JPS61117946A - Data transmission equipment - Google Patents

Abstract

PURPOSE:To eliminate the need for a transmission line supervisory device by selecting data from two ways depending on the priority of advanced order or simultaneous order, transmitting the data in a direction different from the reception direction, abolishing the data received from the other direction and transmitting data in two ways at the transmission from its own station. CONSTITUTION:In transmitting data from a station S1, a detection signal is outputted from a carrier detector 9c to an advanced order discriminating section 10 in a two-way transceiver 6 at the transmission of data, a discriminating signal selecting transmission data from a station master 1 is outputted to a relay control section 11 and the transmission data is transmitted at the same time to stations S2 and S4. Even when the reception data reaches the relay control section 11 during the transmission, the reception of the received data is abolished to eliminate the reception data. The transmitted transmission data collide with each other on a transmission line 5 between the stations S2 and S3, and since the succeeding data is abolished in the S2 and S3, the effect of signal interference due to multi-path caused in a ring transmission line is eliminated. If a faulty state takes place, an open loop is formed and the signal interference due to the multi-path is not generated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a data transmission device in which a plurality of data transmission stations are connected in a ring through a bidirectional transmission path.

[Conventional technology]

As a data transmission device using a conventional bidirectional transmission line,
There is one shown in Figure 9.

That is, in FIG. 9, stations S, , S, . 3 is a transmission line monitoring mechanism that determines whether the transmission line is normal or abnormal; 4 is a transmission line connection/control mechanism installed in the transmission line monitoring mechanism 3;
A transmission path switch 5 for disconnection is a bidirectional transmission path that connects the stations S, St, . . . in a circular manner.

In this type of data transmission equipment, in order to avoid signal interference due to multipaths that occurs during data transmission when the transmission lines are connected in a ring, the transmission line shown in Fig. 9 (a) is normally used.
As shown in , a transmission line switch 4 inserted in the transmission line s
If the transmission line becomes disconnected due to wire breakage or station failure, etc.,
This was detected by the transmission path monitoring mechanism 3, and
As shown in FIG. 2, a back amplifier method is known in which the transmission path switch 4 is closed and data transmission is continued via a separate path.

[Problem that the invention seeks to solve]

However, in the above conventional data transmission device,
Since a transmission line monitoring mechanism is required to detect disconnections and station gate failures, this results in lower reliability and higher costs.In addition, after the transmission line monitoring mechanism detects an abnormal state, the transmission line switch 4 is switched to ensure normal transmission. There is a problem in that it requires recovery time before restarting, and cannot be applied to data transmission that requires quick response.

Therefore, this invention eliminates the need for recovery time when an abnormality occurs and improves reliability by performing optimal processing in abnormal conditions without installing a transmission line monitoring mechanism that detects disconnections or station failures. The object of the present invention is to provide a data transmission device that can be used for high-speed transmission.

[Means for Solving the Problems] In order to solve the above problems, the present invention connects a plurality of stations in a ring through a bidirectional transmission path, and each station can receive data from multiple directions. The system selects one of these data according to its first-come-first-served order or priority order when it arrives simultaneously, and transmits it in a direction different from the receiving direction. The present invention is characterized in that it has a bidirectional transceiver configured to transmit in both directions when transmitting from its own station.

[Effect]

A bidirectional transmitter/receiver of each station selects and receives data transmitted from both directions, transmits the received data in the opposite direction, and prohibits reception of data from the other side at the time of selective reception; In addition, by transmitting data bidirectionally when transmitting from its own station, under normal conditions, data from the station that is the data transmitting side is transmitted bidirectionally, data is transmitted simultaneously to adjacent stations, and this is sequentially transmitted. Transmit via a bidirectional transceiver at each station.

Even if a disconnection occurs in a part of the transmission line from this normal state, or a failure occurs in a part of the stage ten and the circular transmission line becomes an oven loop, data can be sent in both directions and the abnormal state will be established. Since two transmission paths are secured to the location where the error occurred, data can be reliably transmitted to each station.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a diagram of a bidirectional transceiver applicable to the present invention.

FIG. 2 is a block diagram showing a specific configuration.

In Figure 1, SL, S! . . . is a station, which is composed of a station master 1 that processes transmission data and a bidirectional transceiver 6. and,
Bidirectional transceivers 6 of each station SI, St, . . . are connected in a ring by a transmission line 5.

The two-way transceiver 6 is connected to adjacent stations 5N-1 and S, as shown in FIG. . , carrier detectors 9a and 9b that detect whether or not received data received by receivers 7a and 7b connected to transmission side transmission path 5 of , respectively, exist on signal lines 8a and 8b, and a station master to be described later. 1
A carrier detector 9c detects the presence or absence of data on the signal line 13 from the carrier detectors 9a, 9b,
The first-come-first-served ranking determination unit 10 to which the detection signal 9c is supplied and the received data from the receivers 7a and 7b are the received signals, %I
8a and 8b, and a relay control unit 11 to which a determination signal from the first-come-first-served ranking determination unit 10 is supplied; and a transmission signal line 12 that transmits transmission data from the relay control unit 11.
a, 12b, and transmits received data from the relay control unit 11 to the station master 1 via a signal line 13r.
At the same time, transmission data from the station master 1 is supplied via the signal ml 3t, and transmission signal lines 12a and 12b are connected to transmitters 13a and 13b connected to the ends of the transmission path 5. There is.

Here, the first-come-first-served ranking determination section 10 includes a carrier detector 9a,
Based on the detection signals of 9b and 9c, the receiving signal lines 8a, 8b,
When received or transmitted data exists at different times above 13, it is determined which of them existed first to determine the first-come-first-served order and select the received or transmitted data, and each signal line When receiving or transmitting data is simultaneously present in 8a, 8b, and 13t, the receiving or transmitting data is selected based on a preset priority order, and a determination signal corresponding to the selection is output to the relay control section 11.

Based on the determination signal from the first-arrival determination unit 10, the relay control unit 11 accepts only data on any one of the signal lines 8a, 8b, and 13, rejects acceptance of data on other signal lines, and (or 8b) When the above received data is accepted, the received data is signaled! 13r to the station master 1, and also sends the received data to the transmission signal M12b (or 12a) on the opposite side from the receiving side, and when receiving the transmission data from the station master 1, the transmission data is sent to the station master 1. Transmission signal line 12
a and 12b, transmitters I3a and 13b
It converts the data into a transmission signal and simultaneously sends the data to both adjacent stations.

Next, the operation will be explained with reference to FIG. Now, assuming that each station S+=34 is in a normal state and that there is no abnormality in the transmission line 5, an example will be described in which the station S1 transmits desired data to the other stations 32 to S4. At this time, in the bidirectional transceiver 6 of station S, the carrier detector 9a detects that no data exists on the transmission line 5 connected to the transmission side of the bidirectional transceiver 6 of the adjacent station St, S4. , 9b, when the carrier detector 9c sends out the transmission data from the station master 1 with the transmission signal %113 above, the transmission data is detected from the carrier detector 9c at the time of sending out the transmission data. A detection signal indicating the presence is output to the first-come-first-served determination unit 10.

For this reason, the first-arrival determining section 10 outputs a determination signal for selecting the transmission data from the station master 1 to the relay control section 11 .

Therefore, the relay control unit 11 converts the transmission data from the stage master 1 supplied via the transmission signal line 13t into the data DIAI as shown in FIG. 3(II).
It is simultaneously supplied as DIm to transmitters 13a and 13b via transmission signal lines 12a and 12b, and the transmission data is simultaneously sent to adjacent stations S2 and S4 via transmission line 5. Even if the received data reaches the relay control section 11 from the received signals *8a and 8b while this transmission data DtA+I)II+ is being sent, the relay control section 11 rejects acceptance of the received data and erases the received data.

Here, a station SN and an adjacent station SN. , the signal propagation delay time between stations varies depending on the distance between stations and the transmission medium, but the delay time between each station is T14゜Tz-s + T3-4
+74-1, and Tl-2=74-117, -
, <73-.

Then, as shown in FIG. 3(b), the station S2 adjacent to the sending station S1 receives the received data D! directly from the station S via the transmission line 5.
Since A arrives earlier than the received data Dt1 relayed and transmitted by stations S i and S3, the received data I)iA received by the 5Ht device 7a on the station S side
is selected by the first-come-first-served determination unit 10. Therefore, the relay control unit 11 sends the received data DtA to the station master 1, and also sends it to the transmitter 13b via the transmission signal line 12b.
is supplied to the adjacent station S via the transmission line 5.
, is sent to. At this time, assuming that the transmission data from station SI is relatively long, the relay data [)1++ from station S3 is transmitted while the transmission data is being relayed.
is received via the receiver 7b, but since the relay control unit 11 rejects the reception of the received data D2I+ from the receiver 7b, this received data DtN is not relayed. Therefore, the transmission data I)+s sent from station Sl to station 34 is relayed by station S4, 33 and then disappears at station S2, so it never returns to station S.

Similarly, the transmission data DIA sent from station S1 to station S2 is relayed by station S2, then disappears at station S, and station S4.
It never reaches S.

At this time, the transmission data DIA and Dll sent from the station S1 to the stations S2 and S4 at the same time collide and change on the transmission line 5 between the stations 38 and 33, but each station S8 and S
In No. 3, since the later arriving data is discarded, an abnormal situation does not occur, and the influence of signal interference due to multipath occurring in the ring transmission path can be removed.

From this normal transmission state, for example, a stage can be sent.

If an abnormal condition occurs between S8 due to an abnormality in the transmitter 13a or the receiver 7b, or a disconnection in the transmission line 5, the part where the abnormal condition occurs becomes an oven loop, and equivalently becomes a straight transmission line. , no signal interference due to multipath occurs, and the station S2 has the signals shown in FIG.
As shown in d), transmission data from station S1 is transmitted via stations Sa and Ss. That is, in the normal state, the rejected data [)zm shown in the diagonal line in FIG. 3cb> is accepted by the station St as the only valid data.

The data transmission abnormal state described above applies to each station Sl to S4.
Since all of the two-way transceivers 6 have the same function, any transmission line 5 or station S.

Even if a failure occurs in ~S4, normal data can be exchanged, and there is no need for any recovery time for abnormality detection and recovery.

In the above embodiment, there are no restrictions on the material of the transmission line 5, and electric signal transmission lines such as coaxial cables and twisted pair cables can be applied as shown in FIG. As shown, the optical fiber cable 17 can also be applied by using the receivers 7a and 7b of the bidirectional transceiver 6 as optical-to-electrical converters 15a and 15b, and the transmitters 13a and 13b as electric-to-optical converters 16a and 16b. .

Further, in the above embodiment, a case has been described in which stations S I''' S 4 having the same configuration are connected by a ring transmission line 5, but the present invention is not limited to this.
As shown in the figure, a bidirectional transmitter/receiver 6 may be inserted in the annular transmission line 5, and a plurality of multi-drop stations S may be connected to this.

Furthermore, in the above embodiment, the bidirectional transmitter/receiver 6 has two
We have explained the case where data is sent and received from the direction, but as shown in Fig. 8, one end is connected to the star-shaped station S.
, the other end of a plurality of N bidirectional linear transmission lines connected to If the multi-directional transmitter/receiver 20 is configured to be able to relay data, it can also be applied to a star-type transmission line system.

〔Effect of the invention〕

As explained above, according to the present invention, data can be received from both directions, and one data is selected based on the first-come-first-served order or the priority order at the time of simultaneous arrival. A bidirectional transmitter/receiver that transmits data in one direction, rejects data received from the other direction when transmitting, and transmits data in both directions when transmitting from its own station is connected to the bidirectional ring transmission path. Since the configuration is such that all stations receive only valid l data, regardless of whether or not there is a location where data cannot be exchanged due to an abnormality in the transmission path or a station failure, all stations can receive only valid l data and There is no need to install a transmission line monitoring mechanism, which reduces costs and improves reliability. In addition, there is no need for recovery time when an abnormal condition occurs, and transmission line abnormalities can be dealt with promptly. The effect is that it can be applied to high-speed data transmission equipment.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of this invention, FIG. 2 is a block diagram showing an example of a bidirectional transmitter/receiver applicable to this invention, and FIGS. 3 and 4 each show details of this invention. 5 to 8 are block diagrams showing other embodiments of the present invention, and FIGS. 9(a) and 9(bl) are block diagrams showing conventional examples, respectively. is station master, S+, St...
・ is a station, 6 is a bidirectional transmitter/receiver, 7a. 7b is a receiver, 98 to 9c are carrier detectors, 10 is a first-come-first-served determination unit, 11 is a relay control unit, 13a and 13b are transmitters, SN is a multi-drop station, 20 is a multi-directional transceiver, S is a star This is a mold station.

Claims (1)

[Claims] A plurality of stations are connected in a ring by a bidirectional transmission path, and each station is configured to be able to receive data from multiple directions, and receives data from either one according to the order of first arrival or the priority at the time of simultaneous arrival. A two-way station configured to select one station and transmit in a direction different from the receiving direction, reject data entering from other directions during the transmission/reception, and transmit in multiple directions when transmitting from its own station. A data transmission device comprising a transceiver.