JP2003152749A - Remote monitor/control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a remote monitor/control system that can reduce a contact interrupt time on the occurrence of a line fault. SOLUTION: On the occurrence of the fault, a master station ML interrupts a usual contact. The master station ML repeats the usual contact to discriminate whether the interruption results from an instantaneous fault or a consecutive fault, slave stations receiving no contact repetitively inject a fault searching signal on the condition of 'no received signal for a prescribed time or over'. The master station ML repeats the usual contact. On the other hand, the slave stations other than the 1 system of the slave station S3 receives the fault searching signal and stop the injection of the fault searching signal when the fault searching signal injection condition is lost. The master station ML receives the fault searching signal injected from the 1 system of the slave station S3. In this state, the occurrence of the consecutive fault and the position of the consecutive fault are detected when the master station ML receives the fault searching signal of only the 1 system of the slave station S3 for the number of specified times.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a remote monitoring and control system in which a transmission line has a loop shape, and an SDLC (Synchr.
The present invention relates to a remote monitoring control method using an onous data link control method. 2. Description of the Related Art Two remote control systems, a polling system and a token ring system, are currently used in a remote monitoring control system in which a transmission line is looped. The polling method collects data by calling (polling) the slave stations in order from the master station. The token ring method circulates a speech permission signal (token) in a loop, and the communication signal generation station arrives at the token. It is something to send when. The polling method and the token ring method each have characteristics. Here, the difference between the two systems will be described with reference to the drawings. FIGS. 16 and 17 show the line configuration and signal flow of the polling system and the token ring system when the master station has three sets, that is, three sets of three loop lines. It is a schematic block diagram. M1, M2, M3 is the master station, in S1 ₁ to Sn ₃ is the slave station, the master station M1 in the case of the polling method of Fig. 16, M
2, the M3, when the main system M1 _S, M2 _S, M3 slave station S1 ₁ to Sn ₃ in a direction indicated by an arrow from _S, slave station with a status change poll in turn that he polled, master station Contact Note that M1 _J , M2 _J , and M3 _J are the main system M
It is a slave to act in the event of a failure of the _{1 S, M2 S, M3 S} . For this reason, in the case of the polling method, the time required for the polling signal to make a maximum of eight rounds of the loop line is the communication start waiting time for a group of eight slave stations. That is, when there is only a change in the state of one slave station, useless polling is performed up to seven times. In the case of the token ring system shown in FIG. 17, a token is circulated between the master station and the slave station for each loop line. The station contacts the master station when the token signal arrives. Therefore, the communication start waiting time may be at most one loop time. [0005] From the above, the token ring system is better in terms of the communication start waiting time. However, when a state change occurs in many slave stations, useless polling is reduced and the difference is reduced. Fig. 18 and Fig. 2
0 and FIGS. 19, 21A and 21B.
18 and 19 respectively for polling scheme and token ring method the line configuration when a fault (illustrated × mark) is generated between the slave station S1 ₂ and S2 ₂ of 2 groups, 20, 21 a master station The line configuration when a failure occurs in M1 and M3 is shown for the polling method and the token ring method, respectively. As shown in FIGS. 16, 17, and 21, the "token ring system" is referred to here for convenience.
There are two common points and one point different from the general token ring system. The first common point is that the above-mentioned talk permission signal (token) is circulated, and the second common point is that the stations adjacent to the line failure (both the master station and the slave station) change the line configuration and the failure occurs. part is removed (slave station S1 ₂ of FIG. 17 → FIG 19, S2 _2,
S1 _1, Sn ₃ in FIG. 21). This is called loopback. [0008] The difference is the belonging movement of the slave station. Figure 17 →
19, the slave station S1 ₂ is to the master station M2 → master station M1,
In Figure 17 → 21, the slave station S1 ₁ to Sn ₁ and S1 ₃ ~
All Sn ₃ belong to the parent station M2. [0009] In the communication interruption time in the case of a line failure in both systems, no change in the line configuration is required in the polling method, and no communication interruption occurs. However, the line configuration needs to be changed in the token ring system, and communication is interrupted during this change period. As a result, the polling method is better in terms of the communication interruption time in the event of a line failure. But,
The frequency of line failures is low. In recent years, the polling method includes HDLC (High Level Data) with high transmission efficiency.
Link Control) is being adopted. [0010] In the loop-like remote monitoring control system, there are two systems, a polling system and a token ring system.
Two transmission control methods are used. Both of these methods have their advantages and disadvantages, but the token ring method has the disadvantage that the communication interruption time in the event of a line failure becomes longer and the handling of the line failure becomes complicated. In addition, the polling method has a problem that transmission efficiency is deteriorated because the number of line input / output units in the master station increases and unnecessary polling is performed for non-corresponding stations. [0011] There is a known "SDLC system" as a system having higher transmission efficiency in a loop line. In the SDLC method, each slave station that has received the information request signal from the master station can sequentially transmit the information if there is transmission information. Therefore, information of all slave stations in the loop can be communicated to the master station in one loop.
The polling method and the token method described above have a great difference as compared with circulating the contact information for each slave station. But,
The SDLC method is good when the line is normal, but when a line failure occurs, the signal circulating function is lost, so that the measures against the line failure are complicated, and it has been difficult to apply it as a remote monitoring control device. SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and provides a remote monitoring control system which achieves the best transmission efficiency, makes it easy to cope with a line failure, and shortens the communication interruption time when a line failure occurs. It is an object to provide a method. According to the present invention, in order to achieve the above object, a plurality of master stations and a number of slave stations are connected by a loop line for each master station. In the remote monitoring control system that maintains the communication function by changing the assignment of the slave station to each loop line, the slave station that does not receive a signal for a certain period of time transmits a fault search signal for the line and searches for a fault from the upstream. The slave station that has received the signal stops transmitting the failure search signal, and recognizes that a continuous failure has occurred in the line when the number of times that the failure search signal arrives at the master station reaches a predetermined number. It is characterized by doing. DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following, embodiments of the present invention will be described with reference to the drawings, first of all, a fault detection method in a remote monitoring control employing the SDLC method will be described. FIG. 1 is a diagram of a circuit configuration in a normal state.
L is a first master station (master station on the left side in the figure), MR is a second master station (master station on the right side in the figure), and S1, S2 to S3, and S10 are slave stations. The first and second master stations ML, MR and each slave station S1,.
S10 is connected to transmission lines, and these transmission lines are composed of system lines L1 and L3 and system lines L2 and L4. Each line is composed of a pair of transmission lines (not shown). The white circle of each slave station mainly has a relay function (transmits a received signal as it is). The black circle of each slave station mainly has a relay function and a communication function with the master station. Main system; children 1 to 4, children 6 to 10 are called relay stations, and child 5 is called a terminal station. In the circuit configuration diagram constructed as shown in FIG. 1, four line failure patterns (faults indicated by crosses in the figure) as shown in FIG. 2 are taken as target failures. FIG.
(1) Case 1 is a target failure in the case of a single failure of the downlink 1 system line L1, and FIG. 2 (2) Case 2 is a target failure in the case of a single failure of the uplink 2 system line. 2 (3) Case 3 is a target failure in the case of a failure in the same upper and lower line section, and FIG. 2 (4) Case 4 is a target failure in the case of a different upper and lower section line failure. When each line failure in FIG. 2 occurs, the information request signal from the master station is cut off at the failure part (marked by x).
(The thick line indicates the signal reaching range). That is, the communication function between parent and child is lost. In order to restore the communication function between the parent and the child, as shown in FIG. 4 according to each line failure, "temporary operation" is performed until the line failure is recovered. FIG.
A dotted line indicates a signal for detecting recovery from a line failure. In switching the line configuration, the following conditions must be satisfied. The first condition is that, in cases 1, 2, and 3, as shown in FIG. 4, monitoring and control of all slave stations (communication function with the master station) are possible, and the second condition is that When a line failure occurs, the transition time from Fig. 3 to Fig. 4 (interruption time between parent and child communication functions)
The third condition is that when the line failure is recovered,
→ Shortening the transition time (interruption time between parent and child communication functions) in FIG. 1, the fourth condition is to know the recovery of the line failure quickly, (for provisional operation, the number of slave stations is large as shown on the right side of FIG. 4). The contact time will be longer, but not interrupted.)
The fifth condition is to simplify the slave station as much as possible (because the slave station is unmanned, the repair time is long when a failure occurs). The details of the second condition “FIG. 3 → FIG. 4” are as follows from both figures. First, it is detected that the fault is not an instantaneous fault but a continuity fault. (Instantaneous failure recovers spontaneously) Next, the failure site is detected. Next, remove the faulty part from the loop line. (Move the right and left slave stations adjacent to the faulty part to the terminal station.) Finally, move the slave station isolated from the master station to the new master station. (Migrating a conventional terminal station to a relay station) The focus is on detecting a failure site. The slave station search method is preferable in that the time for searching for the fault and detecting the fault part is shortened as much as possible, and the slave station search method is also preferable in terms of the line fault recovery detection time. 3A to 3D, the faulty part cannot be determined, so that the transition time from the occurrence of the fault in FIGS. 3A to 3D to the temporary operation in FIGS. In order to expedite the description, in the embodiment of the present invention, several failure detection methods will be described below. This faulty part detection method includes relay ← → terminal transition time, number of searches, simplicity of search,
In consideration of the simplicity of the slave station, the consistency with the SDLC scheme, the communication suspension time, and the like, it is determined whether the master station search method or the slave station search method is used. A slave station search method (test (failure search) signal injection method) according to an embodiment of the present invention will be described below. FIGS. 5A to 5C show the case 1 in FIG. 3A. In FIG. 5A, when a failure occurs, the normal communication from the master station ML is interrupted. This interruption is shown in FIG.
At the master station M
The normal communication is repeated from L, and the non-reception side of the slave station repeatedly injects a test (failure search) signal with "no reception signal for a certain period of time". This failure search signal injection method is also SDL
It is not the C system (the SDLC system adds an additional transmission signal to the end of the reception signal). In FIG. 5C, the normal communication is further repeated from the master station ML. On the other hand, other than the sub-system S3 of the slave station S3 receives the fault search signal from the above and stops the fault search signal injection when the fault search signal injection condition disappears. The primary system injection failure search signal of the slave station S3 arrives at the master station ML. In this state, the failure search signal of only one system of the slave station S3 is received a prescribed number of times, and the occurrence of the continuous failure and the continuous failure part are detected. FIGS. 5D to 5F show cases 2 to 4 shown in FIGS. 3B to 3D, and FIGS.
Is the result of the same processing as in case 1, and the state at the time of detection of the faulty part is described below. FIG. 5D shows the case 2 (single failure of the upstream system 2 line). In this case, the failure unit is detected from the arrival of the test signal of the secondary system of the slave station S2. FIG. 5E shows a case 3 (a failure in the same section in the upper and lower sections). In this case as well, the failure part is detected from the arrival of the test signal of the secondary system of the slave station S2. FIG. 5F shows case 4 (upper and lower section failure).
In this case, the faulty part is detected from the arrival of the test signal of the secondary system of the slave station S3. Note that the test signal of the secondary system of the slave station S3 includes a reception error of the primary system of the slave station S2 (from the test signal of the primary system of the slave station S2). In the case of FIGS. 5C, 5D, and 5E, the continuous failure site can be detected by the "test signal transmission slave station number" and its one or two systems. However, in the case of FIG. 5 (F), it is determined that “slave station S3 ← → slave station S4” by the method. From FIG. 4d, the continuous failure site is “slave station S1 ← → slave station S”.
Since the slave station S3 receives the test of the slave station S2 originating from the system 1 in the system 1, the slave station S3 receives the "system 1 reception error in the slave station S2" in the test signal of the system 2. This allows the parent left ML to transfer the slave station S1 to the terminal.Next, the operation of the slave station search system in the circuit configuration diagram of FIG. In the time chart of Fig. 6, reference numerals 1 and 2 denote the first system line, the second system line, the parent left shows the first master station, the parent right shows the second master station, and the children 1 to 5 Means a slave station, and the number of slave stations is 5. Fig. 6 describes a slave station search method based on a time chart for instantaneous line failure. Since it is the same process as the master station search method described in 6 above, its time chart and explanation Omitted,
The momentary failure time chart will be described. In FIG. 6, the operation of Case 1 is the same as that of the parent station search method, and therefore the description is omitted here.
In the following, the slave station search method will be described. In case 2, when the information request A1 is transmitted to all slave stations, there is no response from all slave stations because the information request frame on the system line between the parent left and the child 1 has a failure. At this time, if the processing of the portion enclosed by the rectangle in the figure is performed and the next information request is normal, it is assumed that the instantaneous failure has been recovered and the operation returns to normal. FIGS. 7 to 9 are time charts in the case of a continuous fault. These time charts are from the detection of a faulty part to the movement of the dividing unit to the normal operation. FIG. 7 (1) shows the information request A1. Is transmitted, when a continuation failure occurs in the 1-system line of the child 1 and the child 2, the response is normal. The next information request A1 is child 1 as shown in FIG.
→ Interruption due to failure of 1-system line of child 2. Thereafter, the information request A1 is repeatedly transmitted from the parent left. Then, the 1st system of the child 2, the 1st system of the child 3, the 2nd system of the child 2, the 2nd system of the child 1, and the parent left are in a state where there is no received signal. The slave station transmits a failure search signal to the line of the relevant system on the condition that “the absence of the received signal has continued for a predetermined time or more”. In the figure, child 2 starts transmission of a failure search signal to the system 1 line, child 3 to the system 1 line, child 2 to the system 2 line, and child 1 to the system 2 line. The transmission of the fault search signal is stopped by receiving the search signal from the upstream except for the system 1 line of the child 2. Then, a failure search signal is transmitted only in the immediate downstream part of the failure part. If the information of "child 2 line 1 transmission" is included in the fault search signal, the parent left receives this signal only a certain number of times or more (only once, it is initially the child 1 line 2 transmission signal). Detects a continuous failure including the failure part. In FIG. 8A, the child 2 is obtained from FIG. 7B.
A failure search signal is transmitted to the first system line to detect a failure between the child 1 and the child 2. Next, for the dividing part moving process of FIG. 8 (2), a child 1 terminal transfer command is issued from the left side of the parent, and the acknowledgment C3 of the child 1 is viewed. Due to the transition of the child 1 to the terminal station, the failure search signal is looped back as shown. Then, the mode report request B
4 is transmitted, and the response D1 is confirmed. After confirmation, the parent left side operates normally, and the parent left side contacts the parent right side. After that, the operation of the parent right-side divided section is as shown in FIG. FIG. 9 is a time chart on the right side of the parent of the moving part. The failure search signal from the primary line of the child 2 is transmitted to the child 3, and the child 3 relay shift command B is sent from the right side of the parent.
3 is transmitted. With this command, the confirmation response C3 of the child 3 is returned to the right side of the parent. On the other hand, the child 2
A failure search signal is transmitted from the first line to the parent right. Further, the terminal shift command B3 of the child 2 is transmitted from the parent right, and the acknowledgment C3 of the child 2 is transmitted to the parent right. By the transfer of the terminal of the child 2, the system 1 line failure search signal of the child 1 is transmitted to the child 1. When the above terminal transfer is completed, a mode report request B4 is transmitted from the parent right, and since there is a mode report response D1 from each slave station, the parent right also thereafter operates normally. FIG. 10 and FIG. 11 are time charts for continuous failure recovery, in which continuous failure recovery is detected from provisional operation.
FIG. 10A is a time chart of provisional operation until the division unit is normalized. The information request A1 is transmitted from the parent left side, and the absence response C2 from the child 1 is received. On the other hand, the information request A1 is also transmitted from the parent right, and the response is received.
Note that a failure search signal for the child 2 and system 1 lines is output between the child 1 and the child 2. This search signal is received by the two systems of the child 1,
Since the terminal is in the terminal station state, the received signal is relayed to the first system line of the loopback unit 2. However, it does not return to child 2 while the failure of the child 1 → child 2 line continues. If the continuous fault is recovered while this signal is being output, the fault search signal 1
The child 2 detects continuous failure recovery in the round. ((2) in FIG. 10)
(Continuous fault recovery) This fault recovery is transmitted to the parent right and the child 2 in response to the information request A1. In the time chart of FIG. 11, the parent right informs the parent left of this fact and performs normalization of the division part. The parent left transmits the relay transfer command B3 of the child 1, and the parent right transmits the child 3 terminal. A transfer command B3 is transmitted. The parent left receives the acknowledgment C3 of the child 1, and the parent right receives the acknowledgment C3 of the child 3. During this time, the child 1 becomes a relay from the terminal, and the child 3 becomes a terminal from the relay. Note that, while the child 2 remains a terminal, the mode report request B4 is transmitted from the parent left and the parent right, and when the response D1 is received, thereafter, the parent right operates normally and the parent right changes from the parent right to the parent left. Contact will be made. On the other hand, on the parent left, the relay shift command B of the child 2
3 is sent and there is an acknowledgment C3 of child 2. During this time, the child 2 becomes a relay from the terminal, and requests the mode report B4 from the parent left.
Is transmitted, and a response D1 is obtained from each slave station, so that the parent left side also operates normally. The slave station search method is processed as shown in the time chart, and a processing flowchart at that time is shown below. FIG. 12 is a flowchart of a failure recovery process.
In step S81, the previous transmission content is retransmitted, and it is determined whether a frame has been received (S82). As a result of the judgment,
If (Y), it is determined that the frame contents match (S
83), and if (Y), instantaneous failure detection is set to “0” (S
84) Terminate the instantaneous failure countermeasure processing (failure recovery succeeded).
If (N) in step S82, it is determined whether the limit on the number of retransmissions has been exceeded (S85). If (Y), continuous failure detection is set to "1" (S87), and the process is terminated. If the determination is (N), the retransmission count process is set to "+1"
Then, the processing is restarted from step S81. In step S83, if (N), it is determined whether there is a fault detection signal from the slave station (S88). If (N), the process proceeds to step S81. (S89), and if (N), step S81
If (Y), the process proceeds to step S87. In the figure, reference numeral * 1 indicates that a failure has occurred between the master station and the nearest upstream child station, and reference numeral * 2 indicates the occurrence of a continuous failure and the location of the failure from the content of the failure detection signal from the child station. In this way, in the slave station search method, unlike the master station search method, a faulty part is identified at the portions indicated by the above-mentioned codes * 1, 2. FIG. 13 is a flowchart of a continuation failure countermeasure process. Step S91 is a division moving process. The details of the division moving process are as shown in FIG.
After performing the terminal transfer command processing from the parent left to the left child station adjacent to the faulty part in 1, the parent left line normalization is confirmed by a mode report request (S72). If the confirmation is obtained, the parent left contacts the parent right (S73). Next, a terminal transfer instruction process is performed from the parent right to the terminal slave station (S74). Also, a terminal transfer instruction process is performed from the parent right to the right child station adjacent to the failed part (S75). After this processing, the normalization of the parent right line is confirmed by the mode report request (S
76). Then, the continuation failure detection process and the provisional operation process are performed (S77), and the process ends. As a result of this processing, in step S92 shown in FIG. 13, “0” is set during continuous failure detection, and “1” is set during temporary operation. FIG. 14 is a flowchart of the master station search method in the slave station. In step S101, it is determined whether the received frame is addressed to the own station. If (Y), it is determined whether the received frame is for failure search ( S102), and if (N), it is determined whether the terminal / relay or terminal-time main system is designated (S103). If the result of this determination is (N), it is determined whether it is a terminal age line transmission request (S104). If (N), it is determined whether an information request has been received (S105). After determining (S106), if (N), it is determined whether a confirmation message has been received (S107), and the other processing (S107)
108), and returns to step S101. If each of the determination units in steps S102 to S107 determines (Y), the processing in steps S109 to S114 is performed, and the processing in step S1 is performed.
The process returns to 01. Steps S101 to S104
Steps S109 to S111 are processing of both the main system and the slave system, and the others are processing of the master station contact person in charge, which is the main system. FIG. 15 is a flowchart of the slave station search method in the slave station. In step S121, it is determined whether a frame has been received. If (Y), in step S122, it is determined whether the frame is addressed to the own station. If the determination result in step S122 is (Y), it is determined in step S123 whether the frame is for failure detection. If the result of this determination is (N), it is determined whether the terminal / relay or terminal-time main system is designated (S124).
The same processing as Steps S105 to S108 of Step 4 is performed. In step S129, it is determined whether a predetermined time has elapsed when it is determined (N) in step S121. If (N), the process returns to step S121. If (Y), the failure search and transmission in step S132 are performed. S12
The process returns to 1. The determination in step S122 is (N)
If so, the determination in step S130 is performed. If (N), the process returns to step S121. If (Y), the process in step S132 is performed. If the determination in step S123 is (Y), failure information update processing (S131) is performed. If the determination in step S124 is (Y), terminal / relay designation reception processing or terminal-time main system designation reception processing (S133) is performed. Processing is step S12
Return to 1. The processing in steps S125 to S127 is performed in the same manner as in FIG. As described above, according to the present invention,
In the remote monitoring control using the SDLC method, it is possible to simplify the handling at the time of a line failure, to shorten the detection time of a failed part, and to shorten the communication interruption time at the time of a line failure.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit configuration diagram in a normal state. FIG. 2 is an explanatory diagram of a failure pattern to be examined. FIG. 3 is an explanatory diagram showing a state when a line failure occurs. FIG. 4 is an explanatory diagram showing a state during provisional operation. FIG. 5 is a circuit diagram showing an embodiment of the present invention. FIG. 6 is an SD illustrating an operation of an instantaneous failure in the slave station search method.
LC time chart. FIG. 7 is an SD explaining an operation of a continuous failure in the slave station search method.
LC time chart. FIG. 8 is an SDL for explaining the operation on the left side of the parent station in the slave station search method.
Time chart of the C system. FIG. 9 is an SDL for explaining the operation on the right side of the parent in the slave station search method.
Time chart of the C system. FIG. 10 is a time chart of the SDLC system for explaining the operation of continuous fault recovery in the slave station search system. FIG. 11 is a time chart of the SDLC method for explaining the operation of normalizing the division unit in the slave station search method. FIG. 12 is a flowchart of a failure recovery process of the slave station search method. FIG. 13 is a flowchart of a continuation failure countermeasure processing in the slave station search method. FIG. 14 is a flowchart of a master station search method in a slave station. FIG. 15 is a flowchart of a slave station search method in a slave station. FIG. 16 is a schematic configuration diagram of a three-group configuration in a polling method. FIG. 17 is a schematic configuration diagram of a three-group configuration in the token ring system. FIG. 18 is a schematic configuration diagram of a polling method corresponding to a line failure. FIG. 19 is a schematic configuration diagram of a line failure response in the token ring system. FIG. 20 is a schematic configuration diagram of a polling method for dealing with a line failure. FIG. 21 is a schematic configuration diagram of a line failure response in the token ring system. FIG. 22 is a flowchart of a division unit moving process in the master station search method. [Description of Signs] ML: Master station left MR: Master station right S1, S2, S3: Child station

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Tetsuo Fujita             Stock Exchange, 2-1-1-17 Osaki, Shinagawa-ku, Tokyo             Inside Shameidensha (72) Inventor Koichi Kawabe             Stock Exchange, 2-1-1-17 Osaki, Shinagawa-ku, Tokyo             Inside Shameidensha F term (reference) 5K031 AA08 AA09 BA03 CA01 CA05                       DA03 DA06 EA04 EB04                 5K048 AA09 BA31 CA02 DA03 DA06                       DC03 EB03 EB08 FA04 FA07                       GA12 GA14 GB05 HA01 HA02

Claims (1)

Claims 1. A plurality of master stations and a number of slave stations are connected by a loop line for each master station, and by changing the assignment of the slave station to each loop line due to a failure in the loop line. In the remote monitoring control system that maintains the communication function, a slave station that has not received a signal for a certain period of time transmits a fault search signal for the relevant line, and a slave station that has received a fault search signal from upstream transmits a fault search signal. A remote monitoring control method for recognizing that a continuous fault has occurred in a line when the fault is stopped and the number of times the fault search signal arrives at the master station reaches a predetermined number.