JPH06303673A - Data transmission method - Google Patents

Abstract

PURPOSE:To provide the data transmission method able to send prescribed control information sequentially at a high speed. CONSTITUTION:Only data revised in response to various processing result by a control section 11 of a controller 1 are extracted from a memory 13 by a transmission interface section 15 and sent sequentially. A controller 2 receives the data via a data transmission line 9 to revise corresponding control information in a memory 14 and returns an answerback signal when received data are addressed to a concerned equipment. Then the controller 1 resets sent data based on the reception of the answerback signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission method and, more particularly, to a data transmission method using a cyclic method for sequentially transmitting predetermined data.

[0002]

2. Description of the Related Art In an apparatus composed of a plurality of control units in electric power equipment or a system composed of a plurality of computers connected by a data way or the like, a predetermined unit required for processing performed by each control unit or computer. Data, such as output power at the power plant, analog control information such as temperature and pressure of each part, and binary information indicating operation / open / closed states of various pumps, control valves, circuit breakers, etc. Digital data transmission is needed.

Conventionally, a system as shown in FIG. 6 has been adopted as a high-speed digital data transmission method between these control units or between computers. FIG. 6 is a block diagram showing a general structure of a transmission system based on a cyclic system that repeatedly and repeatedly transmits predetermined data. In FIG. 6, reference numeral 61 is a transmission side control device which performs predetermined processing. As a result, a control unit 63 that individually updates various control information stored in the memory 65, and a transmission interface unit that sequentially outputs a series of control information in the memory 65 to the data transmission path 69 for each information in a predetermined order. 67
It consists of and.

Reference numeral 62 denotes a receiving side control device, which stores a control data in the memory 66 and a reception interface section 68 which outputs data received in a predetermined order via the data transmission path 69 to the memory 66 as a series of control information. The control unit 64 is configured to perform a predetermined process based on the above. In addition, the transmission side control device 61 and the reception side control device 62 have a one-to-one correspondence.
The data transmission path 69 is exclusively used for transmission between the two at a predetermined time.

Next, the operation of this transmission system will be described with reference to the flowchart shown in FIG. First, a predetermined process is executed in the control unit 63 of the transmission side control device 61, the result is output to the memory 65, and the predetermined control information is updated in a timely manner without being synchronized with the transmission. The transmission interface unit 67 always reads all the control information from the memory 65 in a predetermined order (step 71).
1, 714), each information is sequentially transmitted to the data transmission path 69 (step 712), and when the transmission of the series of control information is completed (step 713), the control information is updated by the control unit 63. Regardless of whether or not it is performed, a series of control information transmission processing is repeatedly performed.

On the other hand, the receiving interface section 68 of the receiving side control device 62 sequentially receives the control information which is individually divided and sent out in a predetermined order via the data transmission path 69 (step 721) and a predetermined transmission error. If a transmission error is determined by a detection method, for example, a parity check or the like (step 722), it is determined that there is no error, and a series of control information has been received (step 72).
3) A series of control information is assembled from the individual information and output to the memory 66 (step 724).

The control unit 64 fetches the control information for internal processing as the series of control information is updated, and executes a predetermined processing based on the new control information. Therefore, the control information of the transmission side control device 61 is sequentially transferred, and the processing based on the latest control information is realized by the reception side control device 62.

Further, as a general high-speed digital data transmission method, an occasional transmission system is used in which a communication line for data transmission is captured / established as necessary and only predetermined data is transmitted. This differs from the cyclic method described above, in that the communication line between the transmitting side and the receiving side is captured and established in response to the update of data or the request of the receiving side, and the updated data or requested data is requested. Only data is transmitted.

[0009]

Therefore, in such a conventional data transmission method, the former method, in particular, always performs the reception / transmission processing as the processing on the transmitting side and the receiving side in order to realize high-speed transmission. It is necessary to increase the ratio of occupying the data transmission path, and as the control information to be transmitted increases, the time required to transfer and update a series of control information increases and the transmission efficiency deteriorates. was there. Further, there is no method for confirming whether the transmitted information is correctly received by the receiving side, and there is a problem in reliability of data transmission.

On the other hand, according to the latter method, it is necessary to capture and establish a communication line with a predetermined communication partner every time one data is transmitted, and to deal with a collision when a communication line is secured. Since the line control processing of the above becomes complicated, the basic amount of information is decided as the control information to be transmitted, and when it is necessary to transfer and update this at high speed sequentially, for example, the control information can be transmitted at high speed in power equipment. It is not very effective as a transmission method when transmitting. The present invention is intended to solve such a problem, and an object thereof is to provide a data transmission method capable of sequentially transmitting predetermined control information at high speed.

[0011]

In order to achieve such an object, a data transmission method according to the present invention is a data transmission method in which data transmitted from a plurality of data stored in a memory at a transmission side is updated according to various processing results. Are sent in a predetermined order, the receiving side receives them and updates the corresponding data, and at the same time returns an answer back signal indicating that it has been normally received, and the sending side receives the answer back signal and sends this answer back signal. Based on the back signal, the data transmitted earlier is reset to indicate the completion of transmission, and these transmission processes are repeated every predetermined period so that the information updated on the transmitting side is sequentially transferred to the receiving side. Is.

Further, in the above data transmission method,
Instead of extracting and transmitting updated data among a plurality of data on the transmitting side, only the data updated according to various processing results is stored in the memory and is transmitted in a predetermined order. .

[0013]

Therefore, only data updated according to various processing results on the transmitting side is extracted and sequentially transmitted. The receiving side receives this data, updates the corresponding data, and returns an answer back signal indicating normal reception. Subsequently, the transmitter side receives the answerback signal, and based on this, the previous transmission data is reset as the transmission is completed, and such a transmission process is repeatedly executed.

Further, instead of the updated data being extracted and transmitted from the plurality of data on the transmitting side, only the data updated according to various processing results is stored in the memory and is transmitted in a predetermined order. It

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a transmission system based on a cyclic system which is an embodiment of the present invention. In the figure, reference numerals 1 and 2 are control devices, and memories 13 and 14 that store various control information, control units 11 and 12 that perform various processes based on the control information, and a transmission interface unit that controls data transmission processing. It is composed of 15 and 16, respectively.

Each control unit appropriately updates various control information stored in the memory as a result of performing the predetermined processing, and executes various processing based on the control information updated by the transmission processing. Further, each transmission interface unit extracts the updated data from the control information stored in the memory in a predetermined order during the transmission operation and transmits the data, and controls the corresponding control information in the memory according to the answerback signal from the receiving side. Is reset and at the time of receiving operation,
The corresponding control information in the memory is updated based on the received data, and an answer back signal is returned.

Reference numeral 9 denotes a data transmission path, which is a control device 1 or 2.
Besides, a plurality of control devices are connected by a data transmission line 9. It should be noted that the order of sending the transmission data is determined in advance in each of these control devices by, for example, the device number assigned to each control device, and each control device sends the data to the data transmission line 9 in accordance with this order. As a result, time-division management of the data transmission line 9 is realized.

The transmitted data is received by the transmission interface units 15 and 16 of all the control devices and stored in the corresponding locations of the memories 13 and 14. FIG. 3 is a memory allocation diagram showing an internal configuration common to the memories of the respective control devices, and a plurality of areas 31, 3 corresponding to the respective control devices.
2, 33, etc. Further, these areas are, for example, 11 to 1 m for the area 31 and 21 to 2 for the area 32.
The area 33 is composed of each word of 31 to 3 m, and the control units 11 and 12 of the control devices 1 and 2 perform predetermined processing by referring to the areas 31 and 32 corresponding to their own devices. carry out. 35 is the control device 2
, Which is one of the words forming the area 32, which will be used later in the description. Note that each word stores various control information, for example, analog control information such as output power at a power plant, and data corresponding to binary information indicating the operation / open / closed states of various pumps.

Next, referring to the operation flowchart of FIG.
As an operation of the present invention, a case of transmitting the predetermined control information word 35 of the control device 1 to the control device 2 will be described. First, the control unit 11 of the control device 1 performs a predetermined process, and the result is stored in the memory 13. At this time, the control unit 11 determines the processing result, that is, another control device to which the control information should be transmitted, and stores the control information in a predetermined word, for example, the word 35 (see FIG. 3) in the area corresponding to the control device in the memory 13. The data is updated by storing. However, this data update is carried out in a timely manner as needed, not in synchronization with the data transmission. Further, in each word of the memory 13, the data that has not been updated by the control processing of the control unit 11 is in the reset state, for example, all the bits are 0.

Each control device has a data transmission line 9 as described above.
By time-sharing, the predetermined period assigned to each control device is used as the data transmission timing, and the order is predetermined based on the device number assigned to each control device. .

If the control device 1 is now in the data transmission timing (step 211), the transmission interface unit 15 of the control device 1 inspects each word in the area corresponding to another control device in the memory 13 based on a predetermined order. Then, the newly updated data not in the reset state, for example, the word 35 (see FIG. 3) is extracted (step 212). Note that this inspection is restarted from the word for which the inspection was completed at the previous data transmission timing. Also, the inspection order is set in advance in consideration of the importance of the control information stored in each word.

The data thus extracted is added with an address at which the data is to be stored, that is, corresponding area and word information, and transmission error detection information for checking a transmission error, such as a checksum. (Step 213), the data is output to the data transmission line 9 (Step 214).

The control device 2 has a transmission interface section 16
The data transmission path 9 is monitored by, the data transmitted from the control device 1 is received (step 221), the transmission error is determined (step 222), and if it is determined that the reception is normal, the The address information added to the data is analyzed to derive the corresponding area and word information (step 223), and based on this, stored in the memory 14 (step 224). This reception process is similarly performed by all the other control devices.

Here, the derived area information is that of the own station, for example, the address information "21" in the control device 2.
When the area information derived based on (word 35) is that of the own station (step 225), the same data as the received data is immediately returned as an answerback signal indicating that the reception is normally completed. (Step 22
6). The control unit 12 of the control device 2 reads the latest control information stored in the area 32 of the memory 14 corresponding to its own station at predetermined intervals or as needed, and performs control processing based on the latest control information. To do.

The transmission interface section 15 of the control device 1
Monitors the data transmission line 9 for a predetermined period after data transmission (step 215), receives an answerback signal from the control device of the data transmission partner, here the control device 2 (step 216), and receives this answerback signal. And the data transmitted this time are compared (step 217). If a match is confirmed, the data stored in the corresponding word (word 35) of the memory 13 is reset to indicate the completion of transmission (step 217). 218).

On the other hand, when the answerback signal is not confirmed in the transmission interface section 15 of the control device 1 within a predetermined period from the data transmission (step 215), some trouble occurs and the data transmission is not normally carried out. Therefore, the corresponding data in the memory 13 is not reset,
The data is extracted and retransmitted by the transmission interface unit 15 at the next and subsequent data transmission timings.

The data comparison and reset may be performed by calculating an exclusive logical sum (EXCLUSIVE OR) of the answerback signal and the data of the corresponding word. As a result, data comparison and reset are performed at one time, and the processing speed is increased.

Therefore, the control information updated by the control unit 11 of the control device 1 is received by each control device via the data transmission line 9 based on the data transmission timing of the control device 1, and the corresponding control information is updated. At the same time, the control device 2 corresponding to the control information returns the same answerback signal as the received data indicating the normal reception, whereby the control device 1 surely confirms the completion of the transmission.

In the above embodiment, the case where the same signal as the data received as the answerback signal is returned has been described, but it is more important to shorten the period in which the control information is transferred / updated rather than the certainty of confirmation of the transmission completion. In this case, predetermined relatively short fixed length data may be used as the answerback signal.

FIG. 4 is a data correspondence diagram showing the relationship between the transmission data and the answerback signal when fixed length data is used as the answerback signal, and 40 is the control device 1.
Data 45 is fixed length data as an answerback signal.

In the figure, the transmission data 41, 42, 43 are sequentially transmitted at each transmission timing of the control device 1, and fixed length data 46, 47, 48 are sent as answer-back signals from the control device corresponding to each transmission data, respectively. It has been returned. By using relatively short fixed-length data as an answerback signal in this way, the data transmission time is considerably shortened when the transmission data is relatively long data such as analog information measured by various instruments. At the same time, the transmission completion confirmation processing by the transmission side control device is also speeded up, and the transfer / update time of the control information is drastically shortened as a whole.

In the above embodiment, an area corresponding to each control device is provided as the memory configuration of each control device,
The description has been given of the case where the new control information obtained as the control processing result of the control unit is stored in the area corresponding to each control device to be transmitted, but a transmission data buffer different from such a control information storage area is stored in the memory. Alternatively, the transmission interface unit may read out the transmission data from here in a predetermined order and transmit the transmission data at the data transmission timing of the own device.

FIG. 5 is a memory block diagram of a transmission data buffer provided in common to the memories of the respective control devices.
In the figure, 51 and 52 are data to be transmitted,
It is composed of area for storing the data, address information including word information, and error detection data, and is commonly provided in the memory of each control information together with the control information storage area of FIG.

Next, the operation when the transmission data buffer is provided will be described. In this case, the operation data is the same as the above embodiment except that the transmission data is stored in a different place, and an operation flowchart will be described with reference to FIG.

When control information to be transmitted to the control device 2 is generated as a result of the processing in the control portion 11 of the control device 1, the control portion 11 stores the control information in a predetermined empty space in the transmission data buffer of the memory 13. Store in the area in a timely manner.

The transmission interface section 15 receives the data transmission timing of its own control device (step 21).
1), a buffer for transmission data in the memory 13 (see FIG. 5)
Data to be transmitted next is extracted from (step 21
2) The address and the error detection information are added to this (step 213) and sent to the data transmission line 9 (step 214).

The transmission interface 16 of the control device 2 receives the data transmitted from the control device 1 via the data transmission line 9 as in the above embodiment (step 221).
If it is confirmed that there is no transmission error (step 22
2) The address information added to the data is analyzed (step 223), and based on this, this data is stored in the corresponding area and word position of the memory 14 (step 224). This is similarly performed in other control devices. Further, when the transmission interface unit 16 of the control device 2 detects that the area information in which the data should be stored indicates the device itself (step 22).
5) Immediately, the answerback signal is returned to the control device 1 via the data transmission line 9 (step 226).

The transmission interface section 15 of the control device 1
Within a predetermined time after data transmission (step 215),
When this answerback signal is received (step 21)
6) In response, it is confirmed that the transmission data in the transmission data buffer of the memory 13 matches the transmission data (step 217), and the transmission data is stored in the corresponding storage area of the memory 13 and stored in the transmission data buffer. The transmission data is reset (step 218) and the transmission processing of this data is completed. If the answerback signal is not detected within the predetermined time from the data transmission (step 2
15) Similarly to the above embodiment, the data stored in the transmission data buffer of the memory 13 is not reset, and the transmission interface unit 15 is transmitted at the next and subsequent transmission timings.
Is extracted and retransmitted.

Therefore, by providing the transmission data buffer, selection processing such as distinguishing the data that has not been updated when the transmission data is extracted by the transmission interface unit becomes unnecessary, and the processing time during data transmission is improved. .

[0040]

As described above, according to the present invention, the control information newly updated as the cyclic method is extracted and transmitted, and the control information is transmitted in response to the detection of the answer-back signal returned in response to this. Since the data is reset, only the control information required for the transmission process is automatically transferred and updated sequentially, and the completion of the transmission is surely confirmed.
Therefore, in a data transmission method between a plurality of control devices constituting a system such as electric power equipment, the transmission processing load of the control unit of each control device can be reduced, and the control information required by each control device can be obtained at high speed and in a short period of time. It has a special effect that it can be reliably transferred and updated.

[Brief description of drawings]

FIG. 1 is a block diagram of a transmission system according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a data transmission processing operation.

FIG. 3 is a memory allocation diagram showing an internal configuration of a memory.

FIG. 4 is an explanatory diagram showing a correspondence relationship between transmission data and a fixed length answerback signal.

FIG. 5 is a memory allocation diagram showing a configuration of a transmission data buffer provided in the memory.

FIG. 6 is a block diagram of a conventional transmission system.

FIG. 7 is a flowchart showing a data transmission processing operation of a conventional transmission system.

[Explanation of symbols]

 1, 2 Control device 9 Data transmission path 11, 12 Control unit 13, 14 Memory 15, 16 Transmission interface unit 31, 32, 33 Area 40 Transmission data 45 Fixed length answerback signal

Claims (2)

[Claims] 1. The transmitting side extracts, in a predetermined order, data updated according to various processing results from a plurality of data stored in a memory, transmits the extracted data, and the receiving side receives the data and outputs corresponding data. An answer back signal indicating that it has been normally updated and returned is returned, and the transmitter side receives the answer back signal and resets the data transmitted earlier based on this answer back signal to indicate that transmission has been completed. A data transmission method characterized in that the transmission process is repeatedly performed every predetermined period to sequentially transfer the information updated on the transmission side to the reception side. 2. The data transmission method according to claim 1, wherein instead of extracting and transmitting updated data among a plurality of data on the transmitting side, only data updated according to various processing results is stored in a memory. And a data transmission method characterized by transmitting this in a predetermined order.