1. A plant monitoring control system comprising: a controller (3) for monitoring monitored subjects including at least plant equipment (7); a monitoring apparatus (1) connected with the controller (3) via a network (4); and a server (2) connected with the controller (3) via the network (4); wherein said controller (3) has: a monitoring processor (30) for collecting operational data indicating operational states of the monitored subjects from these monitored subjects and transmitting the collected data to the monitoring apparatus (I) and to the server (2) via the network (4); a backup database (32) for storing the operational data collected by the monitoring processor (30); and a backup processor (3 I) operative to send the operational data stored in the backup database (32) to the server (2) via the network (4), to detect whether there is any abnormality in the network (4), and to manage backup administrative information (34) and the backup database (32) on the basis of results of the detection; wherein said server (2) has a database (23) for storing the operational data sent from the controller (3) and a database management processor (20) operative to exchange information with the controller (3) via the network (4), to detect whether there is any abnormality in the network (4), and to manage the database (23) on the basis of results of the detection; wherein said database management processor (20) operates to send a backup data transmission request to the controller (3) via the network (4) on the condition that the network (4) is detected to have recovered to its normal state after the network (4) is detected to have an abnormality and to restore the database (23) to its normal state using the received backup data if the backup data is subsequently received from the controller (3) via the network (4); and wherein said backup processor (3 1) operates to record a date and time (341) at which an abnormality occurred in the network (4) in the backup administrative information (34) (322) if the abnormality in the network (4) is detected, to record a date and time (342) at which the network (4) was restored to its normal state as a recovery date and time of the network in the backup administrative information (34) (326) if the network (4) is detected to have varied from the abnormal state to the normal state, and to send the operational data stored in the backup database (32) during a period of time from the date and time (341) at which the abnormality occurred in the network (4) to the date and time (342) of the recovery of the network (4) as the backup data to the server (2) if the backup data transmission request is received from the server (2).

2. The plant monitoring control system of claim 1, wherein said database management processor (20) operates to record the date and time (341) at which the abnormality occurred in the network (4) in database administrative information (24) (322) if the abnormality in the network (4) is detected, to record the date and time (342) at which the network (4) was restored to its normal state as recovery date and time of the network (4) if the network (4) is subsequently detected to have varied from the abnormal state to the normal state, and to add information including the date and time (241) at which the abnormality occurred in the network (4) and the recovery date and time (242) of the network (4) that are recorded in the database administrative information (24) to said backup data transmission request; and wherein said backup processor (3 1) operates to make a decision as to whether a period of time running from the date and time (241) of the occurrence of the abnormality in the network (4) to the recovery date and time (242) of the network (4) added to the backup data transmission request is coincident with a period of time running from the date and time (341) of the occurrence of the abnormality in the network (4) to the recovery date and time (342) of the network (4) and recorded in the backup administrative information (34) if the backup data transmission request is received from the server (2) and to send the backup data as collated backup data to the server (2) on the condition that both periods of time agree.

3. The plant monitoring control system of claim 1, wherein said database management processor (20) operates to cause the date and time (241) at which an abnormality occurred in the network (4) to be recorded in the database administrative information (24) if the abnormality in the network (4) is detected (3 1 I), to cause the date and time (242) at which the network (4) was restored to its normal state to be recorded as a recovery date and time of the network (4) in the database administrative information (24) if the network (4) was subsequently detected to have recovered to its normal state (3 13), and to add information recorded in the database administrative information (24) and including the date and time (241) of the occurrence of'the abnormality in the network (4) and the recovery date and time (242) of the network (4) to the backup data transmission request; and wherein said backup processor (3 1) makes a decision as to whether the period of time running from the date and time (241) of the occurrence of the abnormality in the network (4) to the recovery date and time (242) of the network (4) and added to the backup data transmission request is coincident with the period of time running from the date and time (341) of the occurrence of the abnorn~alityin the network (4) to the recovery date and time (342) of the - 12 - network (4) and recorded in the backup administrative information (34) if the backup data transmission request is received from the server (2) and sends the operational data stored in the backup database (32) during the period of time running from the date and time of the occurrence of the abnormality in the network (4) to the recovery date and time of the network (4) and added to the backup transmission request as the backup data to the server (2) on the condition that both periods of time are not coincident.

4. The plant monitoring control system of claim 1, wherein said backup processor (3 1) stores operational data collected prior to the occurrence of the abnormality in the network (4) and collected after the network (4) has changed from the abnormal state to the normal state in said backup database (32) and deletes old backup data that has been present for a given period of time (352) to secure an area of the backup database (32).

The present invention relates to a plant monitoring control system having a
function of restoring a database that manages data about the operation of a manufacturing plant.
In a plant monitoring control system, data about the operation of a plant
5 (hereinafter referred to as the operational data) is transmitted from a controller to a server
through a network and accumulated in a database of the server. The data is displayed as trend
information or a history of alarms on the display screen of a monitoring apparatus. One
apparatus as disclosed in JP-A-2013-097458 for managing data obtained by monitoring a plant
operates to collect messages from the plant under control, to accumulate the messages in a
10 database, and to display a warning message on the display screen when the number of
occurrences of messages accumulated in the database exceeds a threshold value.
In recent years, there have been increasing numbers of networks of systems using
public lines or wireless LANs (local area networks). If the connection of a public line or
wireless LAN with a network becomes unstable depending on the environment or the status of
15 the apparatus, and if the network between a controller and a server is cut off temporarily,
operational data that is to be accumulated in the database of the server may be lost.
Operational data lost due to a trouble with the network does not exist in the
database of the server and, therefore, even if the network is restored to its normal state, the
database of the server cannot be recovered.
20 SUMMARY OF THE INVENTION
It is an object of the present invention to provide a plant monitoring control
system which, if an abnormality occurs in a network and operational data to be stored in a
database of a server is not stored, can restore the database of the server to its normal state in a
case where the network is restored to its normal state.
2 5 The foregoing object is achieved in accordance with the teachings of the present
invention by providing a plant monitoring control system which invariably stores operational
data in the controller, the operational data being obtained from a subject monitored by the
controller and which, if a networlc interconnecting the controller and the server is restored to its
normal state after an abnormality occurs in the network, extracts operational data items to be
30 stored in a database of tlle server during a period of time beginning with tlle occurrence of the
abnormality in the network and ending with the date and time of the recovery of the network
from the operational data stored in the controller. The system then transmits the extracted
operational data items as backup data to the server from the controller via the network. The
server stores the backup data received from the controller into the database. Thus, the database
5 is restored to its normal state.
According to the present invention, when a trouble occurs with the network, even
if operational data to be stored is not stored in the database of the server, it is possible to restore
the database of the server to its normal state in a case where the network has recovered to its
normal state.
10 BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an overall block diagram of a plant monitoring control system associated
with the present invention.
FIGS. 2A and 2B are conceptual diagrams of two types of administrative
information associated with the invention.
15 FIG. 3 is a timing chart illustrating processing performed by the plant monitoring
control system shown in FIG. 1.
DESCRIPTION OF TI-IE EMBODIMENTS
An embodiment of the present invention is hereinafter described with reference to
FIGS. 1-3. FIG. 1 shows the whole configuration of a plant monitoring control system
20 according to the embodiment of the invention.
Referring to FIG. 1, the plant monitoring control system has a monitoring
apparatus 1, a server 2, and a controller 3 which are interconnected via a network 4. Input
equipment 5 composed, for example, of a keyboard 5a and a mouse 5b is connected with the
monitoring apparatus 1. A process input-output device 6 is connected with the controller 3.
25 Plant equipment 7 is connected with the process input-output device 6. For example, the plant
equipment 7 is configured including a switch 7a, a sensor 7b, and a pump 7c. The network 4 is
composed, for example, of a public line or a wireless LAN.
The monitoring apparatus 1 is computer equipment having information processing
resources such as a CPU (central processing unit), a memory, and input-output interfaces. For
30 example, the monitoriilg apparatus 1 is composed of an on-screen display processor 10, a
memory 1 1, and a display device 12. Monitoring information 13 obtained by monitoring done
by the controller 3 is stored in the memory 11. A monitoring screen 12b is displayed in a
- 4 -
display area 12a of the display device 12.
The on-screen display processor 10 processes information related to monitoring
on the basis of the monitoring information 13 stored in the memory 11 and the operational data
(in a database 23) routed in from the server 2, and displays the results of processing (such as
5 trend information indicative of the operational states of the plant equipment 7 and the process
input-output device 6 and a history of alarms indicative of abnormalities in the plant equipment 7
and the process input-output device 6) on the monitoring screen 12b of the display device 12.
At this time, characters and numerals reflecting manipulations of the keyboard 5a of the input
equipment 5 are displayed on the monitoring screen 12b. Furthermore, information about a
10 selected position on the monitoring screen 12b is entered as information reflecting manipulations
of the mouse 5b of the input equipment 5 into the on-screen display processor 10.
The server 2 is computer equipment having information processing resources
such as a CPU, memories, and input-output interfaces. For example, the server 2 is composed
of a database management processor 20, memories 2 1,22, and the database 23. Administrative
15 information 24 is stored in the memory 2 1. Monitoring information 25 is stored in the memory
22. The database management processor 20 receives the operational data from a backup
database 32 of the controller 3 via the network 4, receives the monitoring information 25 from
the memory 22, carries out processing to manage the operational data within the database 23
based on the entered operational data or monitoring information 25, and records the results of the
20 processing in the administrative information 24 stored in the memory 2 1.
At this time, the database management processor 20 causes operational data items
which are included in the data stored in the backup database 32 and which indicate the
operational states of the plant equipment 7 and the process input-output device 6 to intercorrelate
with the operating time, stores the operational data items in a data storage area of the database
25 23, detects whether there is any abnormality in the network 4 including the input-output interface
connected with the network 4, intercorrelates the results of the detection (whether there is any
abnormality in the network 4) with the date and time, and records them in the administrative
information 24.
The controller 3 is computer equipment having information processing resources
30 such as a CPU, a memory, and input-output interfaces. For example, the controller is composed
of a monitoring processor 30, a backup processor 3 1, the backup database 32, and a memory 33.
Administrative information 34 is stored in the memory 33. Where a control signal for
controlling the plant equipment 7 is entered from the monitoring apparatus 1 via the network 4,
the monitoring processor 30 routes the entered control signal to the plant equiptnent 7 via the
process input-output device 6, thus controlling the switch 7a, sensor 7b, and pump 7c
constituting the plant equipment 7.
The monitoring processor 30 monitors at least the process input-output device 6
and the plant equipment 7. The monitoring processor 30 receives monitoring information
5 (information including warning information) indicating the states and abnormalities in various
devices being monitored from the process input-output device 6, stores the entered monitoring
information in the backup database 32, and routes the entered monitoring information to the
memory 11 of the monitoring apparatus 1 and to the memory 22 of the server 2 via the network
4.
10 Furthermore, the monitoring processor 30 receives operational data indicative of
the operational states of the devices being monitored from the process input-output device 6,
intercorrelates the received operational data with the operating time (date and time of operation),
stores the operational data in the data storage area of the backup database 32, detects whether the
network 4 including the input-output interface connected with the network 4 is at fault or not,
15 intercorrelates the results of the detection (whether there is any abnormality in the network 4)
with the date and time, and records these pieces of information in the administrative information
34.
FIG. 2A and 2B show the configurations of the two types of administrative
information. In FIG. 2A, the administrative information 24 is treated as administrative
20 information for a database and composed of an abnormality occurrence date and time 241 and a
recovery date and time 242. The abnor~nalityo ccurrence date and time 241 is information
indicating the date and time of the occurrence of an abnormality in the network 4. The
recovery date and time 242 is information indicating the date and time at which the network 4
was recovered from an abnormal condition. In FIG. 2B, the administrative information 34 is
25 treated as administrative information for backup and composed of an abnormality occurrence
date and time 341, a recovery date and time 342, and a backup completion flag 343. The
abnormality occurrence date and time 341 is information indicating the date and time of the
occurrence of an abnormality in the network 4. The recovery date and time 342 is information
indicating the date and time at which the network 4 recovered from an abnormal condition. The
30 backup completion flag 343 is information indicating that a backup of the database 23 has
completed.
FIG. 3 is a timing chart illustrating the processing performed by the plant
monitoring control system associated with the present invention. This timing chart depicts the
flow of processing from a disconnection of the network to recovery of the databases.
In FIG. 3, if the network 4 is operating ilormally (301), the monitoring processor
30 transmits monitoriilg information indicating the states of the plant equipment 7 and process
input-output device 6 or whether there are abnorinalities to the monitoring apparatus 1 and to the
server 2 via the network 4. At this time, the monitoring processor 30 collects operational data
5 from the subjects being monitored and always stores the collected data as backup data in the
backup database 32 (35 1). Instead of storing the operational data at all times, the monitoring
processor 30 may delete old backup data except for data collected over a given time (352) and
form an empty region in the data storage area of the backup database 32. For example,
operational data collected for three minutes can be stored in the backup database 32.
10 Then, if the network 4 is disconnected and the network 4 changes from a normal
state (301) to an abnormal state (generation of an abnormality) (302), the database management
processor 20 of the server 2 detects an abnormality in the network 4 including the input-output
interface of the server 2 (3 11) and causes the date and time 241 (i.e., the results of the detection)
at which an abnormality occurred in the network 4 to be recorded in the administrative
15 information 24 (3 12). At this time, the backup processor 3 1 of the controller 3 detects an
abnormality in the network 4 including the input-output interface of the controller 3 (321),
causes the date and time 341 (i.e., the results of the detection) at which an abnormality occurred
in the network 4 to be recorded in the administrative information 34 (322), and starts to operate
for backing up the backup database 32 (323).
2 0 At this time, in order to prevent the operational data from being collected
incompletely, the backup processor 3 1 stores an operational data set as recovery backup data in
the backup database 32 (324), the operational data set beginning with operational data collected
prior to generation of an abnormality in the network 4 and ending with operational data collected
after recovery of the network 4. For example, the recovery backup data stored in the backup
25 database 32 by the backup processor 3 1 is an operational data set which begins with operational
data indicative of the operating time 1 minute earlier than the date and time 341 of the
occurrence of an abnormality in the network 4 and which ends with operational data indicative of
the operating time 1 minute later than the recovery date and time 342 of the network 4.
If the network 4 then varies from the abnormal state (302) to its normal state
30 (303), the database management processor 20 detects that the network 4 has recovered to its
normal state (3 13), records the recovery date and time 242 (i.e., the results of the detection) at
which the network 4 recovered to its normal state in the administrative information 24 (3 14), and
starts to operate to recover the database (3 15). At this time, the database management
processor 20 refers to the administrative information 24 and searches the database 23. If no
- 7 -
operational data is present in the data storage area of the database 23 which corresponds to a
period of time from the date and time 241 at which an abnormality occurred in the network 4 to
the recovery date and time 242 at which the network 4 recovered to its normal state, the
management processor 20 transmits a backup data transmission request including information to
5 the effect that there is no operational data in this data storage area corresponding to that period of
time (from the abnormality occurrence date and time 241 to the network recovery date and time
242) to the backup processor 3 1 of the controller 3 (3 16).
On the other hand, if the network 4 varies from the abnormal condition (302) to
the normal condition (303), the backup processor 3 1 detects that the network 4 has recovered to
10 its normal state (325) and causes the recovery date and time 342 (i.e., the results of the detection)
at which the network 4 recovered to its normal state to be recorded in the administrative
information 34 (326). Thus, the operation for backing up the backup database 32 is terminated
(327). Then, the backup processor 3 1 turns ON the backup completion flag 343 of the
administrative information 34 (328).
15 At this time, the backup processor 3 1 refers to the administrative information 34
in response to the backup data transmission request received from the database management
processor 20 and makes a decision as to whether the period of time running from the date and
time 241 of the occurrence of an abnormality in the network 4 to the recovery date and time 242
of the network 4 and included in the information added to the backup data transmission request
20 agrees with the period of time recorded in the administrative information 34 and running from
the date and time 341 at which an abnormality occurred in the network 4 to the recovery date and
time 342 of the network 4. If both periods of time are coincident, the recovery backup database
(operational data) stored in the data storage area of the backup database 32 corresponding to the
period of time from the date and time 341 at which an abnormality occurred in the network 4 to
25 the recovery date and time 342 of the network 4 is treated as collated backup data, and the
processor sends the collated backup data to the database management processor 20 of the server
2 (329). At this time, old backup data of the backup data stored in the backup database 32 is
deleted by the monitoring processor 30.
The database management processor 20 of the server 2 carries out an operation
30 for recovering the database 23 in response to the recovery backup data sent from the backup
processor 3 1, stores the recovery backup data (i.e., collated backup data) sent from the backup
processor 3 1 in the data storage area corresponding to the period of time from the date and time
241 at which an abnormality occurred in the network 4 to the recovery date and time 242 of the
network 4, and restores the database 23 to its norn~als tate (3 15).
- 8 -
If those portions of the data storage area of the database 23 from which data have
been lost are restored to their normal state, the database management processor 20 terminates the
operation for recovering the database 23 (3 17) and sends information to the effect that the
operation for recovering the database 23 has ended to the backup processor 3 1 of the controller
5 3.
If the information to the effect that the operation for recovering the database 23
has ended is received from the database management processor 20 of the server 2, the backup
processor 3 1 of the controller 3 confirms that the operation for recovering the database 23 has
ended (330), deletes the recovery backup data stored in the backup database 32 (33 I), and forms
10 an empty region in the data storage area of the backup database 32.
In the present embodiment, operational data lost from the database 23 due to an
abnormality or trouble with the network 4 is temporarily stored as recovery backup data in the
backup database 32 of the controller 3. When the network 4 has recovered to its normal state,
the recovery backup data (operational data) stored in the backup database 32 of the controller 3
15 is sent to the server 2, where the recovery backup data (operational data) is stored in the database
23. Consequently, the database 23 of the server 2 can be restored to its normal state.
According to the present embodiment, when an abnormality occurs in the network
4, if operational data to be stored in the database 23 of the server 2 is not stored, the database 23
of the server 2 can be restored to its normal state in a case where the network 4 has recovered to
20 its normal state.
It is to be understood that the present invention is not restricted to the abovedescribed
embodiment but rather embraces various modifications. For example, the database
management processor 20 sends a backup data transmission request to the controller 3 via the
network 4 on the condition that the network 4 has regained its normal state after an abnormality
25 in the network 4 is detected. Then, if the recovery backup data is received from the controller 3
via the network 4, the database 23 can be returned to its normal state using the received recovery
backup data.
Furthermore, if a backup data transmission request is received from the database
management processor 20, the backup processor 3 1 can send the recovery backup data
30 (operational data) to the server 2 without the need to make a decision as to whether the period of
time from the date and time 241 at which an abnormality occurred in the network 4 to the
recovery date and time 242 of the network 4 is coincident with the period of time from the date
and time 341 at which an abnormality occurred in the network 4 to the recovery date and time
342 of the network 4.
In particular, the backup processor 3 1 can also send the recovery backup data
(operational data) stored in the data storage area of the backup database 32 corresponding to the
period of time from the date and time 341 at which an abnormality occurred in the network 4 to
the recovery date and time 342 of the network 4 to the database management processor 20 of the
5 server 2 on the condition that a backup data transmission request has been received from the
database management processor 20.
In addition, if a backup data transmission request is received from the server 2,
the backup processor 3 1 can make a decision as to whether the period of time added to the
backup data transmission request and running from the date and time 241 at which an
10 abnormality occurred in the network to the recovery date and time 242 of the network is
coincident with the period of time recorded in the backup administrative information 34 and
running from the date and time 341 at which an abnormality occurred in the network to the
recovery date and time 342 of the network. The operational data stored in the backup database
32 during the period of time from the date and time 241 at which an abnormality occurred in the
15 network to the recovery date and time 242 of the network can be treated as recovery backup data
by the backup processor 3 1 on the condition that both periods of time are not coincident. The
backup processor 3 1 can send this recovery backup data to the server 2. In this case, the
database management processor 20 can restore the database 23 to its normal state using the
received recovery backup data.
2 0 The above-described embodiment has been described in detail to facilitate
understanding the present invention. The invention is not always restricted to one having all
the configurations described. Other configurations may be added to the above embodiment.
Also, some configurations of the above embodiment may be deleted. Further, some
configurations of the above embodiment may be replaced by other configurations.
2 5 Additionally, all or some of the above-described configurations and functions may
be implemented in hardware, for example, by designing them using an integrated circuit.
Further, the above-described configurations and functions may be implemented in software by
causing a processor to interpret and execute a computer program realizing the functions.
Information about the computer program, data table, files, and so on that realize the functions
30 can be stored in a storage device (such as a memory, a hard disc, or an SSD (solid state drive)) or
in a storage medium (such as an IC (integrated circuit) card, an SD (secure digital) memory card,
or a DVD (digital versatile disc)).

WE CLAIM:
1. A plant monitoring control system comprising:
a controller (3) for monitoring monitored subjects including at least plant
equipment (7);
a monitoring apparatus (1) connected with the controller (3) via a network (4);
and
a server (2) connected with the controller (3) via the network (4);
wherein said controller (3) has: a monitoring processor (30) for collecting
operational data indicating operational states of the monitored subjects from these monitored
subjects and transmitting the collected data to the monitoring apparatus (I) and to the server (2)
via the network (4); a backup database (32) for storing the operational data collected by the
monitoring processor (30); and a backup processor (3 I) operative to send the operational data
stored in the backup database (32) to the server (2) via the network (4), to detect whether there is
any abnormality in the network (4), and to manage backup administrative information (34) and
the backup database (32) on the basis of results of the detection;
wherein said server (2) has a database (23) for storing the operational data sent
from the controller (3) and a database management processor (20) operative to exchange
information with the controller (3) via the network (4), to detect whether there is any
abnormality in the network (4), and to manage the database (23) on the basis of results of the
detection;
wherein said database management processor (20) operates to send a backup data
transmission request to the controller (3) via the network (4) on the condition that the network
(4) is detected to have recovered to its normal state after the network (4) is detected to have an
abnormality and to restore the database (23) to its normal state using the received backup data if
the backup data is subsequently received from the controller (3) via the network (4); and
wherein said backup processor (3 1) operates to record a date and time (341) at
which an abnormality occurred in the network (4) in the backup administrative information (34)
(322) if the abnormality in the network (4) is detected, to record a date and time (342) at which
the network (4) was restored to its normal state as a recovery date and time of the network in the
backup administrative information (34) (326) if the network (4) is detected to have varied from
the abnormal state to the normal state, and to send the operational data stored in the backup
database (32) during a period of time from the date and time (341) at which the abnormality
occurred in the network (4) to the date and time (342) of the recovery of the network (4) as the
backup data to the server (2) if the backup data transmission request is received from the server
(2).
2. The plant monitoring control system of claim 1,
wherein said database management processor (20) operates to record the date and
time (341) at which the abnormality occurred in the network (4) in database administrative
information (24) (322) if the abnormality in the network (4) is detected, to record the date and
time (342) at which the network (4) was restored to its normal state as recovery date and time of
the network (4) if the network (4) is subsequently detected to have varied from the abnormal
state to the normal state, and to add information including the date and time (241) at which the
abnormality occurred in the network (4) and the recovery date and time (242) of the network (4)
that are recorded in the database administrative information (24) to said backup data
transmission request; and
wherein said backup processor (3 1) operates to make a decision as to whether a
period of time running from the date and time (241) of the occurrence of the abnormality in the
network (4) to the recovery date and time (242) of the network (4) added to the backup data
transmission request is coincident with a period of time running from the date and time (341) of
the occurrence of the abnormality in the network (4) to the recovery date and time (342) of the
network (4) and recorded in the backup administrative information (34) if the backup data
transmission request is received from the server (2) and to send the backup data as collated
backup data to the server (2) on the condition that both periods of time agree.
3. The plant monitoring control system of claim 1,
wherein said database management processor (20) operates to cause the date and
time (241) at which an abnormality occurred in the network (4) to be recorded in the database
administrative information (24) if the abnormality in the network (4) is detected (3 1 I), to cause
the date and time (242) at which the network (4) was restored to its normal state to be recorded
as a recovery date and time of the network (4) in the database administrative information (24) if
the network (4) was subsequently detected to have recovered to its normal state (3 13), and to add
information recorded in the database administrative information (24) and including the date and
time (241) of the occurrence of'the abnormality in the network (4) and the recovery date and
time (242) of the network (4) to the backup data transmission request; and
wherein said backup processor (3 1) makes a decision as to whether the period of
time running from the date and time (241) of the occurrence of the abnormality in the network
(4) to the recovery date and time (242) of the network (4) and added to the backup data
transmission request is coincident with the period of time running from the date and time (341)
of the occurrence of the abnorn~alityin the network (4) to the recovery date and time (342) of the
- 12 -
network (4) and recorded in the backup administrative information (34) if the backup data
transmission request is received from the server (2) and sends the operational data stored in the
backup database (32) during the period of time running from the date and time of the occurrence
of the abnormality in the network (4) to the recovery date and time of the network (4) and added
to the backup transmission request as the backup data to the server (2) on the condition that both
periods of time are not coincident.
4. The plant monitoring control system of claim 1, wherein said backup processor
(3 1) stores operational data collected prior to the occurrence of the abnormality in the network
(4) and collected after the network (4) has changed from the abnormal state to the normal state in
said backup database (32) and deletes old backup data that has been present for a given period of
time (352) to secure an area of the backup database (32).