 Receive software flow 21 Process monitoring device 23 Increase command button 24 Decrease command Button 25 Control command circuit block diagram incorporated in computer 2 26 Transmission data area of computer 1 27 Transmission software flow 111,252 Control command value (analog data) 112,253 Effective value (digital data) 115 Synchronization guaranteed receiving element 173 Reception synchronization data editing 254 Synchronization assurance transmission element 274 Transmission synchronization data editing

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-50661 (JP, A) JP-A-4-364271 (JP, A) JP-A-5-308641 (JP, A) JP-A-8-86 116326 (JP, A) JP-A-6-164527 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G05B 15/00-15/02 G06F 7/00 H04Q 9/00, 9/04

Claims (7)

(57) [Claims] 1. A control program built in a transmitting device.
When editing and transmitting multiple data obtained by control calculation
At least a part of the transmission data is
The result is that only the synchronization output signal is
A control program that operates on the premise of the synchronization guarantee
Of synchronous data transmission in control systems with
And the output signal of the transmitting side device is an analog whose synchronization is guaranteed.
Data and digital data,Multiple data that needs to be synchronized is the smallest unit of memory transfer
Embedded in a bit string such as a word or longword
And  The digital data digitally converts the analog data.
Embedded as specific bits of the coded signal
A method for transmitting synchronous data, characterized in that: 2. The synchronous data transmission method according to claim 1, wherein the set of the analog data and the digital data whose synchronization is guaranteed is represented by a bit string of a word or a long word. Wherein one of the bits is used as the digital data of the set. 3. The synchronous data transmission method according to claim 2, wherein a format of a bit string such as a word or a long word representing the analog data represents a floating point value, and the digital data represents the floating point value. A synchronous data transmission method characterized by being embedded in a bit position representing the least significant part of a mantissa in a bit string representing 4. A transmission device comprising a plurality of control devices for exchanging data with each other, wherein a control circuit built in a transmission-side device edits and transmits a plurality of data obtained by control operation, and transmits the plurality of data in the transmission data. A control circuit which at least partially guarantees only a synchronous output signal of a result of one operation execution, and a control circuit built in a receiving device has a control program having a control program that operates on the premise of the synchronization guarantee. In the transmission device, at least the transmitting device includes the control circuit in which a control program is represented by a combination of symbolic elements such as a control function block diagram and a ladder, and an output signal of the transmitting device is guaranteed to be synchronized. Wherein the control circuit stores a plurality of data requiring synchronization in a memory.
Word or long word, which is the minimum unit of transcription
An apparatus for transmitting synchronous data, comprising means for embedding the digital data in a bit string and embedding the digital data as specific bits of a signal obtained by digitizing the analog data. 5. The synchronous data transmission device according to claim 4, wherein the control circuit on the transmission side has an analog data input terminal and a digital data input terminal, and synchronizes a set of analog data and digital data. A synchronization guarantee transmission element to guarantee,
Means for embedding the set of digital data whose synchronization is guaranteed into specific bits of the digitized analog data. 6. The transmission apparatus for synchronous data according to claim 5, wherein the control circuit on the receiving side extracts the set of the digital data whose synchronization is guaranteed from a specific bit of the digitized analog data. Means, and a synchronization assurance receiving element which has an analog data output terminal and a digital data output terminal and outputs the separated analog data and the extracted digital data as control signals guaranteed to be synchronized, respectively. Characteristic synchronous data transmission device. 7. A control program built in a transmitting device.
When editing and transmitting multiple data obtained by control calculation
At least a part of the transmission data is
The result is that only the synchronization output signal is
A control program that operates on the premise of the synchronization guarantee
Of synchronous data transmission in control systems with
And the output signal of the transmitting apparatus is the first data whose synchronization is guaranteed.
Digital data and the second digital data,Multiple data that needs to be synchronized is the smallest unit of memory transfer
Embedded in a bit string such as a word or longword
And  The second digital data is the first digital data
Characterized by being embedded as specific bits
Synchronous data transmission method.