JPH0239748A - Time information transmission system - Google Patents

Abstract

PURPOSE:To prevent the error of timing and time control between respective control parts and respective controlled parts by preventing the resending of time information, and when the elapsed time from the input of the time notifying signal to the input of the time executing signal is not equal to a set time, preventing the elapsed time as the time information. CONSTITUTION:A set time(T) is set euqally to a time T1 (the time interval between the time notifying signal and the time executing signal at the time of a normal transmission). When transmission information is the time information, it is regarded as the transmission without a resending function, when input data are the time notifying signals, a time is activated, and when the input data are the time executing signals, and the elapsed time from the activation of the time until the decision of the time executing signal is not equal to the prescribed set time T, the input data are not handled as the time information, and timing is not executed when the timer is reset.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention is directed to high-level data link control procedures (Ilig).
h Level Data Link Control
The present invention relates to a data transmission method for transmitting data according to the HDLC method (hereinafter abbreviated as HDLC method), and particularly to a time information transmission method for transmitting time information using the HDLC method.

B0 Summary of the Invention The present invention provides a time information transmission system that transmits time information using an HDLC system that is equipped with a function to retransmit information when a transmission failure occurs. prohibits the retransmission of the time information, and if the elapsed time from the input of the time advance signal to the input of the time execution signal is not equal to the set time, it will not be treated as time information and the time will not be adjusted. This prevents errors in time adjustment and time management between each control station of the remote monitoring control station and between each controlled station when a transmission failure occurs.

C1 Prior Art In recent years, in remote monitoring and control, there has been a demand for expanding the range of monitoring and control and combining it with computers to speed up troubleshooting and improve operational efficiency. Therefore, in order to meet the above requirements, HDLC has recently been adopted as a data transmission method that can easily expand the amount and types of information and is also easy to process by computer.
method has been adopted. This HDLC method has the following advantages.

(1) It is possible to check whether the other party's computer is ready to receive data, whether the other party's computer is capable of receiving data, etc.

(2) When a busy situation occurs, the other station can keep transmitting until it ends.

(3) Data can be automatically retransmitted when a transmission failure occurs, and data loss can be prevented.

(4) Continuous transmission that sends Mi number of data at once, full-duplex transmission that communicates with each other simultaneously, etc. are possible, and the transmission time can be shortened.

The Consultative Committee on International Telegraph and Telephone (CCITT) divides the responsibility for transmission systems into levels as shown in Figure 3. Level I has the role of recognizing data, and the HDLC transmission format shown in Figure 4 (
In terms of frame structure), F (a flag sequence consisting of 8 bits) is used to clarify the beginning and end of a frame, and it is used to specify the station that should receive the command and to display the station that sent the response. This corresponds to A (address part consisting of 8 bits), etc.

In level 2, the receiver has the role of controlling operations such as commands to the other station and responses to the commands as responses, and corresponds to C (control unit composed of 8 bits). In addition, high levels above level 3,
The receiver has various types of information, and falls under ■ (information section with no restrictions on bit configuration).

Currently, there are LSIs that can perform all the work that should be done at level 12 in the HDLC system, and computers only need to do the work at level 3 or higher. Therefore, the burden on the computer is significantly reduced. Furthermore, the transmission efficiency of the HDLC method is also extremely good compared to other methods. In other words, the transmission efficiency is determined by the number of raw data bits/the number of transmitted bits, and in the case of the CDT (cyclic digital transmission) method, it becomes , in the case of the basic method, it becomes , and in the case of the HDLC method, it becomes .

Next, the state of data transmission in the HD LC system will be explained with reference to FIG. Figure 5 shows that during communication between stations A and B,
This shows the case where a transmission failure occurs as shown in G.

For example, "■・3・4" of "rA-, -B code" in the figure indicates that the transmission order number is 3 and the reception order number is 4 in a frame with information (I), and "transmission data is present". The numbers in the column indicate the number of remaining data sets. Also, if a transmission failure occurs at time, as shown in G, the data of "■, 3, and 4" will not reach the B station. Since the A station side is not aware of the occurrence of the failure, it next increments the transmission order number by 1 at time t and transmits the data "■.4.4".

Then, on the 0 station side, the previous time it received the data with the transmission order number "2", and this time it receives the data with the transmission order number "■・4・4", so the transmission order number jumps from 2 to 4. It is recognized that a failure has occurred.

Therefore, at time t4, a retransmission request is issued, and at time t4, a frame without r and a reject signal "REJ-3" are sent.
emits. This rREJ・3” is currently sending order number 2.
This indicates that the frame with transmission order number 3 is expected to be transmitted next since it has been received. Then, at the time, the retransmission request is recognized on the A side, the retransmission conditions are established, and the transmission order number is 3 from time Lll to time t6.
-5 frames of data are retransmitted.

As mentioned above, in the HD LC system, the local station and the other station communicate while mutually confirming the transmission order number, so when a transmission failure occurs, data can be automatically retransmitted, preventing data loss. can be prevented.

D1 Problems to be solved by the invention As an example of expanding the types of information in remote monitoring and control,
There is an application in which the time is unified among all controlled stations, data from each controlled station is tagged with time, and events that occur are analyzed.

For this reason, time information is transmitted from the control center (master station) or from the centralized control center (feeding) to each controlled station (child station) via the control center (master station) to perform time adjustment, time management, etc. Is going.

When performing time management of information generated at a controlled location,
If a transmission failure or transmission error occurs before or after transmitting time information, the fifth
As explained in the figure, since the time information is automatically retransmitted, the time difference between the initial transmission and the retransmission becomes a time error. This error disrupts the time relationship between occurring events, making it impossible to analyze the phenomenon.

Below, frame transmission states will be described for six cases when a transmission failure occurs. In FIGS. 6(a) to (f), the frame marked with "Jiyo" inside is a frame containing a time advance signal, and the frame marked with "Jiji" inside is a frame containing a time execution signal. The frame with numbers inside is a frame that contains other general data, and the numbers are symbols to distinguish time relationships. It is also a frame that includes a beam direct signal written as "REJ" inside. The interval from the time notice signal to the time execution signal is set in advance to a constant time T. This time information (time notice signal and time execution signal) is transmitted at a predetermined cycle. FIG. 6(a) shows a case where a transmission failure occurs at the time point x2, that is, the frame transmitted next to the time execution signal (frame containing +1 data). In this case, the upstream side cannot receive +1 data, but receives +2 data, and since the transmission sequence number of that data has jumped, it can recognize that there is a transmission failure, and issues a reject REJ. Make a retransmission request. Then, on the downstream side, although not shown, the +1 and +2 data are retransmitted.

Therefore, in the case of FIG. 6(a), there is no effect on the time information transmitted before the +1 data.

FIG. 6(b) shows a case where a transmission failure occurs at time x3, that is, a frame containing a time execution signal. In this case, the upstream side cannot receive the time execution signal, but receives +1 data, and since the transmission sequence number of that data is skipped, it can recognize that there is a transmission failure and issue a reject REJ. Make a retransmission request. Then, the downstream side retransmits the time execution signal, +1 and +2 data, starting from the next transmission frame (+2) in the same time zone as the Renoek l-RE J. Since the data is automatically retransmitted in this way, the time from the completion of transmission of the time advance signal to the completion of transmission of the time execution signal is T, which is significantly longer than the set time T. For this reason, time adjustment cannot be performed using the first time execution signal (time point x3), and time adjustment is performed using the retransmitted time execution signal, resulting in a large time error (E).

FIG. 6(c) shows a case where a transmission failure occurs at the time point x5, that is, the frame containing the time advance signal.

In this case, the upstream side cannot receive the time advance signal but does receive the time execution signal, and since the transmission order number is skipped, it can recognize that there is a transmission failure, and reject R.
EJ is issued to request retransmission. Then, the downstream side retransmits the time advance signal 2 time execution signal and +1 data from the next transmission frame (+1) in the same time zone as the rejected REJ (note that the time advance signal and time execution signal at the time of retransmission are simply (The time difference T is completely different from the set time T.) Because the data is automatically retransmitted in this way, it is not possible to adjust the time when the first time execution signal is sent, and the time is adjusted using the retransmitted time execution signal, resulting in a large time error. (E) occurs.

FIG. 6(d) shows a case where a transmission failure occurs at a time point of x6, that is, a frame transmitted immediately before the time notice signal (a frame containing data of -1). In this case, the upstream side cannot receive the -1 data, but receives the time advance signal, and since the transmission sequence number is skipped, it can recognize that there is a transmission failure, and reject REJ.
to issue a retransmission request. Then, the downstream side retransmits the data of the time advance signal and the time execution signal from the time following the time execution signal =11. In this case, since the transmission order number of the first time notice signal is skipped, the signal is not recognized as a normal time notice signal, and therefore, time adjustment is not performed using the first time execution signal. Since the data is automatically retransmitted in this way, the time cannot be adjusted when the first time execution signal is sent, and the time is adjusted using the retransmitted time execution signal, resulting in a large time error (
E) occurs.

FIG. 6(e) shows the time point of x7, that is, 2 of the time notice signal.
A case is shown in which a transmission failure occurs in a frame (a frame containing -2 data) that is transmitted before the first frame. In this case, the upstream side cannot receive data of -2, but receives data of -1, and since the transmission order number is skipped, it can recognize that there is a transmission failure, and reject R.
EJ is issued to request retransmission. Then, on the downward side, time t
,. As shown in FIG. 2, the data of -2, -1 and time advance signal are retransmitted even though it is the time to send the time execution signal. Then, after retransmission, the time is returned. The time execution signal, which could not be transmitted, is now transmitted. In this way, since retransmission data is inserted between the time advance signal sent for the first time and the time execution signal, the time t1 is a time when a long error time (E) has elapsed from the time tll when the transmission of the time execution signal should have been completed normally.
．． The time will be adjusted at

FIG. 6(f) shows the time point of x12, that is, "2" on the upstream side.
” shows a case where a transmission failure occurred in a frame containing data. In this case, the downstream side cannot receive data 2, but receives data 3, and since the transmission order number is skipped, it can be recognized that there is a transmission failure, and the reject signal is sent after the time notice signal. Issues REJ to request retransmission. Then, on the upstream side, 2 and 3 data after data 4
and 4 data is retransmitted. Since the reject REJ intervenes between the time advance signal and the time execution signal, the transmission completion time t14 of the time execution signal is delayed by the time error (E) from the time tea when transmission should normally be completed. Therefore, it is not possible to perform time adjustment at accurate time t13 (however, the time error (E) in this case is small).

The present invention has been made in view of the above points, and its purpose is to:
An object of the present invention is to provide a time information transmission method that does not cause errors in time adjustment even if a transmission failure occurs when transmitting time information using an HD LC method.

21 Means and Effects for Solving the Problems The present invention provides data links from a control center to a controlled center or from a centralized control center to a control center in accordance with a high-level data link control procedure that has a function of retransmitting information when a transmission failure occurs. In a time information transmission method that transmits time information to a controlled station via a time information transmission system, the transmitting side is provided with information determination means for determining whether or not the transmitted information is time information, and the receiving side is provided with a time advance signal. Elapsed time determining means is provided to monitor the elapsed time from when the time is input until the time execution signal is input, and to determine whether the elapsed time is equal to the set time, and to determine whether the transmitted information is time information. When the information determining means determines, retransmission of the time information is prohibited, and when the elapsed time determining means determines that the elapsed time is not equal to the set time, it is not treated as time information. It is said that

F. Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The present invention provides information determining means on the transmitting side and elapsed time determining means on the receiving side in data transmission using the HDLC system, and the information determining means is shown in FIG.
2L). In FIG. 1(1), it is first determined in step S1 whether the transmitted information is time information.

As a result, if the transmission information is time information, step S;
If the information is not time information, transmission is performed without a retransmission function in step S3. In this case, after the information determination means makes a determination, it is determined whether the data is to be transmitted with or without the retransmission function depending on the high level of level 3 or higher described above. If there is no retransmission function, the sending side does not add a sending sequence number, and the receiving side does not recognize the sending sequence number either. Furthermore, even if a retransmission request is received, the transmitting side does not retransmit it. When the transmission data is received, Level 1.2 recognizes the data, requests retransmission for data with a retransmission function when a retransmission request is established, and for data without a retransmission function, the transmission sequence number is changed in the event of a failure. Therefore, no retransmission is requested, and even if retransmission conditions are established due to a failure of the data with retransmission function, retransmission will not be performed.

Further, the elapsed time determining means performs processing as shown in FIG. 1(b). In FIG. 1(b), it is first determined in step S whether the input data is a time notice signal. As a result, if the input data is a time notice signal, step S;
Start the timer at . If the human input data is not a time advance signal, it is determined in step S3 whether it is a time execution signal. As a result, if the input data is not a time execution signal, it is processed as general data in step S4. In addition, if the input data is a time execution signal, the time elapsed from when the timer is activated until it is determined that it is a time execution signal is determined as follows: In step S, it is determined whether or not the time period (time until the end of the process) is equal to a predetermined set time T. As a result, if the elapsed time is equal to the set time T, the manual data is treated as time information, and in step SIl, time adjustment is performed and the timer is reset.

If the elapsed time is not equal to the predetermined set time T, the input data is not treated as time information, the timer is reset in step S7, and no time adjustment is performed.

As described above, the elapsed time determination means of the present invention treats the input data as time information by comparing the elapsed time from when the time notice signal is input until the time execution signal is input with the set time T. Specifically, the set time T is determined as shown in FIG. 6 (a).
) (the time interval between the time notice signal and the time execution signal when they are transmitted normally).

Further, the elapsed time determining means may be one that determines the time according to the procedure shown in FIG. 1(C). In FIG. 1(c), it is first determined in step S whether the input data is a time notice signal. As a result, if the human data is a time advance signal, a timer is activated in step S2, and then in step S it is determined whether or not the timer has timed up. If the human input data is not a time advance signal, it is determined in step S4 whether it is a time execution signal. As a result, if the input data is not a time execution signal, it is processed as general data in step S5. In addition, if the input data is a time execution signal, the elapsed time from when the timer is activated until it is determined that it is a time execution signal (i.e. from when the time advance signal is manually input to when the time execution signal is input) Step S
Judgment is made in step 6. As a result, if the elapsed time is equal to the set time T, the input data is treated as time information, and in step S7, time adjustment is performed and the timer is reset. If the elapsed time is not equal to the predetermined set time T, the input data is not treated as time information, and the timer is reset in step S8, and no time adjustment is performed.

If it is determined in step S that the timer has not timed up, it is determined in step S4 whether or not it is a time execution signal.

If it is determined in step S3 that the timer has timed up, the timer is reset in step S8 and no time adjustment is performed.

Incidentally, the operating time T of the timer. is set longer than the set time T1. Setting in this way is effective when the time execution signal is not input after the time advance signal is input, as in the case of FIG. 7(b), which will be described later.

The transmission method of the present invention comprising the elapsed time determining means and the header information determining means set as described above is shown in FIGS.
When applied to the case (f), the frame transmission states become as shown in FIGS. 7(a) to (f).

First, in the case of FIG. 6(2), the data retransmitted by the retransmission request is the data after +1, and the time information before that is not retransmitted. Moreover, the elapsed time from when the time notice signal is input until when the time execution signal is input is the set time T.
, so the time is adjusted by the transmitted time execution signal as shown in FIG. 7(a), and there is no problem.

Next, if the time execution signal transmitted from the downstream side is lost due to a transmission failure as shown in Figure 6(b), the transmission sequence number is not lost and is rejected on the upstream side as shown in Figure 7(b). No signal is emitted. Therefore, only the time advance signal is received, and the timer times up as described in step S3 of FIG. 1(C), so that time adjustment will not be performed at an incorrect time. In this case, the time cannot be set, but if the precision of the clock is sufficiently improved, the time can be set using the time execution signal transmitted in the next cycle.

Furthermore, even if the time notice signal is missing as shown in FIG. 6(c), the transmission order number is not lost as described above and no reject signal is issued on the upstream side.

Therefore, as shown in FIG. 7(c), only the time execution signal is received, and time adjustment will not be performed at an incorrect time.

In the case of FIG. 6(d), the time advance signal and the time execution signal are not retransmitted as shown in FIG.
．． Only +2 data is retransmitted. Therefore, the time from when the time notice signal is input to when the time execution signal is input is determined by the elapsed time determining means (step S in FIG. 1(b)).
Alternatively, it is determined in step 5Il) of FIG. 1(c) that the time is equal to the set time T1. This allows time adjustment to be performed correctly.

In the case of Figure 6(e), the time notice signal is input on time, but a reject signal is issued on the upstream side, so the downstream side receives data of -2 and -1 as shown in Figure 7(e). After retransmitting, a time execution signal is sent. Therefore, the elapsed time determining means determines that the time 'I'' I+ from when the time advance signal is manually input until the time execution signal is input is not equal to the set time T1 (T I < T I +). As a result, the time execution signal transmitted immediately after the retransmission data (-2, -1) is not treated as time information, and time adjustment will not be performed at an incorrect time.

In addition, in the case of FIGS. 6 and 7(f), the input of the time execution signal is slightly delayed from the scheduled time due to the intervention of the reject REJ, so the time T8 from when the time advance signal is input until the time execution signal is input manually The elapsed time determining means determines that T is not equal to the set time T (TI<Te). As a result, the time execution signal input manually at time 4 is not treated as time information, and time adjustment will not be performed at an incorrect time. Note that if the difference between the time T and TIl is extremely small, T + -T depending on the accuracy of the determination. Although it may be determined that
Even if the time is adjusted in such a case, there is no problem because the error is extremely small.

In addition, in order to transmit without the retransmission function based on the judgment result of the information judgment means, the address must be a global address frame consisting of all rlJ bits as shown in Figure 2 so that a common command can be received by multiple partner stations. Alternatively, the control section may be a non-numbered frame configured in a non-numbered format. Another method is to transmit in transparent mode, but this requires mode switching and is not practical. For time adjustment signals, it is more convenient to use the global address method, which allows signals to be sent to multiple partner stations at the same time.

G8 Effects of the Invention As described above, according to the present invention, time information is not retransmitted, and the elapsed time from when the time advance signal is input until when the time execution signal is input is set as the set time. If they are not equal, they are not treated as time information, so when data is transmitted using the 1 (DLC method), even if a transmission failure occurs, the time information is not treated as time information. This provides an excellent effect in that no time clock corruption or time management errors occur.Furthermore, the advantage of the HDLC method, which is that data can be retransmitted in the event of a transmission failure, is not impaired in any way.

[Brief explanation of the drawing]

FIG. 1(a) is a flowchart showing an embodiment of the information determining means of the present invention, FIG. 1(b) is a flowchart showing an embodiment of the elapsed time determining means of the present invention, and FIG. 1(c) is a flowchart showing an embodiment of the information determining means of the present invention. Flowchart showing an embodiment of the pond of the elapsed time determining means,
Fig. 2 is an explanatory diagram showing the bit structure of a global address, Fig. 3 is an explanatory diagram showing the responsibility sharing level in the transmission method, Fig. 4 is a frame configuration diagram showing the transmission format of the HD LC method, and Fig. 5 is an explanatory diagram showing the transmission format of the HD LC method. HD L when transmission failure occurs
Time chart showing the transmission form using C method, Fig. 6 (
+L) to (f,) are time charts for explaining each frame transmission state in the conventional example, and FIGS. 7(a) to (f) are time charts for explaining each frame transmission state when the present invention is applied. This is a time chart. Fig. 1 (C) BO 艷j ノ下 te opening 1 spring - Meni Q actual license sequence zz of poor name
Lnafrona Y-) Figure 2 Propal address 0 bi-nod scheme fX, circle head) 7
I Figure 4 Frame Saiseizu Circle H Engetsu Do 4

Claims (1)

[Claims] (1) Time information is transmitted from the control center to the controlled station, or from the central control center to the controlled station via the control center, in accordance with a high-level data link control procedure that has a function to retransmit information in the event of a transmission failure. In the time information transmission method, the transmitting side is provided with an information determining means for determining whether or not the transmitted information is time information, and the receiving side is provided with an information determination means for determining whether or not the transmitted information is time information, and a time execution signal is input to the receiving side after the time advance signal is input. elapsed time determining means for monitoring the elapsed time until the time elapsed and determining whether or not the elapsed time is equal to the set time, and when the information determining means determines that the transmitted information is time information, A time information transmission system, characterized in that retransmission of time information is prohibited, and when the elapsed time determining means determines that the elapsed time is not equal to a set time, it is not treated as time information.