CN103905031A - RS-485 bus communication hardware blocking circuit - Google Patents
RS-485 bus communication hardware blocking circuit Download PDFInfo
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- CN103905031A CN103905031A CN201310737038.2A CN201310737038A CN103905031A CN 103905031 A CN103905031 A CN 103905031A CN 201310737038 A CN201310737038 A CN 201310737038A CN 103905031 A CN103905031 A CN 103905031A
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- power driving
- signal generating
- driving circuit
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Abstract
The invention discloses an RS-485 bus communication hardware blocking circuit which comprises a signal generation circuit used for generating standard TTL or CMOS level signals, an isolating circuit used for isolating the signal generation circuit from a power-driven circuit, and the power-driven circuit comprising a positive and negative two-channel output type adjustable stabilized voltage supply and a power output device, wherein the input end of the power-driven circuit is connected with the signal generation circuit through the isolating circuit, and the output end of the power-driven circuit is connected to an RS-485 bus in parallel. By means of the circuit, RS-485 bus communication can be blocked effectively on the premise that a bus communication hardware circuit is not cut off and original bus hardware connection is not damaged.
Description
Technical field
The present invention relates to industrial control system security fields, relate in particular to a kind of RS-485 bus communication hardware blocking circuit.
Background technology
RS-485 bus is one of fieldbus physical layer that bus field is most widely used at the scene at present, multiple fieldbus agreement, comprise Profibus(Profibus-DP), MODBUS(MODBUS serial link protocol) and custom protocol etc., all can be based on RS-485 bus physical layer.
In order to guarantee the fail safe based on RS-485 bus physical layer fieldbus in industrial control system, need to there is exceptional communication on the fieldbus detecting based on RS-485 bus physical layer time, block in time RS-485 bus communication; In the time carrying out the test of RS-485 bus communication, sometimes also need to block RS-485 bus communication.This blocking-up should not cut off bus communication hardware circuit (circuit) and not destroy the in the situation that original bus hardware connecting and carry out.
Summary of the invention
For above-mentioned technical problem, the invention provides a kind of RS-485 bus communication hardware blocking circuit, realize based on signal generating circuit, buffer circuit and power driving circuit, can block RS-485 bus communication moment, do not cut off bus communication hardware circuit, do not destroy original bus hardware and connect.
The invention provides circuit as follows: a kind of RS-485 bus communication hardware blocking circuit, comprising:
Signal generating circuit, for generation of standard TTL or CMOS level signal; Described signal can be interference signal, can be also fixing high level or low level;
Buffer circuit, for isolation signals circuit for generating and power driving circuit; Be used for guaranteeing signal generating circuit safety, accomplish to isolate completely;
Power driving circuit, comprises positive and negative doubleway output adjustable stabilized voltage supply and power-ourput device; Power driving circuit input is connected with signal generating circuit by buffer circuit; Power driving circuit output is attempted by RS-485 bus;
In the time of signal generating circuit outputs level signals, utilize more than the voltage difference between RS-485 bus two lines is urged to by force default absolute value by power driving circuit blocking-up RS-485 bus communication.
Further, described in the time of signal generating circuit outputs level signals, utilize power driving circuit that the voltage difference between RS-485 bus two lines is urged to by force to default absolute value and comprise above:
In the time of described signal generating circuit output high level, utilize power driving circuit the voltage difference between RS-485 bus two lines is urged to by force+more than 6V;
In the time of described signal generating circuit output low level, utilize power driving circuit the voltage difference between RS-485 bus two lines is urged to by force-below 6V.
Further, described buffer circuit is realized by photoelectric coupled device.
In sum, the invention provides a kind of RS-485 bus communication hardware blocking circuit, formed by signal generating circuit, buffer circuit and power driving circuit.Described signal generating circuit is for generation of fiduciary level signal; Described buffer circuit, for signal generating circuit and power driving circuit are kept apart, guarantees the safety of signal generating circuit; Described power driving circuit, the signal sending according to signal generating circuit, the pressure differential of RS-485 bus A, B line-to-line is urged to by force to a certain preset value, make RS-485 bus interface circuit unable in the situation that power driving circuit carries out strong driving, change the polarity of voltage between A, B two lines, thereby the communication of other equipment in blocking-up RS-485 bus, and the strong driving force of described power driving circuit is adjustable.The method of the invention and system do not need to cut off hardware circuit or destroy original hardware connection, just can effectively block RS-485 bus communication.
Accompanying drawing explanation
In order to be illustrated more clearly in technical scheme of the present invention, to the accompanying drawing of required use in embodiment be briefly described below, apparently, the accompanying drawing the following describes is only some embodiment that record in the present invention, for those of ordinary skills, do not paying under the prerequisite of creative work, can also obtain according to these accompanying drawings other accompanying drawing.
Fig. 1 is that a kind of RS-485 bus communication hardware blocking circuit provided by the invention is realized block diagram.
Embodiment
The present invention has provided a kind of RS-485 bus communication hardware blocking circuit, in order to make those skilled in the art person understand better the technical scheme in the embodiment of the present invention, and above-mentioned purpose of the present invention, feature and advantage can be become apparent more, below in conjunction with accompanying drawing, technical scheme in the present invention is described in further detail:
First the present invention provides a kind of RS-485 bus communication hardware blocking circuit, as shown in Figure 1, comprising:
In the time of signal generating circuit 101 outputs level signals, utilize more than the voltage difference between RS-485 bus two lines is urged to by force default absolute value by power driving circuit 103 blocking-up RS-485 bus communication.
Preferably, described in the time of signal generating circuit outputs level signals, utilize power driving circuit that the voltage difference between RS-485 bus two lines is urged to by force to default absolute value and comprise above:
In the time of described signal generating circuit output high level, utilize power driving circuit the voltage difference between RS-485 bus two lines is urged to by force+more than 6V;
In the time of described signal generating circuit output low level, utilize power driving circuit the voltage difference between RS-485 bus two lines is urged to by force-below 6V.
Preferably, described buffer circuit is realized by photoelectric coupled device.
As mentioned above, the present invention has provided a kind of RS-485 bus communication hardware blocking circuit, its at least by: signal generating circuit, buffer circuit and power driving circuit form, more than the voltage difference of the line-to-line of RS-485 bus being urged to preset value by force by power driving circuit, thereby RS-485 bus " is drawn dead ", make other hardware devices in bus cannot change the A of RS-485 bus, the polarity of voltage of B line-to-line, also just cannot change RS-485 bus level, so cannot communicate.Therefore, the given specific embodiment of the present invention, in the situation that not destroying original bus hardware and connecting, is only attempted by described hardware blocking circuit in RS-485 bus, can block RS-485 bus communication at any time.On the fieldbus based on RS-485 bus physical layer, can coordinate industry control safety system blocking-up exceptional communication, also can be used as a kind of means of test RS-485 bus communication.
Above embodiment is unrestricted technical scheme of the present invention in order to explanation.Do not depart from any modification or partial replacement of spirit and scope of the invention, all should be encompassed in the middle of claim scope of the present invention.
Claims (3)
1. a RS-485 bus communication hardware blocking circuit, is characterized in that, comprising:
Signal generating circuit, for generation of standard TTL or CMOS level signal;
Buffer circuit, for isolation signals circuit for generating and power driving circuit;
Power driving circuit, comprises positive and negative doubleway output adjustable stabilized voltage supply and power-ourput device; Power driving circuit input is connected with signal generating circuit by buffer circuit; Power driving circuit output is attempted by RS-485 bus;
In the time of signal generating circuit outputs level signals, utilize more than the voltage difference between RS-485 bus two lines is urged to by force default absolute value by power driving circuit blocking-up RS-485 bus communication.
2. circuit as claimed in claim 1, is characterized in that, described in the time of signal generating circuit outputs level signals, utilizes power driving circuit that the voltage difference between RS-485 bus two lines is urged to by force to default absolute value and comprises above:
In the time of described signal generating circuit output high level, utilize power driving circuit the voltage difference between RS-485 bus two lines is urged to by force+more than 6V;
In the time of described signal generating circuit output low level, utilize power driving circuit the voltage difference between RS-485 bus two lines is urged to by force-below 6V.
3. circuit as claimed in claim 1, is characterized in that, described buffer circuit is realized by photoelectric coupled device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310737038.2A CN103905031A (en) | 2013-12-27 | 2013-12-27 | RS-485 bus communication hardware blocking circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310737038.2A CN103905031A (en) | 2013-12-27 | 2013-12-27 | RS-485 bus communication hardware blocking circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN103905031A true CN103905031A (en) | 2014-07-02 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201310737038.2A Pending CN103905031A (en) | 2013-12-27 | 2013-12-27 | RS-485 bus communication hardware blocking circuit |
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| CN (1) | CN103905031A (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010028357A (en) * | 2008-07-17 | 2010-02-04 | Nec Electronics Corp | Output buffer circuit |
| CN102522978A (en) * | 2012-01-06 | 2012-06-27 | 河南华南医电科技有限公司 | Isolation type power transistor driver |
| CN203311193U (en) * | 2012-12-31 | 2013-11-27 | 人民电器集团有限公司 | Can and Modbus protocol conversion module and intelligent circuit breaker |
| CN103715874A (en) * | 2012-10-09 | 2014-04-09 | 富士电机株式会社 | Gate driving circuit having a fault detecting circuit for a semiconductor switching device |
-
2013
- 2013-12-27 CN CN201310737038.2A patent/CN103905031A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010028357A (en) * | 2008-07-17 | 2010-02-04 | Nec Electronics Corp | Output buffer circuit |
| CN102522978A (en) * | 2012-01-06 | 2012-06-27 | 河南华南医电科技有限公司 | Isolation type power transistor driver |
| CN103715874A (en) * | 2012-10-09 | 2014-04-09 | 富士电机株式会社 | Gate driving circuit having a fault detecting circuit for a semiconductor switching device |
| CN203311193U (en) * | 2012-12-31 | 2013-11-27 | 人民电器集团有限公司 | Can and Modbus protocol conversion module and intelligent circuit breaker |
Non-Patent Citations (1)
| Title |
|---|
| 沈红星: "一种基于RS485总线的网络协议及其实现方法", 《单片机与嵌入式系统应用》 * |
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Application publication date: 20140702 |
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