JPH10290250A - Abnormality monitoring device for network - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an abnormality monitoring device for network by which a network management function is kept in a normal state in a master station unit even on the occurrence of a fault such as a broken line of a data transmission line. SOLUTION: On the occurrence of a fault, slave station units SU (SU1-SU3) are operated in the master mode, a master station unit MU is operated in the virtual slave mode and fault occurrence information including a fault occurrence location is sent from the slave station unit SU in the virtural slave mode to the master station unit MU via a data transmission line, then the network management function in the master station unit is kept in the normal state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication system in which a plurality of station units are connected via a ring-shaped data transmission path permitting cyclic transmission of digital communication data in a single direction. In particular, when a data transmission function in a network is impaired due to a disconnection of a data transmission path or an abnormality of a communication means for receiving and transmitting communication data, etc. The present invention relates to an abnormality monitoring device in a network that can maintain a network management function in a master station unit in a normal state.

[0002]

2. Description of the Related Art Conventionally, a network is generally known in which a plurality of station units are connected via a ring-shaped data transmission path which allows cyclic transmission of digital communication data in a single direction. I have.

In order to exchange communication data between station units in a network configured as described above, a communication IC for receiving and transmitting communication data is provided for each station unit. The communication data is transmitted from the communication IC of the station unit in a predetermined direction on the data transmission path. Then, in the communication IC of the station unit located on the downstream side of the transmission source in the data transmission path, it is sequentially determined whether or not its own station unit is designated as the receiving destination, and the own station unit is designated as the receiving destination. If not, the communication data is transmitted to the station unit located downstream of the own via the data transmission path, while if the own station unit is designated as the destination, the communication data is transmitted via the data transmission path. By using the communication IC to capture communication data, exchange of communication data between station units is realized.

[0004] Among the networks configured as described above, a network adopting a master / slave system as a communication system has been conventionally known. This network is composed of one master station unit serving as a master and other slave station units serving as slaves.

[0005] In the network configured as described above,
The master station unit manages the operation of the entire network and operates so as to maintain the data transmission function in the network, while the slave station unit is normally waiting in a reception waiting state, and the transmission transmitted from the master station unit is performed. Upon receiving communication data including control data such as start or reception start, reception or transmission of communication data is executed.

[0006]

However, according to the conventional network adopting the master / slave method as the communication method described above, when an error such as disconnection or poor connection occurs in the data transmission path, the error occurs. Since the station unit located on the downstream side of the data transmission path where the error occurred cannot receive the communication data, the master station unit cannot grasp the location where the abnormality has occurred in the network. There was an inherent problem to be solved that hindered the network management function.

[0007] The present invention has been made in view of the above-described circumstances, and allows a slave station unit to operate in a virtual master mode even when an abnormality such as disconnection or poor connection of a data transmission path occurs. By operating the master station unit in the virtual slave mode and transmitting the abnormality occurrence information including the location of the abnormality from the slave station unit in the virtual master mode to the master station unit in the virtual slave mode via the data transmission path, An object of the present invention is to provide an abnormality monitoring device in a network that can maintain a network management function in a station unit in a normal state.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a first aspect of the present invention is a ring-shaped data which permits cyclic transmission of digital communication data in a single direction between a plurality of station units. An abnormality monitoring device in a network configured to be connected via a transmission path and used in a network employing a master / slave method as a communication method, wherein the plurality of station units are one master station unit serving as a master. And one or more slave station units serving as slaves. The master station unit includes: a master-side abnormality determining unit that determines whether an abnormality has occurred in the network; and a master-side abnormality determination unit. There is an abnormality in the network in the means Master mode switching means for switching the operation mode of the master station unit itself from a master mode operating as a master to a virtual slave mode virtually operating as a slave when the determination is made. The unit is a slave-side abnormality determining unit that determines whether or not an abnormality has occurred in the network.When the slave-side abnormality determining unit determines that an abnormality has occurred in the network, the unit sets the operation mode of the slave station unit itself, Switching means for switching from a slave mode operating as a slave to a virtual master mode virtually operating as a master, and operating in the virtual master mode when an abnormality occurs in the network. That the slave station unit, to the master station unit operating in the virtual slave mode, the abnormality information including an abnormality occurrence location in the network and gist to be composed as transmitted via said data transmission channel.

According to the first aspect of the present invention, when it is determined by the master-side abnormality determining means that an abnormality has occurred in the network, the master-side operation mode switching means operates the operation mode of the master station unit itself as the master. From the master mode to the virtual slave mode that virtually operates as a slave, while the slave-side abnormality determining means determines that an abnormality has occurred in the network, the slave-side operation mode switching means Change the operation mode from slave mode operating as a slave to
Switch to a virtual master mode that virtually operates as a master. When an abnormality occurs in the network, abnormality occurrence information including an abnormality occurrence location in the network is transmitted from the slave station unit operating in the virtual master mode to the master station unit operating in the virtual slave mode via the data transmission path. Therefore, the network management function of the master station unit can be maintained in a normal state. In addition, abnormality occurrence information including the occurrence of the abnormality and the location of the abnormality
Since the information can be grasped in the master station unit, maintenance when the network falls into an abnormal state can be easily performed.

Further, the invention of claim 2 is characterized in that the plurality of station units include one master station unit serving as a master and a plurality of slave station units serving as slaves.

According to the second aspect of the present invention, the plurality of station units include one master station unit serving as a master and a plurality of slave station units serving as slaves.

According to a third aspect of the present invention, the plurality of slave station units include: a slave-side abnormality determining unit that determines whether an abnormality has occurred in the network; Slave mode switching means for switching the operation mode of the slave station unit itself from a slave mode operating as a slave to a virtual master mode virtually operating as a master, The gist is that the switching timings of the respective slave-side operation mode switching means are set at mutually shifted times on the same time axis.

According to the third aspect of the present invention, the switching timing of the slave-side operation mode switching means provided in each of the plurality of slave station units is set at mutually shifted times on the same time axis. Even if it is determined that an abnormality has occurred simultaneously in all slave station units, the slave station units located on the upstream side are sequentially switched to the virtual master mode, and the abnormality occurrence information obtained by each slave station unit is It can be transmitted to the station unit without exception.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an abnormality monitoring device in a network according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic block diagram of the periphery of an abnormality monitoring device according to the present invention, FIG. 2 is a network configuration diagram to which the abnormality monitoring device according to the present invention is applied, and FIG. FIG. 4 is a flowchart for explaining the operation of the apparatus, and FIG. 4 is an operation flowchart of the abnormality monitoring apparatus according to the present invention.
An embodiment of the present invention will be described below by exemplifying a form in which the present invention is applied to a network connecting various devices provided in a vehicle cabin.

First, the network configuration to which the abnormality monitoring device according to the present invention is applied will be described with reference to FIG. 2. The network allows digital data to be transmitted in a single direction between a plurality of station units. Digital data is exchanged between the station units by transmitting digital data in a single direction from each station unit to the data transmission line 11 by being connected via a data transmission line 11 exhibiting a ring topology. It is configured to be possible. Data transmission path 1
As 1, for example, an appropriate transmission medium such as a plastic optical fiber or an electric wire can be adopted. In the present embodiment, a plastic optical fiber is adopted as the data transmission line 11, and digital data is circulated in a clockwise direction and transmitted as an example.

As a communication system between the station units in the network, a master / slave system is adopted. Among the plurality of station units, one unit operates as a master station unit MU, and one or more other station units operate. Are operated as slave station units SU. That is, the slave station unit S
U is normally in a reception waiting state, but when communication data including a command such as transmission start or reception start is transmitted from the master station unit MU, the slave station unit SU responds to this by transmitting communication data. It is configured to receive or transmit.

The master station unit MU includes, for example, a CD (Compact Disc) changer device, an audio amplifier, and a DVD (Digital Vi).
deo Disc) device N1 such as a device, a radio receiver, a mobile phone, a navigation device, a digital TV, etc.
Is connected. Note that a plurality of devices can be connected to the master station unit MU.

The master station unit MU generates a reference clock such as a system clock SYCLK as an operation timing of the entire network system, and a clock generator (PLL) having a function of maintaining the phase of the generated reference clock with high accuracy. / CG; Phase
Lock Loop / Clock Generato
r) 9a built-in and a clock generator (PLL / C
G) The communication data including the system clock SYCLK generated in 9a is transmitted to each slave station unit SU, while the communication data transmitted from each slave station unit SU is received.

More specifically, the master station unit MU takes in various data transmitted from the device N1 including source data such as digital audio data and digital video data or control data of the device as appropriate. These various data and the system clock SYCLK supplied from the clock generator (PLL / CG) 9a are packetized by adding header information including the transmission source and the reception destination, and the packetized packet data is modulated. Processing, and sends out the packet data after the modulation processing to the data transmission path 11. At the same time, it takes in various data sent from each slave station unit SU, performs demodulation processing on these various data, and performs data demodulation processing. Function for selectively distributing and sending the And a network management function to maintain the entire network to normal.

Further, the master station unit MU
Monitors the presence / absence of communication data sent from the slave station unit SU3 located on the upstream side after transmitting the first communication data at the time of activation of the network system. As a result of the monitoring, the communication data is transmitted within a predetermined time described later. If there is no incoming call, the operation mode of the network is centrally managed by switching its own operation mode from the master mode to the virtual slave mode virtually operating as a slave and waiting for reception of the abnormality occurrence information. It has a network management function.

On the other hand, the slave station unit SU
1, SU2, and SU3 each include one or more devices N
2 to N7 are connected respectively. Each slave station unit SU captures packet data transmitted from the master station unit MU or the slave station unit SU, performs demodulation processing on the captured packet data, and obtains a system clock SYCLK or the like obtained from the demodulated data. Various data are selectively distributed to each of the devices N2 to N7 and transmitted in synchronization with the data transmission, while various data transmitted from the various devices N2 to N7 are taken in, and header information is added to these various data to form a packet. And a function of performing a modulation process on the packetized packet data and transmitting the packet data after the modulation process to the data transmission path 11.

Further, the slave station unit S
Each of U1, SU2, and SU3 monitors the presence or absence of communication data sent from the station units MU and SU located on the upstream side after the system is started, and as a result of this monitoring, each unit SU starts from the time of system startup. If communication data does not arrive within the prescribed time, switch its own operation mode from the slave mode to the virtual master mode that virtually operates as a master, and send out communication data including abnormality occurrence information. Thus, an abnormality occurrence information transmission function for transmitting the abnormality occurrence information to the original master station unit MU is provided.

Next, the master station unit M constituting the abnormality monitoring device in the network according to the present invention will be described.
The internal configuration of U and the slave station unit SU will be sequentially described with reference to FIG. The same reference numerals are given to members having functions common to the master station unit MU and the slave station unit SU, and redundant description will be omitted.

As shown in the figure, the master station unit MU receives light including various data transmitted in the form of optical signals from the slave station unit SU3 located on the upstream side via the data transmission line 11, and A communication IC which converts a received optical signal into an electric signal form and converts packet data including various converted data into the following.
5a, a light receiving unit 1a for transmitting the packet data transmitted from the light receiving unit 1a, demodulating the received packet data, and selectively distributing and transmitting various data after demodulation to the device N1. On the other hand, source data sent from the device N1 or various data including control data and the like are fetched as appropriate, and these various data and the system clock SYCLK supplied from the clock generator (PLL / CG) 9a are transmitted to the transmission source. The packetized packet data is subjected to a modulation process, and the modulated packet data is transmitted to the data transmission path 11 via the light emitting unit 3a described below. A communication IC 5a having a function of performing an operation, and transmitting packet data in the form of an electric signal transmitted from the communication IC 5a into an optical signal. The light emitting unit 3a that converts and transmits the converted packet data to the data transmission line 11a in the form of blinking light, performs operation monitoring and operation control of the communication IC 5a, and receives light in the light receiving unit 1a after the network system is activated. Is constantly monitored and input via the communication line 13a,
When it is determined that there is a possibility of occurrence of an abnormality in the data transmission line 11 on the upstream side, the operation mode of the master station unit MU itself is switched from the master mode to the virtual slave mode, and the communication IC 5a waits for reception of abnormality occurrence information. With this configuration, the system includes a master-side abnormality determination unit and a CPU 7a as a master-side operation mode switching unit having a network management function for centrally managing abnormality occurrence information in the network.

On the other hand, the slave station unit SU
As shown in FIG. 1, each of SU1, SU2, and SU3 has light receiving units 1b, 1c, and 1d, light emitting units 3b, 3c, and 3d, and clock generators 9b, 9c, and 9d, respectively. 1, the demodulation process is performed on the fetched packet data, and various data after the demodulation process are selectively distributed to various devices N2 to N7 and transmitted, while various devices N2 to N7 are transmitted. It takes in various data including source data or control data etc. sent out from, and adds header information including the transmission source and reception destination to these various data and packetizes them. A communication IC 5b as a communication unit having a function of performing a modulation process and transmitting the packet data after the modulation process to the data transmission path 11 via each light emitting unit 3; c, 5d, the operation monitoring and operation control of each communication IC 5, and the light receiving state in each light receiving unit 1 after network system startup is constantly monitored and input via each communication line 13, and the upstream data transmission path 11 When it is determined that there is a possibility of occurrence of an abnormality in the slave unit, the operation mode of each station unit is switched from the slave mode to the virtual master mode to cause each communication IC 5 to transmit the abnormality occurrence information. And CPU 7 as slave side operation mode switching means
b, 7c, 7d.

Next, the operation of the abnormality monitoring apparatus in the network according to the present invention will be described with reference to the operation flowchart shown in FIG. 4 separately for the master station unit MU and the slave station unit SU.

First, the master station unit M
To explain the operation of U, first, as shown in FIG. 4, when the network system is activated (step S
1), the master station unit MU performs a network diagnosis process of diagnosing the occurrence of an abnormality in the network and, when the occurrence of the abnormality is detected, collecting abnormality occurrence information including the location of the abnormality.

That is, the master station unit M
The U CPU 7a causes the communication IC 5a to transmit communication data for network diagnosis, and
a sends out communication data to the data transmission line 11a (step S2).

Next, the CPU 7a monitors and inputs the light receiving state of the light receiving section 1a via the communication line 13a, and the light receiving section 1a receives a correct optical signal within a first predetermined time T1 from the time when the network system is activated. It is determined whether or not it has been performed (steps S3 and S4). Note that the first predetermined time T1 starts from the start of the network system.
The communication data transmitted from the light emitting unit 3a is transmitted to the data transmission path 1
The time is normally set for each network, assuming a time normally required for the light receiving unit 1a to go around the network 1 and receive the light.

As a result of the optical signal reception determination in steps S3 and S4, if the light receiving section 1a receives a correct optical signal within a first predetermined time T1 from the time of activation of the network system, the CPU 7a transmits data over the network. The function is diagnosed as being in a normal state, and the network diagnosis processing is terminated.

On the other hand, as a result of the optical signal reception determination in steps S3 and S4, if the light receiving unit 1a does not receive a correct optical signal within the first predetermined time T1 from the time of starting the network system, If any abnormality occurs, the CPU 7a causes the communication IC 5a to stop sending communication data for network diagnosis, and in response to this, the light emitting unit 3a stops sending communication data to the data transmission path 11a. (Step S
5). Further, the CPU 7a executes a process of switching the operation mode of the master station unit MU itself from the master mode to the virtual slave mode (step S7).
6) The communication IC 5a is made to wait for the reception of the abnormality occurrence information, and it is determined whether or not the light receiving unit 1a has received the correct optical signal within the third predetermined time T3 (steps S7 to S7).
8). Note that, when the operation mode of the master station unit MU itself is switched from the master mode to the virtual slave mode, the third predetermined time T3 is set immediately after the start of the network system on the downstream side of the master station unit MU. Assuming the time normally required for communication data transmitted from the located slave station unit SU1 to circulate through the data transmission path 11 and be received by the light receiving unit 1a, the time is set to an appropriate time for each network.

As a result of the optical signal reception determination in steps S7 and S8, if the light receiving section 1a receives a correct optical signal within a third predetermined time T3 from the time of activation of the network system, the CPU 7a determines the received communication data. The abnormality occurrence information contained therein is acquired (step S9), and the network diagnosis processing is terminated. Thus, according to the abnormality monitoring device for a network according to the present invention, the network management function for centrally managing the abnormality occurrence information in the network can be maintained in a normal state. Further, since the abnormality occurrence information and the abnormality occurrence information including the abnormality occurrence location can all be grasped by the master station unit MU, maintenance when the network falls into an abnormal state can be easily performed.

On the other hand, as a result of the optical signal reception determination in steps S7 and S8, if the light receiving section 1a does not receive a correct optical signal within a third predetermined time T3 from the time of activation of the network system, ie, the master station unit When the operation mode of the MU itself is switched from the master mode to the virtual slave mode and communication data including the abnormality occurrence information cannot be received from the slave station unit SU, the CPU 7a determines whether the abnormality has occurred in the network. Diagnose that it is in an abnormal state that cannot be identified, and abnormally end the network diagnosis processing.

Next, the slave station unit SU
Operation of the slave station unit SU1
Will be described as an example.

As shown in FIG. 4, first, when the network system is activated (step S11), the slave station unit SU1 diagnoses whether or not an abnormality has occurred in the network. An abnormality occurrence information transmission process for transmitting abnormality occurrence information including an abnormality occurrence location to the master station unit MU is executed.

That is, the CPU 7b of the slave station unit SU1 monitors and inputs the light receiving state of the light receiving unit 1b via the communication line 13b, and within a second predetermined time T2 from the start of the network system, the light receiving unit 1b
It is determined whether or not b has received a correct optical signal (steps S12 and S13). Note that the second predetermined time T2 is:
Starting from the start of the network system, assuming the time normally required for communication data transmitted from the master station unit MU to circulate through the data transmission path 11 and be received by the light receiving section 1b of the slave station unit SU1, It is set at an appropriate time for each network.

As a result of the optical signal reception determination in steps S12 and S13, if the light receiving section 1b receives a correct optical signal within the second predetermined time T2 from the time of starting the network system, the CPU 7b transmits data over the network. The function is diagnosed as being in a normal state, and the abnormality occurrence information transmission processing ends.

On the other hand, as a result of the optical signal reception determination in steps S12 and S13, if the light receiving section 1b does not receive a correct optical signal within the second predetermined time T2 from the time when the network system is activated, for example, as shown in FIG. As shown in FIG. 3, when any abnormality occurs in the network such as disconnection of the data transmission line 11a, the CPU 7b
Executes a process of switching the operation mode of the slave station unit SU1 from the slave mode to the virtual master mode (step S14).
The communication data for network diagnosis is sent to C5b, and the light emitting unit 3b receives the data from the data transmission path 11b.
The communication data is transmitted to (step S15).

Next, the CPU 7b waits until a fourth predetermined time T4 elapses from the time of activation of the network system, and when this waiting time is over, the CPU 7b informs the communication IC 5b that an abnormality has occurred and that the light receiving unit 1b receives the notification. The light emitting unit 3a sends out the communication data containing the error occurrence information to the data transmission line 11a in response to the transmission of the error occurrence information including the fact that the communication data cannot be received (step S1).
7) After transmitting the communication data, the transmission processing of the communication data is terminated (step S18).

Each slave station unit S
A second predetermined time T2 used as a reference time for determining whether or not each light receiving unit 1 of U has received a correct optical signal is transmitted from the master station unit MU starting from the start of the network system. Assuming a time normally required for the received communication data to circulate through the data transmission path 11 and be received by the respective light receiving units 1 of the respective slave station units SU, the respective slave station units SU are shifted from each other. Each is set at an appropriate time. Therefore, the time when each slave station unit SU is switched from the slave mode to the virtual master mode is set to a time mutually shifted on the same time axis. Thereby, even if it is determined that an abnormality has occurred in a plurality of slave station units SU at the same time, the slave station units SU located upstream are sequentially switched to the virtual master mode. The abnormality occurrence information can be transmitted to the master station unit MU without exception.

Finally, it is needless to say that the present invention is not limited to the above-described embodiment, but includes embodiments appropriately changed within the scope of the claims.

[0043]

According to the first aspect of the present invention, when an abnormality occurs in the network, the abnormality including the abnormality occurrence part in the network is transferred from the slave station unit operating in the virtual master mode to the master station unit operating in the virtual slave mode. Since the generated information is transmitted via the data transmission path, the network management function of the master station unit can be maintained in a normal state. Further, since the occurrence of the abnormality and the abnormality occurrence information including the location of the abnormality can be grasped in the master station unit, maintenance when the network falls into an abnormal state can be easily performed.

According to the third aspect of the present invention, the switching timings of the slave-side operation mode switching means provided in each of the plurality of slave station units are set at mutually shifted times on the same time axis. Even if it is determined that an abnormality has occurred in a plurality of slave station units at the same time, the slave station units located on the upstream side are sequentially switched to the virtual master mode, and the abnormality occurrence information obtained by each slave station unit is obtained. Can be transmitted to the master station unit without exception.

[Brief description of the drawings]

FIG. 1 is a schematic block configuration diagram around an abnormality monitoring device according to the present invention.

FIG. 2 is a network configuration diagram to which the abnormality monitoring device according to the present invention is applied;

FIG. 3 is a diagram for explaining the operation of the abnormality monitoring device according to the present invention.

FIG. 4 is an operation flowchart of the abnormality monitoring device according to the present invention.

[Explanation of symbols]

Reference Signs List 1 light receiving unit 3 light emitting unit 5 communication IC 7a CPU of master station unit (master side abnormality determination means, master side operation mode switching means) 7b, 7c, 7d C of slave station unit
PU (slave side abnormality judgment means, slave side operation mode switching means) 9 Clock generator (PLL / CG) 11 Data transmission line 13 Communication line MU Master station unit SU Slave station unit N Various devices

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Katsutoshi Nakajima 2771 Ooka, Numazu City, Shizuoka Prefecture Inside Yazaki Corporation

Claims (3)

[Claims] 1. A plurality of station units are connected via a ring-shaped data transmission path permitting cyclic transmission of digital communication data in a single direction, and a master / slave system is used as a communication system. An abnormality monitoring device in a network used for an adopted network, wherein the plurality of station units include one master station unit serving as a master and one or more slave station units serving as slaves. The master station unit includes: a master-side abnormality determining unit that determines whether or not an abnormality has occurred in the network; and the master-side unit when the master-side abnormality determining unit determines that an abnormality has occurred in the network. Own movement A master-side operation mode switching means for switching a mode from a master mode operating as a master to a virtual slave mode virtually operating as a slave, wherein the slave station unit determines whether an abnormality has occurred in the network. When the slave-side abnormality determining unit determines that an abnormality has occurred in the network, the operation mode of the slave station unit itself is changed from the slave mode operating as a slave to a virtual master. And a slave-side operation mode switching means for switching to a virtual master mode operating as a virtual slave mode. An abnormality monitoring apparatus in a network, wherein abnormality occurrence information including an abnormality occurrence point in a network is transmitted to a master station unit operating in a mode via the data transmission path. 2. The network according to claim 1, wherein the plurality of station units include one master station unit serving as a master and a plurality of slave station units serving as slaves. Abnormality monitoring device. 3. The slave station unit includes: a slave-side abnormality determining unit that determines whether an abnormality has occurred in the network; and when the slave-side abnormality determining unit determines that an abnormality has occurred in the network, Slave-side operation mode switching means for switching the operation mode of the slave station unit itself from a slave mode operating as a slave to a virtual master mode virtually operating as a master. 3. The abnormality monitoring apparatus according to claim 2, wherein the switching timing of the means is set at mutually shifted times on the same time axis.