JP2002190802A - Network monitor system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a network monitor system that can recognize occurrence of a fault with respect to each unit of a network at a remote place. SOLUTION: The network monitor system monitors occurrence of a fault in the network consisting of a plurality of units. A master unit 10 in the units has a fault presence detection means 16 of a master side microcomputer 15 that detects the presence of a fault in the network, a RAM 2 that stores the result of detection of the fault presence detection means and a display section 13 that displays the result of detection stored in the RAM.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a network monitoring system for detecting the presence or absence of an abnormality in a network composed of a plurality of units.

[0002]

2. Description of the Related Art Conventionally, such a network monitoring system has been designed to detect the presence or absence of an abnormality in a network constituted by a plurality of units, for example, a ring network constituted by a plurality of units connected by a ring connection.

According to such a network monitoring system, for example, when an abnormality occurs in a network, the occurrence of the abnormality is notified by an alarm or the like.

[0004]

However, according to the above-described conventional network monitoring system, when an abnormality occurs in the network, the occurrence of the abnormality is reported by an alarm or the like, but the alarm or the like can be recognized. If there is no network administrator within the range, there is a problem that it is not possible to recognize the occurrence of an abnormality in the network, and it is not possible to recognize which unit in the network has an abnormality.

[0005] The present invention has been made in view of the above problems, and an object of the present invention is to provide a network monitoring system capable of remotely recognizing the occurrence of an abnormality relating to each unit in a network. is there.

[0006]

In order to achieve the above object, a network monitoring system according to the present invention is a network monitoring system for monitoring an abnormality in a network composed of a plurality of units. The unit includes an abnormality detection unit that detects the presence or absence of an abnormality in the network, a storage unit that stores a detection result of the abnormality detection unit, and a display unit that displays a detection result stored in the storage unit. To have.

Therefore, according to the network monitoring system of the present invention, the master unit among the plurality of units displays the presence or absence of an abnormality in the network on the display means. The occurrence of an abnormality relating to the unit can be remotely recognized.

Further, in the network monitoring system according to the present invention, the master unit recognizes the occurrence of an abnormality in the network based on a detection result of the abnormality presence / absence detecting means. A notification unit is provided for notifying the external terminal outside the network when the occurrence of the abnormality is recognized.

Therefore, according to the network monitoring system of the present invention, when the master unit recognizes the occurrence of an abnormality in the network, the occurrence of the abnormality is notified to an external terminal outside the network. Even if it does, an automatic notification can be made to an external terminal, for example, an organization such as a network management center.

Further, in the network monitoring system according to the present invention, the network is a ring network in which a plurality of units are connected in a ring, and the abnormality detecting means is provided for the unit to which the master unit is connected in a ring. Message transmitting means for transmitting a message every predetermined period, and a message receiving means for receiving the message transmitted by the message transmitting means every predetermined period via a predetermined unit in the ring network. An abnormality determining means for detecting the presence or absence of an abnormality in the network based on whether or not the message receiving means has received a message at predetermined intervals.

Therefore, according to the network monitoring system of the present invention, the master unit transmits a message to the ring-connected unit at predetermined intervals, and transmits this message via the predetermined unit in the ring network to the master unit. Is received at predetermined intervals, that is, taking advantage of the characteristics of the ring network such that the message transmitted from the master unit returns to the master unit,
If the master unit cannot receive a message at predetermined intervals, it detects abnormalities in the network, so the user of the master unit can remotely recognize the occurrence of abnormalities related to each unit in the network. can do.

Further, the network monitoring system according to the present invention is characterized in that the unit determines whether or not the unit has received a message at predetermined intervals, and when the unit determines that the message cannot be received, In place of the message, having an error message transmitting means for transmitting an error message to a master unit, when the error recognition means of the master unit receives the error message in the message receiving means, based on the error message , To recognize the unit where the error occurred.

Therefore, according to the network monitoring system of the present invention, when the master unit receives an error message, the master unit can recognize the unit in which the abnormality has occurred based on the error message. It is possible to recognize which unit in the network failed.

Further, in the network monitoring system according to the present invention, each unit in the network detects a stop of the power supply from the network, and the stop detection unit stops the power supply when the predetermined mode is set. Erasing means for erasing the program stored in the own unit upon detecting the error.

Therefore, according to the network monitoring system of the present invention, when the power supply stoppage due to the unauthorized removal of the unit is detected in the predetermined mode, for example, the theft monitoring mode, the program stored in the unit is stored. So that even if the unit is stolen, the stolen unit will be unusable,
Very useful for theft prevention.

To achieve the above object, a network monitoring system according to the present invention is a network monitoring system for monitoring an abnormality in a network composed of a plurality of units, wherein a master unit in the plurality of units includes:
An abnormality detection unit for detecting the presence or absence of an abnormality in the network, and a display unit for displaying a detection result of the abnormality detection unit are provided.

Therefore, according to the network monitoring system of the present invention, the master unit of the plurality of units is
Since the presence or absence of an abnormality in the network is displayed on the display means without going through the storage means, the user of the master unit can remotely recognize the occurrence of an abnormality relating to each unit in the network.

In the network monitoring system according to the present invention, the master unit has an abnormality recognizing means for recognizing the occurrence of an abnormality relating to a unit in the network based on the detection result of the abnormality presence / absence detecting means. When the abnormality recognition unit recognizes the occurrence of an abnormality related to a unit, the unit related to the occurrence of the abnormality is identified and displayed.

Therefore, according to the network monitoring system of the present invention, when the occurrence of an abnormality relating to a unit in the network is recognized, the unit relating to the occurrence of the abnormality is identified and displayed on the display means. In addition, a unit in which an abnormality has occurred in the network can be easily recognized on the screen.

Further, in the network monitoring system according to the present invention, the display means displays all the units in the network on a screen and identifies and displays the unit relating to the occurrence of the abnormality among all the units.

Therefore, according to the network monitoring system of the present invention, while all the units in the network are displayed on the screen, the unit relating to the occurrence of the abnormality is identified and displayed among all the units. Can easily recognize, on the screen, a unit in which an abnormality has occurred in the network, from the viewpoint of the configuration of the entire network.

A network monitoring system according to the present invention is a network monitoring system for monitoring an abnormality in a network composed of a plurality of units, wherein a master unit in the plurality of units detects the presence or absence of an abnormality in the network. And a storage unit for storing and managing the detection result of the abnormality detection unit.

Therefore, according to the network monitoring system of the present invention, the master unit of the plurality of units stores and manages the presence / absence of an abnormality in the network. Although it is possible, by recognizing the presence / absence of an abnormality in the network on the master unit side, for example, the master unit has a failure recovery function for the entire network, and performs a failure recovery operation when an abnormality occurs in the network. Various processing correspondences are possible.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A network monitoring system according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram showing a configuration of the entire network monitoring system shown in the present embodiment, and FIG. 2 is a block diagram showing a schematic configuration inside the network monitoring system shown in the present embodiment.

The network monitoring system 1 shown in FIG.
Is a network bus (hereinafter simply referred to as a bus) 2
Through a plurality of (for example, five) units 10 and 20 to form a ring network by ring connection,
One of these units is referred to as a master unit 10,
The remaining four units are slave units 20.

As shown in FIG. 2, the master unit 10 includes a bus driver 11 for communication connection with the bus 2, a RAM 12 for storing various data and the like, a display unit 13 for displaying various information, Outside mobile terminal 50
Notification means 14 for wireless connection with the master unit 1
And a master microcomputer 15 for controlling the whole of the master microcomputer 15.

Each slave unit 20A (20B, 20B)
C, 20D), as shown in FIG. 2, a bus driver 21 for communication connection with the bus 2 and an R for storing a control program and the like.
AM 22 and this slave unit 20A (20B, 2B).
0C, 20D) Slave microcomputer 23 for controlling the whole
And

FIG. 3 is a block diagram showing a schematic configuration inside the master microcomputer 15 relating to the master unit 10. As shown in FIG.

The master microcomputer 15 shown in FIG. 3 is provided with an abnormality detecting means 16 for detecting the presence or absence of an abnormality in the network.
And based on the detection result of the abnormality presence / absence detection means 16,
Abnormality recognition means 17 for recognizing the occurrence of an abnormality in the network
And

The abnormality presence / absence detecting means 16 transmits a message to the slave unit 20A at every interval time, which will be described later, and the message transmitting means 16A and the slave unit 20A → the slave unit 20B → the slave unit 20C → the slave unit 20D. A message receiving means 16B for receiving the message transmitted by the message transmitting means 16A and an error message from the slave unit 20, and whether or not the message receiving means 16B has received the message within the message transmission time. And abnormality detecting means 16C for outputting a detection result of the presence or absence of the abnormality.

The master microcomputer 15 sets an interval time, a message transmission time, and an error monitoring time.

First, the interval time is a timing time for transmitting a message from the message transmission means 16A of the master microcomputer 15 to the slave unit 20A.
For example, it is equivalent to 1 sec.

The message transmission time is defined as a normal time when a message transmitted from the message transmitting means 16A is received by the message receiving means 16B via the slave unit 20A → the slave unit 20B → the slave unit 20C → the slave unit 20D. , For example, 10 msec.

Further, the error monitoring time means that if a message transmitted every interval time cannot be received within the message transmission time, the abnormality determination means 16C outputs an abnormality detection result. The abnormality recognizing means 17 recognizes the occurrence of the abnormality, but even in such a case, the message is transmitted again for a certain period until the next interval time comes, and a retry operation for receiving the message is performed. Do. Therefore, an error monitoring time, for example, 100 msec, from the start of the interval time to the time when the retry operation can be continued is set as an error monitoring time. It recognizes that an error has occurred.

FIG. 4 is a block diagram showing a schematic configuration inside the slave microcomputer 23 of the slave unit 20A.

The slave microcomputer 23 shown in FIG. 4 determines whether or not a message has been received at intervals of an interval time. The reception determination means 24 receives the message at intervals of the interval time. If successful, the message transfer means 25 for transferring this message to the next unit, and if the message cannot be received at intervals of time by the reception determination means 24, the preceding slave unit 20 It has a message transmitting means 26 for determining that an abnormality has occurred and transmitting a message such as an error message to the next unit.

Next, the operation of the network monitoring system 1 according to the present embodiment will be described. FIG. 5 is an explanatory diagram simply showing a case where an abnormality occurs in the slave unit 20B, and FIG. 6 is a flowchart showing a processing operation of the master microcomputer 15 relating to the network monitoring processing of the network monitoring system 1 according to the present embodiment. .

The network monitoring process means that even if an abnormality occurs in the slave unit 20 in the network,
This is a process in which the master unit 10 can recognize which slave unit 20 has an abnormality.

The master microcomputer 15 determines whether or not the message has been received through the message receiving means 16B as shown in FIG. 6 (step S1).
1). If you were able to receive the message,
The setting of the error monitoring time is canceled (step S12), and the process proceeds to a main routine (not shown).

If no message can be received in step S11, it is determined whether or not there is a message transmission request for transmitting the next message (step S1).
3). Note that this message transmission request is made for each interval time.

If there is a message transmission request in step S13, the requested message is set in the message transmission means 16A (step S14), the interval time is set (step S15), and the message transmission time is set. (Step S16), message transmission means 1
The message is transmitted to the slave unit 20A through 6A (step S17). Further, an error monitoring time is set (step S18), and the process proceeds to a main routine (not shown).

If there is no message transmission request in step S13, it is determined whether the currently set interval time has elapsed (step S19). If the currently set interval time has elapsed, an interval message is set (step S20), and step S15 is performed.
Move to

If it is determined in step S19 that the currently set interval time has not elapsed, it is determined through the abnormality determination means 16C whether or not the currently set error monitoring time has elapsed (step S21). If the currently set error monitoring time has elapsed, it is recognized through the abnormality recognition means 17 that an error has occurred in the network, and the occurrence of the error is displayed on the display unit 13 (step S2).
2) The process proceeds to a main routine (not shown).

If the currently set error monitoring time has not elapsed in step S21, it is determined whether the currently set message transmission time has elapsed (step S23).

If the currently set message transmission time has elapsed, a message transmission retry operation is performed to transmit the message again (step S24), and again,
The message transmission time is set (step S25), and the process proceeds to a main routine (not shown).

If the currently set message transmission time has not elapsed in step S23, the flow shifts to a main routine (not shown).

Next, the operation of the slave unit 20 for receiving and transferring the message transmitted from the master unit 10 will be described. FIG. 7 is a flowchart showing the processing operation of the slave microcomputer 23 relating to the network monitoring processing of the slave unit 20.

The slave microcomputer 23 determines whether or not the message via the bus 2 has been successfully received through the reception determining means 24 (step S31). If the message can be received through the reception determining means 24, the received message is set in the message transfer means 25 (step S32), and an interval time is set (step S33). Is transmitted to the bus 2 (step S34), and the process shifts to a main routine (not shown).

If the message cannot be received in step S31, it is determined whether or not the currently set interval time has elapsed (step S35). If the currently set interval time has elapsed, it is recognized that an error has occurred in the preceding slave unit 20 and this error message is transmitted to the message transmission unit 26.
Is set (step S36), and the routine goes to step S33.

If the currently set interval time has not elapsed in step S35, it is determined whether there is a message transmission request (step S37). If there is a message transmission request, a message related to the transmission request is set in the message transmission unit 26 (step S3).
8) The process proceeds to step S33.

If there is no message transmission request in step S37, the flow shifts to a main routine (not shown).

For example, assume that an abnormality has occurred in the slave unit 20B as shown in FIGS. 5 (a) and 5 (b).

The slave unit 20A sets a message from the master unit 10 in the message transfer means 25 at every interval time, and the message transfer means 2
5 to the slave unit 20B via the bus.

However, since the slave unit 20B has failed, the slave unit 20C cannot receive a message from the slave unit 20B every interval time. It is determined that an error has occurred, an error message is set in the message transmission means 26, and this error message is transmitted to the slave unit 20D.

When receiving the error message through the slave unit 20D, the master unit 10 can recognize the occurrence of an error in the slave unit 20B based on the error message.

According to the present embodiment, master unit 1
0 transmits a message to the slave unit 20A connected to the ring at every interval time, and the master unit 10 receives the message at every interval time via the slave unit 20A → the slave unit 20B → the slave unit 20C → the slave unit 20D. In other words, taking advantage of the characteristics of the ring network such that the message transmitted from the master unit 10 returns to the master unit 10, if the master unit 10 cannot receive the message at every interval time, the abnormality in the network is determined. Since the detection is performed, the user of the master unit 10 can remotely recognize the occurrence of the abnormality relating to each slave unit 20 in the network.

According to the present embodiment, when the master unit 10 receives an error message from the slave unit 20, the master unit 10 recognizes the slave unit 20 in which an error has occurred based on the error message. The master unit 10 can recognize which slave unit 20 in the network has an abnormality.

In the above embodiment, the master unit 10 recognizes the occurrence of an abnormality in the network. However, when the occurrence of an abnormality in the network is recognized, the mobile terminal such as a network management center outside the network recognizes the occurrence of the abnormality. 50 is automatically notified.

The operation in this case will be described. FIG. 8 shows the master microcomputer 15 relating to the abnormality notification processing.
5 is a flowchart showing the processing operation of the first embodiment.

The master microcomputer 15 shown in FIG. 8 determines whether or not abnormality has been detected through the slave unit 20 (step S41). If the occurrence of an abnormality is detected, the abnormality information relating to the occurrence of the abnormality is stored in the RAM 12 (step S42), and the abnormality information stored in the RAM 12 is displayed on the display unit 13 (step S43).

Further, the master-side microcomputer 15 determines whether or not it has been automatically connected to the portable terminal 50 such as a network management center for maintaining and managing the network through the notifying means 14 (step S44). If the mobile terminal 50 has been automatically connected, the abnormality information is reported to the mobile terminal 50 (step S45), and the processing operation ends.

According to the present embodiment, the master unit 10 of the plurality of slave units 20 displays the abnormality information in the network on the display unit 13, so that the user of the master unit 10 The occurrence of an abnormality relating to each unit can be remotely recognized.

Further, when the master unit 10 recognizes the abnormality information in the network, the occurrence of the abnormality is notified to the portable terminal 50 outside the network. Can be automatically notified to the portable terminal 30.

In the above-described embodiment, the abnormality information in the network is displayed on the display unit 13 of the master unit 10 as shown in step S43 of FIG. The processing operation of the side microcomputer 15 will be described. FIG. 9 is a flowchart showing the processing operation of the master microcomputer 15 relating to the abnormality information display processing, and FIG. 10 is an explanatory diagram showing the display contents of the display unit 13 relating to the abnormality information display processing.

In FIG. 9, the master microcomputer 15
The abnormality information relating to the occurrence of the abnormality stored in the AM 12 is read out (step S71), and the position configurations of the master unit 10 and the slave unit 20 in the network are displayed on the display unit 13 as shown in FIG. 10 (step S71). S72).

Further, the master microcomputer 15 has a RAM
The slave unit 20 involved in the occurrence of the abnormality is identified based on the abnormality information read from the step 12 (step S7).
3) Among the slave units 20 currently displayed on the display unit 13, the slave unit 20 related to the occurrence of the abnormality
Is displayed, for example, by blinking (step S74), and this processing operation ends. The display screen shown in FIG. 10 indicates that an abnormality has occurred in the slave unit 20C.

According to the present embodiment, while all the units (master unit 10 and slave unit 20) in the network are displayed on the screen, among these units, the slave unit 20 related to the occurrence of the abnormality blinks on the display screen. Since the display is performed, the user of the master unit 10 can easily recognize on the screen the slave unit 20 in which an abnormality has occurred in the network, from the viewpoint of the configuration of the entire network.

In the abnormality information display processing shown in FIG. 10, the slave unit 20 relating to the occurrence of the abnormality is blinked on the display screen. Unit 2
It goes without saying that the same effect can be obtained even if 0 is identified and displayed.

Also, in the above embodiment, the master unit 10 stores the abnormality information in the network in the RAM 1.
2, the occurrence of an abnormality in the network is notified to the portable terminal 50, and the occurrence of the abnormality is displayed on the display unit 13 of the master unit 10. When a malfunction is detected in the network, a reset signal is transmitted to the slave unit 20 in the network via a different route from the bus 2 to reset the slave unit 20 related to the occurrence of the fault. Recovery may be executed, and various measures can be taken simply by storing and managing the abnormality information in the network in the RAM 12.

Next, a description will be given of a case where the network monitoring system shown in the above embodiment is applied to a theft monitoring system for preventing the slave unit 20 from being stolen in a network constructed in a vehicle.

This theft monitoring system differs from the network monitoring system shown in FIG. 2 in that the master microcomputer 15 of the master unit 10 sets the theft monitoring mode, the internal configuration of the slave microcomputer 23 of the slave unit 20 and In its operation. FIG. 11 shows a slave unit 2 of a theft monitoring system according to another embodiment.
FIG. 9 is a block diagram showing a schematic configuration inside slave-side microcomputer 23A relating to the “0”.

The slave microcomputer 23A shown in FIG.
Is a stop detecting unit 27 for detecting a stop of supply of backup power from the network, in addition to the reception determining unit 24, the message transferring unit 25, and the message transmitting unit 26.
During the theft monitoring mode described later, the stop detecting means 2
7 detects that the backup power supply is stopped,
And an erasing means 28 for erasing the control program in M22.

FIG. 12 is a flowchart showing the processing operation of the slave microcomputer 23A relating to the theft monitoring system.

The slave microcomputer 23A determines whether the accessory power supply of the vehicle is turned off as shown in FIG. 11 (step S51). If the accessory power has been turned off, the theft monitoring mode is activated (step S52).

When the accessory power is turned on, the currently operating theft monitoring mode is released (step S5).
3).

FIG. 13 is a flowchart showing the processing operation of the slave microcomputer 23A relating to the theft monitoring system.

As shown in FIG. 13, the slave microcomputer 23A determines whether or not a message has been received from the master microcomputer 20 (step S61). If a message has been received, the received message is set in the message transfer means 25, this message is transmitted to the bus 2 (step S62), and the process proceeds to a main routine (not shown).

If the message has not been received in step S61, it is determined whether or not the theft monitoring mode is operating (step S63).

If the theft monitoring mode is in operation, it is determined through the stop detecting means 27 whether backup power is supplied from the master unit 10 (step S64). If the backup power is supplied, the process shifts to a main routine (not shown).

If the backup power is not supplied from the master unit 10 in step S64, the self-erasing program processing for erasing the control program stored in the RAM 22 is executed through the erasing means 28.
(Step S65), the processing operation ends. FIG.
2 and FIG. 13 are similarly performed on the master microcomputer 15 side.

As described above, according to the theft monitoring system, the stop of the backup power supply from the network is detected during the theft monitoring mode operation.
When 0 is removed from the network, the control program stored in the slave unit 20 whose power supply has been stopped is erased, so that the removed slave unit 20 becomes unusable, preventing theft. Is an effective means for

[0082]

According to the network monitoring system of the present invention configured as described above, the master unit among the plurality of units displays the presence or absence of an abnormality in the network on the display means. The user can remotely recognize the occurrence of an abnormality relating to each unit in the network.

According to the network monitoring system of the present invention, the master unit of the plurality of units stores and manages the presence or absence of an abnormality in the network.
Although it is possible to notify and display the above-described abnormality, it is possible to cope with various processes by recognizing the abnormality in the network on the master unit side.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram illustrating an overall configuration of a network monitoring system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a schematic configuration inside a network monitoring system shown in the present embodiment.

FIG. 3 is a block diagram illustrating a schematic configuration inside a master microcomputer in a master unit related to the network monitoring system shown in the present embodiment;

FIG. 4 is a block diagram showing a schematic configuration inside a slave microcomputer in a slave unit related to the network monitoring system shown in the present embodiment;

FIG. 5 is an explanatory diagram illustrating a case where an abnormality occurs in a network related to the network monitoring system according to the present embodiment.

FIG. 6 is a flowchart illustrating a processing operation of a master microcomputer related to a network monitoring process of the network monitoring system according to the present embodiment.

FIG. 7 is a flowchart showing a processing operation of a slave microcomputer related to a network monitoring process of the network monitoring system shown in the present embodiment.

FIG. 8 is a flowchart showing a processing operation of the master microcomputer relating to the abnormality notification processing of the network monitoring system shown in the present embodiment.

FIG. 9 is a flowchart showing a processing operation of the master microcomputer relating to the abnormality information display processing of the network monitoring system shown in the present embodiment.

FIG. 10 is an explanatory diagram showing display contents of a display unit of a master unit relating to an abnormality information display process of the network monitoring system shown in the present embodiment.

FIG. 11 is a block diagram showing a schematic configuration inside a slave microcomputer related to a slave unit of a theft monitoring system shown in another embodiment.

FIG. 12 is a flowchart showing a processing operation of a slave microcomputer related to a theft monitoring process of the theft monitoring system according to another embodiment.

FIG. 13 is a flowchart showing a processing operation of the slave microcomputer related to the theft monitoring processing of the theft monitoring system shown in another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Master unit 12 RAM (storage means) 13 Display part (display means) 14 Notification means 15 Master side microcomputer 16 Abnormality detection means 16A Message transmission means 16B Message reception means 16C Abnormality determination means 17 Abnormality recognition means 20 Slave unit 23 Slave side Microcomputer 24 reception determining means 25 message transferring means 26 message transmitting means 27 stop detecting means 28 erasing means 50 portable terminal (external terminal)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tomoyuki Hirano 5-35-2 Hakusan, Bunkyo-ku, Tokyo Inside Clarion Co., Ltd. (72) Inventor Fumika Ueno 5-35-2 Hakusan, Bunkyo-ku, Tokyo Clarion Within ON Co., Ltd. (72) Inventor Kazichi Kobayashi 5-35-2, Hakusan, Bunkyo-ku, Tokyo F-term within Clarion Co., Ltd. 5B089 GB02 KA12 KB03 KC30 KC47 MD09 5C087 AA02 AA03 BB58 BB71 DD03 DD08 DD43 EE05 5K030 GA14 KA23 LA01 MB01 5K031 AA08 BA03 CB09 EA07 5K035 BB02 BB03 EE02 GG02 JJ01 KK01 KK04

Claims (9)

[Claims] 1. A network monitoring system for monitoring an abnormality in a network composed of a plurality of units, wherein a master unit in the plurality of units includes an abnormality presence / absence detection means for detecting the presence / absence of an abnormality in the network. A network monitoring system, comprising: storage means for storing the detection result of the abnormality presence / absence detection means; and display means for displaying the detection result stored in the storage means. 2. An abnormality recognition unit for recognizing the occurrence of an abnormality in the network based on a detection result of the abnormality presence / absence detection unit. 2. The network monitoring system according to claim 1, further comprising a notification unit configured to notify an external terminal outside the network of the occurrence. 3. The network is a ring network in which a plurality of units are connected in a ring, and the abnormality detection means transmits a message to the unit to which the master unit is connected in a ring at predetermined intervals. Message transmitting means, and a message transmitted by the message transmitting means.
Message receiving means for receiving at predetermined intervals via a predetermined unit in the ring-type network; and abnormality in the network based on whether or not the message receiving means has received a message at predetermined intervals. 3. The network monitoring system according to claim 1, further comprising an abnormality determining unit that detects presence / absence. 4. The unit, comprising: a reception determination unit configured to determine whether the message is received at predetermined intervals; and if the reception determination unit determines that the message cannot be received, instead of the message, An error message transmitting unit that transmits an error message to a master unit, wherein the abnormality recognition unit of the master unit receives the error message by the message receiving unit, and based on the error message, a unit in which an abnormality has occurred. The network monitoring system according to claim 3, wherein the network monitoring system recognizes the information. 5. A unit in the network, comprising: a stop detecting means for detecting a stop of power supply from the network; and a stop unit detecting a stop of power supply by the stop detecting means while a predetermined mode is being set. 5. The network monitoring system according to claim 1, further comprising an erasing means for erasing a program stored in said network. 6. A network monitoring system for monitoring an abnormality in a network composed of a plurality of units, wherein a master unit in the plurality of units includes an abnormality presence / absence detection means for detecting the presence / absence of an abnormality in the network. A display unit for displaying a detection result of the abnormality detection unit. 7. The abnormality recognition means for recognizing occurrence of an abnormality relating to a unit in the network based on a detection result of the abnormality presence / absence detection means, wherein the display unit comprises: 7. The network monitoring system according to claim 6, wherein when the occurrence of an abnormality related to the unit is recognized, the unit related to the occurrence of the abnormality is identified and displayed. 8. The display means, while displaying all units in the network on a screen,
8. The network monitoring system according to claim 7, wherein a unit related to the occurrence of the abnormality is identified and displayed among all the units. 9. A network monitoring system for monitoring an abnormality in a network composed of a plurality of units, wherein a master unit in the plurality of units includes an abnormality presence / absence detection unit for detecting the presence / absence of an abnormality in the network. And a storage unit for storing and managing a detection result of the abnormality presence / absence detection unit.