JPH0564264A - Data transmission system - Google Patents

Abstract

PURPOSE:To provide a data transmission system where the reliability of data transmission and reception is secured and also a protocol is simplified. CONSTITUTION:The transmission side 1 having a storing means 11 collecting data inputted from a measuring instrument, etc., by a fixed cycle so as to internally hold it and a data transmitting means 14 transmitting stored data to a reception side, and the reception side 2 having a data receiving means 21 receiving data transmitted from the transmission side are provided in the data transmission system where the transmission side is provided with a judgement information adding means 15 adding a redundant code to transmission data as the code for detecting a data error in a data transmission line and the reception side is provided with a judging means 22 checking the validity of data received in the reception side based on the redundant code of data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission system, and more particularly to a data transmission system for collecting data of measuring instruments and the like.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional example. The conventional example of FIG. 3 is
Data sent from a plurality of measuring devices, such as the first measuring device, the second measuring device, and the third measuring device, which periodically collects data, and data sent from the data sending side. It is composed of the receiving side of the data to be received.

In the conventional example shown in FIG. 3, first, data A from a first measuring device, data B from a second measuring device, and data from a third measuring device at a certain collection time T are acquired. Assuming that the data is C, the data transmitting side transmits the collected data A, B, C to the data receiving side when the data collection from each measuring device is completed. When the data from the first measuring device at the next data collection time T + ΔT is A, the data from the second measuring device is B ′, and the data from the third measuring device is C, the data transmitting side performs each measurement. When the data collection from the device is completed, the collected data at time T and the collected data at time T + ΔT are compared, and only different data, that is, the data B ′ from the second measuring device in the conventional example of FIG. 3 is transmitted. Start the timer. Then, 1 is put in the transmission counter to store the number of transmissions. When the data receiving side receives the data B ′, it sends a reception confirmation response command to the data transmitting side to inform that the data B ′ is correctly received. After transmitting the data B ′, the data transmission side prepares to transmit the next collected data when it receives a reception confirmation response command from the data reception side within a preset time.

Here, if the data transmitting side is the data B '
After sending, if you can not receive the reception confirmation response command from the data receiving side within the preset time,
It is considered that the data receiving side has not correctly received the data B ′, the data B ′ is transmitted to the data receiving side again, and the timer is started. Then, the transmission counter is incremented by 1, and a reception confirmation response command from the data receiving side is awaited. After retransmitting the data B ′, the data transmission side prepares to transmit the next collected data when it receives a reception confirmation response command from the data reception side within a preset time. However, if the data transmission side cannot receive the reception confirmation response command from the data reception side within the preset time after transmitting the data B ′, the transmission counter is checked and if the number is within the preset number of times. For example, the data B ′ is retransmitted. However, if the transmission counter exceeds the preset number of times, error processing is started.

[0005]

However, in the above-mentioned conventional example, since the reliability of data transmission is ensured by exchanging the reception confirmation response command, the data transmitting side detects a change in data. At the same time as holding and transmitting the data internally, a function to start a timer to wait for reception of a reception confirmation response, a function to stop the timer if a reception confirmation response is received before the timer times out, and a timer When a time-out occurs, it needs a function to resend the internally held data, and the data receiving side needs a function to detect the validity of the data when it receives the data and to send a reception confirmation response when the data is normal. Since the sending and receiving protocols are complicated, it is necessary for the data sending side and the data receiving side to have a function to control them. There is a disadvantage that that.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a data transmission system capable of improving the disadvantages of the conventional example, especially ensuring the reliability of data transmission / reception, and simplifying the protocol.

[0007]

Therefore, in the present invention, there is provided a storage means for collecting and internally holding data input from a measuring device or the like at regular intervals, and a data transmitting means for transmitting the stored data to a receiving side. In a data transmission system having a transmitting side having the same and a receiving side having a data receiving means for receiving data sent from the transmitting side, the transmitting side is provided with a redundant code for detecting a data error on the data transmission path. A configuration is provided in which the determination information adding means for adding to the transmission data is provided, and the receiving side is provided with a determination means for checking the validity of the data received by the receiving side based on the redundant code of the data. I am collecting. This aims to achieve the above-mentioned object.

[0008]

The storing means on the data transmitting side collects the data input from each measuring device at a certain collection time T and holds it internally. When the transmission timing signal generated by the fixed cycle generating means is sent to the data sending means, all the collected data accumulated in the accumulating means are read out, and a command to add a redundant code to the judgment information adding means is issued based on the collected data. put out.
The judgment information adding means is instructed by the data sending means,
A redundant code is calculated based on the collected data, and the calculated redundant code is added to the collected data and sent to the data sending means. When the data sending means receives the collected data to which the redundant code is added from the judgment information adding means, it sends the collected data to the data receiving side.

On the data receiving side, the data receiving means receives the data sent from the data transmitting side. And
The received data is sent from the data receiving means to the judging means. In the judging means, the redundant code added to the collected data is checked, and the data judged to be normal are treated as valid data and the data judged to be in error are treated as invalid data. Furthermore, on the data transmission side, when a preset period ΔT has elapsed after data collection, data input from each measuring device is collected again and the same processing as above is performed. The same processing as above is performed on the data receiving side.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

In the embodiment shown in FIG. 1, the data transmission side 1 generates a storage means 11 for collecting data input from the outside such as a measuring instrument at a fixed cycle and internally holding it, and a transmission timing signal 13 at a fixed cycle. On the transmission path, the fixed cycle generating means 12, the data sending means 14 for sending all the collected data accumulated in the accumulating means to the data receiving side 2 by using the transmission timing signal 13 generated by the fixed cycle generating means 12 as a trigger. CRC (Cyclic)
Redundancy Check: Cyclic redundancy check)
It comprises a judgment information adding means 15 for adding a code and a parity when transmitting data. Further data receiving side 2
Is a CRC for checking the validity of the data received by the data receiving means 21 and the data receiving means 21 for receiving the data sent from the data transmitting side 1 in a fixed cycle.
It is provided with a judging means 22 for making the data, which is judged to be normal by checking the code or parity, valid data.

Here, the CRC code is one of the error checking methods at the time of data transmission, in which a bit string forming a text is attached with a cyclic code calculated by another specific expression based on the bit string, and an error occurs. It is a redundancy check that detects and corrects. Excellent in detecting burst errors and random errors.

Next, the operation of this embodiment will be described with reference to FIG. Here, it is assumed that three measuring devices are connected to the data transmitting side 1 for the sake of easy understanding.

(A) The storage means 11 of the data transmitting side 1 is
At a certain collection time T, the data input from each measuring device is collected and internally stored. Here, the data from the first measuring device is A, the data from the second measuring device is B, and the data from the third measuring device is C.

(B) When the transmission timing signal 13 generated by the fixed period generating means 12 is sent to the data sending means 14, all the collected data (A, B,
C) is read out, and a command for adding a redundant code such as a CRC code or parity for detecting a data error on the transmission path is issued to the determination information adding means 15 based on the collected data.

(C) The judgment information adding means 15 receives a command from the data sending means 14 and sends a CR based on the collected data.
A redundant code such as a C code or parity is calculated, the calculated redundant code is added to the collected data, and the data sending means 14 is executed.
Send to.

(D) When the data sending means 14 receives the collected data to which the redundant code is added from the judgment information adding means 15, it sends it to the data receiving side 2.

(E) On the data receiving side 2, the data receiving means 21 receives the data sent from the data transmitting side 1. Then, the received data is sent from the data receiving means 21 to the judging means 22.

(F) The judging means 22 checks the CRC code or the redundant code such as parity added to the collected data, and makes the data judged to be normal valid data and the data judged to be error invalid data.

(G) Further, the data transmitting side 1 collects the data input from each measuring device again and stores the data internally when a preset period ΔT has elapsed after the data collection. Here, the data from the first measuring device is A,
Data B ′ from the second measuring device and data from the third measuring device are C.

(H) When the transmission timing signal 13 generated by the constant period generating means 12 is sent to the data sending means 14, all the collected data (A,
B ′, C) are read out, and a command for adding a redundant code such as a CRC code or parity for detecting a data error on the transmission path is issued to the determination information adding means 15 based on the collected data.

After (i), the same processing as (c) to (f) above is performed.

(J) Further, on the data transmission side 1, when a preset period ΔT has elapsed after data collection, data input from each measuring device is again collected and internally held. Here, the data from the first measuring device is A,
Data B ′ from the second measuring device and data from the third measuring device are C.

(K) When the transmission timing signal 13 generated by the fixed cycle generating means 12 is sent to the data sending means 14, all the collected data (A,
B ′, C) are read out, and a command for adding a redundant code such as a CRC code or parity for detecting a data error on the transmission path is issued to the determination information adding means 15 based on the collected data.

After (l), the same processing as (c) to (f) above is performed.

As described above, the present system does not require a means for holding the transmitted data and waiting for the reception confirmation response, and the data transmitting side 1 transmits all the collected data from the fixed cycle generating means 12. The data is periodically transmitted by the timing signal 13, and the data receiving side 2 only determines whether the received data is valid or invalid.

If the data is lost, the data is received by the data receiving side 2 at the next timing. Since this data also includes the information of B'that the receiving side could not receive as data, the data of B'will not be lost.

[0028]

Since the present invention is constructed and functions as described above, according to the present invention, the means for detecting a change in data, the means for internally holding the data, and the means for waiting for the reception of a reception confirmation response are described. Data is received without the need for a time measuring means, a means for stopping the timer when a reception confirmation response is received before the time-out, a means for resending the internally held data when the timer times out, a means for checking the number of retransmissions, or an error processing means. The receiving side does not need a means to send a reception confirmation response when the received data is normal,
Furthermore, highly reliable data transmission can be performed without requiring a means for controlling a complicated communication protocol on the transmitting and receiving side. For this reason, the configuration and control on both the transmitting and receiving sides can be simplified, the number of parts can be reduced and the maintainability can be improved, and the reliability of data transmission can be improved even though the protocol is simplified. It is possible to provide an unprecedented excellent data transmission system.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a sequence diagram of data transmission according to an embodiment of the present invention.

FIG. 3 is a sequence diagram of data transmission in the conventional example.

[Explanation of symbols]

 1 data transmitting side 2 data receiving side 11 accumulating means 12 fixed period generating means 13 transmission timing signal 14 data transmitting means 15 judgment information adding means 21 data receiving means 22 judgment means

Claims (2)

[Claims] 1. A transmitting side having a storing means for collecting and internally holding data input from a measuring instrument at regular intervals, a data transmitting means for transmitting the accumulated data to a receiving side, and a transmitting side from this transmitting side. In a data transmission system including a receiving side having a data receiving means for receiving the received data, a decision information adding means for adding a redundant code to the transmitting data for detecting a data error on the data transmission path on the transmitting side. The data transmission system, wherein the receiving side is equipped with a judging means for checking the validity of the data received by the receiving side based on the redundant code of the data. 2. A transmitting side having a storing means for collecting and internally holding data input from a measuring instrument at regular intervals, a data transmitting means for transmitting the accumulated data to a receiving side, and a transmitting side from this transmitting side. In a data transmission system including a receiving side having a data receiving means for receiving the received data, a decision information adding means for adding a redundant code to the transmitting data for detecting a data error on the data transmission path on the transmitting side. In addition to the above, the receiving side is equipped with a judging means for checking the validity of the data received by the receiving side based on the redundant code of the data, and the data transmitting means is provided with A data transmission system characterized in that it is equipped with a fixed period generating means for regulating transmission timing.