JPH0481903B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fault diagnosis device for multi-branch transmission lines.

[Conventional technology]

As a means of communication between a plurality of stations, a method is widely used in which all stations are connected to a pair of transmission paths to facilitate communication, such as adding stations or changing transmission paths. The transmission line in this method has a multi-branch transmission structure in which a number of Y-shaped connections consisting of a contact point 66 and three partial transmission lines 67 to 69 are consecutive as shown in Fig. 6, and the number of stations is N. A complex multi-branch transmission line consisting of (N-2) contacts and (2N-3) partial transmission lines is constructed.

A conventional fault diagnosis method using this method is, for example, the method described in Japanese Patent Publication No. 57-26027.
An outline of this method will be explained based on FIG. 7. The station 71 includes a receiver 73 and a driver 74 that respectively transmit and receive signals, a transmission circuit 75 that performs parallel-to-serial conversion of signals, a monitoring and disconnection circuit 77 that constantly monitors the presence or absence of transmission signals, a terminal computer 76, a counter 78 Consists of etc. The monitoring disconnection circuit 77 is
If a transmission signal is not sent within a predetermined time, the internal timer cannot be reset.
Disconnect the relay 72 and perform a self-diagnosis of the transmission section.
If a failure in the transmission section is discovered here, the relay 72 remains disconnected, and if it is not a failure in the transmission section, the relay 72 is connected again. At this time, if there is a failure in the transmission section of another station, the transmission can be continued through the multi-branch transmission line 70 because that station is disconnected. On the other hand, if the multi-branch transmission line 70 itself is at fault, the monitoring disconnection circuit 77 disconnects the relay 72 again. A counter 78 counts the number of disconnections and connections of the relay 72, and when the calculated value exceeds a certain number of times, the multi-branch transmission line 70
It is determined that the problem is with the device itself.

[Problem that the invention seeks to solve]

This method can determine whether the fault is in the station or the multi-branch transmission line, but when a fault occurs in the multi-branch transmission line, it cannot be determined which partial transmission line is at fault. Since maintenance and replacement of a multi-branch transmission line is performed for each partial transmission line, there is a problem in that maintenance and replacement cannot be performed unless the partial transmission line in which a fault has occurred cannot be identified.

The purpose of the present invention is to prevent failures in multi-branch transmission lines.
The purpose is to improve maintainability by determining which partial transmission line is at fault using a simple circuit and procedure.

[Means for solving problems]

The above objects include a timer for measuring time, a first means for resetting the timer when a communication is received from an adjacent station in a direction that goes around the multi-branch transmission line, and the timer This is accomplished by providing at each station second means for providing a fault indication when the first means does not reset the first means within a predetermined time.

[Effect]

Stations that are adjacent to each other in a direction that goes around the multi-branch transmission line along the multi-branch transmission line are defined as diagnostic target stations for each station.
Then, each station diagnoses only the partial transmission path between its own station and the station to be diagnosed, and displays a failure indication when a failure is detected. By doing this, one partial transmission line can be diagnosed only by two stations in different combinations, making it possible to determine which partial transmission line is at fault based on the combination of stations displaying the fault. It is something.

〔Example〕

The present invention will be explained in detail below with reference to the drawings.

FIG. 2 is an overall configuration diagram of an embodiment of the present invention. The ten stations 1-10 are connected by a multi-branch transmission line consisting of 17 partial transmission lines 11-27, and communication between the stations is performed.

In this case, the loop that goes around the multi-branch transmission line along the multi-branch transmission line becomes the single loop 28 shown in FIG. Although the loop 28 is a counterclockwise loop, there is no problem even if it is a counterclockwise loop, and the effect of the invention is the same. Through the loop 28, each of the stations 1 to 10 is changed from 1→
They will be adjacent to each other in the order of 2 → 3 → 4 → 5 → 6 → 7 → 8 → 9 → 10 → 1, and station x
The diagnostic target station is station x-1.
becomes. However, the diagnosis target station of station 1 is station 10.

Each station monitors the presence or absence of reception from the station to be diagnosed, and if it is unable to receive communication from the station to be diagnosed even after a predetermined period of time has elapsed due to a failure in the partial transmission path between the own station and the station to be diagnosed, Displays a fault.

Here, the fault display operation will be explained by taking as an example a case where a fault occurs at the fault occurrence point 29 of the partial transmission line 17. The station 4 includes a partial transmission line 15,
Since the presence or absence of reception from the diagnostic target station 3 is monitored via the terminals 16, 17, and 18, a failure at the failure location 29 is displayed. In addition, the station 8 also has partial transmission lines 23, 21, 19, 1
Since the presence or absence of reception from the diagnostic target station 7 is monitored via stations 7 and 24, the failure location 29
A failure is displayed due to a failure. However, since the stations other than the stations 4 and 8 do not include the partial transmission path 17 between them and the station to be diagnosed, no failure will be displayed due to a failure at the failure location 29. Since the only partial transmission line that is commonly diagnosed by stations 4 and 8 is partial transmission line 17, when stations 4 and 8 display a fault, it can be determined that the partial transmission line 17 is at fault.

As described above, one partial transmission path is diagnosed by two stations, and the combination of the two stations is different for each partial transmission path. Therefore, it is possible to determine which partial transmission path is at fault from the combination of stations displaying the fault.

FIG. 3 shows a determination circuit for determining a faulty partial transmission line from a combination of stations displaying a fault. Signal E1
-E10 are fault indication signals from the stations 1 to 10, respectively, which become "1" when a fault occurs. Gates 50-66 are gate circuits that output "1" when both inputs are "1", and output signals E11-E27, respectively.
Signals E11 to E27 are each transmitted through the partial transmission line 11.
~27 is a signal indicating that a failure has occurred,
It becomes "1" when a failure occurs.

FIG. 4 shows the configuration of a station according to the present invention. The station 31 includes a driver 32 and a receiver 33 that transmit and receive signals, respectively, a transmission circuit 34 that performs parallel-to-serial conversion of signals,
It consists of a receiving circuit 35 that performs serial-parallel conversion of signals, a computer 36, a timer 37, a flip-flop 38, a digital switch 42, and the like. Then, the computer 36 transmits the signal to the multi-branch transmission line 30 via the transmitting circuit 34 and the driver 32, and
0, it is received by the computer 36 via the receiver 33 and the receiving circuit 35. The digital switch 42 is
This is a setting device for setting the diagnosis target station number, and the diagnosis target station number is set in advance.

When the computer 36 receives a signal, it checks the reception status, and if the reception is normal, it determines whether the transmission source station number and the diagnosis target station number set in the digital switch 42 match, and if they match, the computer 36 checks the reception status. resets the timer 37. The processing flow of the above computer is shown in FIG.

The timer 37 constantly measures time, and if it is not reset within the processing time, it times up and sets the flip-flop 38. The flip-flop 38 displays a fault by setting the fault display signal 43 to "1" and lighting up the LED 41 via the gate 40. switch 39
is for resetting the flip-flop 38. As a result of the operations described above, the station 31
displays a failure when it cannot receive communication from the station to be diagnosed within a predetermined period of time.

Explain how to detect failures using a timer.

In the case of a system in which the bus occupancy order of each station 1 to 10 is 1→2→...10→1...

Therefore, station 4 can receive transmissions from station 5 for a certain period of time, and station 8 can receive transmissions from station 5 for a certain period of time. If there is no transmission within that time, it is determined that there is an abnormality.

In the case of a system in which the operation procedure of each station 1 to 10 follows a predetermined procedure.

That is, for example, 1→2→1→1→3→4→2→...
It also applies to cases such as...

〔Effect of the invention〕

According to the present invention, when a fault occurs in a multi-branch transmission line, it is possible to determine which partial transmission line is at fault.
A diagnostic device for multi-branch transmission lines with improved maintainability can be realized.

[Brief explanation of the drawing]

1 and 2 are overall configuration diagrams of an embodiment of the present invention, FIG. 3 is a circuit diagram of a discriminating circuit, FIG. 4 is a configuration diagram of a station, FIG. 5 is a flowchart during reception, and FIG. The figure is an explanatory diagram of a multi-branch transmission line, and FIG. 7 is a configuration diagram of a conventional example. 1 to 10, 31, 71...Station, 11
~27, 30, 70...Partial transmission line, 36...Computer, 37...Timer, 38...Flip-flop, 42...Digital switch, 43...Fault indication signal.

Claims (1)

[Claims] 1. In a system in which a plurality of stations are connected by one multi-branch transmission line and each station performs communication by occupying a line according to a predetermined order, the system comprises: a timer that measures time; and a multi-branch transmission line. a first means for resetting the timer when a communication from an adjacent station is received in a direction that goes around the transmission path along a multi-branch transmission path; A fault diagnosis device for a multi-branch transmission line, characterized in that each station is provided with a second means for displaying a fault when the reset is not performed within a predetermined time determined by the order.