JPS6062765A - Transmission control method in loop transmission system - Google Patents

Abstract

PURPOSE:To cope with a fault of a transmission line and its extension by connecting transmission controllers corresponding to two loop transmission lines with the 3rd transmission line. CONSTITUTION:Transmission controllers 11, 12, 13 are connected clockwise, to a loop 1 transmitting data counter, and transmission controllers 21, 22, 23 corresponding to the transmission controllers 11, 12, 13 are connected to a loop 2 transmitting data clockwise. The transmission controller pairs 11 and 21, 12 and 22, 13 and 23 are connected respectively by detour transmission lines 100, 200 and 300 transmitting data is two-ways and also connected to transmission/reception terminal devices 31, 32 and 33. Through the constitution above, if a loop 1 or 2 is faulty, the data exchange between the transmission/reception terminal devices is conducted by combining and using the normal part of the loop 1 or 2 with the detour transmission line.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a loop transmission system for transmitting data between a plurality of devices via a loop-shaped transmission line.

[Background of the invention]

(1) In a transmission system using a conventional loop transmission line,
In order to determine the timing of data transmission and reception in each of the plurality of transmission control devices connected to the loop and to take measures against partial loop failures, one of the transmission control devices is used as a mask transmission control device, and the other transmission control devices The device is used as a slave transmission control device, and the former grasps the transmission status of the entire loop, thereby determining the above-mentioned transmission/reception timing and taking measures against loop failures. For this reason,
The problem is that the mask transmission control device becomes a large-sized device, and if the mask transmission control device breaks down, transmission becomes completely impossible.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to eliminate such problems and provide a highly flexible loop transmission system structure that can cope with transmission path failures and expansions without using a master transmission control device.

[Summary of the invention]

In order to achieve the above object, the present invention includes first and (2) second loop-shaped transmission paths, and a plurality of first a transmission control device connected to the second loop-shaped transmission path, and provided in pairs with the first transmission control device, respectively;
a plurality of second transmission control devices that control the transmission of signals on the loop; A loop transmission system comprising a third transmission path connecting the second transmission control device, and even if any transmission control device or line breaks down, a detour can be flexibly formed to connect the second transmission control device to the other transmission control device. This provides a configuration that does not affect the operation of the system.

[Embodiments of the invention]

The present invention will be explained below based on Examples.

The loop transmission system shown in FIG. 1 has a loop 1 that transmits data in a counterclockwise direction and a loop 2 that transmits data in a clockwise direction. are connected to the loop 2, and a transmission control device 2 paired with each of these devices 11, 12 and 13 is connected to the loop 2.
1,22°23 are connected. Each pair of devices 11 and 2
1゜(3) 12 and 22.13 and 23 are respectively connected by detour transmission paths 100 and 200゜300 that can transmit data in both directions, and are connected to transmitting and receiving terminals 31, 32 and 33 in both directions, respectively. Lines 311 to 313 capable of transmitting data,
321--323. Sending/receiving terminal 3
1, 32° 33, when only devices 11, 12, 13 and loop 1, devices 21 to 23 and loop 2 are normal, these devices 11 to 13 and loop 1, devices 21 to 23 and loop 2 are used. , mutually exchange data. If there is a failure in these devices or loops,
For example, if there is a failure in any of the devices 11 to 13 or loop 1, these terminals 31 to 33 will be disconnected from the devices 11 to 13, the normal partial devices 21 to 23 of loop 1, and the detour transmission line 1.
00°200.300 and loop 2, and if there is a failure in any of the devices 21 to 23 or loop 2, data is exchanged in the same way.

Therefore, the transmission control devices 11, 12, and 13 transmit data on loop 1 during normal operation (4), and
When there is an abnormality in the function of receiving data on loop 1 and the transmission system of loop 1, detour routes 100 and 2 are used, respectively.
00, 300, and also has the function of receiving data on this detour. The devices 21 to 23 are constructed in exactly the same way.

FIG. 2 shows internal circuit blocks of the transmission control device 11. Other transmission control devices also have exactly the same structure. The device 11 includes an interface 51 for exchanging data with the loop 1, a detour transmission line 100, and a line 3.
11, and an interface 61 for exchanging data with the first interface 51, 6 for storing messages received through these interfaces 51, 6, respectively. a second receive buffer 71.73 and these interfaces 51.6
1, and a processing device 41 and timers 90 to 92 to control the transmission and reception of these messages.
and registers (5) 93-95. Portions of the transmission control device 11 other than the interfaces 51 and 61 are realized by a microcomputer.

FIG. 3 is a detailed block diagram of the interface 51, and FIG. 4 shows a portion of the interface 61 that is connected to the detour transmission line 100. The configuration of the portion of the interface 61 connected to the line 311 is not shown because it is exactly the same as that in FIG. 4. In FIG. 4, the reference symbols shown in FIG. 3 with a prime (') attached thereto are exactly the same as those in FIG. The portions of the interface 61 that are connected to the line 311 will be referred to as necessary by adding two primes (“) to the reference numbers of the corresponding portions in FIG.

The circuit of FIG. 4 differs from the circuit of FIG. 3 only in that it does not include gates 61-64 and register 65.

The operation of this device 11 will be explained below with reference to FIGS. 2 to 4.

If there is no abnormality in the transmission system of loop 1, (6) II OTT is set in registers 93 to 95 as described later. At this time, the device 11 transmits data from the terminal 31 to another terminal, for example, the terminal 33, in the following manner.

The data to be transmitted is transmitted in the form of a message as shown in FIG. That is, the message 500 includes a flag area (F) 501 indicating that it is the start part of the message, and a reception address area (RA) 502 that is data for specifying the transmission control device that should receive the message. A transmission address area (SA) 503, which is data for displaying the transmission control device, and an area for data to be transmitted (
D) 504 and message error detection data area (F
e2) 505, and a flag area (F) 506 indicating the end of the message.

First, a message to be transmitted is received by the processing device 41 from the terminal 31 via the interface 61, and stored in the transmission buffer 81 under the control of the processing device 41.

This message (7) is stored in the transmission buffer 81 together with data indicating the number of times it has been transmitted. For messages that have been input from the terminal 31 and have not been sent yet, the number of times they have been sent is jl.
0 It is.

The processing device 41 performs the first . Second receive buffer 71.73. A search is made to see if there is a message to be transmitted in the transmission buffer 81.

In this case, when detecting that there is a message to be transmitted in the transmission buffer 81, the processing unit 41 sets 1'' in the register 65 in the interface 51 via the line 65A, indicating that the transmission is in progress. At the same time, the first eight bits of the message to be sent are input to the register 59 in the interface 51 via the line 59A, and the counter 60 is reset via the line 60A.

The 8-bit data in register 59 is processed by the clock generator (
CLK) 58 and is output serially. AND gate 62 is in an open state because the output of register 65 is "1".

Therefore, the output of the register 59 is sent to the transmitter 53 via this Antogame (8) Toro 2 and the OR gate 64, and is output to the loop 1. At this time, or gate 64
There is no other input to . This is because the AND gate 63 is in the closed state due to the output "0" of the inverter 61. Counter 60 is a 3-bit counter that counts the output of CLK 58, and outputs an overflow signal on line 60B after counting 8-bit clocks.

In response to this overflow signal, processing unit 41 sends the next eight bits of the message to be sent in transmission buffer 81 to register 59. By repeating this operation, a message of a predetermined length can be sent to loop 1. In this way, when the transmission of the message to be transmitted in the transmission buffer 81 is completed, the transmission circuit data of the message is set to "1", and the register 65 is set to 11.
Set 011. Further, the processing device 41 sets the timer 90 @ the set time of the timer 90 is set to a value somewhat larger than the time required for the message to go around the loop 1.

(9) When the message sent from this device 11 reaches the receiver 52 of the device 12, the synchronization signal detector 54 detects the pit sequence of this received message and sends a synchronization signal synchronized with each bit of this pit sequence. Output. The data received by the receiver 52 is stored in an 8-bit register 56.
is stored in synchronization with this synchronization signal. counter 5
A 3-bit counter 5 outputs an overflow signal onto a line 55A when it counts eight synchronizing signals. Processing unit 41 within device 12 stores the message in register 56 in first receive buffer 71 in response to this overflow signal.

If the device 12 is not transmitting a message at this time, 11011 is stored in the register 65. Therefore, since the AND gate 63 is in the open state,
This received message is sent as it is to the ANDGATE 6
3. It is sent to the transmitter 53 via the OR gate 64 and transferred onto the loop 1 again.

Upon receiving this message, the processing device 41 (10) decodes the sending address in the received message to determine whether or not this sending address is its own address. If it is detected that the address is not its own address, it continues to capture data in units of 8 bits as described above. Since this received message has already been transferred onto loop 1, processing device 41 does not need to transfer this message to loop 1 again. In order to indicate that this transfer is not necessary, the contents of register 65 are fetched from line 65B and stored in the first reception buffer as data accompanying the received message. If the processing device 41 detects that this sending address is its own address,
The register 65 is immediately set to 0'' via the line 65A to stop the transfer of the remaining part of the message from the receiver 52 to the transmitter 53, and this remaining part is stored in the first receiving buffer 71. The flag area 506 in the message indicates that the entire message has been received.
(FIG. 5), the processing device 41 sets It O91 in the register 65 again (11).

If the device 12 is transmitting a message, the register 65 is set to 1''. Therefore, the message received by the receiver 52 is not sent to the transmitter 53 but is stored in the first reception buffer 71. Stored.

If the sending address of this received message is not its own, this message is sent to loop 1 again.
must be transferred to. To indicate this necessity, the content "1" of register 65 is stored in first receive buffer 71.

The device 12 that has received the message decodes whether the receiving address of the message in the first receiving buffer is its own. If the message is one's own, the message is sent to the terminal 32 and deleted. On the other hand, as in the current example, if the receiving address of this message is not the own, the bit associated with this message indicating whether transmission is necessary or not is '1', then the self 12) Then, this message is deleted from the first reception buffer 71. If this bit is "0", this message is deleted without being received. When the message sent out on loop 1 reaches the interface 51 of the device 13, it is stored in the first receive buffer 71 in the terminal 13, and the received address is sent to the processing device, in the same way as described above with respect to the device 12. 41, and as in the present example, if it is determined that the message is to be sent to the terminal 33, this first message is sent at the sending time determined by the self.
The message in the receive buffer 71 of is sent to the terminal 33 and the loop 1 via the interfaces 61 and 51, respectively. In this way, data is transmitted from terminal 11 to terminal 33, and this message is transferred onto loop 1. A message sent from device 13 to loop 1 is transmitted through loop 1 and reaches device 11. Device 11 receives this message via interface 51 and stores it in first receive buffer 71 .

In the device 11, the message (13
) - detects that the sending address in the first receiving buffer specifies itself, and the message in this first receiving buffer and the original message in the sending buffer 81 are erased;
It is not transferred to loop 1.

The processing device 41 resets the timer 90.

If for some reason the message is not returned to device 11, timer 90 times up. The processing device 41 is
In response to the time-up signal from timer 90, the previously transmitted message stored in transmission buffer 81 is transmitted to loop 1 again. Each time this message is retransmitted, the number of transmissions data in the transmission buffer 81 that accompanies this message is counted up. This retransmission is repeated a predetermined number of times unless the message sent by the device 11 is received by the device 11 within a predetermined cycle time.

Even if the device 11 repeatedly sends the same message a predetermined number of times, this message goes through loop 1 once and is sent to the device 11.
If the processing device 41 learns that the data has not been returned because the number of transmission data in the transmission buffer 81 exceeds a predetermined value (14), the processing device 41 determines that there is a loop abnormality and performs processing to form a detour. Start. This process will be explained using FIG. 6. In Figure 6, the first
Reference numerals that are the same as in the figures indicate the same thing. In Figure 6,
In addition to the system of FIG. 1, transmission control devices 14, 15 .
16 and 24°25.26 and detour transmission line 400
,500°600 are added. The configuration of these added devices is the same as the device in FIG. Also the 6th
In the figure, transmission control devices 11 and 21.12 and 22.
The transmitting and receiving terminals connected to 13 and 23, 14 and 24, 15 and 25, 16 and 26, respectively, are not shown for the sake of simplicity.

In the device 11 that has detected an abnormality in the loop transmission system, the processing device 41 sets "1" in the register 93 indicating that it has received a transmission permission check request, and then sends a transmission permission check command and the adjacent transmission on loop 1. A first message containing a receiving address that specifies the control device 12 and a sending address consisting of the device's own address is transmitted onto loop 1 (15). A second message containing a check request command and a sending address having its own address is sent onto the detour transmission line 100. Furthermore, a timer 91 is set. The set time of the timer 91 is set by the devices 11, 12,
The time required for a message to make one round on the small loop 201 including 22 and 21 is made somewhat longer.

The device 12 specified by this first message receives this first message in the first reception buffer 71,
Processing device 41 detects that the received address is its own address and decodes the command and sending address in this first message. As a result of decoding, the processing device 41 in the device 112 learns that this command is a transmission permission check command and that the sending address is not its own. A message consisting of a command and a sending address is sent onto the detour transmission line 200. When the device 22 detects that a signal is input to the interface (16) 61 from the line 200, the processing device 41 transfers the message on the line 200 to the second receiving buffer 73 in response to this detection result. take in. It detects that the receiving address in this captured message is its own address, the command in this message is a request to check whether transmission is possible, and it detects that the sending address is not its own, and this message After changing the reception address of , to an address specifying device 21, the message is sent onto loop 2. This message is loop 2
When you pass through and reach the device 21, this outfit! In 21,
via the interface 51, the first receiving buffer 7]
Store this message in. The processing device 41 determines that the receiving address in this message is its own;
Then, it detects that the command in this message is a command requesting a check on transmission permission and that the transmission address is not its own, and sends this message to the detour line 100 via the interface 61.

When the device 11 detects that a message has been input via this line 100 (17), it takes this message into the first reception buffer 71 and detects that the reception address in this message is its own. However, it decodes the command and sending address in the sent message, and since the sending address is its own, it knows that the small loop 201 connecting the devices 11, 12, 22, and 11 is normal. Thereafter, the timer 91 is reset and the register 94 is set to "1" to indicate that the transmission is possible or not. The bit in register 95 remains at "O" to indicate that loop 1 power is available.

On the other hand, when the device 21 receives the second message sent on the line 100 from the device 11, the processing device 41 stores the second message in the second reception buffer 73, and then When it detects that the received address in this message is its own, it decodes the command and sending address in this message. As a result of decoding, this code requests a check for transmission permission (18), and is a message sent from the device 11 paired with the device 21 on a loop different from the loop 2 to which the device 21 is connected. When the processing device 41 learns, it sets 111'' in the register 93 to indicate that it has received the transmission permission check request, and then inputs the sending address indicating itself, the receiving address indicating the device 26, and the transmission permission check request. A message containing a command indicating a check request is sent onto loop 2. Further, a timer 91 is set. In device 26.16.11, the same processing as previously described for devices 12, 22.21 is performed, and when small loop 106 is normal, device 21.
, a message including a command indicating a request to check whether or not transmission is possible is inputted from the detour transmission path 100 and the address of this device is used as the receiving address and the sending address, and the message is sent to the device 2.
1 decodes this message, and in order to show that the small loop 106 is normal and there is no need to use the detour 100 (19), the register 95 remains set to II Ojl and checks whether transmission is possible. The register 94 is set to 1'1'' to indicate completion, and the timer 91 is activated.
Reset.

In this way, the transmission possibility check of the small loops 201 and 106 is completed.

Regarding the transmission possibility check process of the small loop 106, among the devices 26.1611 involved in message transfer, the device 21 on the same loop as the device 21 that issued the transmission possibility check command performs the transmission possibility check among the devices 26.1611. When a message containing a command indicating a request is received, "1" is set in the register 93 to indicate this.

Regarding the transmission possibility check process of the small loop 201, among the devices 12゜22.21 involved in message transfer,
The device 12 that is on the same loop as the device 11 that issued the message containing the transmission availability check command sets '1' in the register 93 therein.

As a result of the above processing, 111" is set in register (20) 93 of device 12.26, and 1" is set in register 94.
is not set. In this way, the register 93 “
1" is set, and the device whose register 94 is not set to "1" transmits a message including a command indicating a transmission permission check request, with itself as the transmission source.

For example, device 26 checks whether transmission is possible in the small loop 605 connecting devices 26, 25, 15, and 16 in exactly the same way as device 21 did, and registers the 94 is set to 111'', and register 95 remains at 110''.

Device 12 is also connected to device 12 in exactly the same way as device 21.26.
, 13, 23, and 22. Check whether transmission is possible in the small loop connecting , 13, 23, and 22. In this case, if the device 13 is out of order,
A message including a command indicating a transmission permission check request issued from the device 12 does not return to the device 12 when the timer 91 times out. The device 12 is
At this time, the above-mentioned message (21) for checking whether transmission is possible is transmitted repeatedly a predetermined number of times, and if it is still not detected that this loop is possible to transmit, the register 94 is set to 1'' to determine whether transmission is possible. Along with indicating that the check has been completed.

"1" is shown in the register 95, indicating that this small loop is abnormal and that the detour transmission line 200 should be used.

Further, the transmission control device 25, which has received the message including the transmission permission check command from the device 26, similarly performs a transmission permission check on its own.

In the example of FIG. 6, the device 25 is in trouble due to the device 24 failing.
To indicate that the detour transmission line 500 should be used, 1'1'' is set in the register 95.

In this way, each transmission control device checks the register 95 to determine whether or not to use the detour transmission line. For example, in FIG. 6, devices 12, 25 each know to use a detour transmission path. In this way, the device in which "1" is set in the register 95, the register 6
5 to 1" (22) and fetch the message received from loop 1 or 2 into the first reception buffer 7].
This message is transferred to the detour transmission path 200 or 500, respectively. On the other hand, in the device 22.15, messages input from the detour transmission path are stored in the second reception buffer 73, and if the sending address of the message in the second reception buffer 73 is not its own, all messages are routed. - Transfer to group 2 or 1. When it is your own,
Do not forward. In either case, the contents of this second receive buffer are then cleared. As a result, the message input to the device 12 is transferred onto the loop 2 via the detour transmission line 200 and the device R22, and then transferred onto the loop 1 again via the detour signal path 500 and the device W115 in the device 25. I have been transferred. In this way, a closed transmission path shown by thick line 4 in the figure is formed.

In the above-described operation, the transmission control device that has received the transmission permission check request and has issued the transmission permission check command as the sender (23) sets the timer 92 at the time of this transmission. The set time of this timer is set to be somewhat longer than the time it takes for the transmission permission check command to go through each normal loop 1 or 2. When each transmission control device receives a message containing a transmission possibility check command from an adjacent transmission control device on the same loop before this timer expires, it sends a message containing the transmission possibility check command with itself as the source. Do not send messages.

In this way, even if loop 1 returns to normal after becoming temporarily abnormal, this process of checking whether transmission is possible is prevented from being repeated permanently.

Also, the device 12.25 with 1” set in register 95
The device 12 in loop 1 periodically transmits a message containing a loop failure recovery check command to loop 1. The receiving address and sending address of this message are both your own address. The other device 13 that receives this message resends this message on loop 1 if it is normal. Do not send to the detour transmission line 300 (
24) Yes. Since the following devices 14, 15, 16, 11 are normal, this message is returned to device 12, so attachment 12 sets all registers 93-95 to "0". However, when the device [13] has not recovered from the failure, a message containing this failure recovery check command is sent to the device [13].
Since it does not return to 2, it is determined that loop 1 is abnormal, and registers 93 to 95 are left as they are. At this time, the device 12 periodically transmits a message containing a transmission permission check command to the loop including the devices 13, 23, 22.12, and if the devices 13, 23, 22 are all in normal condition, , sets register 95 to 110 jl. The above is an explanation of system operation when the transmission control device connected to loop 1 detects an abnormality in the transmission system of loop 1. The same applies when .

As described above, each transmission control device on loops 1 and 2 sends a message containing the small loop transmission availability check command (25) if the transmission path of loops 1 and 2 is abnormal. Furthermore, when each transmission control device on loop 1゜2 receives a message containing a transmission permission check command, it forwards the message and also sends a transmission permission check command from itself. A check is made as to whether or not the small loop can be transmitted. In this way, by having each transmission control device check whether transmission is possible for a portion of loops 1 and 2, even if a failure occurs in a portion of loops 1 and 2, a detour can be created without using the master station. I can do it.

Although the case of a unidirectional loop-shaped transmission line has been described above, the present invention is not limited to this, but can also be applied to a bidirectional transmission line with the same idea.

〔Effect of the invention〕

As explained above, according to the present invention, each transmission control device has equal functions, and their mutual relationships are equal, and it is possible to flexibly handle cases where there is no master control device that manages the entire system. This is a possible loop transmission system. In this case, each transmission control device is highly unique and can select a transmission line such as a detour transmission path based on local judgment (26), making it possible to freely form a network configuration.

When a failure or abnormality occurs in the transmission path, you can configure a detour network with little impact on other devices, add new transmission control equipment, delete it, or perform maintenance on an ad hoc basis. The network as a whole has high fault tolerance, and allows each transmission control device to autonomously form a network with the required configuration.

As described above, according to the present invention, each node has autonomy.

This enables a fraction processing system that is highly unique, yet highly reliable and highly flexible despite being equal.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram of a loop-shaped transmission system according to the present invention, FIG. 2 is a more detailed block diagram of a transmission control device used in the system of FIG. 1, and FIGS. FIG. 5 is a diagram showing the format of the message to be transmitted. FIG. 6 is a diagram for explaining the process of forming a detour in the event of a failure in the system (27) of FIG. 1. . 1.2...Loop, 11-16.21-26...Transmission control device, 31...Transmission/reception terminal, 41...Processing device, 51.61...Interface, 71...First
Reception buffer, 73...Second reception buffer, 81...
・Transmission buffer, 90-92...Timer, 93...
・Register for indicating that the transmission possibility check request has been accepted, 94...Register for indicating that the transmission possibility check has been completed, 95...Register for indicating the transmission possibility check result, 100, 200, 300° (2
8) 1st item 37. 31: σD 21st! I

Claims (1)

[Claims] 1. A first and a second loop-shaped transmission path, and a plurality of first transmission control devices connected to the first loop-shaped transmission path and controlling transmission of signals on the loop. , a plurality of second transmission control devices connected to the second loop-shaped transmission path, each provided in pairs with the first transmission control device, and controlling transmission of signals on the loop; The first step is to A loop transmission system comprising: a third transmission path connecting the second transmission control device. 2. The loop transmission system according to item 1, wherein a common information device is connected to the pair of transmission control devices.