JPS5980042A - Loop transmitter - Google Patents

Abstract

PURPOSE:To reorganize a line in a smooth and quick way without using specially a circuit controller, by holding a token, and requesting investigation of the state of a transmission line through a transmitter having the right of transmission, then receiving the result of investigation. CONSTITUTION:The transmitters 10 connected with transmission lines of R and L lines 11 and 12 having opposite directions to each other. The transmission is usually carried out through the line 11; while the loop-back transmission is performed through the circuit 12 when the line 11 and the transmitter 10 have faults. At the same time, a faulty area 14 is separated. Plural transmitters 10 have exactly same functions, and the right of transmission is set up by receiving just a single token existing in the system. A transmitter 10 having the token gives the token to the next transmitter 10 via the line 11 when the transmission of data is over.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a transmission device that has a loop-shaped transmission path and controls data transmitted and received via the transmission path.

[Technical background of the invention]

In a system where a transmission path is configured in a loop and multiple transmission devices are connected to it, if each transmission device sends data to the transmission path at will, this data will cause interference on the transmission path. , it is necessary to control the transfer rights by some means.There are several ways to do this,
The transmission device according to the present invention employs a token passing method that has been well known in the past. In the L method, there is only one transmission right called a token in the system, and only the transmission device that holds this right can transmit. A transmission device that does not hold a token is only allowed to receive transmitted data from a transmission device that does have a token.

However, it has not been generally established how to generate only one token in a system and how to transfer this token between transmission devices.

In the conventional device, a special transmission device for monitoring and control is provided in the transmission path, and this device generates tokens and controls sending and receiving the tokens to and from each transmission device.

[Problems with background technology]

However, if there is an abnormality in this device or the transmission line connected to it, the system will stop, so a backup device is essential, and control between these two devices becomes complicated.

In addition, if the transmission equipment malfunctions, it may be disconnected or
The monitoring device also controls the integration of fL into the transmission system after failure recovery, but this is often inconvenient in operation because the failed device and the monitoring device are separated by a distance.

As described above, transmission systems in which transmission control is performed at one location have had problems with system reliability and operational operability.

[Purpose of the invention]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a loop transmission device that overcomes the drawbacks of conventional devices.

[Summary of the invention]

The present invention connects a plurality of transmission devices with a double loop-shaped transmission path with the transmission directions opposite to each other, and establishes the transmission right by receiving a token that exists only once in the system. In the transmission device to be controlled, the first transmission device holding the token checks the state of the adjacent second transmission device and the transmission path between them via the double loop-shaped transmission path, and if it is normal, the first transmission device holds the token. The first transmission device is a loop transmission device that can request the second transmission device to investigate the state of the third transmission device adjacent thereto and the transmission path therebetween, and the token A transmission device that does not hold the token can sequentially request an investigation of the status of the adjacent transmission device and the transmission path between them, and can notify the result of the status investigation to the transmission device that holds the token. can notify the transmission device capable of transmitting by broadcast transmission, and if the transmission device or one or more parts of the transmission path is disconnected and loopback transmission is performed, the failure can be notified to the repaired transmission device. This is a loop transmission device that, when activated, receives the token, investigates the status of the previously disconnected portion, and notifies it through the broadcast transmission to reconfigure the line.

[Embodiments of the invention]

An embodiment of the present invention will be described with reference to the drawings.

Figure 1 is a system configuration diagram using the loop transmission device in this embodiment. The transmission device 10 has an R line 11. whose data transmission directions are opposite to each other. They are connected by a transmission line called L line 12 and have a double loop structure. Transmission is normally performed through the R line 11, and when an abnormality occurs in the R line 11 or the transmission device 10, loopback transmission is performed using the L line 12, and the abnormality occurring portion 14 is disconnected.

The transmission devices i according to the present invention each have completely equivalent functions. The transmitter is a token-passing system that relies on receiving only one token in the system. When the transmission device 10 holding the token completes the transmission of data to be notified to other transmission devices 10,
The token is delivered to the next transmission device 10 via the R line 11.

Here, the former device will be referred to as an upstream station, and the latter device will be referred to as a downstream station.

Also, the transmission device that holds the token is called a mask, and the other devices are called slaves.

Therefore, there is no device specially provided for controlling transmission. When the transmission device 10 that has received the token has no data to transmit, it immediately hands over the token to the downstream station. When all transmission devices do not have data to transmit, only tokens are circulating on the transmission path.

The transmission format is rB, which transmits data between specific transmission devices.
Both n transmission and broadcast transmission in which all slave transmission devices receive data transmitted from a mask transmission device are possible. These identifications are performed in the third portion SA of the transmission frame 13, which will be described later.

In n:n transmission, the slave transmission device 10 takes a confirmation response that it has correctly received the data. On the other hand, in broadcast transmission, no acknowledgment is received from each slave device. When the transmitted data returns via all the slave devices, the mask device compares the received data with the transmitted data and determines that the data was correctly transmitted if they match.

FIG. 1(b) shows a transmission form when a transmission line fails.

Since the transmission line has a double loop configuration, the transmission equipment 10 (STN and STN/
) is R line 11. An example is shown in which 1+1 data received on the L line 12 is transmitted to the opposite line.

FIG. 2 is a diagram showing the format of data flowing through the transmission path, and the format of data passed between the transmission devices 10 will be explained with reference to this diagram.

The transmission frame 13 consists of six parts (referred to as fields).

The first part is the command CMD. This is to identify the contents of the transmission frame 13, and is a test (TES)
T), line configuration (CNF), text (TEXTo)
, retransmission text (TEXTI), token (TOK)
EN).

Either an acknowledgment (ACK) or a negative acknowledgment (NAK) is entered.

The second part SA is for specifying the transmission device that should receive the transmission frame, and indicates that the transmission frame is received by all transmission devices only when this value is 1° C., that is, it is a broadcast transmission.

The third part PA represents the address of the transmitter of the mask transmitting the transmission frame.

The fourth part N specifies the data length of the text part TEXT that follows.

The fifth part, text part TEXT, is where information to be transmitted from the mask to the slave is entered.

The final check section BCC is provided to detect bit errors in the transmission frame.

FIG. 3 is a diagram showing the internal structure of the transmission device according to the present invention.

The flow of transmission data within one transmission device 10 will be explained with reference to FIG. 3.

First, in the slave state, K 2 of transmission frame 13
Partial CM D (r) Contents are TEXTO, TEXT
1 (7) Explain the operation of Toki.

Since the transmission device 10 in the slave state receives data via the R line 11, the reception control circuit 103 writes the data into the reception buffer 101.

If the third part SA of the transmission frame 13 is 110'', which indicates broadcast transmission, or is different from the address of its own transmission device, the received data is immediately sent to the R line 11 through the transmission control circuit 104. If the address is the address of 104 first part CMDiACK of transmission frame 13 throughout.

The second part SAi master's address, i.e. the value of the third part PA of the received transmission frame 13, the third part P
Ai Send as your own address.

Broadcast transmission or data sent to oneself is in the reception buffer 101. This data is transmitted to the equipment connected to the transmission device 10 by the control circuit 108.
Hand it over in its entirety.

During loopback transmission as shown in FIG. 1(b), data also flows through the L line 12. At this time, the data received from the reception control circuit 106 is sent to the transmission control circuit 1 as is.
05 to the next transmission device 10.

Next, the operation when the transmission device 10 in the masked state transmits data will be described with reference to the same drawing.

It is assumed that data to be transmitted has been written from a device connected to the transmission device 10 to the transmission buffer 102 via the reception control circuit 107. Writing to the transmission node 102 is possible even when the transmission device 10 is in a masked or slave state.

The data to be transmitted is the fifth part E of the transmission frame 13.
XT, and the other parts are generated by the transmission device 10.

If this data is to be sent to a specific transmission device, the second part SA of the transmission frame 13 is set to that address. If you want to send it to all slaves, set this value to 1'
07 for broadcast transmission. When the seven transmission frames 13 are assembled in this way, the changeover switch 109
．． It is transmitted to the R circuit 11 via the transmission control circuit 104.

The method of confirming whether transmitted data has been correctly received differs between broadcast transmission and n:n transmission. In broadcast transmission, when the data returns via all slave transmission devices, this data is written to the reception buffer 101 via the reception control circuit 103. If this content matches the content of the transmission buffer 102, it is assumed that the data has been transmitted correctly.

In rBn transmission, it is assumed that the transmission frame 13 with the acknowledgment ACK sent from the received slave transmission device is correctly transmitted when it is received from the reception control circuit 103.

The masked transmission device that holds the token has the right to transmit. When the transmission is completed, the mask transmission device sends the first portion CMD of the transmission frame 13 as a token TOKEN to the 1fA 11 eight times via the transmission control circuit 104. The transmission device 1° that has received the token performs the above-mentioned masking process if there is transmission data in the transmission node 102 of its own device. When there is no transmission data, the received token is immediately sent to the R line 11 via the transmission control circuit 104.

By the way, in order to express the operation of one transmission device 10 in a precise and easy-to-understand manner, it is appropriate to divide the operation state into a plurality of states and describe the detailed operation and state transition in each state. The transmission device 10 according to the present invention will also be explained in accordance with this with reference to the state transition diagram shown in FIG.

All transmission devices 10 can take any one of the following states. Transitions between states are shown by paths PHj in FIG.

0: On...Waiting for power off state...When initialization processing is completed and the self-diagnosis result is normal.

2: Master check...Sends a test frame, checks operable circuits, and creates line configuration data.
This data is transmitted to the operational transmission device 10.

Generate a token.

3. Reception processing of test frames.

4: Transmission device that holds online mask...mark/token. When there is data to be transmitted within its own transmission device, it is assembled into a transmission frame 13 and transmitted.

5: Online slave...Receives the transmission frame 13 sent from the online master 4.

6: Down...A state where a retrospective abnormality has occurred.

The operation of the transmission device 10 described above is the operation in a steady state when transmission is normally performed.

FIG. 4 is a diagram showing the operation of the transmission device of FIG. 3 in a state transition diagram.

In the state transition diagram of FIG. 4, the transmission device 10 having the transmission right called mask is in the state of online master 4, and is in the state of transmission 1i10fi online slave 5 which receives data, called slave. When the mask passes the token to the downstream slave transmission device 10, the path is P4. , when the slave receives this, the confirmation means path is P54.

Next, the operation when reconfiguring the line of the transmission device 10 of the present invention will be described.

The operation of reconfiguring the line occurs in the following three cases.

■ When all transmission devices are powered on.

■ When an abnormality occurs in the line, that is, when the abnormal part is disconnected and transmission starts using only the normal part.

■ When a line reconfiguration request is made to any transmission device. .

First, the case (■) will be described.

When each transmission device 10 is powered on, it initializes itself and performs self-diagnosis. This is the OFF 0 state in FIG. If it is determined to be normal by self-diagnosis, route P. Transition to wait state 1 through □.

In wait state 1, it is checked whether there is an activation request to start transmission. Examples of startup requests include when an operator presses a start switch attached to the transmission device 10, data sent from a device connected to the transmission device 10, etc.
The method of making the request is not included in the present invention.

For example, if the start switch has been pressed, the device immediately transitions to master check state 2 via path P1□. If the start switch is not pressed, the first part CMD of the transmission frame 13 from another transmission device 10 is tested (TEST) until it is pressed or from another transmission device 10.
Waiting for reception of data (hereinafter referred to as test frame) 0 In master check state 2, a line test is performed. The line test is an operation of checking the status of the transmission line with other transmission devices 10 using the R line 11 and the L line 12, and generating line configuration data representing the line status that allows transmission. When the line test starts, the transmission device 10 in the master check state 2 transmits a test frame, so all the transmission devices 10 in the wait state 1 transition to the slave check state 3. The details of the line test will be described later.0 When the line configuration data is created using the line test, the loop-shaped transmission line consisting of the R line 11 and the L line 12 and all the transmission equipment 10 connected to this are shown in Figure 1 (a). ), the line configuration data is sent to all transmission devices 10 via the R line 11. When there is an abnormality in the transmission path as shown in Fig. 1(b), if the device in master check state 2 is 5TNo. Line configuration data is sent to the third transmission device 5TNI+□ via the L line 12.

The line configuration data is the fifth part EX of the transmission frame 13.
T and the first part CMD is the circuit configuration (CNF)
, the second part SA is 1'0'' of broadcast transmission. The transmission device 10 in the master check state 2 transmits the transmission frame 13 to the R line 11 via the transmission control circuit
transmission device 1 in all slave check status 3.
This data returned via 0 is sent to the reception control circuit 10.
3 to the reception pamphlet 101. The previously sent transmission frame and the contents of the received packet are compared, and if they match, it is assumed that the line configuration data has been transmitted correctly, and the data is sent to the online master 4 via route P24 in FIG.
Transition to state. On the other hand, when the transmission device 10 of slave check 3 receives the line configuration data, it transits to the state of online slave 5 via path "35."

This completes the reconfiguration of the line, and in subsequent operations, tokens circulate on the line and transitions between the states of online master 4 and online slave 5 occur.

Next, the case (2) of line reconfiguration will be described.

When transmission is performed in online mask state 4 and online slave state 5, an abnormality may occur in the line.

Abnormalities include:

■ Transmission is no longer possible due to a break in the transmission line or a failure in the transmission equipment.

■ Noise entered the transmission path, causing a bit error in the transmitted data.

@ Token disappearance.

■ Multiple tokens were generated and sent by different transmission devices.

Excluding failure of transmission device 10 in online mask state 4■
In the case of and ■, the transmission device 10 in online mask state 4
can detect these anomalies.

If an abnormality is detected, a transition is made to master check state 2 via path P4□ in FIG. 4, and a circuit check is performed to discover the abnormal part. When the other transmission devices 10 in the online slave state 5 start the line check, the transmission devices 10 in the online slave state 5
3 to the slave check state 3. The subsequent operations have already been described, so they will be omitted.

If the transmission device in online mask state 4 fails or there is a bit error while transmitting the token, the @ token will disappear. Also, ■ may occur due to some reason. At this time, all the transmission devices 10 transition to the down state 6 via the path "46" 56. Each transmission device 10 starts a start-up timer (not shown) while waiting for reception. The start-up timer has a different value for each transmission device 10, and this time TMo is TMo=value of the address of the kX transmission device 10 (in seconds). The value of k is determined by the operating speed of the transmission device 10, the delay time of the transmission path, the number of transmission devices 10 connected to the nine lines, and the like.

Transmission equipment 1 where the IJ-J' timer has timed out
0-ha transits to master check state 2 via route P6□ and immediately enters line check. Other transmission devices 10 whose start-up timers have not timed out receive test frames from the transmission device 10 in master check state 2, so they stop this timer and transfer to slave check state 3 via path P63. Transition to. The subsequent operations have already been described, so they will be omitted.

FIG. 5 shows the line reconfiguration operation described above in the form of a flowchart.

Next, we will discuss the case (2) of line reconfiguration. In this case, as shown in Figure 1 (b), there is an abnormality in a part of the transmission line or transmission equipment, and this part is disconnected and loop-no-knock transmission is performed. In this state, it is time to repair the failure of these abnormal parts and make them participate in transmission.The procedure for this is shown in FIG. When the repair of the failure is completed, the transmission device transits from the off state 0 to the wait state 1 and waits for the reception of the test frame, as described in case (2) above for line reconfiguration.Furthermore, the operator A reconfiguration request is made from a start switch attached to the transmission device 10 or from a device connected to the transmission device 10. The transmission device 10 that can issue a reconfiguration request is in online mask state 4. Or it must be a transmission device in online slave status 5.

When a reconfiguration request is received, the transmission device 10 receives the token and enters the online mask state 4, then transits to the master check state 2 and immediately enters a line check. Another transmission device 10 in online slave state 5 receives the test frame and transitions to slave check state 3.

The subsequent operations have already been described, so they will be omitted.

The operation of the final example line test will be explained with reference to FIG.

The transmission device MASTER in master check state 2 is first R
Test frame F from line 11. 1, and the first part CMD of the transmission frame 13 from the downstream transmission device 5 LAVE 1 via the L line 12 acknowledges (ACK)
Waits for the reception of data (hereinafter referred to as an acknowledgment frame). If there is no response within the predetermined time TM□, the transmission device or the R line 11. It is assumed that there is an abnormality in the L line 12. In order to avoid transient errors caused by noise, etc., the same frame is retransmitted multiple times when there is no response. When the downstream transmission device 5LAVEl receives the test frame, it transfers its own device address to the third part PA of the transmission frame 13. and sends an acknowledgment frame F□□ to the upstream station. When the upstream station MASTER receives this acknowledgment frame F□□, it sends an acknowledgment frame F. Send 2. Downstream station 5LAVE l is this frame F. 2, the upstream station MASTER performs the same operation on the downstream station 5LAVE2. Transmission device 5 sends the acknowledgment frame F2□ from LAVE2 to transmission device 5
When LAVEl receives this, the master check state 2
is sent to the transmission device MASTER via the L line 12. All of the following transmission devices in slave check state 3 S LAV
The same operation as described above is performed for E F .

In this way, the transmission device MAS in master check state 2
TER is the acknowledgment frame F1□, F2□.

Line configuration data representing the line status that can be transmitted from F31 is generated.

All transmission equipment 10 and lines 11 and 12 are shown in Figure 1(a).
The above operation is performed if the transmission line is normal as shown in Figure 1(b), but the line check operation when there is an abnormality in the transmission line as shown in Figure 1(b) will be explained with reference to the timing chart in Figure 8. Transmission bag in check state 2 [MASTER starts line check for the transmission device in slave check state 3 at the downstream station. When the transmission device and transmission path of the downstream station are normal, the operation is the same as described above, but when there is an abnormality on the downstream side of the transmission device SLA1 in slave check state 3, the operation is as follows.

Upon receiving the acknowledgment frame F4□ from the upstream station, the transmission device 5LAVE transmits the test frame F4 to the downstream station.
OR line 11'' which sends out 5□ via R line 11!
If there is an abnormality in the TAKE transmission device SI, AYE, +1,
WAu response frame F6□ is not returned. Fixed time T
If no response is received after M□, test frames F531 F54 are transmitted multiple times. If no acknowledgment frame is returned even after transmitting the test frame RT□ a predetermined number of times, it is regarded as abnormal and an L is sent to the upstream station.
The first part CMD of the frame 13 transmitted via the line 12
The data is sent as a negative acknowledgment (NAK).

When the transmission device MASTER in the master check state receives this transmission frame F55, it then performs a line check on the line on the opposite side. The way to check the lines is that the test frame is transmitted on the L line 12, and the acknowledgment frame from the downstream station is received on the R line 11, and the transmission and reception timing of each frame is the same as that in Figures 7 and 8. be.

〔Effect of the invention〕

Thus, according to the present invention, line reorganization can be carried out smoothly and quickly without the need to specially provide a transmission device for supervisory control on the line, and the parts that are disconnected due to line reconfiguration can be minimized. It is.

Further, since there is no transmission device for supervisory control, there is no need for a backup device in case of failure of the transmission device, so the transmission system can be realized at low cost and reliability against failures is increased.

[Brief explanation of drawings]

Figures 1 (a) and (b) are overall block diagrams when the transmission device according to the present invention is connected, Figure 2 is a diagram showing the format of data flowing through the transmission path, and Figure 3 is an example of an implementation of the present invention. A block diagram showing the internal configuration of the transmission device in the example, FIG. 4 is a state transition diagram of the operation of the device in FIG. 3, FIGS. 5 and 6 are flow diagrams showing the operation of line reconfiguration, and FIG. 7 FIG. 8 is a timing chart of data flowing through the transmission line during a line test. 10...Transmission device, 11...8 lines, 12...L
Line, 13...Transmission frame, 14...Failure occurrence part, 101...Reception buffer, 102...Transmission buffer, 103, 106, 107...Reception control circuit, 104, 105, 108...・Transmission control circuit, 1
09... Selector switch. Applicant's agent Kiyoshi Inomata Figure 6 1--Restoration of the late V.

Claims (1)

[Claims] 1. A plurality of transmission devices are connected by a double loop-shaped transmission line with the transmission directions opposite to each other, and the transmission right is only one in the system.
In a transmission device that controls establishment by receiving only one existing token, the first transmission device holding the token controls the state of the adjacent second transmission device and the transmission path between them in the double loop. If the state is normal, the first transmission device instructs the second transmission device to check the state of the third transmission device adjacent thereto and the transmission path therebetween. A loop transmission device characterized by being able to make requests. 2. The second transmission device that does not hold the token,
The state of the third transmission device adjacent to this and the transmission path therebetween is investigated via the double loop transmission path, and if it is normal, the third transmission device adjacent to this is checked. 4. The loop transmission device according to claim 1, wherein the loop transmission device can request to investigate the status of the four transmission devices and the transmission path therebetween. 3. The transmission device that does not hold the token can notify the transmission device that holds the token of the result of investigating the state of the adjacent transmission device and the transmission path between them. Loop transmission device. 4. The transmission device holding the token transmits the same data to all of the transmission devices capable of transmitting, via one or the double loop-shaped transmission path, information on the transmission devices and transmission paths capable of transmission. The loop transmission device according to claim 3, which can notify by broadcast transmission. 5. When loop-knock transmission is performed by disconnecting the transmission device or one or more portions of the transmission path, if any transmission device involved in the loop-knock transmission is activated, the above-mentioned When the transmission device receives the token, it investigates the status of the previously disconnected part, and transfers information on the transmission device and transmission path that can transmit to the transmission device that was involved in the loop-mack transmission and the previously disconnected part. 2. The loop transmission device according to claim 1, wherein the communication device notifies the separated transmission device through one or two loop-shaped transmission paths to reconfigure the line.