JPS5957535A - Disconnection of line detecting circuit of digital signal transmission circuit - Google Patents
Disconnection of line detecting circuit of digital signal transmission circuitInfo
- Publication number
- JPS5957535A JPS5957535A JP57166505A JP16650582A JPS5957535A JP S5957535 A JPS5957535 A JP S5957535A JP 57166505 A JP57166505 A JP 57166505A JP 16650582 A JP16650582 A JP 16650582A JP S5957535 A JPS5957535 A JP S5957535A
- Authority
- JP
- Japan
- Prior art keywords
- output
- circuit
- receiving
- current
- signal
- 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
- H04B—TRANSMISSION
- H04B3/00—Line transmission systems
- H04B3/02—Details
- H04B3/46—Monitoring; Testing
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Monitoring And Testing Of Transmission In General (AREA)
- Dc Digital Transmission (AREA)
Abstract
Description
【発明の詳細な説明】
本発明は、ディジタル信号伝達システムに係り、特に、
信号伝送ケーブルの断線の起こり得るシステムにおいて
、断線の起きたことを速やかに検知して、誤動作を未然
に防ぐ必要のある場合に適する０
従来のディジタル信号伝達システムにおいて、受信側で
、受信したパルス数を累積するなどの用途に用いられる
場合には、伝送ケーブルが断線すると、その後送信され
るパルスが受信されないため、パルスの累積に誤りを生
じることになり、この累積誤差に起因する、他の機器の
誤動作の発生に及んではじめて、異常が検知され、しか
も、原因が、伝送ケーブルにあることを知るには、ざら
に時間を要するという欠点があった。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a digital signal transmission system, and more particularly, to a digital signal transmission system.
Suitable for systems where the signal transmission cable may break, and where it is necessary to quickly detect the occurrence of a break and prevent malfunctions.0 In a conventional digital signal transmission system, the received pulse When the transmission cable is used for purposes such as accumulating numbers, if the transmission cable is disconnected, the pulses transmitted subsequently will not be received, resulting in an error in pulse accumulation, and other The problem is that an abnormality is detected only after a malfunction occurs in the equipment, and it takes a long time to find out that the cause is the transmission cable.
本発明の目的は、ディジタル信号伝速システムにおける
、主に伝送ケーブル断線による故障を速やかに検出し、
これに起因する、他のシステムの誤動作を未然に防止す
るための、断線検ｌｔｉ ｆｏ路を提供することにある
。The purpose of the present invention is to promptly detect failures mainly due to transmission cable disconnections in digital signal transmission systems,
The object of the present invention is to provide a disconnection detection path to prevent malfunctions of other systems caused by this.
ディジタル信号伝達方式の一種である、差動電流ループ
方式においては、ループの正方向に電流が流れる場合、
及び、負方向に電流が流ｎ−る場合の２つの状態で、デ
ィジタル信号の２値を表現しているが、このループを構
成する伝送ケーブルが断線すると、どちらの方向にも電
流が流れケいという第３の状態が生ずる。この第５の状
態を検出することにより、前記目的を達するようにした
ものである。In the differential current loop method, which is a type of digital signal transmission method, when current flows in the positive direction of the loop,
The binary value of the digital signal is expressed in two states, i.e., when the current flows in the negative direction, and when the transmission cable that makes up this loop is broken, the current flows in either direction. A third condition arises: no. The above object is achieved by detecting this fifth state.
次に本発明の一冥施例を図によって説明する。Next, one embodiment of the present invention will be explained with reference to the drawings.
第１図について説明すると、送信回路２は、送信すべき
信号ＸＳを受けて差動電流出力Ｘ＋、Ｘ−を出力する、
差動電流ドライバ１を、出力回路として備えており、１
によりドライブされる電流は、伝送ケーブル３を通して
、受信回路４中の、電流制限用抵抗５及び、正電流受信
用フォトカプラ９又は、負電流受信用フォトカプラ７と
接続これている。フォトカプラ７の出力ＸＤは、受信信
号そのものであり、これを必要とする任意の回路へ接続
されている。フォトカプラ９の出力は、フォトカプラ７
の出力と共に、論理積素子１１に接続されており１１の
出力信号ＳＣをもって、断線検出出力とする。この出力
信号ＳＣは、外部システムの非常停止信号などとして、
外部システムの誤動作を防止するために使用される。Explaining FIG. 1, the transmitting circuit 2 receives the signal XS to be transmitted and outputs differential current outputs X+ and X-.
A differential current driver 1 is provided as an output circuit.
The current driven by is connected through the transmission cable 3 to a current limiting resistor 5 and a positive current receiving photocoupler 9 or a negative current receiving photocoupler 7 in the receiving circuit 4. The output XD of the photocoupler 7 is the received signal itself, and is connected to any circuit that requires it. The output of photocoupler 9 is the output of photocoupler 7.
It is connected to the AND element 11 together with the output of , and the output signal SC of 11 is used as a disconnection detection output. This output signal SC can be used as an emergency stop signal for an external system, etc.
Used to prevent malfunction of external systems.
次に、動作について説明する。Next, the operation will be explained.
今、Ｘｅ＝Ｈであるとき、差ａ電流ドライバ１の出力Ｘ
４−＝Ｈであり、Ｘ−＝Ｌである。したがって、ドラ
イバ１の出力′電流は、ドライノ（１→ケーブル３＋フ
ォトカゾラ９−９−電流制限用抵抗５−ケーブル３啼ド
ライバ１の順で流れるＯよって、フォトカプラ７の出力
トランジスタはＯＦＦ、フォトカプラ９の出力トランジ
スタ７はＯＮ ｔ、、その結果、出力ＸＲ＝Ｈ，ＸＤ＝
Ｌとなる。よって、送信信号ＸＳ＝受（Ｕ信号ＸＲ＝Ｈ
であると共に出力ＸＲと出力Ｘ、Ｄの論理積である断線
検出信号ＳＣけ、５Ｏ＝Ｈ−Ｌ＝Ｌとなり、断線してい
ないことを示している。Now, when Xe=H, the output X of the difference a current driver 1
4-=H and X-=L. Therefore, the output current of driver 1 flows in the order of Draino (1 → Cable 3 + Photocazola 9 - 9 - Current limiting resistor 5 - Cable 3 - Driver 1). Therefore, the output transistor of photocoupler 7 is OFF, and the photocoupler The output transistor 7 of 9 is ON t, and as a result, the output XR=H, XD=
It becomes L. Therefore, transmission signal XS = received (U signal XR = H
In addition, the disconnection detection signal SC which is the logical product of the output XR and the outputs X and D becomes 5O=HL=L, indicating that there is no disconnection.
Ｘｅ−りであるときも、同様にして、この場合は、ＸＲ
＝Ｌ、ＸＤ＝Ｈとなり、送・１す信号ｘｓ＝受信信号Ｘ
Ｒ＝Ｌであると共に、Ｓ Ｏ＝Ｌ −Ｈ＝Ｌとなり、こ
れも、断線していないことを示している。Similarly, when Xe-ri, in this case, XR
=L, XD=H, sending/1st signal xs=receiving signal
R=L and S O=L −H=L, which also shows that there is no disconnection.
次に、ケーブル３が断線したとすると、明らかに、フォ
トカプラ７及び９の相方共、その出力トランジスタがＯ
Ｆ Ｅｌ”するため、ＸＲ＝ＸＤ＝Ｈとなり、断線検出
信号ＢＣは、５Ｃ−Ｉｉ・Ｈ＝）（となり、断線が生じ
たことを知ることができる。Next, if cable 3 is disconnected, it is clear that the output transistors of both photocouplers 7 and 9 are OFF.
Therefore, XR=XD=H, and the disconnection detection signal BC becomes 5C-Ii·H=)(, which indicates that a disconnection has occurred.
なお、正常な状聾でも、送信データの、Ｈ−＄Ｌ。In addition, even if the hearing condition is normal, the transmission data is H-$L.
又はＬ−＋Ｈの変遷時、フォトカプラ７及び、フォトカ
プラ９が共に０ＦＰＫなる短い時間が存在するので、断
線検出信号ＳＣを受ける回路の動作が非常に速い場合は
、第２図に示す如く、ＳＣ＠号を、低域通過フィルタ１
２を通した出力ｓ ｃ’を、断線検出信号として用いる
など、送信データの、変遷時間に比べて、十分長い応答
時間をもたせることにより、断線の誤検出を防止するこ
とができる０
本発明によれば、ディジタル信号伝送システムにおけろ
、ケーブル断線を、速やかに検出して、必要〃らば、こ
れによる外部７ステムの誤動作を、未然に防止すること
ができると共に、外部システムにとって、停止の要因が
、ケーブル断線によるものであることを、直ちに知るこ
とができるため故障からの復旧をスピードアップするこ
とができる０Or, during the transition of L-+H, there is a short time when both the photocoupler 7 and the photocoupler 9 are 0FPK, so if the circuit receiving the disconnection detection signal SC operates very quickly, as shown in FIG. SC@, low pass filter 1
The present invention makes it possible to prevent erroneous detection of a disconnection by providing a sufficiently long response time compared to the transition time of the transmitted data, such as by using the output s c' through 2 as a disconnection detection signal. According to the above, in a digital signal transmission system, it is possible to promptly detect a cable disconnection and, if necessary, prevent malfunction of the external 7 stems due to this. Since you can immediately know that the cause is a cable break, you can speed up recovery from failures.
第１図は、本発明断線検出回路の実施例を示す回路図、
第２図は、低域通過フィルり回路の一例を示す回路図で
ある。FIG. 1 is a circuit diagram showing an embodiment of the disconnection detection circuit of the present invention;
FIG. 2 is a circuit diagram showing an example of a low-pass filter circuit.
Claims (1)
、前記差１ｌＩｌ電流出力回路の出力である差動電流信
号を伝送する、伝送ケーブルと、前記伝送ケーブルに接
続され、前記差動電流信号を受信する受信回路とから成
る、ディジタル信号伝送システムにおいて、前記受信回
路１１（１で受信する正方向の電流、負方向の電流のい
ずれの電流も流れていないことを検出する回路を設けた
ことを！時機とする、ディジタル信号伝送回路の断線検
出回路。a digital signal transmission circuit including a differential current output circuit; a transmission cable that transmits the differential current signal that is the output of the differential current output circuit; and a transmission cable that is connected to the transmission cable and transmits the differential current signal. In a digital signal transmission system consisting of a receiving circuit for receiving signals, a circuit is provided for detecting that neither a positive direction current nor a negative direction current is flowing in the receiving circuit 11 (1). !Disconnection detection circuit for digital signal transmission circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57166505A JPS5957535A (en) | 1982-09-27 | 1982-09-27 | Disconnection of line detecting circuit of digital signal transmission circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57166505A JPS5957535A (en) | 1982-09-27 | 1982-09-27 | Disconnection of line detecting circuit of digital signal transmission circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS5957535A true JPS5957535A (en) | 1984-04-03 |
Family
ID=15832594
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57166505A Pending JPS5957535A (en) | 1982-09-27 | 1982-09-27 | Disconnection of line detecting circuit of digital signal transmission circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5957535A (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55138949A (en) * | 1979-04-17 | 1980-10-30 | Fujitsu Ltd | Open line detection circuit |
-
1982
- 1982-09-27 JP JP57166505A patent/JPS5957535A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55138949A (en) * | 1979-04-17 | 1980-10-30 | Fujitsu Ltd | Open line detection circuit |
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