JPS63215241A - Loop type lan and its controller - Google Patents

Abstract

PURPOSE:To smoothly attain data relay and quick loop acquisition with a simple equipment by forming a communication line by an optical fiber, providing a couple of photoelectric converters on each node, juxtaposing the subloop of a similar constitution with the main loop of the constitution to above and using the subloop so as to acquire a loop. CONSTITUTION:Each node has an LAN controller LCT and a terminal control section 71. A loop acquisition signal reception section 55 monitors a back loop 3B when no loop acquisition signal Dc of other node exists, loop switches 49, 51 are switched from the relay state into the acquisition state and its own logic address is sent continuously to the loop 3B. When the logic address in the returned signal Dc is coincident with its own logic address, the loop acquisition is finished. When the loop acquisition is successful, the reception bit in the signal Dc is set prior to the transmission of a frame and the signal Dc added with its own address number is transmitted continuously. The signal Dc flows through the loop 3B, is received by the reception section 55 of other node and all other nodes enter the reception state. Then the frame transmission to the main loop 3M is started and after the end of transmission, the switches 49, 51 are thrown to the position of the repeater side.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) This invention relates to a loop type LAN (local area network system) and its ilJ III M M k
: III.

(Prior art) A loop type LAN, in which an appropriate number of terminals and connected nodes are connected in a loop through a data communication line such as optical fiber, is suitable for FA or OA because it has excellent expandability and versatility. It is often used.

Here, in the conventional loop type LAN, each node determines the destination address of the data formed into a frame,
A data relay method is adopted in which if the address is for the node itself, it is fetched into the node itself, and if not, the frame is transmitted to the next node.

Furthermore, in order to avoid competition in communication lines, conventional loop LANs have mostly adopted a token bus system.

In this token bus system, a so-called token is circulated through a loop line, and only the node that obtains this token is given the right to transmit data.

(Problems to be Solved by the Invention) However, as described above, in the conventional loop type LAN, because a data buffer is interposed at the relay point and a token bus method is adopted, There are the following problems.

In other words, in the conventional data relay method, each node determines the destination address, which causes a delay equal to the address determination time multiplied by the number of relay nodes, resulting in poor data transmission efficiency. .

Also, episode 11i1! ! In the token bus method as a 49 method, a so-called minicomputer for token management is used.
This requires a large number of computers, and the burden on the hardware and software is enormous.

Furthermore, in this token bus system, the tokens circulate and data cannot be transmitted until after the token is obtained, so the start time of data transmission is delayed by that amount.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a loop type LAN and its control device that can quickly perform loop acquisition work with a simple device and can perform data relay smoothly. .

[Structure of the Invention] (Means for Solving the Problems) To achieve the above object, the present invention provides a loop type LAN in which an appropriate number of terminals and connectable nodes are connected in a loop through a data communication line. The data communication line is formed of an optical fiber, and each node is connected to the optical fiber and converts the optical signal coming from one of the optical fibers into an electrical signal without passing through a data buffer door, and also transmits the converted electrical signal. A pair of opto-electrical converters that output signals as optical signals to the other optical fiber are provided, and a sub-loop having a similar configuration is arranged in parallel to the main loop composed of the optical fiber and the pair of opto-electric converters. , Loop acquisition control that outputs to each node a signal indicating that it wants to acquire a loop for the subloop and a signal that the loop is acquired, and acquires the loop after waiting for the signal output by itself to appear in the subloop. When loop acquisition is performed by the control unit and the control unit, data with a transmission destination is output to the main loop, and when self-addressed data appears in the main loop, this data is captured and output to a predetermined terminal. It is characterized by having a data control section.

(Function) In the present invention, the pair of opto-electrical converters are connected to the data buffer 7.
Relay data at high speed without going through it.

Further, a subloop for loop acquisition control is provided for the main loop for data communication, and a loop acquisition control unit connected to the subloop controls the loop I for the subloop.
It outputs a signal indicating that it wants to gain and a signal indicating that it is acquiring a loop, and waits for the signal it outputs to appear on the rib loop before acquiring the loop.

(Embodiment) FIG. 1 is a system configuration diagram of a loop type LAN, showing an embodiment of the present invention.

As shown in the figure, the LAN shown in this example is configured by connecting a plurality of nodes 1 in a loop with mutual optical fiber pairs 3, and each node 1 has a maximum of six terminals 7 connected via terminals 5. It is now possible to connect.

FIG. 2 is a block diagram C showing the internal structure of the node 1.
be.

The node 1 has an opto-electrical converter 9.11 connected to the directional optical fiber pair 3 and an R3-232G interface 13 connected to the terminal 7,
A ROM19. R
In addition to the AM 21, it is configured by connecting a large number of control elements 23 to 39.

The mutually directional optical fiber pair 3 is a main loop 3M through which light passes counterclockwise and clockwise.

and a barrier loop 3B as a sub-loop, and the opto-electric converter 9 performs opto-electric conversion between these loops 3M and 3B. Main loop 3M is for data communication, and buckle-13B is for main loop 3.
This is especially provided in this example to control the line acquisition of M.

The MPU (microprocessing unit) 15 is
Using the RAM 21 for data storage, instructions read from the ROM 19 are executed.

L E 0.23 is for displaying the status of the communication line and the contents of initial settings. The SW (switch) is used to reset each channel and perform initial setting operations when connecting the terminal 7 and the like.

A DMAC (direct memory access controller) is used instead of the MPU 15 to transfer data at high speed.

The high-speed synchronous communication 1/F (interface) 29 and the loop communication controller 31 are for arbitrating the right to use the loop and for transmitting and receiving the loop line.

Various PTM (programmable timers) 33°35.
37 is for generating a regular interrupt signal and a baud rate for asynchronous communication.

The asynchronous communication 1/F 39 is for serial data communication between the terminal 7 and the node 1. R823
2CI/F is the asynchronous communication I/" R8232CM
It is meant to suit the occasion.

3 and 5 are block diagrams showing the control functions of the node 1, and FIG.
FIG. 5 is a block diagram of the terminal control section. FIG. 4 and FIG. 6 are explanatory diagrams of respective signals sent to the pack loop 38 and the main loop 3M.

The node 1 shown in FIG. 1 is constructed by combining the LAN&lJ system shown in FIG. 3 and a terminal control section 71. Here, since the gist of the present invention is mainly constituted by a loop acquisition method, in this embodiment, only the function fm part as a loop communication unit that performs loop acquisition processing is referred to as the L A N gA control device. .

As shown in FIG. 3, the LAN i control neck LCT includes an optical transceiver section 41.43 of the pack loop 30, which is configured by dividing the opto-electrical converter 9.11 into functions, and an optical transmitter/receiver section 41.43 of the main loop. It has transmitting/receiving sections 45 and 47.

The pack-loop optical transmitter 41 is equipped with a pack-loop switch 49 for pack-loop line control, and the main-loop optical transmitter 45 is equipped with a main-loop line aIIl.
A main loop switch 51 for tII is provided. Regarding the actions of these switches 49 and 51, see the seventh section.
This is explained in detail in the figure.

In addition, the LANυ control device LCT outputs a signal O for loop acquisition.
a transmitting/receiving section 53.55 that transmits and receives the frame DF, and a transmitting/receiving section 57.5 that transmits and receives the frame DF to and from the terminal control section 71 (described in detail in FIG. 5) connected to the terminal 7.
9 and a frame DF monitoring unit 61.

Furthermore, the LAN control device LCT has the buckle-138.
and clock signal CLKF3 for main loop 3M.
, CLKM. Reference code CLK indicates other clock signals for transmission and reception.

As shown in FIG. 4, the loop acquisition signal transmitter 53
The signal DC generated at the top synchronization detection bit 65
Next, it consists of a reception control bit 67 for issuing a reception command to other nodes, No. 13 indicating that a loop is to be acquired, and its own logical address 69 that includes the meaning of acquiring a loop.

The frame transmitter 57 not only transmits the frame DF shown in FIG. 6, but also has a function of outputting a signal S for interlocking control of the loop switches 49 and 51.

The operation of the LAN control device LCT having the above-mentioned configuration will be explained in detail below in FIG.

On the other hand, as shown in FIG. 5, the terminal control section 71
It has buffers 73 and 75 for transmitting and receiving frames DF to and from the L A N till Ill device LOT,
In addition, in order to perform data communication between terminals 7, channels (C) 11 to 11 equipped with transmitting and receiving buffers BR and BT are provided.
CH6). The illustrated arrows indicate the flow of data.

The operation of the terminal control section 71 is as follows.

First, data reception from the terminal 7 is performed by interrupt processing. The received data is sequentially stored in the reception buffer SR, and when one block of data is stored, the destination address is determined, and if it is terminal 7 in the same node, the contents of the reception buffer 3H are stored in the transmission buffer of the corresponding channel. Transfer to BT.

If the destination is a data block addressed to a terminal connected to another node, it is stored in the frame transmission buffer 73. As shown in FIG. 6, the data stored in the frame transmission buffer 773 has a flag FS attached to the beginning indicating that it is the beginning of a frame, and then a logical address A of the transmission destination.

A command C indicating data properties, data (DATA), a CRC for checking reliability of the data, and finally a flag FO indicating that it is the rear end of the frame are attached.

The frame DF formed in this way is used for the loop control work described later, and the frame transmission 157 shown in FIG.
, and is sent to a predetermined node via the main loop 3M.

On the other hand, data received from the main loop 3M to the reception buffer 75 is transferred by DMA using the action of DMA027.

When the reception of a unit frame is completed, an interrupt signal is generated, an error check is performed here, and if the unit frame is normal, its destination is determined, and B is sent to the transmission buffer of each terminal 7.
It is then transferred to terminal 7 in 1-byte units.
sent to.

Figures 7 to 9 show LANfijJ111vtii&L
c1-17)) FIG. 7 is a flowchart of loop acquisition processing, and FIG. 8 is an explanatory diagram of loop acquisition processing.

The terminal 7 shown in FIG.
The data is sent to the reception buffer 8r+ of the corresponding channel, and the destination address is matched in the frame transmission buffer 73 to form a frame DF.

At step J3 in step 701 in FIG.
The pack loop 3B is constantly monitored, and if the signal DC output from another node is not detected, the process moves to step 702.

In step 702, the loop switch 49.51 is switched from the relay state II (the state shown in FIG. 8) to the acquisition state. By performing this operation, it becomes possible to send data to the main loop 3M and pack loop 3B.

In step 703, it continuously transmits its own logical address to the packed loop 3B to notify other nodes that the loop is in use.

In step 704, the logic Tg! in the signal DC that has gone around the pack roof 3B and returned! Determine whether the address is yours. If it matches its own logical address, it interprets that the main loop 3M is not being used by another node, ends the loop acquisition, and moves to step 709.

However, if the logical address of another node is detected in step 704, it is interpreted that there is another node requesting acquisition of the main loop 3M at the same time, and step 704
Move to 5.

In step 705, from the logical address of the received node,
Determine the priority order between self and other nodes.

It is agreed that the smaller the logical address, the higher the priority.

If it is determined in step 705 that another node has a higher priority, loop acquisition is closed and the process moves to step 706, where the loop switches 49 and 51 are returned to the relay side, and then the switch At 707, the transmission of the signal Qc is stopped.

On the other hand, in step 709, in view of the success of loop acquisition, the receive bit 67 in the signal [)C is turned on prior to transmitting the frame [)F, and the signal D with its own logical address is turned on.
Send C continuously. This signal DC is pack roof 3
B, and is received by the loop acquisition signal receiving unit 5 of the other node, and all other nodes enter the reception system.

In step 710, the frame DF is sent to the main loop 3M.
Start sending.

In step 711, it is determined whether the transmission of the frame DF has been completed, and after the transmission of all frames DF has been completed, the process moves to step 712.

In step 712, the loop switches 49 and 51 are switched to the relay side.

In step 713, the transmission of the signal □c is stopped, and the frame transmission work is ended.

Next, an example of the actual operation of the node 1 will be explained using a time chart.

FIG. 9 shows (I) when a loop acquisition signal from another node is detected and the loop is released even though the loop M green signal has been output from the own node, and (n) frame transmission and reception based on successful loop acquisition. When performing (I[I), for the three conditions when frame transmission is completed and the loop is opened, one transmitting node and one receiving node IR(ok), 1R(
3 is a time chart showing an example of a control state under each condition of NG).

The receiving nodes 1R(ok) and IR(N a ) are shown by classifying cases of address matching and non-matching, respectively.

■Example of detecting simultaneous acquisition and opening the loop (state 1) In order to send a frame, we checked whether a loop acquisition signal existed on the pack loop 3u, and found that the signal [)C from other nodes was Since it was detected, the loop was determined to be in use.

(Status 2) Check the usage status of the loop again! However, since the loop g+signal [)C was not detected, it was determined that the loop was in an unused state.

(State 3) Therefore, the loop switches 49 and 51 were switched to the acquisition state.

(State 4) Next, a loop acquisition signal DC indicating that its own node logical address has been set is continuously transmitted to the packed loop 3B.

(State 5) The loop acquisition signal DC sent to the buckle-613B was detected after going around the loop line.

(Status ff16) When the node logical address of the detected acquisition signal [)C was checked, the value of another node was detected. Therefore, it was determined that there was a node 1 that started loop acquisition at the same time, and the priority was compared with itself.

(State 7) As a result of comparing the priorities, it was determined that the other node had a higher priority, so loop switch 49.
51 was returned to the relay state, and then the transmission of the loop acquisition signal @Dc was stopped.

■Example of frame transmission based on loop acquisition ■-1 Frame sending node (state 8) to (state fffi 11) State 2 to state B
Same as 5.

(Status fffi12) When the node logical address on the detected loop acquisition signal □c was checked, it matched with its own value.

(State 13) Therefore, it is determined that the loop has been acquired exclusively, and prior to sending the frame to the main loop 3M, the frame receiving unit 5 of the other node
In order to perform the receiving operation of 9, a receiving control signal was output.

(State 14) Now that the relaxation node is ready for reception, it transmits the frame DF to the main loop-3M.

ll-2 frame receiving node (address match) (state 2
2) In state 13, the node that acquired the loop outputs a reception control signal, and as a result, the frame receiving unit 59 of the receiving node starts operating.

(923) Then, from the main loop 3M, the frame [
)F was received. Next to the head flag of the frame is the destination address, and this value is compared with the own node address, and since they match, subsequent reception continues.

(Received the end flag of frame DF sent from main loop 3M.

(Status ff125) An interrupt was generated at the same time as the completion flag was received.

(State 26) At the same time as the reception end interrupt, the operation of the frame reception unit is stopped.

ll-3 frame receiving node (address mismatch) (state 27) Same as state 22.

(State 28) The destination address 8 following the frame head flag Fs is compared with the own node address, and it is determined that they do not match.

(State 29) The operation of the frame receiving unit 59 was stopped in order to stop receiving the frame OF sent from the main loop 3M.

■Example of opening the loop at the end of frame transmission (case B1
5) The transmission of the end flag Fe of the frame OF has ended.

(B16) A frame transmission end interrupt was generated at the same time as the transmission of frame l)F was completed.

(Condition j [17 and 18) Since the transmission of the frame DF has been completed, the loop switches 49 and 51 are put into the relay state in order to immediately open the loop.

(State 19) The transmission of the loop acquisition signal 1)c has been stopped.

(Statement [20) Received! The IJ control signal was returned to its original state.

(State 21) Interrupt processing has ended.

As mentioned above, in this example, pack loop 3B and LAN
Control equipment r! Loop acquisition is quickly performed by the operation of the loop acquisition signal transmitting/receiving units 53 and 55 placed in the RLcT.

Furthermore, since the LAN control device LOT is easy to configure, it can be manufactured at low cost.

Furthermore, since no data buffer is interposed in the loop, data relay is performed smoothly and data transmission efficiency is increased.

In the embodiment described above, the phase-directional optical fiber 3 is used to flow the signal for loop acquisition to the pack loop 3B, but the signal flow direction of the main loop and the sub-loop may be the same direction.

It should be noted that this invention is not limited to the above-mentioned embodiments, but can be implemented in other @s by making appropriate design changes.

[Effects of the Invention] As described above, according to the present invention, the line acquisition means of the data transmission loop includes a sub-loop for line acquisition arranged in parallel with the loop, and an L through which a loop acquisition signal is passed through the loop.
Since it is configured with A N tiII control device, each node is
A vacant line can be quickly obtained when desired.

Further, in the present invention, since data at each node is directly relayed without going through a buffer, highly efficient data transmission can be performed.

[Brief explanation of the drawing]

The drawings all show embodiments of the invention, and FIG.
N system configuration diagram, Figure 2 is a block diagram showing the hardware configuration of the node, Figure 3 is a block diagram showing the functions of the LAN control device, Figure 4 is an explanatory diagram of the loop acquisition signal, and Figure 5 is the terminal control. 6 is an explanatory diagram of the frame structure, and FIG. 7 is a block diagram showing the functions of the section 70-
FIG. 8 is a time chart showing the signal status of each part, and FIG. 9 is an explanatory diagram showing the operation of the L A N t, II control device. 1... Node 3... Directional optical fiber pair 3M... Main loop 3B... Pack loop 7... Terminal 49... Pack loop switch 51... Main loop switch 53... Loop Acquisition signal transmitter 55...Loop acquisition signal receiver S...Loop switch 1Ilj control signal DC...Loop acquisition signal DF...Frame LCT...LAN control device

Claims (3)

[Claims] (1) In a loop type LAN in which an appropriate number of terminals and connectable nodes are connected in a loop through a data communication line, the data communication line is formed of an optical fiber, and each node is connected to the optical fiber. A pair of opto-electrical converters are provided that convert an optical signal coming from one optical fiber into an electrical signal without going through a data buffer, and output the converted electrical signal as an optical signal to the other optical fiber, A sub-loop with a similar configuration is installed in parallel to the main loop consisting of the pair of opto-electrical converters, and a signal is sent to each node indicating that the sub-loop wants to acquire a loop and that the loop has been acquired. a loop acquisition control unit that outputs a signal and acquires a loop by waiting for the signal output by itself to appear in the subloop, and when the control unit acquires a loop, transmits data with a transmission destination to the main loop. The loop type LAN is characterized in that it is provided with a data control unit which outputs data addressed to itself and also captures data addressed to itself when it appears in the main loop and outputs the data to a predetermined terminal. (2) The signal to the effect that the loop is to be acquired is a signal indicating its own priority, and the loop acquisition control unit is configured to control when the loop acquisition control unit has a higher priority than the priority of other parties appearing in the sub-loop. 2. The loop type LAN according to claim 1, wherein the loop type LAN continuously outputs a signal indicating that the loop is being acquired. (3) In a loop-type LAN control device in which an appropriate number of terminals and connectable nodes are connected in a loop through a main loop and sub-loop consisting of optical fibers, each node is provided with an optical fiber of the main loop and the sub-loop. two pairs of opto-electrical converters that are connected to each fiber and convert the signal coming from one optical fiber into an electrical signal without going through a data buffer, and output the converted electrical signal to the other optical fiber as an optical signal; , a loop acquisition control that outputs a signal to the subloop to the effect that it wants to acquire a loop and a signal to the effect that the loop has been acquired, and acquires the loop by waiting for the signal output by itself to appear in the subloop; a data control unit that outputs data with a destination to the main loop when a loop acquisition is performed by the main loop, and captures this data when self-addressed data appears in the main loop and outputs it to a predetermined terminal; A loop type LAN control device characterized by comprising: