JPH045300B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a system of multiple signal transmission lines that are divided and provided between information devices such as a central processing unit and a terminal device, a control device and a controlled device, etc. The present invention relates to a line control system, and particularly relates to a signal transmission line control system suitable for automatically switching line systems to ensure normal signal transmission when a line failure occurs.

[Background of the invention]

Such signal transmission lines are applied to various information devices, and here, as a specific example, one applied to a remote monitoring and control device will be explained.

A remote monitoring and control device monitors the status of controlled equipment installed at a location away from the control center equipment (hereinafter referred to as the master station) at the master station, and also monitors the status of the controlled equipment installed at a location away from the control center equipment (hereinafter referred to as the slave station). It has the function of giving control commands via the In addition, in many cases, slave stations are also provided with control functions so that they can perform some degree of control without having to individually issue control commands from the master station. In such a case, control commands are given between slave stations having related devices to be controlled while exchanging information such as interlock signals with each other by means of communication functions between the slave stations.

The above-mentioned remote monitoring and control device is generally formed by providing one master station for multiple slave stations, but if the system scale is large, the slave stations may be grouped into multiple groups as shown in Figure 1. The system is divided and a master station is installed for each group.

In FIG. 1, CC ₁ to _{CC 3} are master station devices installed in the master station, and SS ₁ to _{SS 10} are slave station devices installed in each slave station. The slave stations SS ₁ to SS ₁₀ are divided into three groups (group A to group C) corresponding to the master stations CC ₁ to CC ₃ , and each has an independent loop-shaped transmission line 1A, 1.
B, 1C.

The master station CC ₁ is connected to the slave station SS ₁ as shown in Fig. 2.
are each configured as shown in FIG. 3, and the other master stations CC ₂ and CC ₃ and slave stations SS ₂ to _{SS 10} also have the same configuration. In the master station CC ₁ , 2 is a supervisory control console having a man-machine function, which displays the status of the equipment to be controlled by the slave station or the presence or absence of a failure. It also has the function of generating control operation signals for devices using switches and the like. Reference numeral 3 denotes a control console coupling unit, which has the function of driving lamps, indicators, etc. on the control console 2 and encoding contact signals of switches output from the control console 2. Reference numeral 4 denotes a transmission control section, which has a transmitting/receiving function of converting a serial signal from the transmission path 1A into parallel signals or converting an equipment control signal from the desk coupling section 3 into a serial signal and sending it out. 5 is a modem device.

In the slave station SS ₁ shown in FIG. 3, 7 is a modem device, 8 is a transmission control section, and 9 is a switchboard coupling section.
This arrangement board coupling section 9 is a coupling circuit for outputting control signals to the controlled equipment 10 and for receiving status display signals, failure signals, and the like. 6 is a line switching unit, which has the function of switching the line according to the relay mode state like SS ₂ shown in FIG. 1 and the terminal mode state like SS ₃ , and the function of outputting a diagnostic signal when a line fault occurs. etc. The slave stations (SS ₃ and SS ₈ in the example shown in FIG. 1) in the terminal mode state have adjacent independent transmission lines 1A and 1B, 1B and 1
C is connected, and can be physically connected or disconnected by the line switching unit 6. Normally, a slave station in terminal mode is logically opposed to the master station via the transmission line of the group to which it belongs, and is designed to monitor adjacent transmission lines for abnormalities. It's getting old. When an abnormality such as line breakage occurs somewhere on the loop-shaped transmission path, the line switching unit 6 switches the line and puts the slave stations on both sides of the faulty section into terminal mode, essentially expanding or contracting the loop-shaped transmission path. At the same time, the transmission line system is switched, thereby maintaining communication between the master station and the slave stations. In other words, as shown in Figure 4,
If a line disconnection occurs between SS ₄ and SS ₅ ,
The line system is reconfigured as shown in b and c, and SS ₄ is
Built into the transmission line connected to CC ₁ . That is, SS ₄ and SS ₅ transition from relay mode to terminal mode operation state, and SS ₃ transitions from terminal mode to relay mode, so that even if SS ₄ is disconnected from the transmission path of CC ₂ , CC ₁ transmission line extends to SS ₄ ,
The grid is reconfigured to connect to CC ₁ . When such automatic system reconfiguration is performed, for example, in SS ₄ in FIG. 4, the opposing master station is switched from CC ₂ to CC ₁ .

Information communication between the master station and the slave stations is carried out using transmission codes as shown in FIG. In other words, a synchronizing signal with a specific code SYC (empty car) indicating a line empty state as shown in FIG. 5a usually circulates on the transmission path. The master station or slave station making the transmission request receives the circulating line vacancy status code SYC (vacant) and then sends information starting with the line occupancy status code SYC (full) as shown in Figure 5b. Communicate. Figure 5b
In, F is a transmission control code indicating the type of transmission control procedure, FR is a transmitting station code, TO is a receiving station code,
I is a message code and contains information such as device display and control contents. Also, P is an error control parity bit.

As a transmission control procedure, a reply verification method as shown in FIG. 6 and a double transmission method as shown in FIG. 7 are generally used. Note that the symbol R in these figures represents a received signal, and the symbol S represents a transmitted signal.
The reply verification method is used for normal equipment control or display communication, and as shown in Figure 6, the transmitting station (CC ₁ in this case) transmits the selection code S as the transmission signal S at t ₁ , The slave station (SS ₂ in this case) specified by the receiving station code transmits the reply code. The transmitting station cross-checks the selection code C with the reply code H at t ₃ , returns the command code S at t ₄ , sends and receives the command code S at t ₅ , and returns to the line empty state at t ₆ . Sends the code SYC (empty car) and ends the transmission. On the other hand, the receiving station SS ₂ compares and confirms the selection code CE and the command code SI, and ends the reception. In this manner, in the reply verification method, information communication is completed when the transmitting and receiving stations in the loop transmission line respond to each other.

Next, in the double transmission system, as shown in Figure 7, the transmitting station (in this case, SS ₂ ) transmits the selection code S at t ₇ , and after transmitting and receiving this code S at t ₃ , continue
At _t9 , the command code shi is sent and the transmission is completed. In this case, each slave station in the loop transmission path completes reception by checking the selected code C and the command code C without making any response such as a reply code.

During such a transmission control procedure, a line failure as shown in Figure 4 occurs, causing a failure in the transmission line 1A of CC ₁ .
When CC ₂ 's slave station SS ₄ is incorporated, the problem is how CC ₁ can confirm this fact and continue to communicate information to SS ₄ . For example, if a display or operation switch for monitoring and controlling SS ₄ is not provided on the control console 2 of the master station CC ₁ , the control console 2 of CC ₁ will not be able to monitor and control it even if it is incorporated. Therefore, each of the master stations CC ₁ , CC ₂ , and CC ₃ must necessarily provide redundant displays, etc. for the slave stations of the adjacent group on their respective monitoring and control desks. Moreover, these monitoring and control functions for systems other than the own group are not necessary when the transmission line is normal, and these functions must be activated only when a slave station from another group is incorporated due to a line failure. Must be. This increases and complicates the configurations of the console connection unit 3 and the control console 2 of the master station, and includes display devices and control switches that are normally unnecessary. This has the disadvantage that it becomes complicated and may lead to erroneous operations.

Furthermore, as shown in Figure 4, if a failure occurs in the transmission line between SS ₄ and SS ₅ , the transmission line between groups A and B will be cut off, so that the slave stations of group A and other groups may The disadvantage is that communication between slave stations becomes impossible.

[Purpose of the invention]

An object of the present invention is to enable each slave station to communicate with its original master station in the event of a failure in the transmission line, and to ensure the communication function between arbitrary slave stations. The purpose of this invention is to provide a signal transmission line control system.

[Summary of the invention]

The present invention provides a line switching means in which a plurality of slave stations each have two sets of receiving and transmitting signal terminals, and the connection of these two sets of signal terminals is switched to switch the own station to either a relay station or a terminal station. The two sets of signal ends of each slave station are systematically connected to the signal ends of adjacent slave stations on both sides to form a loop-shaped transmission path having an outgoing path and a return path, and the transmission path The plurality of slave stations are divided into a plurality of slave station groups according to The slave station on one side, which is inserted into the loop of the transmission line in the section to which it belongs and located at the boundary between the slave station groups on the transmission line, switches the line switching means to connect the terminal stations of the slave station groups on both sides. The other slave stations switch the line switching means to become relay stations for the transmission line to which they are connected, and each master station and each slave station each has a transmission control means, and the transmission control means Therefore, it transmits and receives signals with the master station or slave station of the slave station group to which it belongs, and also transmits signals with the slave stations of other slave station groups via the transmission control means of the terminal station. In a signal transmission line control system configured to perform transmission and reception, the respective master stations are interconnected by a common bus, and each master station mutually transmits and receives signals via the common bus and belongs to a different slave station group. It has a function of transmitting and receiving signals between slave stations, and provides system connections to the master station and the slave stations, including the arrangement of each slave station on the transmission path and the connection status of each master station and each slave station group. A management table for recording the status is provided, and each slave station is provided with a failure detection means for detecting a line failure in the transmission line section with the adjacent slave station, and the slave stations on both sides of the section where the line failure has occurred are to the terminal station, and reports this to the other slave stations belonging to the transmission path connected to the own station and the master station, and among the slave stations that received this report, the transmission is normal from the perspective of the reporting slave station. A terminal station that belongs to the roadside and is interposed between itself and the master station on the transmission path switches itself to a relay station and communicates this fact to other slave stations that belong to the transmission path connected to it. Each master station and each slave station that received these reports modify the contents of the management table according to the change in the grid connection status,
Each master station and each terminal station refer to the corrected management table to recognize the line fault location and the change in the system connection state, and communicate information to different slave station groups via the common bus and the transmission path. By having a configuration that transmits and receives signals between the master station and the slave station,
Even if a failure occurs in the transmission line, each slave station can communicate with its original master station, and the aim is to ensure communication functions between arbitrary slave stations.

[Embodiments of the invention]

Hereinafter, the present invention will be explained based on examples.

FIG. 8 shows the overall system configuration of an embodiment of the present invention. The difference _in this figure from the conventional example shown in _FIG . Master stations CC ₁ to _{CC 3} are the 9th
As shown in the figure, the control console coupling section 3 and the transmission control section 4
It is connected to a common bus 12 via a common bus coupling unit 11 connected to a common bus 12 . The master stations CC ₁ to _{CC 3} and the slave stations SS ₁ to _{SS 10} (hereinafter, both the master station and the slave stations are referred to as posts) are equipped with a management table whose contents can be used to recognize the grid connection status, as necessary. It is being That is, the master stations CC ₁ to _{CC 3} are shown in Fig. 10 a to d.
A post arrangement definition table, a post management table, _a terminal post management table, and a CC post management table are provided as shown in _FIG . is provided.

The post arrangement definition table defines how each post is arranged, as shown in FIG. 10a. In accordance with the arrangement shown in FIG. 8, post numbers are assigned to each post in order from the left side in the figure, and the posts are stored in table addresses 0 to 12 in the order of arrangement. With this table, it is possible to recognize a post placed on the left or right side of the own post. For example, the post located to the left of post No. 4 of table address 3 is the post indicated by table address 2, 1, 0.
No. 1 to No. 3, and the post with table address 3
Posts placed to the right of No. 4 are posts No. 5 to No. 13 indicated by table address 4 and later.
It is.

As shown in Figure 10b, the post management table stores information for managing which transmission line loop each post belongs to, and is used to manage terminals of master stations CC ₁ to CC ₃ and slave stations. This table is required at the station (terminal post). That is, from the perspective of the post provided with the post management table, the affiliation classification data x indicates whether other posts belong to the own transmission loop, to the left loop, or to the right loop. ₁ , x ₂ , and x ₃ are stored in correspondence with each post number. The data in the corresponding category is recorded as "1", and the others are recorded as "0". For example, the post management table provided in CC ₁ in the grid connection state shown in FIG.
The contents are as shown in Figure 1a. In other words, the posts belonging to the self-loop are CC ₁ , SS ₁ to SS ₃ , and the posts belonging to the right-hand loop are CC ₂ , SS _3.
~SS ₈ indicates that there are no posts belonging to the left loop. in the same way
The contents of the post management tables provided in SS ₃ , SS ₈ and CC ₂ are as shown in FIGS. 11b to 11d, respectively.

The terminal post management table is a table managed by each master station, and, as shown in FIG. 10c, is a management table for recognizing the line status on the opposite side of the terminal post belonging to its own loop. Table address 0 has the terminal post number on the left side of the self-loop.
Address 1 contains data x ₄ indicating the line status on the opposite side of that post, address 3 contains the terminal post number on the right side of the self-loop, and address 4 contains data x ₄ indicating the line status on the opposite side of that post. are stored respectively. Data x ₄ is “0” when the line is normal,
When an abnormality occurs, it is recorded as "1". For example, the terminal post management table provided in the master station CC ₁ in the grid connection state shown in FIG. 8 has the contents shown in FIG. 12a. In other words, since the terminal post on the left side of the self-loop does not exist, the contents of table addresses 0 and 1 are both "0", address 3 has the post number of SS ₃ , and address 4 has the opposite of SS ₃ . The line status on the side, that is, on the right side in FIG. 8, is stored. Similarly, the terminal post management table provided in the master station _CC2 has the contents shown in FIG. 12b.

The CC post management table defines how each master station CC ₁ to _{CC 3} is arranged.
As shown in FIG. 10d, the post number of each CC post is stored in table addresses 0 to 2 sequentially from the left side in accordance with the layout shown in FIG.

Regarding the operation of the embodiment configured in this way,
This will be explained below.

The system connection state of the signal transmission circuit shown in Fig. 8 is as follows:
It is recorded in each management table, and each master station
CC ₁ to CC ₃ and slave stations SS ₁ to _{SS 10} transmit and receive signals while referring to the management table as necessary. For example, when there is inter-station transmission information to be sent from SS ₅ of group B to SS ₂ of group A, transmission path 1A,
If there is no abnormality in 1B and _each post in the system, the dotted line shown in the figure is
Information is directly transmitted and received between the slave stations via the route _C1 . Now, if a line failure occurs at point P in the figure, it will no longer be possible to send and receive information through the above-mentioned route _C1 . In such a case, posts SS ₄ and SS ₅ on both sides of the line failure point will detect this and
Switch your post to terminal mode and use SS ₃
Report to that effect. As a result, SS ₃ switches from terminal mode to relay mode, and slave station SS ₄ is incorporated into transmission loop 1A. As a result, the connection state of the system becomes as shown in FIG. The contents of the management table included in each post are changed according to the changes in these system connections. Therefore, the signal transmission between SS ₂ and SS ₅ is as shown in the dotted line in Figure 8.
The path shown in C ₂ , i.e. SS ₅ → transmission loop 1B → CC ₂
→Common bus 12→CC ₁ →Transmission loop 1A→SS ₂ ,
This is made possible by Similarly, SS ₄
Information such as the status display of the controlled equipment sent from the control device is transmitted via the route shown by the dotted line _B2 in the case of a line failure, instead of the normal route (dotted line _B1 shown in Figure 8), and the information sent from the This allows it to be displayed on the monitoring and control desk of CC ₂ , the master station.

As mentioned above, the signal transmission lines of multiple systems are formed so that they can be connected to each other, and the signal transmission lines are formed so that they can be cut at any position, and the signal transmission lines are formed so that they can be disconnected at any position. We are trying to reorganize the transmission line. However, if the reorganization is not performed correctly, or if the signal transmission line is duplicated during normal operation, the same information will be transmitted through two routes, resulting in duplicate information or double reception. This may occur and cause problems. Therefore,
Signal transmission control must be executed correctly according to the connection status of the system. This signal transmission control is performed based on the contents of each management table by the transmission control units 4 (Fig. 2) and 8 (Fig. 3) of each post.
It is now being carried out by Therefore, the contents of the aforementioned management table must be changed to match the current transmission line system.

Here, the procedure for modifying the contents of the management table is explained in the 15th step.
This will be explained along the flowcharts shown in FIGS. Note that the correction factor is a line failure that occurred at point P shown in FIG. When the posts of SS ₄ and SS ₅ detect a line failure, the operations a in FIG. 15 and a in FIG. 16 are executed, respectively. SS ₄ post is step 1
At step 01, the relay mode is switched to the terminal mode, and at step 102, a mode report "mode change detected, line abnormality detected" is transmitted. In the SS ₃ post that received the terminal mode switching report from the SS ₄ post, the 15th
The operations in Figure b are performed. That is, in step 112, the contents of the data x ₁ , x ₂ , x ₃ of the post management table provided in the own post are all set to "0". Then, in step 113, the own post is switched from the terminal mode to the relay mode, and in step 114, a mode report "Mode changed, line normal" is transmitted to the transmission path to which the own post is connected. Based on the mode report sent from SS ₃ post, SS ₁ and SS ₂ , and SS ₄ ,
Each post of CC ₁ is shown in Figure 15 c, d, e, respectively.
Perform the processing shown in That is, when posts SS ₁ and SS ₂ receive a mode report of "mode change" in step 121, their own post sends a mode report with "mode change not changed, line normal" to the other post in step 122. Send to. In the post SS ₄ , after switching the post to the terminal mode in step 101 and transmitting a mode report in step 102, the post management table is modified in step 300.

The procedure for correcting the management table of a post which is in normal relay mode and temporarily becomes terminal mode when a line abnormality occurs is shown in FIG. That is, in step 301, when the device shifts to temporary terminal mode, in step 302, classification data x ₁ , x ₂ ,
Clear x ₃ to "0", and in step 303, modify classification data x ₁ of the management table owned by the user to "1" for the post number of the sending post of the mode report received from then on. .

Thereby, the temporary terminal mode post can register the names of posts belonging to the loop to which it belongs as a table.

Returning to FIG. 15e, in step 141, CC ₁ adds its own post number to the mode report reception data as a release source code, and releases it to the common bus 12. Then, in step 400, the following post management is performed. The table is corrected.

FIG. 18 shows the procedure for modifying the post management table performed by the CC when the loop to which it belongs expands. That is, in step 401, when a mode report of "switching to relay mode" is received from the post which is in the normal terminal mode, in step 402,
For the post number that sent the mode report, the classification data x ₁ , x ₂ , x ₃ of the post management table,
For mode reports set to 1, 0, and 0 and received thereafter, in step 403, the classification data x ₁ of the post management table is corrected to 1 for the post number of the sending post of each mode report.
If there is a terminal mode report among the received mode reports, in step 404, the post placement definition table (Fig. 10a) is referred to to determine whether the sending post of the report is a post on the left side or a post on the right side. If the post is on the left side, step 40
5, the post number and the line status on the opposite side are registered in table addresses 0 and 1 of the terminal post management table, respectively.Similarly, if the post is on the right side, the terminal post management is performed in step 406. Register in table addresses 2 and 3 of the table.

On the other hand, each post belonging to transmission loop 1B also
The management table is modified in the same manner as the posting in the corresponding mode of the transmission loop 1A described above. That is,
As shown in Figure 16a, the SS ₅ post is in step 1.
The relay mode is switched to the terminal mode in step 51, and a mode report is transmitted in step 152, similar to SS ₄ . Upon receiving this mode report, CC ₂ , SS ₅
and SS ₈ , and the posts SS ₆ and SS ₇ , respectively, in steps 161 and 5, as shown in Figure 16b, c, and d.
00, process 300, and processes 171 and 172 to process the management table.

Here, step 5 for CC ₂ to modify the management table
00 is performed according to the procedure shown in FIG. 19, and the procedure 300 in which SS ₅ and SS ₈ modify the management table is performed according to the procedure shown in FIG. 17.

Figure 19 shows the post management table modification procedure when the loop to which the CC belongs is shortened.When a mode report of "terminal mode switching" is received in step 501, the mode report is sent in step 502. It is determined whether or not the posted post is placed on the left side with respect to the own post by referring to the post placement definition table. If it is located on the left side, the process moves to step 503, and for each post number from the beginning of the post arrangement definition table to the table address where the post number of the post that sent the mode report is stored. , set the contents of data x ₁ in the post management table to “0”.
Next, in step 504, the post number and line status of the mode report transmission post are registered in table addresses 0 and 1 of the terminal post management table, respectively, as shown in FIG. 13a. Continued to step 505
In step 506, a mode report with the content "No mode change, line normal" is sent, and in step 506, the content of data x ₁ in the post management table is set to "1" for the post number of the mode report sending post. Fix it. On the other hand, if it is determined in step 502 that the mode report transmission post is on the right side, the process moves to step 507,
Refer to the post placement definition table and set the post management table data x ₁ for the post with the post number stored after the table address where the post number of the mode report originating post is stored. Correct the contents to “0”. Next step 5
In step 08, the post number and line status of the mode report transmission post are registered in table addresses 2 and 3 of the terminal post management table as shown in FIG. This completes the modification of the post management table.

In addition, each post of CC ₁ to CC ₃ is connected to the common bus 12.
Upon receiving the mode report data sent via , the management table is modified according to the procedure shown in FIG. First, in step 181, it is determined whether the source code of the mode report data is a post adjacent to the own post (left or right side) by referring to the CC post arrangement table. If it is an adjacent post, the process moves to step 182, and in the post management table, the classification data x ₂ or x Correct the contents of ₃ .

Here, the time relationship of the above-mentioned post management table correction operation will be explained using the system related to the transmission path 1A as an example. First, post SS ₄ , which has switched from relay mode to terminal mode, performs the process shown in Figure 15a, sends a mode report, and then executes the process shown in Figure 15D, which includes the process shown in Figure 17. Ru. On the other hand, the post that received the mode report from post SS ₄
Figure 15c for SS ₃ and posts SS ₁ and SS ₂ , respectively.
processing is executed, and a mode report is sent for each. When the mode report from each post SS ₁ to _{SS 4} is received by the master station post CC ₁ , the master station post CC ₁ executes the process shown in FIG. 15e including the process shown in FIG. Modify the contents of the post management table for posts belonging to . Then, based on the mode report reception data released in step 141 of this process, other master station post CCs execute the process shown in FIG. 20 and modify the contents of the post management table for posts belonging to other loops. .

By modifying the management table in this way, for example, the post management tables provided in CC ₁ , SS ₃ , SS ₈ , CC ₂ , and SS ₅ can be changed to the second one.
Modified as shown in Figures 1a-e. In addition, the changes in the content before and after the correction are indicated with arrows at the parts to be corrected.

Next, in a state where the transmission line system has been reorganized due to the line fault as described above, information transmission between slave stations sandwiching the line fault will be explained with reference to Figs. 22 and 23 a to c. explain.

Figure 22 shows that if communication occurs between slave stations from SS ₆ to post SS ₃ while a line failure continues to occur between posts SS ₄ and SS ₅ , the slave station will be contacted via the dotted line A ₂ in the figure. This indicates that an interim communication will take place. That is, in the case of the normal system configuration shown in FIG. 8, the post of SS ₃ can directly receive communication information between slave stations of the post of SS ₆ . However, if a line failure occurs at point P, it becomes necessary to communicate between slave stations via different transmission path loops.

In other words, in Fig. 22, all contents of the post management table provided in the terminal post of SS ₅ are cleared to "0" when the own station shifts to terminal mode, and then it is set to normal line mode. "1" is set only for posts that have been reported. Therefore, since there is no mode report from the left loop where the line abnormality exists, all data x ₂ including SS ₃ should be "0". As a result, SS ₅ can recognize that it cannot send and receive signals on behalf of SS ₃ via its own station. It can be similarly recognized in SS ₄ . In other words, each terminal station can distinguish whether there is a line abnormality in its left or right loop using the post management table, and only for posts for which "1" is set in the left or right loop classification. ,
It is designed to perform proxy reception and transmission.

In this case, the posts CC ₂ , SS ₅ and SS ₈ are
When the selection code SE transmitted from the post of SS ₆ is received, whether the post of the receiving station code TO of the selection code belongs to the own loop or to the left and right loops is determined as shown in steps 201 and 202 in Fig. 23a. The determination is made based on the post management table. In this example, both the posts SS ₅ and SS ₈ and the post SS ₃ are determined not to belong to the own loop or to the adjacent loop (left or right), so interception is not performed. On the other hand, CC ₂ is the step 21 in Figure 23b.
1, 212, and 213, it is determined that the post of the receiving station code belongs to the left loop, and it is determined from the terminal post table that there is a line abnormality in the left line of SS ₅ . This results in
CC ₂ 's post receives inter-slave communication information from SS ₆ 's post in step 214, and then receives it in step 21.
5, the proxy reception data is released onto the common bus 12. The CC ₁ and CC ₃ posts that have received inter-slave station contact information from the common bus 12 determine in step 221 whether the post with the receiving station code belongs to their own loop, as shown in FIG. If the message does not belong to the loop, proxy transmission is not performed. In this example, it is determined that the post of CC ₁ belongs to the own loop, and proxy transmission is performed in step 222. In this way, information can be sent and received between the slave stations with the line failure point P in between.

〔Effect of the invention〕

As explained above, according to the present invention, even if a line failure occurs in a signal transmission line divided into multiple systems, each slave station can send and receive information to and from the original master station. This has the advantage of being able to secure a signal transmission line between any slave stations, thereby improving the reliability and operation rate of signal transmission and preventing erroneous operations.

[Brief explanation of drawings]

FIG. 1 is a system configuration diagram of a conventional remote monitoring and control device, FIG. 2 is a configuration diagram of a conventional master station device, FIG. 3 is a configuration diagram of a conventional slave station device, and FIGS. 4 a to c 5 is a diagram illustrating a line configuration change method when a line failure occurs in a conventional remote monitoring and control device, FIGS. time chart,
FIG. 7 is a time chart illustrating a transmission control procedure using the two-way transmission method, and FIG. 8 is an overall system configuration diagram of a remote monitoring and control device according to an embodiment of the present invention.
FIG. 9 is a configuration diagram of the master station device of the embodiment shown in FIG.
Figures 10 a to d are configuration diagrams of various management tables of the embodiment, Figures 11 a to d, Figures 12 a and b, and
Figures 3a and 3b are example diagrams showing the specific contents of the management table, Figure 14 is a system configuration diagram of the remote monitoring and control equipment reorganized after a line failure occurred, and Figures 15a to 15e and 15e are diagrams. Figures 16a-d, Figure 17, 1st
8, FIG. 19, and FIG. 20 are flowcharts for explaining the procedure for modifying the management table in each post, and FIGS. 21 a to e are diagrams showing specific examples of post management tables modified due to the occurrence of line failures. , FIG. 22, and FIGS. 23 a to 23 c are a system configuration diagram and a flowchart for explaining the communication function between slave stations when a line failure occurs. CC ₁ ~ CC ₃ ... Master station device, 1A, 1B, 1C...
...Transmission path, SS ₁ to SS ₂ ... Slave station device, 2 ... Monitoring control console, 3 ... Table coupling section, 4, 8 ... Transmission control section, 5, 7 ... Modulation and demodulation device, 6 ... Line switching section,
11...Common bus coupling section, 12...Common bus.

Claims (1)

[Claims] 1. A plurality of slave stations each have two sets of receiving and transmitting signal terminals, and include a line switching means that switches the connection of the two sets of signal terminals to switch the own station to either a relay station or a terminal station. The two sets of signal ends of each slave station are systematically connected to the signal ends of the adjacent slave stations on both sides to form a loop-shaped transmission line having an outgoing path and a return path, and a loop-shaped transmission path is formed along the transmission path. The plurality of slave stations are divided into a plurality of slave station groups, a plurality of master stations are provided corresponding to each of the slave station groups, and the input and output signal terminals of the master stations are connected to the section to which the corresponding slave station group belongs. A slave station on one side inserted into the loop of the transmission line and located at a boundary between the slave station groups on the transmission line is made a terminal station for the slave station groups on both sides by switching the line switching means, The other slave stations switch the line switching means to become relay stations for the transmission line to which they are connected, and each master station and each slave station each have a transmission control means, and the transmission control means allows the other slave stations to Sends and receives signals with a master station or a slave station of a slave station group to which the station belongs, and also transmits and receives signals with slave stations of other slave station groups via the transmission control means of the terminal station. In the signal transmission line control method of the configuration, the respective master stations are interconnected by a common bus, and each master station transmits and receives signals to and from each other via the common bus, and also transmits and receives signals between slave stations belonging to different slave station groups. The system shall have a function of transmitting and receiving signals on behalf of the master station and the slave station, and record the system connection status including the arrangement of each slave station on the transmission path and the connection status of each master station and each slave station group, respectively. a management table is provided for each slave station, and a failure detection means is provided for detecting a line failure in a transmission line section between the slave station and an adjacent slave station;
The slave stations on both sides of the section where the line failure has occurred each switch themselves to terminal stations, and report this to the other slave stations and the master station that belong to the transmission path connected to their own station.
Among the slave stations that received this report, the terminal station that belongs to the normal transmission line side from the perspective of the reporting slave station and that is interposed between itself and the master station on that transmission line switches itself to a relay station, This is reported to other slave stations and the master station belonging to the transmission path connected to the own station, and each master station and each slave station that receive these reports update the management table in accordance with the change in the system connection status. The contents are corrected, and each master station and each terminal station refer to the corrected management table to recognize the line fault location and the change in the system connection state, and transmit the data via the common bus and the transmission path.
A signal line control system characterized by having a configuration in which signal transmission and reception between a master station or a slave station belonging to different slave station groups is performed on behalf of the master station or slave stations.