JP2001339413A - Network system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that it is necessary to investigate a wide range since slave station units 2 are called from a master station unit 1 and the range of no response is defined as an investigation section in the case of abnormality in a conventional network system. SOLUTION: Each of station units 1 and 2 calls each of other adjacent station units 1 and 2 to decide abnormality.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a network system in which a plurality of station units are connected to each other by a bus through a network, and more particularly to an improvement which enables an abnormality occurring in a station unit or a network to be detected efficiently and accurately. It is about.

[0002]

2. Description of the Related Art FIG. 12 is a system configuration diagram showing a configuration of a conventional network system disclosed in Japanese Patent Application Laid-Open No. 6-326716. In the figure, 23 is a master station unit, 24 is a slave station unit, and 25 is the master station unit 23 and a plurality of slave station units 24,
, 24 are connected to each other. In the following description, when the master station unit 23 and the slave station units 24,...
Called.

Next, the operation will be described. Each station unit 23, 24 is connected to another station unit 2
When the information to be transmitted to the stations 3 and 24 is generated, the address of the other station units 23 and 24 is added to the information and the transmission signal is output to the network 25. Then, the other station units 23 and 24 monitor the network 25 and, when detecting a signal to which the address of the own station is added, receive the signal and perform a process according to the received signal.

A specific pattern is transmitted from the master station unit 23, and a system failure is determined according to the presence or absence of a response signal of each slave station unit 24 in response to the specific pattern.

[0005]

Since the conventional network system is configured as described above, it is true that some investigation sections are specified based on the response signals from the slave station units 24,. Although it is possible, in practice, it was extremely difficult to specify the survey section with sufficient accuracy for the following reasons.

When an abnormality such as a disconnection or a short circuit occurs in the network 25, ideally, the slave station unit 2 located closer to the master station unit 23 (hereinafter also referred to as the upstream side) than the location where the abnormality has occurred.
,..., 24 are all considered to be able to return the response signal of the above-mentioned predetermined pattern. However, when an abnormality occurs in the network 25, the transmission formed by the network 25 is actually performed. Since the characteristics of the road are changed, the slave station units 24,..., 24 located on the upstream side in the vicinity of the location where the abnormality has occurred cannot almost always return a response signal of the predetermined pattern. As a result, it was determined that there was an abnormality including a section (upstream section) completely different from the position where the abnormality actually occurred, and the investigation section could not be specified with sufficient accuracy.

Further, in order to actually specify the location where an abnormality has occurred, it is necessary to perform an inspection on each of the sections on the downstream side of the above-mentioned section on the upstream side. Required much time and effort.

In particular, when a differential type network whose both ends are terminated with a terminating resistance element is used as the network 25, the impedance characteristic of the transmission line at the time of an abnormality changes greatly from the normal time, so that each station unit The signals transmitted to the network 25 by the nodes 23 and 24 are unnecessarily reflected at the abnormal end, so that such an upstream section always occurs. Further, the above-mentioned abnormal reflection or the like tends to appear more conspicuously as the communication speed of the signal increases. Therefore, in a recent FA (factory automation) system using the high-speed network 25, each of the station units 23, 24
Due to the fact that they are separately installed on a large site in the factory, it took a great deal of time and effort to detect the location of the abnormality and repair it.

Even if the survey section is specified in this manner, whether there is an abnormality in the network 25 in the section or the station units 23, 24 in the section is determined.
More time and effort was required to accurately determine whether there was an abnormality in the device.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem. Even if a plurality of station units are connected to each other via a bus, it is possible to efficiently and accurately detect a location where an abnormality has occurred. The purpose is to obtain a network system that can be used.

[0011]

In a network system according to the present invention, information for identifying each other is assigned, a plurality of station units communicating with each other using the identification information, and the plurality of station units are connected to each other. And a first network used as a transmission path during the mutual communication, wherein each of the station units transmits various transmission signals to which the identification information has been added to the first network. Transmitting means for receiving, from a first network, a transmitting signal to which its own identification information is added, and identification information holding for holding identification information of another station unit connected adjacently in the first network. Means and identification information of the other adjacent station units are added. A transmission signal for the test with is transmitted to the transmission means have, in which comprises a monitoring means for monitoring the reception by said receiving means of the response signal, and display means for displaying the monitoring result of the monitoring means.

[0012] The network system according to the present invention comprises:
The monitoring means transmits a test transmission signal at at least two or more communication speeds.

[0013] The network system according to the present invention comprises:
When the monitoring means determines that the receiving means does not receive the response signal, the monitoring means further causes the transmitting means to transmit a test transmission signal to which the identification information is added, and determines whether or not the receiving means receives the signal. To monitor.

[0014] The network system according to the present invention comprises:
Each station unit is provided with a start switch for starting the monitoring means.

[0015] The network system according to the present invention comprises:
One of the plurality of station units is provided with starting means for outputting a starting signal to the monitoring means of all the station units including the station unit, and the monitoring means of all the station units outputs the monitoring result to the starting means. Send to the provided station unit,
Further, the display means of the station unit provided with the starting means displays the monitoring result of all the station units.

[0016] The network system according to the present invention comprises:
A second network that connects the plurality of station units is provided, and the activation unit and the monitoring unit transmit signals using the second network.

The network system according to the present invention comprises:
A second network for bus-connecting the plurality of station units to each other in the same manner as the first network, wherein the activation unit and the monitoring unit both transmit their respective signals using the first network or the second network; Is for monitoring a network different from the network used for the transmission.

The network system according to the present invention comprises:
The starting means periodically outputs a starting signal.

The network system according to the present invention comprises:
The activating means outputs an activating signal in accordance with switching of a network used for normal communication.

The network system according to the present invention comprises:
Information for identifying each other is assigned, a plurality of station units that communicate with each other using the identification information, and a bus connection between the plurality of station units, and a second station unit that is used as a transmission path during the mutual communication. In a network system including one network,
The first network is a differential network whose both ends are terminated with a terminating resistance element, and a current source that supplies a predetermined current to the first network, and a current source that supplies current from the current source. A voltage detecting means for detecting a voltage generated in the first network; and a display means for displaying a detection result by the voltage detecting means.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1 FIG. FIG. 1 is a system configuration diagram showing a network system according to Embodiment 1 of the present invention. This network system is used in an FA system or the like. In the figure, 1 is a master station unit (station unit), 2 is a slave station unit (station unit), 3 is a differential type network in which both ends of a twisted pair cable or a coaxial cable are terminated with terminating resistance elements. This is a first high-speed network (first network) for connecting the master station unit 1 and the plurality of slave station units 2,. In the following, when the master station unit 1 and the slave station unit 2 are described collectively, only the station units 1 and 2 will be described.
Called. And these station units 1,
2 is assigned an identification number for identifying each other, and the station units 1 and 2 that have received the transmission permission from the master station unit 1 transmit a signal to which the identification numbers of the destination station units 1 and 2 are added. The other station units 1 and 2 monitor the first high-speed network 3 and, when detecting a signal to which the identification number of the own station is added on the first high-speed network 3, receive the signal. I do. In such a communication process, the station units 1 and 2 directly communicate with each other. The transmission permission may be assigned independently by the master station unit 1 or may be controlled to be assigned in response to a request from each slave station unit 2.

In each of the station units 1 and 2,
A communication unit 4 is connected to the first high-speed network 3, transmits a signal to which the identification number of the transmission destination is added to the first high-speed network 3, and receives a signal to which the identification number of the own station is added ( (Transmission means, reception means), 5 is the communication unit 4
A central processing unit (monitoring means, starting means) for managing the communication processing by the CPU, and a test switch (starting switch) 6 for outputting a test interrupt signal to the central processing unit 5.

FIG. 2 is a functional block diagram showing functions realized by the respective central processing units 5 according to the first embodiment of the present invention when the test interrupt signal is input. In the figure, 7 is another station unit 1 connected adjacently in the first high-speed network 3.
A monitoring function for causing the communication unit 4 to output a test transmission signal to the communication unit 2 and monitoring whether or not the communication unit 4 receives the response signal. Communication status determination function for determining status, 9
Is a notification function for transmitting the determination result from the communication unit 4 to the master station unit 1, and 10 is a display function for displaying the determination result on a display unit (not shown).

Next, the operation will be described. When information to be transmitted to the other station units 1 and 2 is generated, the central processing unit 5 of each of the station units 1 and 2 adds the identification numbers of the other station units 1 and 2 to generate a transmission signal. I do. The communication unit 4 outputs this transmission signal to the first high-speed network 3 when receiving the transmission permission from the master station unit 1. This transmission signal propagates in the first high-speed network 3, and its energy is consumed and disappears in the terminal resistance elements at both ends of the first high-speed network 3. The communication units 4 of the other station units 1 and 2 communicate with the first high-speed network 3
When a signal to which the identification number of the own station is added is detected, this signal is received and output to each central processing unit 5. The central processing unit 5 performs processing according to the received signal. Each of the station units 1 and 2 basically stores the identification numbers of all the other station units 1 and 2 other than its own in an identification information holding means (not shown).

As described above, when the plurality of station units 1 and 2 are communicating with each other, the first high-speed network 3 is disconnected or short-circuited, or the communication unit 4 of any one of the station units 1 and 2 fails. When an abnormality occurs, first, a process of specifying a survey section is performed. Specifically, in response to the operation of the test switch 6 provided in the master station unit 1, the test switch 6
Outputs a test interrupt signal to the central processing unit 5, and the central processing unit 5 outputs a start signal to the first high-speed network 3 in response thereto. The start signal may be individually output to each of the slave station units 2,..., 2, but processing can be performed more efficiently by using broadcast communication or the like.

FIG. 3 is a flow chart showing the flow of processing performed by each of the station units 1 and 2 in the process of roughly specifying a survey section according to the first embodiment of the present invention. In the figure, ST1 is a transmission step of transmitting a test transmission signal to which the identification number is added to the adjacent station units 1 and 2 in the first high-speed network 3, and ST2 is a process performed by the central processing unit 5 by the communication unit 4. A reception determining step of monitoring the reception of the response signal, and determining that an abnormality has occurred if no response signal has been received, and a normal state if the response signal has been received, a normal transmission step of transmitting the monitoring result to the master station unit 1, and a monitoring step ST4. A normal display step of displaying the result on the display unit, ST5 is an abnormal transmission step of transmitting the monitoring result to the master station unit 1, and ST6 is an abnormal display step of displaying the monitoring result on the display unit.

In the master station unit 1, if the monitoring results of the station units 1 and 2 are all normal, a message to that effect is displayed on a display unit (not shown) to monitor any one of the station units 1 and 2. If the result is abnormal, the section in which the abnormality is detected is displayed on the display unit.

If there is an abnormal detection section, the section is examined next. If an abnormality occurs in the first high-speed network 3 itself, there is a possibility that there are station units 1 and 2 to which the activation signal itself has not been input. Do. Specifically, the user operates the test switch 6 of each of the station units 1 and 2 in the section to sequentially perform the communication test. When a test interrupt signal is input from the test switch 6, the central processing unit 5 of each of the station units 1 and 2 executes the flowchart shown in FIG. Thus, the slave station units 2,..., 2, which could not be checked by the start signal from the master station unit 1, can be tested. The section including the units 1 and 2 can be specified as the final survey section.

As described above, according to the first embodiment, the master station unit 1 and the plurality of slave station units 2,..., 2 are bus-connected by the first high-speed network 3, and A communication unit for transmitting the transmission signal to the first high-speed network by adding the identification number of the transmission destination to the first high-speed network and receiving the transmission signal to which the identification number of the own station is added from the first high-speed network; And other station units 1
Identification information holding means for holding the identification number of the second station unit and the central unit for transmitting the test transmission signal from the communication unit 4 by adding the identification numbers of the adjacent station units 1 and 2 and monitoring the reception of a response signal to the transmission signal for the test. A processing device 5,
Since the display unit is provided with a display unit for displaying the monitoring result, each of the station units 1 and 2 can detect a communication abnormality between the adjacent station units 1 and 2 and display it.

In particular, the start signal is output from the master station unit 1, and all the station units 1, 2 are displayed on the display of the master station unit 1 based on the responses from the slave station units 2,. Since the monitoring result of No. 2 is displayed, it is possible to judge the approximate fault occurrence section in the master station unit 1, so that every time a fault occurs, all the station units 1 and 2 are individually determined.
It is no longer necessary to check the location, and it is possible to efficiently check the location where the abnormality has occurred.

In addition to the above configuration, a test switch 6 for activating a monitoring function or the like is provided in each of the station units 1 and 2. The test can be individually performed in the station units 1 and 2, and the effect is that the investigation section can be narrowed down. In particular, even if the first high-speed network 3 is divided at a plurality of locations, there is an effect that the presence or absence of an abnormality can be detected for each section of the station units 1 and 2.

Therefore, since the communication abnormality can be detected only between the station units 1 and 2 around the abnormality occurrence location, the abnormality occurrence location can be surely found in the abnormality detection section, and
In the case where there is no response signal to the master station unit 1, it is not necessary to inspect all the station units 1 and 2 on the downstream side of the location where the abnormality has occurred. There is an effect that the time and labor required for finding and repairing it can be significantly reduced.

Embodiment 2 FIG. FIG. 4 is a system configuration diagram showing a network system according to Embodiment 2 of the present invention. In the figure, reference numeral 11 denotes a transmission signal for test transmitted from the communication unit 4 at a normal communication speed. If the result is abnormal, the transmission signal for test is further transmitted from the communication unit 4 at a lower speed than the communication speed. It is a central processing unit (monitoring unit, starting unit) that transmits data and makes a determination based on those response signals. The other configuration is the same as that of the first embodiment, and the description is omitted.

Next, the operation will be described. The central processing unit 11 causes the communication unit 4 to transmit a test transmission signal at a normal communication speed. If the result is abnormal, the central processing unit 11 further transmits a test transmission signal from the communication unit 4 at a speed lower than the communication speed. Send and monitor their response signals. Then, the two monitoring results or the judgment result based on the two monitoring results are transmitted to the master station unit 1 and displayed on the display unit. At this time, if both of the monitoring results are abnormal, the first high-speed network 3
Alternatively, if it can be determined that there is an abnormality in the station units 1 and 2 and the abnormality is only at a high communication speed,
It can be determined that the first high-speed network 3 itself has an abnormality. This is because the higher the communication speed, the greater the waveform distortion, and the more likely it is to detect an abnormality. Other operations are the same as those in the first embodiment, and a description thereof will be omitted.

As described above, according to the second embodiment, central processing unit 5 switches the communication speed of the test transmission signal and transmits the test transmission signal at at least two or more communication speeds. Therefore, it is possible to perform the detection process of the investigation section at a communication speed lower than the communication speed used for the actual communication. Therefore, it is possible to reduce the abnormality detection caused by the waveform distortion and the like, and to reduce the total section in which the communication abnormality is detected, so that the investigation section is more efficiently specified and repaired. There is an effect that can be.

Embodiment 3 FIG. FIG. 5 is a system configuration diagram showing a network system according to Embodiment 3 of the present invention. In the figure, 12 changes the communication speed and, if the result of the monitoring is abnormal, further transmits a communication test signal including its own identification information, and monitors whether or not the communication unit receives the response, It is a central processing unit (monitoring means, starting means) for making a judgment by integrating these monitoring results. The other configuration is the same as that of the second embodiment, and the description is omitted.

Next, the operation will be described. FIG. 6 is a flowchart showing a flow of processing performed by the central processing unit 12 according to Embodiment 3 of the present invention. In the figure, S
T7 is a self-station transmission step for transmitting a communication test signal including its own identification information, and ST8 is a process in which the central processing unit 12 monitors the reception of the response signal by the communication unit 4, and if no reception is performed, an abnormal occurrence is detected. In this case, the station is determined to be normal. ST9 is a normal transmission step of transmitting the monitoring result of the station to the master station unit 1.
T10 is a normal display step of displaying the monitoring result of the own station on the display unit, ST11 is an abnormal transmitting step of transmitting the monitoring result of the own station to the master station unit 1, and ST11.
Reference numeral 12 denotes an abnormality display step for displaying the monitoring result of the own station on the display unit. Other operations are the same as those in the first embodiment, and a description thereof will be omitted.

As described above, according to the third embodiment, when the communication unit 4 does not receive a response signal from the other station units 1 and 2, the central processing unit 12 further executes its own Since a communication test signal including the identification information is transmitted and the communication unit 4 monitors whether the communication test signal is received,
There is an effect that it can be determined whether or not the communication abnormality is caused by the own station units 1 and 2.

Embodiment 4 FIG. 7 is a system configuration diagram showing a network system according to Embodiment 4 of the present invention. In the figure, reference numeral 13 denotes a second network for connecting a plurality of station units 1 and 2 to each other, and reference numeral 14 denotes monitoring by the same processing as in the third embodiment, and also uses the second network 13 to start signals and monitoring results. Central processing unit to send and receive (monitoring means, starting means)
It is. Other configurations and operations are the same as in the third embodiment, and a description thereof will be omitted.

As described above, according to the fourth embodiment, since the start signal and the monitoring result are transmitted and received using the second network 13, abnormalities occur in a plurality of sections in the first high-speed network 3. Even if
In the master station unit 1, the investigation sections for each of them can be specified collectively, and there is an effect that the investigation sections can be specified efficiently.

Embodiment 5 FIG. FIG. 8 is a system configuration diagram showing a network system according to Embodiment 5 of the present invention. In the figure, reference numeral 15 denotes a second high-speed network (second network) for connecting a plurality of station units 1 and 2 to each other by a bus in the same manner as the first high-speed network 3.
A central processing unit 6 selects a normal one of the first high-speed network 3 and the second high-speed network 15 to perform normal communication, and performs monitoring and communication by the same processing as in the fourth embodiment. It is a device (monitoring means, starting means). Other configurations and operations are the same as in the fourth embodiment, and a description thereof will not be repeated.

As described above, according to the fifth embodiment, the second high-speed network 15 for bus-connecting the plurality of station units 1 and 2 to each other in the same manner as the first high-speed network 3 is provided. Are both the first high-speed network 3 or the second high-speed network 1
5, and the central processing unit 16 monitors a network different from the network used for the transmission. Therefore, even if an abnormality occurs, these two networks are switched and used. By doing so, the network suspension period can be set to the time required for the switching, and even if abnormalities occur in a plurality of sections, the master station unit 1 collectively collects the investigation sections for each. Thus, there is an effect that the survey section can be efficiently specified.

Embodiment 6 FIG. FIG. 9 is a system configuration diagram showing a network system according to Embodiment 6 of the present invention. In the figure, reference numeral 17 designates one of the first high-speed network 3 and the second high-speed network 15 which is normal, performs normal communication, and periodically starts an activation signal by the same processing as in the fourth embodiment. The central processing unit (monitoring means, starting means) for transmitting to the central processing unit. Other configurations and operations are the same as in the fifth embodiment, and a description thereof will not be repeated.

As described above, according to the sixth embodiment, the central processing unit 17 of the master station unit 1
Causes the startup signal to be output periodically, so that the abnormality is periodically monitored, and if an abnormality occurs, the network is switched immediately, so that the network suspension period can be further reduced. Moreover, when a network in which an abnormality has occurred is restored, the restoration can be confirmed online without stopping communication in the other normal network, and the network can be safely and reliably restored.

Embodiment 7 FIG. 10 is a system configuration diagram showing a network system according to Embodiment 7 of the present invention. In the figure, 18 is the first high-speed network 3
And a central processing unit (monitoring means) that selects a normal one of the second high-speed network 15 and performs normal communication, and transmits a start signal at the time of network switching by the same processing as in the fourth embodiment. , Activation means). Other configurations and operations are the same as those of the fifth embodiment.
The description is omitted.

As described above, according to the seventh embodiment, the central processing unit 18 of the master station unit 1
Outputs an activation signal in response to the switching of the network used for normal communication, so if an error occurs in the network used for normal communication, immediately switch this to immediately determine the survey section. Can be. Moreover, when a network in which an abnormality has occurred is restored, the restoration can be confirmed online without stopping communication in the other normal network, and the network can be safely and reliably restored.

Embodiment 8 FIG. FIG. 11 is a system configuration diagram showing a configuration of the first high-speed network 3 or the second high-speed network 15 of the network system according to the eighth embodiment of the present invention and its peripheral parts. In the figure,
Reference numeral 19 denotes two conductors of the twisted pair cable or coaxial cable, and reference numeral 20 denotes these conductors 19 and 19, respectively.
A terminating resistor element having a predetermined impedance value for connecting the two conductors at both ends of the network.
A constant current source (current source) 22 for supplying a predetermined constant current to the components 9 and 19 has a display unit (not shown), and detects and displays a voltage generated between the two 19 and 19 conductors. It is a detector (voltage detection means, display means). The other configuration is the same as that of the seventh embodiment including the station unit, and the description is omitted.

Next, the operation will be described. Constant current source 21
When the power is supplied from the first high-speed network 3
If the second high-speed network 15 itself is normal, the voltage corresponding to the resistance value shown in the following equation 1 is detected by the voltage detector 22 because the two terminating resistance elements 20 are connected in parallel. You. Further, when the first high-speed network 3 itself or the second high-speed network 15 itself is disconnected, only one terminating resistance element 20 is connected, so that a voltage corresponding to the resistance value shown in the following equation 2 is obtained. The voltage is detected by the voltage detector 22. Further, when the first high-speed network 3 itself or the second high-speed network 15 itself is short-circuited, the voltage corresponding to the resistance value shown in the following Expression 3 is detected by the voltage detector 22. However, in the following equation, the resistance value of the high-speed network itself is ignored because it is very small, Rc is the resistance value of the terminating resistance element 20, and R is the resistance value of an equivalent circuit to which a constant current is supplied.
Other operations are the same as those in the seventh embodiment, and a description thereof will not be repeated.

R = Rc / 2 Equation 1 R = Rc Equation 2 R = 0 Equation 3

As described above, according to the eighth embodiment, the first high-speed network 3 and the second high-speed network 15 are differential networks whose both ends are terminated by the terminating resistance element 20, and A constant current source 21 for supplying a predetermined current to one high-speed network 3 or the second high-speed network 15; and a constant current source 21 for supplying a current from the constant current source 21 to the first high-speed network 3 or the second high-speed network 15. And a voltage detector 22 that detects and displays the voltage to be applied, if there is an abnormality in the first high-speed network 3 itself or the second high-speed network 15 itself, it can be detected and displayed as a change in resistance value. .

Therefore, when an abnormality occurs, it can be immediately determined whether the abnormality is the abnormality of the first high-speed network 3 itself or the second high-speed network 15 itself or the abnormality of the station units 1 and 2 itself. In the case of an abnormality in the first high-speed network 3 itself or the second high-speed network 15 itself, it is possible to further determine whether the short-circuit or the disconnection has occurred. The method can be narrowed down, and there is an effect that the time and labor required for identifying a location where an abnormality has occurred and repairing the location can be significantly reduced.

[0052]

As described above, according to the present invention, information for identifying each other is allocated, and a plurality of station units that communicate with each other using this identification information and the plurality of station units are connected to each other. In a network system comprising a bus connected and a first network used as a transmission path during the mutual communication,
Each of the station units, transmitting means for transmitting the various transmission signals with the identification information added to the first network, receiving means for receiving the transmission signal with its own identification information added from the first network, Identification information holding means for holding the identification information of another station unit connected adjacently in the first network, and a test transmission signal to which the identification information of the other adjacent station unit is added to the transmission means; The transmission unit includes a monitoring unit that monitors reception of the response signal by the reception unit, and a display unit that displays a monitoring result of the monitoring unit, so that each station unit communicates with another adjacent station unit. It is possible to detect a communication error between them and display it. Therefore,
Since the communication abnormality can be detected only between the station units around the abnormality occurrence location, the abnormality occurrence location can be reliably detected in the abnormality detection section, and all the downstream sides of the abnormality occurrence location can be detected. This eliminates the need to inspect each one, so that the time and labor required to efficiently specify a survey section and repair it can be significantly reduced.

According to the present invention, the monitoring means causes the test transmission signal to be transmitted at at least two or more communication speeds. Therefore, the waveform at the time of high-speed communication is determined based on the difference between the monitoring results at the two communication speeds. It is possible to determine whether or not an abnormality is detected due to distortion or the like, and accordingly, there is an effect that the investigation section can be narrowed accordingly.

According to the present invention, when the monitoring means determines that the receiving means does not receive the response signal, the monitoring means further causes the transmitting means to transmit a test transmission signal to which its own identification information is added. Monitors whether or not it receives this, so that each station unit can individually determine whether or not a communication error is caused within its own station unit.

According to the present invention, each station unit is provided with an activation switch for activating the monitoring means. Therefore, even if the network is disconnected, it is possible to detect the presence or absence of an abnormality in each section of each station unit. effective.

According to the present invention, one of the plurality of station units is provided with the starting means for outputting the starting signal to the monitoring means of all the station units including the station unit, and the monitoring of all the station units is performed. The means transmits the monitoring result to the station unit provided with the activating means, and the display means of the station unit provided with the activating means displays the monitoring results of all the station units. In the provided station unit, it is possible to determine the approximate abnormality occurrence section. Therefore, by simply examining only the station units in the section where the abnormality has occurred, the location where the abnormality has occurred can be detected.
It is not necessary to check all the station units each time an abnormality occurs, and it is possible to more efficiently find the location where the abnormality has occurred.

According to the present invention, the second network for connecting the plurality of station units is provided, and the activation unit and the monitoring unit transmit their respective signals using the second network. Even if an error has occurred, it is possible to obtain information on all the station units whose monitoring results were normal, so it is possible to determine that a plurality of errors have occurred in the station unit provided with the activation unit. can do. Therefore, there is an effect that a plurality of survey sections can be surveyed at a time and repaired efficiently.

According to the present invention, a second network for connecting a plurality of station units to each other by a bus in the same manner as the first network is provided, and both the activating means and the monitoring means use the first network or the second network, respectively. A signal is transmitted, and the monitoring means monitors a network different from the network used for the transmission. Therefore, even if an abnormality occurs, the two networks are switched and used to reduce the network suspension period. The time required for the switching can be set, and even if an abnormality has occurred in a plurality of sections, each of them can be simultaneously determined in the station unit provided with the activation means, and the repair can be efficiently performed. There is an effect that can be.

According to the present invention, the activation means periodically outputs the activation signal. Therefore, the abnormality is periodically monitored, and if an abnormality occurs, the network is switched immediately, and the network suspension period is set to substantially equal to or less than the period. Can be reduced. Moreover, when the network in which the abnormality has occurred is restored, the completion of the restoration can be confirmed without stopping the communication in the other normal network, and the network in which the abnormality has occurred can be safely and reliably brought into a usable state. There is an effect that can be restored.

According to the present invention, the start-up means outputs the start-up signal in accordance with the switching of the network used for the normal communication. Therefore, if an abnormality occurs in the network used for the normal communication, the start-up means is switched immediately. In addition, the survey section can be determined immediately. In addition, when the network in which the abnormality has occurred is restored, the restoration can be confirmed without stopping communication in the other normal network, and the network can be safely and reliably restored.

According to the present invention, information for identifying each other is allocated, a plurality of station units communicating with each other using the identification information, and the plurality of station units are bus-connected to each other. A first network used as a transmission line at the time of the first network, the first network is a differential network terminated at both ends thereof by a terminating resistance element, and a predetermined current is supplied to the first network. Since the power supply includes a current source to be supplied, a voltage detection unit that detects a voltage generated in the first network when current is supplied from the current source, and a display unit that displays a detection result by the voltage detection unit, If there is an abnormality in the first network itself, it can be detected and displayed as a change in resistance value. Therefore, when an abnormality occurs, it is possible to accurately determine whether the abnormality is the abnormality of the first network itself or the abnormality of the station unit by immediately determining whether the abnormality has occurred. This has the effect of significantly reducing the time and labor required to repair it.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram showing a network system according to a first embodiment of the present invention.

FIG. 2 is a functional block diagram illustrating functions realized by the central processing units according to the first embodiment of the present invention when the test interrupt signal is input and the like;

FIG. 3 is a flowchart illustrating a flow of a process performed by each station unit in a process of roughly specifying a survey section according to the first embodiment of the present invention;

FIG. 4 is a system configuration diagram showing a network system according to a second embodiment of the present invention.

FIG. 5 is a system configuration diagram showing a network system according to a third embodiment of the present invention.

FIG. 6 is a flowchart showing a flow of processing performed by a central processing unit according to Embodiment 3 of the present invention.

FIG. 7 is a system configuration diagram showing a network system according to a fourth embodiment of the present invention.

FIG. 8 is a system configuration diagram showing a network system according to a fifth embodiment of the present invention.

FIG. 9 is a system configuration diagram showing a network system according to a sixth embodiment of the present invention.

FIG. 10 is a system configuration diagram showing a network system according to a seventh embodiment of the present invention.

FIG. 11 is a system configuration diagram showing a configuration of a first high-speed network or a second high-speed network and peripheral portions thereof in a network system according to an eighth embodiment of the present invention.

FIG. 12 is a system configuration diagram showing a configuration of a conventional network system.

[Explanation of symbols]

Reference Signs List 1 master station unit (station unit), 2 slave station unit (station unit), 3 first high-speed network (1st network), 4 communication unit (transmitting unit, receiving unit), 5 central processing unit (monitoring unit, starting unit) ), 6 test switch (start switch), 7 monitoring function, 8 communication state determination function, 9 notification function, 10 display function, 11 central processing unit (monitoring unit, starting unit), 12 central processing unit (monitoring unit, starting unit) , 13 second network, 14 central processing unit (monitoring unit, starting unit), 15 second high-speed network (second network), 16 central processing unit (monitoring unit, starting unit), 17 central processing unit (monitoring unit, Starting means), 18 central processing unit (monitoring means, starting means), 19 conductors, 20 terminating resistance elements, 2 1 constant current source (current source), 22 voltage detector (voltage detection means, display means).

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Fumihiko Nakamura 2-6-1, Otemachi, Chiyoda-ku, Tokyo Inside Mitsubishi Electric Engineering Co., Ltd. (72) Nobukazu Fukui 2-6-, Otemachi, Chiyoda-ku, Tokyo No. 2 Mitsubishi Electric Engineering Co., Ltd. F term (reference) 5K030 GA12 HA08 HC14 KA23 MB01 MB20 MC03 MD04 5K032 AA06 DA01 DA11 DA17 DB12 DB19 DB31 EA03 EA05 EA07 EC01 EC04

Claims (10)

[Claims] An information for identifying each other is allocated, a plurality of station units communicating with each other using the identification information, a bus connection between the plurality of station units, and transmission during the mutual communication. In a network system including a first network used as a path, each of the station units includes a transmission unit that transmits various transmission signals to which the identification information has been added to the first network, and an identification information of its own. Receiving means for receiving the transmitted signal from the first network, identification information holding means for holding identification information of another station unit connected adjacently in the first network, and identification of the other adjacent station unit When the transmitting means transmits a test transmission signal to which information is added, A network system comprising: a monitoring unit that monitors reception of the response signal by the receiving unit; and a display unit that displays a monitoring result of the monitoring unit. 2. The network system according to claim 1, wherein the monitoring means transmits a test transmission signal at at least two or more communication speeds. When the receiving means determines that the response signal has not been received, the monitoring means further causes the transmitting means to transmit a test transmission signal to which the identification information is added, and the receiving means receives the response signal. 2. The network system according to claim 1, wherein whether to perform the monitoring is monitored. 4. The network system according to claim 1, wherein each station unit is provided with an activation switch for activating a monitoring unit. 5. One of a plurality of station units.
First, a starting means for outputting a starting signal to the monitoring means of all the station units including the station unit is provided, and the monitoring means of all the station units transmits the monitoring result to the station unit provided with the starting means. 2. The system according to claim 1, wherein the display means of the station unit provided with the activation means displays the monitoring results of all the station units.
The network system according to any one of claims 1 to 3. 6. The network according to claim 5, wherein a second network for connecting the plurality of station units is provided, and the activation unit and the monitoring unit transmit respective signals using the second network. system. 7. A second network for connecting a plurality of station units to each other by a bus in the same manner as the first network, wherein both the activation unit and the monitoring unit transmit respective signals using the first network or the second network. 6. The network system according to claim 5, wherein the monitoring means monitors a network different from the network used for the transmission. 8. The network system according to claim 5, wherein the activation unit periodically outputs an activation signal. 9. The network system according to claim 5, wherein the activation unit outputs an activation signal in response to switching of a network used for normal communication. 10. Information for identifying each other is assigned, a plurality of station units that communicate with each other using the identification information, and a bus connection between the plurality of station units, and transmission during the mutual communication. A first network used as a path, wherein the first network is a differential network having both ends terminated by a terminating resistance element, and a current source for supplying a predetermined current to the first network. And a voltage detecting means for detecting a voltage generated in the first network when a current is supplied from the current source, and a display means for displaying a detection result by the voltage detecting means.