JPS59168737A - Multi-drop transmission system - Google Patents
Multi-drop transmission systemInfo
- Publication number
- JPS59168737A JPS59168737A JP58041920A JP4192083A JPS59168737A JP S59168737 A JPS59168737 A JP S59168737A JP 58041920 A JP58041920 A JP 58041920A JP 4192083 A JP4192083 A JP 4192083A JP S59168737 A JPS59168737 A JP S59168737A
- Authority
- JP
- Japan
- Prior art keywords
- data
- station
- transmission
- transmission line
- polling
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
- H04L12/40—Bus networks
- H04L12/403—Bus networks with centralised control, e.g. polling
Abstract
Description
【発明の詳細な説明】
本発明はマルチ・ドロップ伝送方式に関し、特に親局か
らの共用伝送路にマルチ・ドロップ形式で複数の子局を
接続し、親局から各子局への一括ポーリングに基づきデ
ータ伝送を行うマルチ・ドロップ伝送方式に関する。[Detailed Description of the Invention] The present invention relates to a multi-drop transmission system, and in particular, connects a plurality of slave stations in a multi-drop format to a shared transmission path from a master station, and performs batch polling from the master station to each slave station. This invention relates to a multi-drop transmission method for transmitting data based on
マルチ・ドロップ伝送は伝送路を共用しているため、送
信したい局が勝手なタイミングでデータを送出すると他
の局のデータと衝突する可能性がある。従って、マルチ
・ドロップ伝送では何らかの優先制御によシデータの衝
突を避けるか、衝突したときはその後の処理により伝送
路にデータを送出する局は、最終的に１局になるように
している。Since multi-drop transmission uses a shared transmission path, if a station that wants to transmit sends out data at arbitrary timing, there is a possibility that it will collide with data from other stations. Therefore, in multi-drop transmission, some kind of priority control is used to avoid data collisions, or when a collision occurs, subsequent processing is performed so that only one station ultimately sends data to the transmission path.
このようなマルチ・ドロップ伝送の優先制御方式の１つ
として、ポーリング方式がある。これは、親局が子局に
対して順次ポーリングを行い、送信データの有無を確認
していく方式である。この方式は、局数が少ない時には
比較的伝送効率は良好である。しかしながら、局数が多
くなるとポーリングの順番が自分にまわってくるのに時
間を要し、また各子局に送信データがなくても親局は各
子局をノー次ポーリングしていく際のオーバーヘッドの
ため、送信したい局にポーリングがまわってくるのは遅
くなる。従って、マルチ・ドロップ伝送システムの伝送
効率は悪いものとなっていた。A polling method is one of the priority control methods for such multi-drop transmission. In this method, the master station polls the slave stations in order to check whether there is data to be transmitted. This method has relatively good transmission efficiency when the number of stations is small. However, as the number of stations increases, it takes time for the polling order to reach the master station, and even if each slave station has no data to send, the master station incurs overhead when polling each slave station in turn. As a result, polling takes a long time to arrive at the station you want to transmit from. Therefore, the transmission efficiency of the multi-drop transmission system has been poor.
本発明は上記の点に鑑みてなされたもので、親局から各
子局に対して一括ポーリング金行い、自局に送出したい
データがあるときは各子局に内蔵されたタイマを動作さ
せそのタイム・アンプ後に、伝送路信号検出器によシ伝
送路に信号がないことを確認してデータ伝送を行うよう
にすることにより、システムの信頼性及び伝送効率の向
上を計ると共に、各局が分担する伝送制御上の優先権の
均一化を計ったマルチ・ドロップ伝送方式を提供するこ
とを目的とする。The present invention has been made in view of the above points, and the master station performs bulk polling on each slave station, and when there is data to be sent to the own station, a timer built in each slave station is activated. By using a transmission line signal detector to confirm that there is no signal on the transmission line after time amplification before data transmission, system reliability and transmission efficiency are improved, and each station The purpose of this invention is to provide a multi-drop transmission system that equalizes priority in transmission control.
以下本発明の一実施例を添付された図面と共に説明する
。An embodiment of the present invention will be described below with reference to the attached drawings.
第１１！Ｓｌ ｕ本発明が適用されるマルチ書ドロップ
伝送方式による伝送システムの一例を示す構成図、第２
図は第１図に示さｎる各子局の内部構成例を示すブロッ
ク図である。11th! Slu Second block diagram showing an example of a transmission system using a multi-book drop transmission method to which the present invention is applied.
FIG. 1 is a block diagram showing an example of the internal configuration of each slave station shown in FIG.
これらの図面において、１は親局、２は伝送路３に接続
された複数の局、Ａは伝送路３を終端する終端抵抗であ
る。４は伝送路３への送信データ及び伝送路３からの受
信データを夫々送受信する送受信器、５は伝送路３上の
送受信データの有無を検出する伝送路信号検出器、６は
送受信データ用の菟変換及びソＰ変換を行う変換回路、
７け伝送制御用ＣＰ［Ｊ、８は伝送制御用メモリ、９は
所定の時間幅内で、所定の時間間隔の倍数でランダムに
出力状態が変化するタイマである。１０は伝送制御用Ｃ
ＰＵ７と伝送制御用メモリ８．タイマ９等とを接続する
ための伝送制御用ＣＰＵバスである。ｌ］はこの伝送制
御用ｃＰＵバスに接続さｎた外部装置用インターフェー
スで、図示されない外部装置との受は渡し信号１２の入
出力を行う。In these drawings, 1 is a master station, 2 is a plurality of stations connected to the transmission line 3, and A is a terminating resistor that terminates the transmission line 3. 4 is a transmitter/receiver for transmitting and receiving data to and from the transmission line 3, 5 is a transmission line signal detector for detecting the presence or absence of transmitted and received data on the transmission line 3, and 6 is for transmitting and receiving data. a conversion circuit that performs U conversion and SO P conversion;
7 transmission control CP[J, 8 is a transmission control memory, and 9 is a timer whose output state changes randomly at multiples of a predetermined time interval within a predetermined time width. 10 is C for transmission control
PU7 and transmission control memory8. This is a transmission control CPU bus for connecting timer 9 and the like. 1] is an interface for an external device connected to this cPU bus for transmission control, and inputs and outputs a transfer signal 12 to and from an external device (not shown).
本発明の一実施例は上記のように構成されておシ、以下
その動作について説明する。One embodiment of the present invention is constructed as described above, and its operation will be described below.
親局は子局にデータを送シたいときには優先して送シ、
各子局のデータを収集する時はすべての子局が受信でき
不ポーリングを送出することＫより行うものとする。各
子局２は親局１がらの一括ポーリングに対しタイマ９を
動作させ、タイムアツプ後自局の送信データの有無をチ
ェックし、送信データがある場合には、伝送路信号検出
器５によシ伝送路３に信号がないことを確認してデータ
を送出する。この場合、伝送路信号検出器５により伝送
路３に信号があると判断された時にはデータの送信を行
わず、次のポーリングの機会を待つ。When the master station wants to send data to the slave station, it sends it with priority.
When collecting data from each slave station, it is assumed that all the slave stations are able to receive and send a non-polling signal K. Each slave station 2 operates a timer 9 in response to the batch polling from the master station 1, and after the time-up, checks whether there is transmission data from its own station, and if there is transmission data, it sends a signal to the transmission path signal detector 5. After confirming that there is no signal on the transmission path 3, data is sent. In this case, when the transmission line signal detector 5 determines that there is a signal on the transmission line 3, no data is transmitted, and the next polling opportunity is waited for.
なお上述したタイマ９のランダムな出力状態は例えばテ
ーブル化された乱数発生器からの乱数の発生とその値に
よシ決定される。乱数発生のアルゴリズムは各子局２で
同様であるため、値が一致し々いようにシステムの復帰
時に、親局がシステムリセットの情報を流し、各子局は
このシステムリセット情報を受信して、乱数の初期値を
セットする。なお、この場合各子局の乱数の初期値は異
なるように設定されている。The above-described random output state of the timer 9 is determined, for example, by the generation of random numbers from a tabulated random number generator and their values. The random number generation algorithm is the same for each slave station 2, so when the system returns, the master station sends system reset information, and each slave station receives this system reset information so that the values match. , set the initial value of the random number. In this case, the initial values of random numbers for each slave station are set to be different.
なお、親局はポーリングの送信後、一定時間経過しても
いずれの子局からも応答がない時は、全子局に送信デー
タがないと判断し、次のポーリングに移る。Note that if the master station does not receive a response from any of the slave stations even after a certain period of time has passed after transmitting polling, it determines that there is no data to be transmitted to all slave stations and moves on to the next polling.
本発明は以上のようであり、従来のように親局が順次子
局をポーリングして送信データの有無を確認しなくても
、一括ポーリングにより全子局のデータの有無を確認す
ることができ伝送効率を向上することができる。また各
子局の優先順位は、ランダムな出力状態を有するタイマ
によシ決定されるので、平均的には略同じ優先順位とな
り、システムを組むときは使いやすい。The present invention is as described above, and it is possible to check the presence or absence of data in all slave stations by polling all at once, without the need for the master station to sequentially poll the slave stations to check the presence or absence of transmitted data as in the past. Transmission efficiency can be improved. Furthermore, since the priority order of each slave station is determined by a timer having a random output state, the priority order is approximately the same on average, making it easy to use when building a system.
第１図は本発明に係るマルチ・ドロップ伝送方式を説明
する説明図、第２図は第１図の各子局の内部構成例を示
すブロック図である。
１・・・親局、２φ・・子局、３・・・伝送路、Ａ・・
・・終端抵抗、４・・・送受信器、５・・・伝送路信号
検出器、６・・・変換回路、７・・・伝送制御用ＣＰＵ
８−・・伝送制御用メモリ、９・・・タイマ、１０・・
・伝送制御用ＣＰＵパス、１１０・外部装置インターフ
ェース、１２・・・外部装置費は渡し信号。FIG. 1 is an explanatory diagram illustrating a multi-drop transmission system according to the present invention, and FIG. 2 is a block diagram showing an example of the internal configuration of each slave station in FIG. 1. 1... Master station, 2φ... Slave station, 3... Transmission path, A...
... Terminating resistor, 4... Transmitter/receiver, 5... Transmission line signal detector, 6... Conversion circuit, 7... CPU for transmission control
8-... Memory for transmission control, 9... Timer, 10...
- CPU path for transmission control, 110 - External device interface, 12... External device cost is a passing signal.
Claims (1)
複数の子局を接続し、各子局へのポーリングに基づきデ
ータ伝送を行う伝送システムにおいて、各子局に所定の
時間幅内で所定時間間隔の倍数でランダムに出力状態が
変化するタイマと、伝送路の信号の有無を検出する伝送
路信号検出器とを設け、親局は子局すべてが受信できる
ポーリングを送出し、このポーリングを受けた各子局に
自局に送出したいデータがあるときは、前記タイマを動
作させ、そのタイム・アップ後に前記伝送路信号検出器
にょシ伝送路の信号の有無をチェックし、伝送路に信号
がないことを確認した後にデータの送信を行うと共に、
親局からのポーリングに対して各子局に送出したいデー
タがない場合はポーリング送出時点で前記タイマを動作
させ、所定時間経過後、いずｎの子局からも応答がない
時は、各子局に送出したいデータがないものと見なして
、次のポーリングを行うようにしたことを特徴とするマ
ルチ・ドロップ伝送方式。(1) In a transmission system in which multiple slave stations are connected to a shared transmission path from a master station in a multi-Φ drop format and data is transmitted based on polling to each slave station, each slave station is A timer whose output state changes randomly at multiples of a predetermined time interval and a transmission line signal detector that detects the presence or absence of a signal on the transmission line are provided, and the master station sends out polling signals that can be received by all slave stations. When each slave station that has received data has data that it wants to send to its own station, it operates the timer, and after the time is up, the transmission line signal detector checks the presence or absence of a signal on the transmission line, and sends the signal to the transmission line. After confirming that there is no signal, data is sent and
If there is no data to be sent to each slave station in response to polling from the master station, the timer is activated at the time of polling transmission, and if there is no response from any n slave stations after a predetermined period of time has elapsed, each slave station A multi-drop transmission method characterized by assuming that there is no data to be sent to the station and performing the next polling.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58041920A JPS59168737A (en) | 1983-03-14 | 1983-03-14 | Multi-drop transmission system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58041920A JPS59168737A (en) | 1983-03-14 | 1983-03-14 | Multi-drop transmission system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS59168737A true JPS59168737A (en) | 1984-09-22 |
Family
ID=12621683
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58041920A Pending JPS59168737A (en) | 1983-03-14 | 1983-03-14 | Multi-drop transmission system |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59168737A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6352330U (en) * | 1986-09-24 | 1988-04-08 | ||
| JPS6453647A (en) * | 1987-08-25 | 1989-03-01 | Nec Corp | Polling system |
| JPH01192239A (en) * | 1988-01-28 | 1989-08-02 | Fujitsu Ltd | Polling system in communication circuit |
| JPH0621862A (en) * | 1991-11-05 | 1994-01-28 | Fujitsu Ten Ltd | Radio communication method |
-
1983
- 1983-03-14 JP JP58041920A patent/JPS59168737A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6352330U (en) * | 1986-09-24 | 1988-04-08 | ||
| JPH0526848Y2 (en) * | 1986-09-24 | 1993-07-07 | ||
| JPS6453647A (en) * | 1987-08-25 | 1989-03-01 | Nec Corp | Polling system |
| JPH01192239A (en) * | 1988-01-28 | 1989-08-02 | Fujitsu Ltd | Polling system in communication circuit |
| JPH0621862A (en) * | 1991-11-05 | 1994-01-28 | Fujitsu Ten Ltd | Radio communication method |
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