JPH09107374A - Fault recovery device for monitor control station in loop line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a fault in a master station to be supported. SOLUTION: Slave stations S22 , Sn-12 are arranged to ends of loop lines FD12 , FD22 connecting a master station M2 and the slave stations S22 , Sn-12 . Branch changeover switches SW1a, SW1b are provided to input terminals of the slave stations S22 , Sn-12 , 1st fixed contacts A of the switches SW1a, SW1b are connected to transmission lines FD12 , FD22 and a 2nd fixed contact B is connected to a transmission line FD3. Moving contacts C of the changeover switches SW1a, SW1b are connected to the input terminals of the slave stations S22 , Sn-12 , a hybrid transformer HT is provided to an incoming line FDI3 of a transmission line connecting the master station M3 and the slave station sn3 and the 1st fixed contact A and the moving contact C of the changeover switch SW2 are provided to an outgoing line FD23 . An output terminal of the transformer HT is connected to one terminal of a backup central monitor control installation BKM3 . via an incoming information transmission line FD3 and a 2nd fixed contact B of the changeover switch SW2 is connected to the other terminal of the installation BKM via an outgoing information transmission line FD4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a supervisory control station installed in advance in a place different from a normal supervisory control station when a failure occurs in the supervisory control station in a remote supervisory control system in which a transmission line is looped. The present invention relates to a failure recovery device for a supervisory control station in a loop line, which enables supervisory control by switching monitoring operations.

[0002]

2. Description of the Related Art Two remote transmission control systems, a polling system and a token ring system, are currently used in a remote monitoring and control system in which a transmission line has a loop shape. The polling method collects data by calling (polling) the slave stations in order from the master station, and the token ring method allows a speech permission signal (token) to circulate in a loop and the contact signal generating station when the token arrives. It is something to send.

The polling method and the token ring method each have characteristics. Here, the difference between the two methods will be described with reference to the drawings. In FIGS. 13 and 14, there are shown a line configuration and a signal flow showing a line configuration and a signal flow in the case where the master station is three sets, that is, three sets of loop lines 3 groups. 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. 13, 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 master M
It is a slave to act in the event of a failure of the _{1 S, M2 S, M3 S} . Therefore, in the case of the polling method, the communication start waiting time is a period in which the polling signal makes a maximum of eight rounds of the loop line in a group of eight slave stations. That is, when there is only a status change in one slave station, useless polling is performed up to seven times.

In the case of the token ring system shown in FIG. 14, a master station and a slave station are made to circulate a token for each loop line, and when the token signal circulates the loop line, a child whose state does not change. 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] In view of the above, the token ring method is better in terms of the waiting time for starting communication. However, when a state change occurs in many slave stations, useless polling is reduced and the difference is reduced. Figure 1 and Figure 1 for handling line failures
7 and FIGS. 16 and 18A and B.
FIGS. 15 and 16 show the line configurations for the polling method and the token ring method, respectively, when a failure (marked with X in the figure) occurs between the two groups of slave stations S1 ₂ and S2 ₂ , and FIGS. The line configurations when a failure occurs in the master stations M1 and M3 are shown for the polling method and the token ring method, respectively.

As shown in FIGS. 14, 16, 18A, and 18B, the term "token ring method" is used here for convenience, but the common token ring method has two common points and 1 point.
There are differences in points.

The first common point is to circulate the above-mentioned speech permission signal (token), 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. Parts are removed (slave stations S1 ₂ , S2 ₂ in FIG. 14 → FIG. 16,
18A and 18B, S1 ₁ , Sn ₃ ). This is called loopback.

[0008] The difference is the belonging movement of the slave station. Figure 14 →
In FIG. 16, the slave station S1 ₂ moves from the master station M2 to the master station M1,
14 to 18A and 18B, the slave stations S1 _{1 to} Sn ₁ and S
All 1 _{3 to} Sn ₃ belong to the master station M2 and are moving.

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 the communication interruption does not occur. 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.

However, as a countermeasure against the destruction of the "central monitoring and control equipment on the master station side" due to an earthquake or the like, it has become necessary to install "backup central monitoring and control equipment". At this time, of course, "centralized monitoring and control equipment on the master station side"
It is necessary to provide a sufficient space between the "centralized monitoring and control equipment for backup". For that purpose, it is necessary to enable communication of information with the slave station not only with the "centralized supervisory control equipment on the master station side" but also with the "centralized supervisory control equipment for backup". That is, the transmission line between the slave station and the "centralized supervisory control equipment for backup" must be secured.

[0011]

The backup transmission path is normally the same as that between the working master station and the slave station.
That is, in the case of FIG. 13 and FIG.
There are 3 lines. However, since the backup transmission line is not normally used, the number of transmission lines should be as small as possible. As a method to reduce the backup transmission line,
In the case of the token ring system, FIG.
Central monitoring and control equipment BK for backup as shown in 8B
The transmission line FD connected to M (information is transmitted from the slave station to the equipment BKM is called an up line, and in the opposite case, the line is made up of two lines, and each line is composed of two pairs). However, although the remote monitoring and control method using the token ring method can be configured with a small number of backup transmission lines, the token ring method also has the following problems.

(1) For example, as shown in FIG. 19, there is a case where a backup transmission line needs to be drawn from the slave station Sn ₃ based on geographical conditions. In that case, if a failure occurs in the master stations M1 to M3 due to an earthquake or the like, the above loopback operation is performed when the backup centralized monitoring and control equipment BKM operates, that is, the failed adjacent stations (S2 ₂ , S2 ₃ ) are for loop backup. The centralized monitoring and control equipment BKM has only the slave stations under the control of the master station M2, Sn-1 ₂ and Sn _{2 in} the figure, and there is a problem that the slave stations S1 ₂ and S2 ₂ of the master station M2 cannot configure a loop line. .

(2) In addition, the installation room of the host computer in the centralized supervisory control equipment on the master station side is destroyed and goes down, and the installation room of the transmission controller of the centralized supervisory control equipment on the master station side is not destroyed and operates. In the enabled state, the supervisory control state of the master station disappears and only the transmission function remains. Then, the adjacent slave station determines that the line is normal and the loopback of the slave station is not performed,
The line configuration is not as shown in FIGS. 18A and 18B but remains as shown in FIG. Therefore, there is a problem that the downed slave station under the jurisdiction of the centralized supervisory control facility cannot be controlled.

(3) The backup centralized supervisory control facility and the backup transmission line do not operate during normal times. Therefore, there is a problem in that the backup centralized monitoring and control facility is left unattended in the event of a failure and loses the guarantee that it will operate when necessary.

The present invention has been made in view of the above circumstances, and reduces the number of backup transmission lines and ensures that when a failure occurs in the master station, the backup centralized supervisory control facility ensures the loopback configuration of the slave station. It is an object of the present invention to provide a failure recovery device for a supervisory control station in a loop line that is capable of supporting the failure of the master station by performing the above.

[0016]

The first invention of the present invention is as follows:
A remote monitoring control system in which multiple master stations and multiple slave stations are connected by a loop line for each master station, and communication functions are restored by changing the belonging of slave stations to each loop line due to a failure of the loop line or master station. In the remote monitoring control system, a hybrid coupler is inserted in an upstream line connecting the master station and the slave station, and a changeover switch is provided in the downlink line, and the remote monitoring control system is arranged in an area different from the plurality of master stations. Is used as a backup centralized supervisory control facility, the supervisory control information sent from the output of the hybrid coupler is constantly supplied to the backup centralized supervisory control facility, and the backup centralized supervisory control facility is used as a master station. When a failure occurs in all the master stations other than the above, the changeover switch is operated to connect the downlink line of the backup centralized supervisory control equipment to the slave stations. , A branch changeover switch is provided on at least one of the up line and the down line of the loop line from the one master station, which branch and branch circuits are respectively connected to different slave stations. When all the obstacles occur, the branch changeover switch is operated so that the supervisory control information from the backup centralized supervisory control equipment is transmitted to all the slave stations.

A second aspect of the present invention is characterized in that the changeover switch is operated by remote control.

In a third aspect of the invention, at least two sets of a hybrid coupler provided in an upstream line connecting the master station and the slave station, a changeover switch provided in the downlink line, and a centralized supervisory control facility for backup are provided, each of which is provided. It is characterized in that the group is a centralized supervisory control facility for backup of different master stations.

According to a fourth aspect of the invention, a backup centralized supervisory control facility is connected to one of a large number of slave stations so that the supervisory control information of one master station is always supplied and a fault occurs in the master station. Also, when the transmission control unit of the master station is operating, the carrier sent from the transmission control unit to the slave station is stopped or the carrier is inserted by inserting a switch in the downlink of the loop line. The feature is that it is not supplied to the slave station.

According to a fifth aspect of the present invention, a plurality of monitoring control system groups in a polling system in which a plurality of master stations and a plurality of slave stations are connected by a loop line are provided, and the master station and slave stations are connected to each group. Insert a hybrid coupler in the upstream line,
A switch is provided on the downlink, and the master station of the remote monitoring and control system, which is installed in each area different from the plurality of master stations of each group, is used as the backup centralized monitoring control equipment. Is constantly supplied with the monitoring control information sent from the output of the hybrid coupler, and when the failure occurs in all the master stations other than the backup centralized supervisory control equipment as the master station, the changeover switch is operated. By connecting the downlink of the centralized supervisory control equipment for backup to the slave stations, the centralized supervisory control equipment for backup recovers each group when a failure occurs in each master station. Is.

According to a sixth aspect of the present invention, only one centralized supervisory control facility for backup is provided in one of the supervisory control system groups, and a switching unit is provided between the loop lines of each supervisory control system group.
When a failure occurs in each master station, the switching unit is operated by remote control so that all slave stations in each group are connected, and failure recovery is performed with one centralized supervisory control facility for backup. It is a feature.

A seventh aspect of the present invention is characterized in that at least two centralized supervisory control facilities for backup are provided in one of the supervisory control system groups.

According to an eighth aspect of the present invention, a plurality of supervisory control stations having a plurality of master stations as one group are respectively arranged at distant locations, and these supervisory control stations are provided as one backup central supervisory control facility when a failure occurs. It is characterized by having been backed up.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a first embodiment of the present invention, and the first embodiment is when there are three transmission lines in the token ring system and three branch parts to the master station M2. In FIG. 1, the ends of the loop lines (hereinafter referred to as transmission lines) FD1 ₂ and FD2 ₂ that connect the master station M2 and the slave stations S2 ₂ and Sn-1 ₂ are usually slave stations S2 ₂ and Sn-.
It is arranged in the vicinity where 1 ₂ is installed. So the slave station S2
₂ , branch switch SW1 at the input of Sn-1 ₂
a and SW1b are provided and their switches SW1a and SW1b are provided.
The first fixed contact A is connected to the ends of the transmission lines FD1 ₂ and FD2 ₂ , and the second fixed contact B is connected to the transmission line FD5.
Movable contact C of branch selector switches SW1a and SW1b
Is connected to the input terminals of the slave stations S2 ₂ and Sn-1 ₂ . Master station M3
To the upstream line FD1 ₃ of the transmission line connecting the slave station and the slave station Sn ₃ with a hybrid transformer (hybrid coupler) HT and the downstream line FD2 ₃ to the first fixed contact A of the switch SW2.
And a movable contact C are provided. The output end of the hybrid transformer HT is connected to one end of the backup centralized supervisory control facility BKM _S via the upstream information transmission line FD3, and the second fixed contact B of the changeover switch SW2 is connected to the downstream information transmission line F.
It is connected to the other end of the facility BKM via D4.

It should be noted that, through the slave station Sn ₃ , the signals of the three groups of uplinks enter both the regular master station M3 and the backup centralized supervisory control equipment BKM _S , and the backup centralized supervisory control equipment BKM _S and the uplink are constantly monitored. If possible, only the downlink from the backup centralized supervisory control facility BKM _S cannot be constantly monitored, but there is no problem because it can be verified at the time of disaster drills as appropriate.

By providing the branch changeover switches SW1a and SW1b at the locations where the transmission path is branched into three as described above, even if a failure occurs in the master station M2, the movable contacts C of the branch changeover switches SW1a and SW1b are kept. By switching to the second fixed contact point B, the slave station S2 ₂ and Sn-1 ₂
Are connected by the transmission path FD5, and a loop configuration becomes possible.

FIG. 2 is a schematic configuration diagram showing a second embodiment of the present invention. In the second embodiment, the hybrid transformer HT and the changeover switch SW3 are provided on the transmission lines FD1 ₁ and FD2 ₁ of the master station M1 of the first embodiment. And the centralized monitoring and control equipment BKM _J for backup. This figure 2
With this configuration, even if a line failure occurs at one place between the backup centralized supervisory control facility and all slave stations, supervisory control can be performed from both ends.

FIGS. 3A to 3C show a backup centralized monitoring control facility BKM when the master stations M1 to M3 all go down (failure occurs) due to an earthquake or the like in the system having the three-branched transmission path configured as described above. 3A is an operation explanatory diagram showing a process in which all slave stations recover from the failure by FIG.
1~M3 indicates the slave station S1 ₁ to Sn ₃ belonging to each master station M1~M3 when the down all. FIG. 3B shows each master station M1.
When M3 goes down, the adjacent slave stations of the master stations M1 and M2 are changed to terminal stations and each slave station is connected (the master central station M3 is operated by the backup centralized supervisory control equipment BKM on behalf of the branch station). The slave stations are not connected. Therefore, as described above, as shown in FIG. 3C, the branch changeover switches SW1a and SW1.
By switching b, the slave stations between the branch sections are electrically connected, so that the slave stations are moved to the above-mentioned location, and each slave station is recovered from the failure by the supervisory control information from the backup central supervisory control equipment BKM. To be done.

The branch selector switch SW1
Although a and SW1b have been described as being manually performed, the remote control line switching position may be used by remote control to switch when a failure occurs in the master station M2.

FIG. 4 is a schematic configuration diagram showing a third embodiment of the present invention. In the third embodiment, even if all the monitoring control devices including the host computer of the master station are down, the master station M
When the transmission control units 1 to M3 are normal (when the host computer and the transmission control unit are installed in separate rooms), the slave station S1 ₁ adjacent to the master station M1 sets the transmission path to normal and the slave station loopback configuration do not become. As a countermeasure against this, as shown in FIG. 5, when the master stations M1 to M3 stop the carrier of the modem on the condition that all the equipments on the host side are down, it becomes the same as the line disconnection, that is, the line failure. Station M1
The adjacent slave station S1 ₁ has a loopback configuration. Then
The slave stations are reassigned and all slave stations enter the backup centralized supervisory control equipment BKM. When the monitoring control device goes down by inserting the switch SW1 in the transmission line FD,
If the switch SW1 is opened, the line is disconnected and the slave station S1 ₁
Is looped back and has the same effect as above. Stop the carrier of the modem as above or switch S
If W1 is opened, the centralized supervisory control facility for backup BKM can be configured to include all slave stations in the loop line. Also in the case of the third mode, the configuration of the backup centralized supervisory control equipment BKM is the same as that of the first mode.

FIG. 6 is a schematic block diagram showing a fourth embodiment of the present invention. In the fourth embodiment, one backup central supervisory control equipment BKM is provided, and the supervisory control devices MS1 to MS1 are provided by this one equipment BKM. The backup of the MS 4 is performed. It is effective when the installation intervals of the respective monitoring controls MS1 to MS4 are sufficiently long and the simultaneous failure occurrence rate at two locations such as an earthquake is small. In this case, the monitoring control device M
A means for selecting a corresponding data area under the condition that any one of S1 to MS4 is selected is required.

FIG. 7 is a schematic configuration diagram showing a fifth embodiment of the present invention. In the fifth embodiment, a centralized monitoring control facility for backup (hereinafter referred to as backup) BKM is provided in each of groups 1 to 3 of the polling system. M1 _{S to} M3 _S are master stations, M1 _{J to} M3 _J are master stations consisting of slave systems, and S1 _{1 to} Sn ₃
Is a slave station, SL is a backup line, HT is a hybrid transformer, SW is a changeover switch, and each backup BKM is connected to the backup line SL.

In the fifth mode configured as described above, the master stations M1 _{S to} M3 _S went down due to an earthquake or the like (shown by ×)
At this time, if the operation is performed as shown in FIG. 8, the protection line SL will be half of the regular line.

FIG. 9 is a schematic block diagram showing a sixth embodiment of the present invention. This sixth embodiment is a group 1 and a group 2 of the polling method.
By providing the switching unit 1 and the switching unit 2 in the service lines in the adjacent portions between the groups 2, 2 and 3, by providing only one backup BKM and providing the backup line SL in only one group,
When the master station goes down due to an earthquake or the like, if the switching units 1 and 2 are switched as shown in FIG. 10 to connect the first group and the second group and the second group and the third group to operate, the standby line SL is the regular line. 1 / of
Becomes 6.

The switching method is the same as the token ring method. In the first method, the control position of the switching unit 1 is set to the slave station Sn ₁ as shown in FIG. 10, and the control position of the switching unit 2 is set to the switching position 2 as shown in FIG. It is installed in each slave station Sn ₂ and switches from the backup BKM in the order of the switching unit 1 → the switching unit 2 by remote control. In the second method, a changeover switch is installed in each of the changeover units 1 and 2, and the switch is changed over at the installation place. In this polling method, the addresses of the third group in FIG. 9 are allocated so that they do not overlap, and the backup BKM targets the slave stations of the third group as polling targets.

FIG. 11 is a block diagram of the token ring system shown in FIG.
1) between centralized monitoring control equipment for backup and slave stations
FIG. 7 is a schematic configuration diagram showing a seventh embodiment of the present invention that enables monitoring control of all slave stations even if a line failure occurs at one place. In this seventh embodiment, two backup BKM _S and BKM _J are provided. The backup line SL is used for connection, and the switching units 1 and 2 are used to switch and connect between the groups. In the case of the backup BKM _S and BKM _J operations, the switching units 1 and 2 are switched and connected as shown in FIG. 12 as in the case of FIG. Compared with FIG. 13, it is clear that FIG.
It is a loop line that includes groups.

Even in the case of the above-mentioned polling method, as shown in FIG. 6, one backup BKM may be provided and each group may be installed at a distance.

[0038]

As described above, according to the present invention,
By using the token ring method, even if the centralized monitoring control equipment goes down in an emergency such as an earthquake, it can be connected to the centralized monitoring control equipment for backup with the minimum number of transmission lines and the monitoring control can be continued, and the centralized backup equipment can be used. There is an advantage that the normality of the supervisory control equipment can be constantly monitored. Further, even if the polling method is used, there is an advantage that the monitoring control can be continued in an emergency without significantly increasing the number of transmission lines.

[Brief description of the drawings]

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

FIG. 2 is a schematic configuration diagram showing a second embodiment of the present invention.

3A to 3C are operation explanatory views of the first embodiment.

FIG. 4 is a schematic configuration diagram for explaining a third embodiment of the present invention.

FIG. 5 is a schematic configuration diagram showing a third embodiment.

FIG. 6 is a schematic configuration diagram showing a fourth embodiment of the present invention.

FIG. 7 is a schematic configuration diagram showing a fifth embodiment of the present invention.

FIG. 8 is an operation explanatory view of the fifth mode.

FIG. 9 is a schematic configuration diagram showing a sixth embodiment of the present invention.

FIG. 10 is an operation explanatory view of the sixth mode.

FIG. 11 is a schematic configuration diagram showing a seventh embodiment of the present invention.

FIG. 12 is an operation explanatory view of the seventh mode.

FIG. 13 is a schematic configuration diagram of a three-group configuration in a polling method.

FIG. 14 is a schematic configuration diagram of a three-group configuration in the token ring system.

FIG. 15 is a schematic configuration diagram of line failure handling in the polling method.

FIG. 16 is a schematic configuration diagram of line failure handling in the token ring system.

FIG. 17 is a schematic configuration diagram of line failure handling in the polling method.

FIG. 18A and FIG. 18B are schematic configuration diagrams of line failure handling in the token ring system.

FIG. 19 is a schematic configuration diagram of line failure handling in the token ring system.

[Explanation of symbols]

M1 to M3 ... Master station S1 _{1 to} Sn ₃ ... Slave station SW1, SW2, SW3 ... Changeover switch SW1a, SW1b, Branch changeover switch BKM _S , BKM _J ... Centralized monitoring control equipment for backup FD1 ₁ , FD1 _{2 to} FD1 ₃ , FD2 ₃ , FD1 to FD5
… Transmission path

Claims (8)

[Claims] 1. A communication function is restored by changing the affiliation of a slave station to each loop line due to a failure of the loop line or the master station, etc. In the distant monitoring control system, a hybrid coupler is inserted in an upstream line connecting the master station and the slave station, and a changeover switch is provided in the downlink line, and the hybrid switch is arranged in an area different from the plurality of master stations. The master station of the remote monitoring control system is used as a backup centralized supervisory control equipment, and the backup centralized supervisory control equipment is constantly supplied with the supervisory control information sent from the output of the hybrid coupler, and the backup central supervisory control equipment is supplied. When a failure occurs in all master stations other than the master station, operate the changeover switch to connect the backup centralized supervisory control equipment downlink to the slave station. In addition, a branch changeover switch is provided in at least one of an up line and a down line connected to different slave stations by branching the up line and the down line of the loop line from the one master station. In a loop line characterized in that, when all the master stations are in trouble, the branch changeover switch is operated so that the supervisory control information from the backup centralized supervisory control equipment is transmitted to all the slave stations. Failure recovery device for monitoring and control station. 2. The fault recovery device for a supervisory control center in a loop line according to claim 1, wherein the branch changeover switch is operated by remote control. 3. At least two sets of a hybrid coupler provided in the upstream line connecting the master station and the slave station, a changeover switch provided in the downlink line, and a centralized supervisory control facility for backup are provided, and each set is separately provided. 2. The fault recovery apparatus for a supervisory control station in a loop line according to claim 1, wherein the supervisory centralized supervisory control equipment is a backup central supervisory control facility. 4. A communication function is restored by changing the affiliation of the slave station to each loop line due to a failure of the loop line or the master station, etc. In the distant monitoring control system, a centralized monitoring control facility for backup is connected to one of the plurality of slave stations so as to constantly supply the monitoring control information of one master station, and a failure occurs in the master station. Also, when the transmission control unit of the master station is operating, the carrier sent from the transmission control unit to the slave station is stopped or the carrier is inserted by inserting a switch in the downlink of the loop line. A failure recovery device for a supervisory control station in a loop line, which is characterized in that it is not supplied to a slave station. 5. An upstream line in which a plurality of monitoring control system groups in a polling system in which a plurality of master stations and a plurality of slave stations are connected by a loop line are provided, and the master station and the slave stations are connected to each group A hybrid coupler is inserted in the base station, a changeover switch is provided in the downlink, and the master station of the remote monitoring control system arranged in a region different from the plurality of master stations of each group is used as a backup centralized monitoring control facility. , The backup centralized supervisory control equipment is constantly supplied with the supervisory control information sent from the output of the hybrid coupler, and a failure has occurred in all master stations other than the backup centralized supervisory control equipment. At this time, operate the changeover switch to connect the downlink of the centralized monitoring and control facility for backup to the slave station, and to backup each group when a failure occurs in each master station. A failure recovery device for a supervisory control station in a loop line, characterized in that recovery is performed by a centralized supervisory control facility. 6. A centralized supervisory control facility for backup is provided in one of the supervisory control system groups, and a switching unit is provided between the loop lines of each supervisory control system group to cause a failure in each master station. At this time, the switching unit is operated by remote control so that all slave stations of each group are connected, and failure recovery is performed by one centralized supervisory control facility for backup. Item 5. A failure recovery device for a supervisory control station in a loop line according to Item 5. 7. A failure recovery device for a supervisory control center in a loop line according to claim 5, wherein at least two centralized supervisory control facilities for backup are provided in one of the supervisory control system groups. 8. A communication function is restored by changing the affiliation of a slave station to each loop line due to a failure of the loop line or master station, etc. In the remote monitoring and control system, a plurality of monitoring control stations, each having a plurality of parent stations as one group, are arranged at a remote location, and the monitoring control stations are backed up by one centralized monitoring and control facility for backup when a failure occurs. A failure recovery device for a supervisory control station in a loop line, which is characterized in that