CN110554935A - Facility monitoring system and communication method in facility monitoring system - Google Patents

Abstract

The present invention addresses the problem of providing a facility monitoring system that uses BACnet and that can employ a redundant structure for a controller that connects devices within a facility, and a communication method in the facility monitoring system. The monitoring system includes a monitoring device, a 1 st controller (11) and a 2 nd controller (12), at least 2 controllers are connected to each other via a BACnet, one of the 1 st controller (11) and the 2 nd controller (12) operates as a controller of an operating system, the other operates as a controller of a standby system, a common virtual IP address is assigned to the 1 st controller (11) and the 2 nd controller (12), and a controller of the 1 st controller (11) and the 2 nd controller (12) that operates as a controller of the operating system communicates with the monitoring device (2) using the virtual IP address.

Description

Facility monitoring system, and communication method in the facility monitoring system

technical field

The present invention relates to a facility monitoring system in which at least two controllers connected to equipment installed in a facility, and a communication method in the facility monitoring system, and devices installed in the facility through the controllers The monitoring devices that monitor or control the equipment are connected to each other via BACnet (Building Automation and Control Network: Building Automation and Control Network).

Background technique

Conventionally, there has been known a technique in which a plurality of devices are divided into devices of an active system and devices of a backup system to be redundant.

For example, Patent Document 1 discloses a technique in which, in a server-client system in which a client terminal and two servers are connected via a network, one server is used as the server of the working system, and the other is used as the server of the standby system, and When it is determined that an abnormality has occurred in the server of the working system, server switching is performed so that the client terminal accesses the server of the standby system.

prior art literature

Patent Literature

Patent Document 1: Japanese Patent Laid-Open No. 2010-9462

SUMMARY OF THE INVENTION

Invention to solve problem

Conventionally, in a facility monitoring system in which a monitoring device performs monitoring and control of equipment in a facility through a controller connected to the facility, it is not possible to use the technology represented by the above-mentioned Patent Document 1 for the controller. Redundant structures like those used by servers in the prior art.

In a facility monitoring system, if the redundant structure used in the conventional server is to be adopted for the controller, the monitoring device for monitoring or controlling the controller must have the function of judging which controller is the working system.

On the other hand, BACnet is widely used in facility monitoring systems. For example, in BACnet, if a redundant structure is desired for the controller, some monitoring devices of other companies may be developed to have the above-mentioned functions. However, it is more difficult to develop products from other companies. As described above, when a redundant structure is adopted for the controller of one's own company, there is a situation in which the controller and the monitoring device of another company cannot communicate with each other.

In this way, especially in a facility monitoring system using BACnet, there is a problem that a redundant structure cannot be adopted for the controller.

The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to provide a facility monitoring system and a communication method in the facility monitoring system, which can be used for a controller connected to a device in a facility in a facility monitoring system using BACnet. Redundant construction.

technical solutions to problems

A facility monitoring system according to the present invention includes a monitoring device, a first controller, and a second controller, and at least two controllers are connected to each other via BACnet, and the facility monitoring system is characterized in that the first controller and the second controller One of them operates as the controller of the working system, and the other operates as the controller of the standby system. A common virtual IP address is assigned to the first controller and the second controller. The controller that operates the controller of the work system uses the virtual IP address to communicate with the monitoring device.

effect of invention

According to this invention, in the facility monitoring system using BACnet, a redundant structure can be adopted for the controller connected to the equipment in the facility.

Description of drawings

FIG. 1 is a diagram showing a configuration example of a facility monitoring system according to Embodiment 1. FIG.

2A and 2B are block diagrams showing a configuration example of a controller according to Embodiment 1. FIG. 2A shows a configuration example of a first controller that is a controller of a working system, and FIG. 2B shows a first controller that is a controller of a standby system. 2 Configuration examples of the controller.

3 is a flowchart for explaining an operation related to communication between a controller and a monitoring device in the facility monitoring system according to Embodiment 1. FIG.

4 is a flowchart for explaining the operation of the second controller as the backup system in the facility monitoring system according to the first embodiment.

5 is a flowchart for explaining the operation of the first controller as the work system in the facility monitoring system according to Embodiment 1. FIG.

6 is a flowchart for explaining the operation of self-abnormality detection by the first controller as the work system in the facility monitoring system according to Embodiment 1. FIG.

Detailed ways

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Embodiment 1.

FIG. 1 is a diagram showing a configuration example of a facility monitoring system according to Embodiment 1. FIG.

The facility monitoring system according to Embodiment 1 is applied to, for example, a building monitoring system or the like.

The facility monitoring system includes a first controller 11 , a second controller 12 , and a monitoring device 2 .

The first controller 11, the second controller 12, and the monitoring device 2 are connected via a network, and use BACnet as a communication network. Using BACnet, for example, the monitoring device 2 manufactured by another company can be easily incorporated into the facility monitoring system manufactured by the own company. In addition, since BACnet is a well-known network communication protocol, detailed description is abbreviate|omitted.

In the following description, the first controller 11 and the second controller 12 are also collectively referred to as "controller 1".

In addition, although description is abbreviate|omitted in FIG. 1, the controller 1 is not only connected to the monitoring apparatus 2, for example, may be connected to the controller of another system.

The controller 1 is connected to equipment (not shown) in the facility via the lower network, and monitors or controls the equipment based on the control of the monitoring device 2 . By equipment, we mean sensors, lighting, switches, motors, etc., which are located in the facility.

In addition, the controller 1 collects the measurement values obtained by the device from the device at a predetermined cycle.

In Embodiment 1, the device monitored or controlled by the controller 1 is referred to as a monitoring point, and the measured values acquired at the monitoring point are referred to as monitoring point data.

The monitoring device 2 monitors or controls the controller 1 . The monitoring device 2 monitors or controls the monitoring point by the controller 1 . Specifically, for example, the monitoring device 2 acquires monitoring point data from the controller 1 and causes a display device (not shown) to display information related to the acquired monitoring point data. A manager or the like monitors or controls the monitoring point by checking the display device.

In the facility monitoring system, either the first controller 11 or the second controller 12 operates as a controller of the working system, and the other operates as a controller of the standby system.

In addition, a common virtual IP address is assigned to the first controller 11 and the second controller 12, and the controller 1 of the first controller 11 and the second controller 12, which operates as a controller of the work system, uses the virtual IP address. By communicating with the monitoring device 2, monitoring and control of monitoring points are performed.

In the monitoring device 2 , a virtual IP address is stored as an IP address for communication with the controller 1 .

In addition, the first controller 11 and the second controller 12 perform survival monitoring with each other, and switch which one becomes the controller of the working system.

In addition, the first controller 11 and the second controller 12 have fixed addresses assigned to them. Communication between the first controller 11 and the second controller 12 can be performed using a fixed address.

The operations related to the communication between the controller 1 and the monitoring device 2 and the operations related to survival monitoring and switching between the controllers 1 will be described in detail later.

FIG. 2 is a block diagram showing a configuration example of the controller 1 according to the first embodiment.

In FIG. 2 , it is assumed that the first controller 11 is the controller of the working system, and the second controller 12 is the controller of the standby system. FIG. 2A shows a configuration example of the first controller 11 , and FIG. 2B shows the second controller. 12 configuration example.

In addition, in FIG. 2 , for the convenience of explanation, the first controller 11 and the second controller 12 only show the components that function when they are the controllers of the working system, and the controllers that are the standby system, respectively. The first controller 11 and the second controller 12 basically have the same configuration. The first controller 11 also has the constituent parts of the second controller 12 shown in FIG. 2B , and the second controller 12 also has the constituent parts of the first controller 11 shown in FIG. 2A . In the following description, the first controller 11 is the controller of the working system and the second controller 12 is the controller of the standby system. However, the first controller 11 may be the controller of the standby system. Let the second controller 12 be the controller of the work system.

The controller 1 is executed by software-based program processing using a CPU (Central Processing Unit: Central Processing Unit). In addition, the controller 1 includes an input interface device (not shown) and an output interface device (not shown), which perform communication with external devices such as other controllers 1 and monitoring devices 2 .

As shown in FIG. 2A , the first controller 11 includes a survival confirmation command reception unit 111 , a response transmission unit 112 , a communication control unit 113 , a detection unit 114 , and a notification unit 115 .

The existence confirmation command receiving unit 111 receives the existence confirmation command transmitted from the second controller 12 . In Embodiment 1, the so-called survival confirmation command is a command for monitoring the occurrence of an abnormality in the controller of the operating system.

The response transmission unit 112 transmits a response command in response to the survival confirmation command received by the survival confirmation command reception unit 111 to the second controller 12 .

The communication control unit 113 validates the virtual IP address. Specifically, the communication control unit 113 communicates with the monitoring device 2 using the virtual IP address. In addition, the communication control unit 113 transmits information for communicating with the first controller 11 to the monitoring device 2 . See below for details.

The detection unit 114 detects the abnormality of the first controller 11 itself. The so-called abnormality of the first controller 11 itself is, for example, an abnormality of the communication function of the first controller 11 , a failure of the software of the first controller 11 , or the like. Further, the detection unit 114 may detect, for example, that the power supply of the first controller 11 is about to be turned off as an abnormality.

The notification unit 115 notifies the second controller 12 of the occurrence of the abnormality when the detection unit 114 detects the abnormality of the first controller 11 itself.

As shown in FIG. 2B , the second controller 12 includes a survival confirmation command transmission unit 121 , a response reception unit 122 , a switching unit 123 , a communication control unit 124 , and an alarm unit 125 .

The existence confirmation command transmission unit 121 transmits the existence confirmation command to the first controller 11 . The existence confirmation command sending unit 121 transmits the existence confirmation command at a predetermined cycle.

The response reception unit 122 receives, from the first controller 11 , a response command in response to the survival confirmation command transmitted by the survival confirmation command transmission unit 121 .

The switching unit 123 switches the controller 1 and operates itself (the second controller 12 ) as a controller of the work system. The switching unit 123 includes a first switching unit 1231 and a second switching unit 1232 .

When the response command is not received by the response receiving unit 122, the first switching unit 1231 determines that an abnormality has occurred in the first controller 11, and switches the controller 1 so that the second controller 12 is the controller of the operating system , and use the virtual IP address to communicate with the monitoring device 2 .

The second switching unit 1232, when notified from the notification unit 115 of the first controller 11 that an abnormality has occurred in the first controller 11, determines that an abnormality has occurred in the first controller 11, and switches the controller 1 so that the first controller 11 is abnormal. The controller 12 is set as the controller of the work system, and communicates with the monitoring device 2 using a virtual IP address.

In addition, in FIG. 2B , although the switching unit 123 is assumed to include the first switching unit 1231 and the second switching unit 1232, this is only an example, and the switching unit 123 may include the first switching unit 1231 or the second switching unit 1232. anyone.

When the switching unit 123 has switched the controller 1 , the communication control unit 124 enables the virtual IP address and performs communication with the monitoring device 2 using the virtual IP address.

Moreover, the communication control part 124 transmits the information for making it communicate with the 2nd controller 12 to the monitoring apparatus 2 based on the control from the switching part 123. See below for details.

When the switching unit 123 has switched the controller 1 , the alarming unit 125 outputs alarm information notifying the abnormality of the first controller 11 to the monitoring device 2 .

The operation of the controller 1 in the facility monitoring system according to Embodiment 1 will be described.

In the following description of the operation, first, the first controller 11 is used as the controller of the working system, and the second controller 12 is operated as the controller of the backup system.

First, the operation related to the communication between the controller 1 and the monitoring device 2 in the facility monitoring system according to the first embodiment will be described.

3 is a flowchart for explaining the operation related to the communication between the controller 1 and the monitoring device 2 in the facility monitoring system according to the first embodiment.

When the controller 1 is activated, the controller 1 determines whether or not it is the controller of the operating system (step ST301).

In Embodiment 1, which controller 1 of the first controller 11 and the second controller 12 becomes the controller of the operating system is determined by, for example, whether or not it has been activated first. Specifically, the controller 1 that is activated first becomes the controller of the operating system. When the controller 1 is activated, the control unit (not shown) transmits a confirmation signal whether to activate or not to the controller 1 of the counterpart. When the controller 1 of the counterparty receives the acknowledgment signal, it sends to the controller 1 which sent the acknowledgment signal, a response signal indicating that it has activated itself. In the controller 1 that transmits the confirmation signal, the controller 1 of the other party is determined to be activated before the controller 1, and the controller 1 of the other party is activated as the controller of the backup system. On the other hand, when the controller 1 of the counterpart is not activated, no response signal is sent. The controller 1 that sent the confirmation signal judges that it is activated before the counterparty's controller 1, and is activated as the controller of the working system.

In addition, when viewed from the first controller 11 , the second controller 12 is the counterpart controller 1 , and when viewed from the second controller 12 , the first controller 11 is the counterpart controller 1 .

In Embodiment 1, for example, a manager or the like can appropriately determine which controller 1 of the first controller 11 and the second controller 12 is to be the controller of the work system. In this case, the administrator or the like causes the controller of the work system to start up first.

Here, since the first controller 11 is the controller of the work system (in the case of YES in step ST301 ), it communicates with the monitoring device 2 using the virtual IP address (step ST302 ). Then, the first controller 11 performs, for example, a process based on control from the monitoring device 2 , or transmits monitoring point data collected from the monitoring points to the monitoring device 2 . In addition, the first controller 11 communicates with the monitoring points, and performs monitoring and control of the monitoring points, collection of monitoring point data, and the like.

The first controller 11 , which is a controller of the work system, transmits information for communicating with itself to the monitoring device 2 as the address of the controller 1 . Specifically, for example, the communication control unit 113 of the first controller 11 transmits GARP (Gratuitous Address Resolution Protocol: Gratuitous Address Resolution Protocol) to the monitoring device 2 to update the ARP cache. In the monitoring apparatus 2, when a GARP is received, the ARP table is updated, and the MAC address of the first controller 11 is set to the IP address of the ARP table. As a result, the monitoring device 2 can communicate with the first controller 11 as the controller of the work system using the virtual IP address without being aware of the first controller 11 or the second controller 12 .

On the other hand, since the second controller 12 is the controller of the backup system (in the case of NO in step ST301 ), the virtual IP address is invalidated (step ST303 ). That is, communication with the monitoring device 2 is not performed.

Next, the operation related to the survival monitoring between the first controller 11 and the second controller 12 and the switching of the controller of the operating system in the facility monitoring system according to the first embodiment will be described.

First, the operation of the second controller 12 as the controller of the backup system will be described.

FIG. 4 is a flowchart for explaining the operation of the second controller 12 serving as the backup system in the facility monitoring system according to the first embodiment.

The existence confirmation command transmission unit 121 stands by until the predetermined existence confirmation command transmission time (in the case of "No" in step ST401 ) is reached.

When the survival confirmation command transmission time is reached (YES in step ST401 ), the survival confirmation command transmission unit 121 transmits the survival confirmation command to the first controller 11 (step ST402 ).

Then, the second controller 12 waits for the first controller 11 to receive a response command in response to the existence confirmation command sent in step ST402.

The response receiving unit 122 determines whether there is a response from the first controller 11 within the set time (step ST403). Specifically, the response reception unit 122 determines whether or not a response command in response to the survival confirmation command transmitted by the survival confirmation command transmission unit 121 in step ST402 has been received from the second controller 12 within the set time. In addition, the setting time is preset.

When the response receiving unit 122 determines that there is a response within the set time (in the case of YES in step ST403 ), the process returns to step ST401 .

When the response receiving unit 122 determines that there is no response within the set time (“NO” in step ST403 ), the response receiving unit 122 outputs information notifying this to the switching unit 123 .

The first switching unit 1231 of the switching unit 123 determines that an abnormality has occurred in the first controller 11, switches the controller 1 so that the second controller 12 is set as the controller of the work system, and uses the virtual IP address to monitor the The device 2 communicates (step ST404).

At this time, the first switching unit 1231 transmits information for communicating with the second controller 12 to the monitoring device 2 via the communication control unit 124 as the address of the controller 1 . Specifically, for example, the communication control unit 124 transmits GARP (Gratuitous ARP) to the monitoring device 2 based on an instruction from the first switching unit 1231 to update the ARP cache. The monitoring device 2 updates the ARP table when receiving the GARP, and sets the MAC address of the second controller 12 in the virtual IP address of the ARP table. As a result, the communication control unit 124 enables the virtual IP address, and the monitoring device 2 does not need to recognize that the controller of the work system is switched to the second controller 12. After that, the second controller 12 can be regarded as the controller of the work system. The controller communicates with the second controller 12 .

In step ST404, the first switching unit 1231 switches the controller 1, and the communication control unit 124 transmits to the monitoring device 2 information for communicating the monitoring device 2 and the second controller 12, thereby establishing the second controller 12 and the monitoring device At the time of communication of 2, the alarm unit 125 outputs alarm information notifying the abnormality of the first controller 11 to the monitoring device 2 (step ST405).

In the monitoring device 2, upon receipt of the alarm information, for example, a message such as "there is an abnormality in the controller" is displayed on the display device. In addition, for example, the alarm information may include information on the cause of an abnormality such as inability to communicate or power off, and the monitoring device 2 may cause the display device to display the information on the cause. A manager or the like can detect that some abnormality has occurred in the controller 1, and can quickly perform an inspection of the controller 1 or the like.

In this way, the second controller 12 performs the survival monitoring of the first controller 11, and when it is determined that the first controller 11 is abnormal, it switches the controller 1 so as to set itself as the controller of the operating system. Even if the switching of the controller 1 is performed, the monitoring device 2 uses the virtual IP address for the communication with the controller 1 as before the switching, so it is not necessary to recognize that the switching has been performed.

In addition, when the first controller 11 is restarted after recovery, it functions as a controller of the backup system. Specifically, when the first controller 11 is activated, a confirmation signal of whether to activate or not is transmitted to the second controller 12 . Here, the content sent from the second controller 12 to the confirmation signal is a response signal during activation. Therefore, the second controller 11 determines itself as the controller of the backup system.

In this way, the second controller 12 that has been switched to be the controller of the work system still functions as the controller of the work system after the first controller 11 is restored. Thereby, unnecessary switching of the controller 1 can be avoided.

4, when the response receiving unit 122 does not receive the response command within the set time, the survival confirmation command transmission unit 121 may retry the transmission of the survival confirmation command a preset number of times.

Next, the operation of the first controller 11 as the controller of the operating system will be described.

FIG. 5 is a flowchart for explaining the operation of the first controller 11 as the work system in the facility monitoring system according to the first embodiment.

As a premise of the operation described in FIG. 5 , the first controller 11 communicates with the monitoring device 2 using a virtual IP address. Specifically, the communication control unit 113 communicates with the monitoring device 2 using the virtual IP address.

The survival confirmation command receiving unit 111 determines whether or not the survival confirmation command transmitted from the survival confirmation command transmission unit 121 of the second controller 12 has been received (step ST501 ).

In step ST501, when the existence confirmation command is not received (in the case of NO in step ST501), step ST501 is repeated.

In step ST501, upon receiving the survival confirmation command (in the case of YES in step ST501), the response transmission unit 112 transmits to the second controller 12 the survival confirmation command received by the survival confirmation command reception unit 111 in step ST501. The response command of the response (step ST502).

In this way, survival monitoring is performed between the first controller 11 and the second controller 12 .

In the facility monitoring system according to the first embodiment, it is not necessary to perform survival monitoring between the redundant first controller 11 and the second controller 12 , and a device for detecting whether an abnormality occurs in the controller of the operating system is additionally provided. Wait. In addition, it is possible to quickly switch the controller 1 when an abnormality in the controller of the operating system is detected.

In the first embodiment, the first controller 11 , which is a controller of the work system, may detect that an abnormality has occurred in itself, and notify the second controller 12 , which will be described in detail below.

6 is a flowchart for explaining the operation of self-abnormality detection by the first controller 11 as the work system in the facility monitoring system according to the first embodiment.

The detection unit 114 detects whether or not an abnormality has occurred in the first controller 11 itself (step ST601 ).

In step ST601, when no abnormality has occurred in itself (in the case of NO in step ST601), step ST601 is repeated.

In step ST601 , when an abnormality occurs in itself (in the case of YES in step ST601 ), the detection unit 114 outputs information indicating that the abnormality has occurred to the notification unit 115 .

When the detection unit 114 detects an abnormality in the first controller 11 itself in step ST601, the notification unit 115 notifies the second controller 12 of the occurrence of the abnormality (step ST602).

When the second controller 12 receives a notification that the first controller 11 is abnormal, the second switching unit 1232 determines that the first controller 11 is abnormal, and switches the controller 1 . The specific operation of switching the controller 1 by the second switching unit 1232 is the same as the specific operation of switching the controller 1 by the first switching unit 1231 described in step ST404 in FIG. 4 , and thus repeated description is omitted.

In addition, in the above-mentioned Embodiment 1, although the controller 1 is set to two, the first controller 11 and the second controller 12, this is only an example, and three or more controllers 1 may be connected to the network. The facility monitoring system may be configured to include at least one controller of the working system and at least one controller of the backup system redundant with the controller of the working system.

As described above, according to Embodiment 1, the facility monitoring system is configured such that one of the first controller 11 and the second controller 12 operates as a controller of the working system, and the other operates as a controller of the standby system, A common virtual IP address is allocated to the first controller 11 and the second controller 12; the controller 1 of the first controller 11 and the second controller 12, which operates as a controller of the work system, uses the virtual IP address to perform and monitor Device 2 communication. When either the first controller 11 or the second controller 12 operates as the controller of the work system, since the monitoring device 2 communicates using the virtual IP address, it is not necessary to recognize which one is the work system. controller. Therefore, the monitoring device 2 does not need to have the function of determining which of the controllers 1 is the working system. Therefore, in the facility monitoring system using BACnet, a redundant structure can be adopted for the controller 1 connected to the equipment in the facility.

In addition, the controller of the working system is configured to include: a survival confirmation command receiving unit 111 that receives a survival confirmation command transmitted from the controller of the standby system; The controller of the standby system is configured to include: a survival confirmation command sending unit 121 that sends a survival confirmation command to the controller of the working system; and a response receiving unit 122 that receives a response command from the working system The controller receives a response command that responds to the survival confirmation command sent by the survival confirmation command transmission unit 121 ; and the switching unit 123 (first switching unit 1231 ) executes the controller when the response reception unit 122 does not receive the response command 1 to set the controller of the standby system as the controller of the working system, and use the virtual IP address to communicate with the monitoring device 2 .

In addition, the controller of the working system is configured to include a detection unit 114 that detects an abnormality of the controller of the working system itself, and a notification unit 115 that, when the detection unit 114 detects an abnormality, notifies the controller of the backup system Notifying the occurrence of the abnormality, the controller of the backup system is configured to include a switching unit 123 (second switching unit 1232 ) that performs the above-described switching of the controller 1 when the occurrence of the abnormality is notified from the notification unit.

Therefore, in the redundant controller 1, it is not necessary to additionally include a device for detecting whether the controller of the working system is abnormal, and the redundant controllers 1 mutually monitor the existence of each other, and it is possible to detect the control of the working system. When an abnormality occurs in the controller, the switching of the controller 1 is performed quickly.

The controller of the standby system is configured to include an alarm unit 125 that outputs alarm information to the monitoring device 2 notifying an abnormality of the controller of the working system when the switching unit 123 switches the controller 1 . Therefore, a manager or the like can detect that some abnormality has occurred in the controller 1, and can quickly perform inspection of the controller 1 or the like.

In addition, the invention of this patent application can carry out the deformation|transformation of the arbitrary structural elements of embodiment, or the omission of arbitrary structural elements of embodiment within the scope of the invention.

[Symbol Description]

1 Controller

2 Monitoring device

11 1st controller

12 2nd controller

111 Survival confirmation command receiving section

112 Response sending part

113, 124 Communication Control Department

114 Inspection Department

115 Notification Department

121 Survival confirmation command sending part

122 Response receiving section

123 Switching section

125 Alarm Department

1231 Switch 1

1232 Second switching unit.

Claims (6)

1. A facility monitoring system comprising a monitoring device, a first controller and a second controller, and at least 2 controllers are connected to each other via BACnet, the facility monitoring system being characterized in that, One of the first controller and the second controller operates as a controller of a working system, and the other operates as a controller of a standby system, and the first controller and the second controller are allocated in common the virtual IP address, Among the first controller and the second controller, a controller operating as a controller of the work system communicates with the monitoring device using the virtual IP address. 2. The facility monitoring system according to claim 1, characterized in that, The controller of the working system has: a survival confirmation command receiving section that receives a survival confirmation command sent from the controller of the standby system; and a response transmission unit that transmits a response command in response to the survival confirmation command received by the survival confirmation command reception unit, The controller of the backup system has: a survival confirmation command sending unit, which sends the survival confirmation command to the controller of the working system; a response receiving unit that receives, from a controller of the work system, the response command in response to the survival confirmation command sent by the survival confirmation command transmission unit; and When the response command is not received by the response receiving unit, a switching unit switches the controller to set the controller of the standby system as the controller of the working system, and uses the virtual IP address to switch the controller communicate with the monitoring device. 3. The facility monitoring system according to claim 1 or 2, characterized in that, The controller of the working system has: a detection unit that detects the abnormality of the controller itself of the working system; and a notification unit that, when the detection unit detects the abnormality, notifies the controller of the backup system of the occurrence of the abnormality, The controller of the backup system includes a switching unit that switches the controller so that the controller of the backup system becomes the controller of the working system when the occurrence of the abnormality is notified from the notification unit. controller and use the virtual IP address to communicate with the monitoring device. 4. The facility monitoring system of claim 2, wherein The controller of the backup system includes an alarm unit that outputs, to the monitoring device, alarm information notifying an abnormality of the controller of the working system when the switching unit has switched the controller. 5. The facility monitoring system of claim 3, wherein: The controller of the backup system includes an alarm unit that outputs, to the monitoring device, alarm information notifying an abnormality of the controller of the working system when the switching unit has switched the controller. 6. A communication method in a facility monitoring system comprising a monitoring device, a first controller and a second controller, and at least two controllers are connected to each other via BACnet, the communication method in the monitoring system being characterized by , One of the first controller and the second controller operates as a controller of a working system, and the other operates as a controller of a standby system, and the first controller and the second controller are allocated in common the virtual IP address, Among the first controller and the second controller, a controller operating as a controller of the work system communicates with the monitoring device using the virtual IP address.