JP3082437B2 - Disconnection detection device in local area network - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disconnection detecting device provided in a local area network for detecting a disconnection of a communication line.

[0002]

2. Description of the Related Art Conventionally, as an apparatus for detecting a disconnection of a communication line in a local area network (hereinafter simply referred to as LAN) of this type, for example, Japanese Patent Application Laid-Open No.
As disclosed in Japanese Unexamined Patent Application Publication No. 947, one device constituting a LAN continuously transmits a disconnection detection signal returned to the device after looping around the other devices at predetermined time intervals to configure the LAN. When all devices do not receive the disconnection detection signal within a predetermined time, it is determined that the communication line is disconnected, and this is notified in advance by an alarm device such as a buzzer or a lamp provided for each device. It has been known.

[0003]

However, the above-described conventional disconnection detecting device in a LAN is effective for specifying a disconnection point of a communication line. Since it is necessary to provide a monitoring device including a timer or the like for monitoring whether or not the disconnection detection signal is received within a predetermined time, the configuration of each device becomes complicated. As a result, there is a problem that the cost of the entire system also increases.

Accordingly, the present invention relates to a LAN,
It is an object of the present invention to provide a disconnection detecting device capable of accurately detecting a disconnection point of a communication line connecting the above devices while simplifying an internal configuration of each device constituting the device.

[0005]

That is, according to the present invention, which has been made to achieve the above object, as shown in FIG. 1, a communication means for performing data communication with another device via a communication line, A local area formed by connecting a plurality of devices each provided with an abnormality notifying unit for notifying the occurrence of an abnormality and a driving unit for driving the abnormality notifying unit in response to an external notification command in a ring shape by the communication line. A disconnection detection device that is provided in a network and detects a disconnection of the communication line, wherein at least once within a predetermined time, a cyclic signal returned to the device by making a round of each device is transmitted from the communication unit to one of the devices. A cyclic signal transmitting means for transmitting in the device direction, and an abnormality detecting means for detecting an abnormality when the cyclic signal transmitted by the cyclic signal transmitting means is not received by the communication means within a predetermined time. Means, and a notification command means for transmitting a command signal for performing a notification command to the drive means in each device when the abnormality detection means detects a fault, from the communication means toward one of the devices. Characteristic LAN
Is a gist of the disconnection detecting device.

[0006]

In the apparatus for detecting a disconnection in a LAN according to the present invention having the above-described configuration, the cyclic signal transmitting means makes a loop through each device constituting the LAN at least once within a predetermined period of time and returns the information to the apparatus. Circulating signal is transmitted from the communication means toward one device. Then, the abnormality detecting means detects the abnormality when the traveling signal is not received by the communication means within a predetermined time. Next, when the abnormality detecting means detects an abnormality, the notification command means causes the communication means to transmit a command signal for performing a notification command to the driving means in each device constituting the LAN in the direction of one device.

[0007] Then, receiving the notification instruction, L
Driving means in each device constituting the AN drives abnormality notification means provided in each device, and the abnormality notification device notifies an operator or the like of an abnormality in the communication line. Here, the reason that the abnormality detecting means can detect the abnormality is that if the communication line is broken somewhere, the traveling signal is not received within a predetermined time. Also, the disconnection point of the communication line can be specified
This is because, in one device direction in which the command signal is transmitted, the notification command is not transmitted to devices subsequent to the device arranged next to the disconnection point of the communication line, and the abnormality notification unit of those devices is not driven. .

Therefore, it is possible to detect that the communication line has been disconnected just before the device in which the abnormality notification means does not operate.

[0009]

An embodiment of the present invention will be described below with reference to the drawings. First, FIG. 2 is a schematic configuration diagram illustrating an entire configuration of a transport line 2 in a sewing factory that is integrally controlled by each component device of a LAN to which the present invention is applied.

The transfer line 2 of the present embodiment shown in FIG. 2 is formed by arranging a plurality of stations 4 each having a sewing device such as a sewing machine for different uses in each process. Is transported to the transport body 6 holding the. The transport body 6 is transported on the main rail 8 in the direction of the arrow in FIG. 2, and is branched and carried into the corresponding horseshoe-shaped station rail 12 from the main rail 8 by a desired branching mechanism 10. Then, the work is guided to a desired station 4 where sewing of the sewing product is performed. Thereafter, the transport body 6 exits the station 4 and joins the main rail 8 again from the station rail 12 and is transported to the station 4 where the next step is performed.

Next, FIG. 3 is a schematic configuration diagram showing the internal configuration of each electronic control unit constituting a LAN for controlling the transport line 2. As shown in FIG. 3A, the LAN on the transport line 2 of the present embodiment is connected to one main controller 20 which is a control center of the transport line 2 and to the transport line 2 in accordance with an instruction from the main controller 20. A plurality of control devices 22 for driving and controlling the various actuators provided to transport the transport body 6 are provided.
And are connected in a ring shape. And
Communication between the devices is performed in one direction indicated by an arrow of the optical fiber cable 24. Further, the control device 22 is provided for each station 4 shown in FIG.

Here, in the present embodiment, the main controller 20 is configured to also function as the disconnection detecting device of the present invention. The main controller 20 displays a keyboard 26 for inputting processing conditions such as the number of lots to be sewn and the number of lots per lot, the progress of sewing work, and the like. Is connected to a display 28 as abnormality notification means of the present invention for displaying the abnormality of the present invention.

The main controller 20 includes an E / O converter for converting an electric signal into an optical signal for performing data communication with each controller 22 via an optical fiber cable 24, and an optical signal to an electric signal. A communication circuit 30 as a communication means of the present invention comprising an O / E converter for conversion and the like;
And an input / output circuit 32 as a driving means of the present invention, which is a well-known interface with the display 28, and various control based on information from the communication circuit 30 and the input / output circuit 32 which are constituted by a well-known CPU, ROM, RAM and the like. A central processing unit (hereinafter, simply referred to as a CPU) 34 for executing calculations, communication processing, and the like.

In this embodiment, the communication circuit 30 is composed of only a communication driver circuit, and all communication processing is performed by C.
The PU 34 may be configured to perform the processing, or the communication circuit 30 may be provided with a separate CPU from the CPU 34 to perform the communication processing. Main controller 2 configured as described above
0 is an optical fiber cable 2
, Control of data communication performed via the keyboard 4, processing conditions input from the keyboard 26, notification of loading of the carrier 6 into the station 4 transmitted by the respective control devices 22 and received by the communication circuit 30, and respective sewing operations And the integrated control of the transport line 2 for transmitting the transport control data and the like of the transport body 6 to each control device 22 by grasping the processing status from the notification of the completion of the transport, the notification of the unloading of the transport body 6 to the main rail 8, The main function involved is to detect disconnection of the optical fiber cable 24 and the like.

On the other hand, as shown in FIG. 3B, each control device 22 has an end switch 36 for notifying the main control device 20 of the end of the work in the station 4, and the branching mechanism 1
0 and various actuators 38 for operating the various mechanisms provided on the transport line 2 such as a transport chain (not shown) to transport the transport body 6, and abnormality notification means of the present invention for displaying an abnormality on the transport line 2 LED40 etc. are connected.

Each of the control devices 22 is a main control device 2
0, an input / output circuit 44 which is an interface between the end switch 36, the various actuators 38, the LED 40 and the like, and is constituted by a transistor and the like as a driving means of the present invention, and a well-known CPU, ROM, RA
A central processing unit (hereinafter, simply referred to as a CPU) 46 that is configured by an M or the like and performs various control processes, communication processes, and the like. Then, by the operation of the CUP 46, the transport control of the transport body 6 on the transport line 2 and the like are performed based on the communication processing and the transport control data transmitted from the main controller 20.

Hereinafter, in the LAN configured as described above, the optical fiber cable 24 which is mainly executed by the CPU 34 of the main controller 20 and is a main process according to the present invention.
The disconnection detection processing will be described with reference to FIG. First, as a premise, in the LAN according to the present embodiment, an apparatus serving as a transmission source attaches an address previously allocated to data to be transmitted and transmits the data. When each device receives the data, it loads the data into the internal memory, identifies the transmission source from the address, and determines whether or not the device has transmitted the data first. Then, when it is determined that a source other than itself is the transmission source, this data is transmitted to the next device on the optical fiber cable 24 as it is. As a result, a signal transmitted from any of the devices including the main control device 20 to the optical fiber cable 24 always goes around each device and returns to the device of the transmission source.

FIG. 4 is a flowchart for explaining the disconnection detection processing of the optical fiber cable 24, which is executed by the CPU 34 of the main controller 20. In addition, main controller 2
In parallel with the disconnection detection process shown in FIG. 4, the CPU 34 of the CPU 0 performs a process of receiving data, a process of fetching received data into an internal memory, a process of determining a transmission source of the data, and a process of receiving the data. When it is determined that the received signal is a signal other than the transport control data and the inspection signal transmitted in S130 or S150 (the signal is not the transmission source of the main controller 20), the received data is directly used as the next controller 22 on the optical fiber cable 24. And a communication process (not shown) composed of a transmission process for transmitting data to

First, when the power is turned on, the CPU 34 of the main controller 20 starts an internal timer (not shown). Then, in S110, based on the input information from the keyboard 26 and the received data from the communication circuit 30, the transport control data for each control device 22 is processed and calculated.

At S120, it is determined whether or not there is transport control data to be actually transmitted (hereinafter simply referred to as control data) as a result of the processing at S110. When it is determined that there is control data, the process proceeds to S130, and the data is transmitted in S130.

On the other hand, if it is determined in S120 that there is no control data as a result of the processing in S110, the process proceeds to S140. In S140, it is determined whether or not a predetermined time T1 has elapsed from the value of the internal timer started at power-on. If it is determined that the predetermined time T1 has not elapsed, the process returns to S110 and repeats the above processing. If there is control data within the predetermined time T1, the control data is transmitted in S130.

If it is determined in S140 that the predetermined time T1 has elapsed, the flow shifts to S150, and in S150, an inspection signal for the optical fiber cable 24 not related to the transport control is transmitted. When the transmission of the control data or the inspection signal is executed in S130 or S150, respectively,
In S160, the internal timer of the CPU 34 is restarted. Here, the internal timer is restarted so that it is possible to determine whether or not a predetermined time T1 has elapsed since the previous transmission of the control data or the inspection signal when S140 is next executed. Further, this is for measuring a predetermined time T2 described later.

In the following S170, S130 or S150
It is determined whether or not the transmitted control data or inspection signal has been received by the communication circuit 30 of the main control device 20 after making a round of each control device 22. When it is determined that the received control data or inspection signal has been received, the process returns to S110. Are repeated. As a result, at least once within the predetermined time T1, the main controller 2
Control data or an inspection signal is transmitted from 0 to each control device 22, and the processing of S160 and S170 is executed each time.

On the other hand, if it is determined in S170 that the transmitted control data or inspection signal has not been received, the process proceeds to S18.
Move to 0. In S180, it is determined whether or not a predetermined time T2 has elapsed from the transmission of the control data or the inspection signal executed in S130 or S150, based on the value of the internal timer started in S160. Here, the predetermined time T
2 is set to be sufficiently smaller than the predetermined time T1, and slightly longer than the time during which the control data or the inspection signal makes a round of each device.

If it is determined in step S180 that the predetermined time T2 has not elapsed, the process returns to step S170 to wait for reception of the transmitted control data or inspection signal. If it is determined in S180 that the predetermined time T2 has elapsed, the process proceeds to S19.
0, and in S190, the fact that somewhere in the optical fiber cable 24 is broken is notified to the input / output circuit 3 of the main controller 20.
2 on the display 28. Then, the process further proceeds to S200, where a command signal for turning on the LED 40 included in each of the control devices 22 is transmitted.

Each of the control devices 22 receiving this command signal drives each LED 40 by the input / output circuit 44 of each control device 22 to light it. That is, in this disconnection detection processing, S130 and S150 for transmitting control data or a test signal as a cyclic signal are cyclic signal transmitting means of the present invention, S170 and S180 are abnormality detecting means of the present invention, and S190 and S200 are Each functions as the notification command means of the present invention.

As described above, the disconnection point of the optical fiber cable 24 is specified. The reason why the disconnection point can be specified will be described with reference to FIG. For example, as shown in FIG. 5, twelve control devices 22 (22a, 22b,.
2k, 221), the control device 22g and the control device 2
It is assumed that the optical fiber cable 24 is disconnected (marked by x) between 2h. At this time, the command signal transmitted by the main control device 20 includes control devices 22a, 22b,.
2k, 22l, the LED 40 (40
a, 40b,..., 40k, 40l).

However, the control devices 22h, 22i, 22j,
22k and 221 cannot receive this command signal,
The LEDs 40h, 40i, 40j, 40k, and 40l remain off. That is, it is possible to visually detect that the optical fiber cable 24 is disconnected at the boundary between the place where the LED 40 is turned on and the place where the LED 40 is turned off.

For example, in FIG.
When a disconnection occurs between 0 and the control device 22a, only the display 28 notifies the disconnection, and when a disconnection occurs between the control device 22l and the main control device 20,
All LEDs 40a, 40b, including the display 28,
, 40k, 40l are lit, so that even in these cases, the disconnection location can be specified.

As described above, in the LAN on the transport line 2 of the present embodiment, the main controller 20 constituting the LAN performs the processing for detecting the disconnection of the optical fiber cable 24 as the disconnection detecting apparatus of the present invention. Each control device 22
However, according to a command signal transmitted from the main control device 20, the LED 40 provided for each device is turned on to display a broken portion.

For this reason, each control device 22 does not need to be provided as an additional device irrespective of the basic function other than the LED 40 for notifying the occurrence of disconnection and its driving circuit. The configuration is simplified. Also,
As a result, the cost of the entire system is kept low.

In the above-described embodiment, a signal transmitted from any device including the main control device 20 to the optical fiber cable 24 always travels in one direction to each device and is returned to the transmission source device. Under this condition, the disconnection detection device in which the main control device 20 transmits the control data or the inspection signal at least once within the predetermined time T1 has been described, but at least the main control device 20 is used as a transmission source. Even in a LAN in which only control data or a check signal to be transmitted circulates in each direction in each control device 22 and is returned to the main control device 20, the same effect as in the above embodiment can be obtained.

In this case, each control device 22 determines the control data or the inspection signal transmitted by the main control device 20 as a transmission source, and transmits this to the next control device 22 on the optical fiber cable 24 as it is. It is good if you do
There is no particular restriction on the transmission direction of other data.

Further, the control data and the inspection signal are considered completely differently, and at least only the inspection signal transmitted by the main control device 20 is made to go around each device in one direction. Even in a disconnection detecting device configured to transmit an inspection signal, the same effect as in the above embodiment can be obtained by applying the present invention.

In this case, each control device 22 determines at least the inspection signal transmitted by the main control device 20 from the received data, and transmits it to the next control device 22 on the optical fiber cable 24 as it is. So that
For example, in the disconnection detecting process executed by the CPU 34 of the main control device 20 shown in FIG. 4, the process returns to S110 immediately after the execution of S130. Then, in S170,
It is only necessary to determine whether or not the inspection signal transmitted in S150 has been received.

[0036]

As described above, in the apparatus for detecting disconnection in a LAN according to the present invention, the presence / absence of disconnection of the communication line is detected by the cyclic signal transmitting means and the abnormality detecting means.
The notification command means gives a notification command to the driving means provided in each device constituting the LAN. Then, the driving means in each device, which has received the notification instruction in this way, drives the abnormality notification means provided in each device, and specifies the disconnection point of the communication line based on the operation status of the abnormality notification means.

Therefore, if the disconnection detecting device for a LAN according to the present invention is used, it is possible not only to accurately detect the disconnection point of the communication line connecting each device constituting the LAN, but also to detect other than the predetermined one device. Each device does not need to be provided as an additional device not related to the basic communication function, other than a device for notifying the occurrence of disconnection, and the configuration of each device is simplified. Thus, the cost of the entire system can be kept low.

Further, when the disconnection detecting device in the LAN according to the present invention is provided in a predetermined one of a plurality of devices constituting the LAN as in the above-described embodiment, the communication line can be more efficiently connected. Disconnections and their locations can be detected.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating the configuration of the present invention.

FIG. 2 is a schematic configuration diagram illustrating an entire configuration of a transfer line 2 in a sewing factory according to the embodiment.

FIG. 3 is an LA for controlling the transfer line 2 of the embodiment.
FIG. 2 is a schematic configuration diagram illustrating an internal configuration of each electronic control device configuring N.

FIG. 4 is a diagram illustrating a C of a main controller 20 in the LAN according to the embodiment;
5 is a flowchart illustrating a disconnection detection process of the optical fiber cable 24 executed by the PU 34.

FIG. 5 is an explanatory diagram illustrating that when a disconnection of the optical fiber cable 24 occurs in the LAN of the embodiment, the disconnection location can be specified.

[Explanation of symbols]

2 ... Conveying line 4 ... Station 6
… Conveyor 8… Main rail 10… Branch mechanism 12
... station rail 20 ... main controller 22 (22a, 22b, ..., 22k, 22l) ... controller 24 ... fiber optic cable 26 ... keyboard 28 ... displays 30, 42 ... communication circuits 32, 44 ... input / output circuit 3
4, 46 CPU 36 End switch 38 Actuator 40 (40a, 40b, 40k, 40l) LED

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-114137 (JP, A) JP-A-63-246947 (JP, A) JP-A-1-220549 (JP, A) JP-A 63-246 219296 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H04L 12/437

Claims (1)

(57) [Claims] 1. A communication unit for performing data communication with another device via a communication line, an abnormality notification unit for notifying the occurrence of an abnormality, and a drive for driving the abnormality notification unit in response to an external notification command. And a plurality of devices each having a means,
A disconnection detection device provided in a local area network connected in a ring shape by the communication line and detecting disconnection of the communication line, wherein the device loops around each of the devices at least once within a predetermined time. A cyclic signal transmitted from the communication means in the direction of one device; and a cyclic signal transmitted by the cyclic signal transmitting means within a fixed time, when the cyclic signal is not received by the communication means, Abnormality detection means for detecting an abnormality; and notification command means for transmitting, when the abnormality detection means detects an abnormality, a command signal for performing a notification command to the drive means in each of the devices from the communication means in the direction of one of the devices. A disconnection detection device in a local area network, comprising: