CN105067892B - A kind of cable resistance detection circuit - Google Patents
A kind of cable resistance detection circuit Download PDFInfo
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- CN105067892B CN105067892B CN201510608793.XA CN201510608793A CN105067892B CN 105067892 B CN105067892 B CN 105067892B CN 201510608793 A CN201510608793 A CN 201510608793A CN 105067892 B CN105067892 B CN 105067892B
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Abstract
The invention discloses a kind of cable resistance detection circuits, including：Impedance detection circuit judges that protection circuit disconnects protective relay with protective relay when cable is with alternating current, when cable does not have alternating current, is closed protective relay with judgement protection circuit, the exchange is exchanged；One end of the impedance detection circuit is electrically connected with direct current detection voltage back end; and be electrically connected with cable by protective relay, the other end is electrically connected with control module, when cable does not have alternating current; it is closed protective relay, the impedance variations of cable are detected using impedance detection circuit.First determine whether direct current supply or Alternating Current Power Supply；Under DC state, whether detection cable terminating impedance state is normal, realizes under a kind of no Alternating Current Power Supply state, the circuit structure of the stolen alarm of cable.
Description
Technical field
The invention belongs to on-line monitoring of cable technical fields, and in particular to a kind of cable resistance detection circuit.
Background technology
Due to there is a large amount of precious metal material in cable, the stolen event of cable frequent occurrence.Occur currently on the market
There are many cable theft-prevention equipment, such as video is antitheft, wireless telecommunications are antitheft, survey electric current is antitheft, power carrier (Power Line
Carrier, PLC) antitheft etc. a series of burglary-resisting installation.
Above there are certain defect, existing wireless anti-theft circuit maximum distance can only achieve in distance using wireless anti-theft pattern
Within the scope of 500m, and the mutual interference of on-air radio signal is received, according to not smooth at signal transmission, easily reported by mistake
Phenomenon.And in the case of no Alternating Current Power Supply module, terminal needs to export a direct current in power distribution cabinet for wireless anti-
It steals terminal to use, this method is turned on light moment in dusk street lamp, easily scurried into DC power-supply circuit according at alternating voltage, makes straight
Stream power supply circuit is burnt, and destroys theft-proof terminal.
Some producers use the big inductance short circuit of terminal or bulky capacitor is short-circuit, the unexpected change of electric current on test cable
Change, this scheme is susceptible to wrong report in the road lighting cable of road is antitheft.But this mode is suitble to the feelings of Alternating Current Power Supply always
Condition just can not judge whether cable is stolen if original AC dump.
Invention content
For the above-mentioned technological deficiency present in the prior art, the present invention provides a kind of cable resistance detection circuits, first
First judge direct current supply or Alternating Current Power Supply；Under DC state, whether detection cable terminating impedance state is normal, realizes a kind of
Without under Alternating Current Power Supply state, cable is stolen the circuit structure of alarm.
A kind of cable resistance detection circuit, including：Impedance detection circuit protects circuit with judgement is exchanged,
The exchange judges that protection circuit has protective relay RY3B1, when cable has alternating current, disconnect protection after
Electric appliance RY3B1 is closed protective relay RY3B1 when cable does not have alternating current；
One end of the impedance detection circuit is electrically connected with direct current detection voltage back end, and by protective relay RY3B1 with
Cable is electrically connected, and the other end is electrically connected with control module, when cable does not have alternating current, is closed protective relay RY3B1, profit
The impedance variations of cable are detected with impedance detection circuit.
Optionally, further include direct current output protection circuit, one end and the impedance detection electricity of the direct current output protection circuit
Road, the electrical connection of direct current detection voltage back end, the other end are electrically connected with protective relay RY3B1.
Optionally, the direct current output protection circuit includes DC output circuit and differential amplifier circuit, and the difference is put
Big circuit ensures that the field-effect tube of DC amplification circuit is constantly in conducting state, while protecting field-effect tube will not be because of short circuit
And cause to burn circuit.
Optionally, the DC output circuit includes：Direct current detection voltage back end is by first resistor R3B4 in parallel, second
The input terminal of the drain electrode and impedance detection circuit of resistance R3B5 connection field-effect tube Q3B1, the source electrode connection the of field-effect tube Q3B1
The anode of one diode D3B4, and pass through the normally-closed contact that the 5th resistance R3B7 is connected to relay, the grid of field-effect tube Q3B1
Pole is connected with the cathode of the first diode D3B4, and controls power supply, the one or two pole by the 6th resistance R3B6 connection grids
The anode of pipe D3B4 is connected with the source electrode of field-effect tube Q3B1.
Optionally, the differential amplifier circuit includes：Second triode Q3B3, the first triode Q3B2, the first periphery electricity
Hinder R3B8, the second peripheral resistance R3B9, third periphery resistance R3B10, one end of the described first peripheral resistance R3B8 and field-effect
The source electrode of pipe Q3B1 is connected, and the other end of the described first peripheral resistance R3B8 is connected with the base stage of the first triode Q3B2, and first
The collector of triode Q3B2 is connected with the grid of the collector of the second triode Q3B3, field-effect tube Q3B1 respectively, and described
The emitter of one triode Q3B2 is electric with the emitter of the second triode Q3B3, the normally-closed contact of relay, the second periphery respectively
The one end for hindering R3B9 is connected, the base stage of the second triode Q3B3 respectively with the other end of the second peripheral resistance R3B9, third
One end of peripheral resistance R3B10 is connected, the other end ground connection of the third periphery resistance R3B10.
Optionally, the exchange judges that protection circuit includes：Cable is electrically connected with the input terminal of the reversed gate circuit of two-stage, and two
The output end of the reversed gate circuit of grade is connected with the first photoelectric coupled circuit U3A1, is output in control module, is judged using optocoupler signal
Whether there is Alternating Current Power Supply on present cable.
Optionally, further include：Cable and inductance L3B1, half-wave rectifying circuit and the second diode D3B1, bleeder circuit and
The series circuit that regulator circuit is constituted is connected, and the input terminal of the other end and the reversed gate circuit of two-stage of the regulator circuit is electrically connected
It connects.
Optionally, further include：The input terminal connection two of relay driving chip UB2C, the relay driving chip UB2C
The output end of the reversed gate resistor of grade, the control terminal of the output end connection protective relay RY3B1 of relay driving chip UB2C.
Optionally, the impedance detection circuit includes the first amplifier UA9A, the second amplifier UA10A, the second optocoupler, and described the
One one end amplifier UA9A connects the first divider resistance R3A1, the bleeder circuit of the second divider resistance R3A1 compositions, the amplifier
The other end of UA9A connects one end of the second optocoupler, and the input terminal of the other end connection amplifier UA10A of second optocoupler is described
The output end of amplifier UA10A is connected with control module.
Optionally, second optocoupler is linear optical coupling, and the voltage of the light emitting diode of linear optical coupling can be according to partial pressure electricity
There is different brightness in the difference of pressure, feeds back to the photosensitive output end of linear optical coupling, the resistance of photosensitive output end will be according to direct current
Branch pressure voltage can change, and the voltage of variation is input to control module after amplifier UA10A amplifications.
Compared with prior art, the present invention at least has the following technical effect that：
Entire circuit is applied in cable theft-prevention circuit, first determines whether direct current supply or Alternating Current Power Supply；In DC state
Under, whether detection cable terminating impedance state is normal, can realize under a kind of no Alternating Current Power Supply state, the electricity of the stolen alarm of cable
Line structure.
Description of the drawings
Fig. 1 is that the direct current output of the cable resistance detection circuit of the embodiment of the present invention protects circuit and exchanges judgement protection electricity
The electrical block diagram on road；
Fig. 2 is the electrical block diagram of the impedance detection circuit of the cable resistance detection circuit of the embodiment of the present invention；
Fig. 3 is that the alternating current-direct current of the embodiment of the present invention judges the first photoelectric coupled circuit structural schematic diagram of protection circuit；
Fig. 4 is a kind of structural representation of cable anti-theft system application of the cable resistance detection circuit of the embodiment of the present invention
Figure.
Specific implementation mode
In order to more specifically describe the present invention, below in conjunction with the accompanying drawings and specific implementation mode is to technical scheme of the present invention
And its operation principle is described in detail.
Fig. 2 and Fig. 3 are please referred to Fig.1, the cable resistance detection circuit of the embodiment of the present invention includes：Direct current output protection electricity
Road, exchange judge protection circuit and impedance detection circuit impedance detection circuit, the exchange judge protection circuit have protect after
Electric appliance RY3B1 disconnects protective relay RY3B1 when cable has alternating current, when cable does not have alternating current, is closed and protects
Protect relay RY3B1；One end of the impedance detection circuit is electrically connected with direct current detection voltage back end, and is protected by direct current output
Circuit, protective relay RY3B1 are electrically connected with cable, and the other end is electrically connected with control module, when cable does not have alternating current,
It is closed protective relay RY3B1, the impedance variations of cable are detected using impedance detection circuit.
Due to may be caused to damage to impedance detection circuit, direct current detection voltage back end when there is exchange in cable,
In the present embodiment, a direct current output is added between impedance detection circuit, direct current detection voltage back end and cable and protects circuit.
In other embodiments, can also one end of impedance detection circuit be directly electrically connected with cable by protective relay RY3B1.
The direct current output protection circuit includes DC output circuit and differential amplifier circuit, and DC output circuit includes：
Direct current detection voltage back end is by the drain electrode of first resistor R3B4, second resistance R3B5 connection field-effect tube Q3B1 in parallel, field effect
Should pipe Q3B1 source electrode connect the first diode D3B4 anode, and by the 5th resistance R3B7 be connected to relay it is normally closed touch
Point, the grid of field-effect tube Q3B1 are connected with the cathode of the first diode D3B4, and pass through the 6th resistance R3B6 connection grid controls
The anode of power supply processed, the first diode D3B4 is connected with the source electrode of field-effect tube Q3B1.The differential amplifier circuit includes：
Second triode Q3B3, the first triode Q3B2, the first peripheral resistance R3B8, the second peripheral resistance R3B9, third periphery resistance
One end of R3B10, the described first peripheral resistance R3B8 are connected with the source electrode of field-effect tube Q3B1, the described first peripheral resistance R3B8
The other end be connected with the base stage of the first triode Q3B2, the collector of the first triode Q3B2 respectively with the second triode Q3B3
Collector, field-effect tube Q3B1 grid be connected, the emitter of the first triode Q3B2 respectively with the second triode
The emitter of Q3B3, the normally-closed contact of relay, one end of the second peripheral resistance R3B9 are connected, the second triode Q3B3's
Base stage is connected with one end of the other end of the second peripheral resistance R3B9, third periphery resistance R3B10 respectively, third periphery electricity
Hinder the other end ground connection of R3B10.
The differential amplifier circuit ensures that the field-effect tube of DC amplification circuit is constantly in conducting state, while protecting field
Effect pipe will not cause to burn circuit because of short circuit so that the DC voltage at direct current detection voltage back end when detecting can always all
It is in the conduction state.
In embodiments of the present invention, the voltage at direct current detection voltage back end is 13.5V, is the operating voltage of chip, grid control
The power supply of power supply processed is 18.5V.In other embodiments, the two voltages may be other suitable values.
Referring to FIG. 1, the exchange of the present embodiment judges that protection circuit includes：Cable and inductance L3B1, half-wave rectifying circuit
Be connected with the series circuit that regulator circuit is constituted with the second diode D3B1, bleeder circuit, the other end of the regulator circuit with
The input terminal of the reversed gate circuit of two-stage is electrically connected, and the output end of the reversed gate resistor of two-stage is electrically connected with the first photoelectric coupled circuit U3A1,
It is output in control module using optocoupler signal, judges whether there is Alternating Current Power Supply on present cable.
In other embodiments, can also cable be directly electrically connected with the input terminal of the reversed gate circuit of two-stage, two-stage is reversed
The output end of gate circuit is connected with the first photoelectric coupled circuit U3A1, is output in control module using optocoupler signal, judges electricity now
Whether there is Alternating Current Power Supply on cable.Since alternating current after the reversed gate circuit of two-stage by that can convert digital signal, can directly export
Judged to control module.
In the present embodiment, the output end of the reversed gate resistor of the two-stage is also connected with the input of relay driving chip UB2C
End, the output end connection protective relay RY3B1 of relay driving chip UB2C.When relay driving chip UB2C obtains two-stage
After the signal of the output end of reversed gate resistor, protective relay RY3B1 can be directly controlled and disconnect or be closed.
In the present embodiment, when Alternating Current Power Supply, the first diode D3B1 cut-offs, the second diode D3B2 conductings, while into
Row halfwave rectifier is divided by 3rd resistor R3B1 and the 4th resistance R3B2, after zener diode DZ3B1 voltage stabilizings, is obtained
10V voltages, after the reversed gate circuit of two-stage, through relay driving chip so that relay coil both end voltage is 13V, after
The electric shock state of electric appliance is overturn, and the output channel of direct current 13.5V is disconnected, and protects the logical of 13.5V direct currents and ac cable
Direct current is protected on road.Simultaneously after two-stage gate circuit, the T3_P signals of output are input on the first photoelectric coupled circuit U3A1, make optocoupler
Work, it is low level that optocoupler, which exports T3_STAT signals, which is input in control unit, you can to judge present cable
On whether have Alternating Current Power Supply.
In the present embodiment, the impedance detection circuit includes the first amplifier UA9A, the second amplifier UA10A, the second optocoupler,
Described one end first amplifier UA9A connects the bleeder circuit, described of the first divider resistance R3A1, the second divider resistance R3A1 compositions
The other end of amplifier UA9A connects one end of the second optocoupler, and the other end of second optocoupler connects the input terminal of amplifier UA10A,
The output end of the amplifier UA10A is connected with control module.
Second optocoupler is linear optical coupling, and the voltage of the light emitting diode of linear optical coupling can be according to branch pressure voltage not
Together, there is different brightness, feed back to the photosensitive output end of linear optical coupling, the resistance of photosensitive output end will be according to DC partial voltage electricity
Pressure can change, and the voltage of variation is input to microcontroller after amplifier UA10A amplifications.
Referring to FIG. 4, an a kind of Application Example --- cable theft-prevention of the cable resistance detection circuit for the present invention
System, the cable anti-theft system include：Anti-theft control unit 10, theft-proof terminal unit 20, central control unit 30,
Central control unit 30 includes centralized control module 31, concentrates communication module 32, concentrates communication module 32 and concentrates
Control module 31 is connected, and communication is utilized between concentration communication module 32 and the principal communication module 12 of anti-theft control unit 10
Interface is communicated, and passes through power carrier communication with theft-proof terminal unit 20.
The anti-theft control unit 10, including：Main control module, principal communication module 12, principal communication module 12 and master control
Molding block is connected；Whether exchange judges protection circuit 13, be connected respectively with main control module 11 and cable 13, have in detection cable
Alternating current；Impedance detection module, includes the impedance detection circuit of sample circuit 14 and the embodiment of the present invention, and sample circuit 14 is distinguished
It is connected with main control module and cable, acquires the impedance on cable and information of voltage, and cable is obtained using impedance detection circuit
The variation of resistance, in the present embodiment, the main control module and impedance detection circuit are integrated in same MCU, at other
In embodiment, it can also be provided separately.
The theft-proof terminal unit 20, including：Terminal control module 21, terminal communication module 22, voltage detecting control
Module 23, terminal communication module 22 are connected with terminal control module 21, and terminal communication module 21 with concentrate communication module 32 it
Between pass through power carrier communication；Voltage detecting control module 23 includes a concatenated relay and a resistance, one
The both ends of relay and a resistance are connected respectively on firewire and zero curve, and relay is controlled by terminal control module 21
System.When detecting that relay is closed by terminal control module 21 when not having alternating current on cable, firewire and zero curve conducting allow anti-
Steal in the impedance detection module detection circuit of control unit 10 whether impedance is preset value, if cable is stolen, cable
Impedance moment becomes larger, and the luminous moment of corresponding linear optical coupling is dimmed, so as to very easily notify control module cable
Whether it is stolen.
Embodiment described above is merely illustrative of the technical solution of the present invention, rather than its limitations；Although with reference to aforementioned reality
Applying example, invention is explained in detail, it will be understood by those of ordinary skill in the art that：It still can be to aforementioned each
Technical solution recorded in embodiment is modified or equivalent replacement of some of the technical features；And these are changed
Or it replaces, the spirit and model of each embodiment technical solution of the embodiment of the present invention that it does not separate the essence of the corresponding technical solution
It encloses.
Claims (9)
1. a kind of cable resistance detection circuit, which is characterized in that including：Impedance detection circuit protects circuit with judgement is exchanged,
The exchange judges that protection circuit includes：Cable is electrically connected with the input terminal of the reversed gate circuit of two-stage, two-stage reverse swing door electricity
The output end on road is connected with the first photoelectric coupled circuit U3A1, is output in control module using optocoupler signal, judges on present cable
Whether Alternating Current Power Supply is had；
The exchange judges that protection circuit has protective relay RY3B1, when cable has alternating current, disconnects protective relay
RY3B1 is closed protective relay RY3B1 when cable does not have alternating current；
One end of the impedance detection circuit is electrically connected with direct current detection voltage back end, and passes through protective relay RY3B1 and cable
Electrical connection, the other end are electrically connected with control module, when cable does not have alternating current, are closed protective relay RY3B1, are utilized resistance
Anti- detection circuit is detected the impedance variations of cable.
2. cable resistance detection circuit according to claim 1, which is characterized in that further include direct current output protection circuit,
One end of the direct current output protection circuit be electrically connected with impedance detection circuit, direct current detection voltage back end, the other end and protect after
Electric appliance RY3B1 electrical connections.
3. cable resistance detection circuit according to claim 2, which is characterized in that direct current output protection circuit includes
DC output circuit and differential amplifier circuit, the differential amplifier circuit ensure that the field-effect tube of DC amplification circuit is constantly in
Conducting state, while field-effect tube being protected not cause to burn circuit because of short circuit.
4. cable resistance detection circuit according to claim 3, which is characterized in that the DC output circuit includes：Directly
Drain electrode and impedance inspection of the stream detection voltage end by first resistor R3B4, second resistance R3B5 connection field-effect tube Q3B1 in parallel
The input terminal of slowdown monitoring circuit, the source electrode of field-effect tube Q3B1 connects the anode of the first diode D3B4, and passes through the 5th resistance R3B7
It is connected to the normally-closed contact of relay, the grid of field-effect tube Q3B1 is connected with the cathode of the first diode D3B4, and passes through
Six resistance R3B6 connection grids control power supply.
5. cable resistance detection circuit according to claim 3, which is characterized in that the differential amplifier circuit includes：The
Two triode Q3B3, the first triode Q3B2, the first peripheral resistance R3B8, the second peripheral resistance R3B9, third periphery resistance
One end of R3B10, the described first peripheral resistance R3B8 are connected with the source electrode of field-effect tube Q3B1, the described first peripheral resistance R3B8
The other end be connected with the base stage of the first triode Q3B2, the collector of the first triode Q3B2 respectively with the second triode Q3B3
Collector, field-effect tube Q3B1 grid be connected, the emitter of the first triode Q3B2 respectively with the second triode
The emitter of Q3B3, the normally-closed contact of relay, one end of the second peripheral resistance R3B9 are connected, the second triode Q3B3's
Base stage is connected with one end of the other end of the second peripheral resistance R3B9, third periphery resistance R3B10 respectively, third periphery electricity
Hinder the other end ground connection of R3B10.
6. cable resistance detection circuit according to claim 1, which is characterized in that further include：Cable and inductance L3B1, half
Wave rectification circuit and the second diode D3B1, bleeder circuit are connected with the series circuit that regulator circuit is constituted, the regulator circuit
The other end be electrically connected with the input terminal of the reversed gate circuit of two-stage.
7. cable resistance detection circuit according to claim 1, which is characterized in that further include：Relay driving chip
The output end of the input terminal connection reversed gate resistor of two-stage of UB2C, the relay driving chip UB2C, relay driving chip
The control terminal of the output end connection protective relay RY3B1 of UB2C.
8. cable resistance detection circuit according to claim 1, which is characterized in that the impedance detection circuit includes first
Amplifier UA9A, the second amplifier UA10A, the second optocoupler, described one end first amplifier UA9A connect the first divider resistance R3A1, second
The bleeder circuit of divider resistance R3A1 compositions, the other end of the amplifier UA9A connect one end of the second optocoupler, second light
The input terminal of the other end connection amplifier UA10A of coupling, the output end of the amplifier UA10A are connected with control module.
9. cable resistance detection circuit according to claim 8, which is characterized in that second optocoupler is linear optical coupling,
The voltage of the light emitting diode of linear optical coupling different brightness can occur, feed back to linear optical coupling according to the difference of branch pressure voltage
Photosensitive output end, the resistance of photosensitive output end will can change according to DC partial voltage voltage, and the voltage of variation passes through amplifier
It is input to control module after UA10A amplifications.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510608793.XA CN105067892B (en) | 2015-09-22 | 2015-09-22 | A kind of cable resistance detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510608793.XA CN105067892B (en) | 2015-09-22 | 2015-09-22 | A kind of cable resistance detection circuit |
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| CN105067892A CN105067892A (en) | 2015-11-18 |
| CN105067892B true CN105067892B (en) | 2018-09-25 |
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| CN201510608793.XA Active CN105067892B (en) | 2015-09-22 | 2015-09-22 | A kind of cable resistance detection circuit |
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Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN107688133A (en) * | 2017-10-26 | 2018-02-13 | 绵阳高新区探索科技有限责任公司 | Control box has access to electricity short-circuit detecting circuit on charging gun cable |
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| JPH11178197A (en) * | 1997-12-08 | 1999-07-02 | Hioki Ee Corp | Ac measuring apparatus |
| CN2508252Y (en) * | 2001-11-23 | 2002-08-28 | 贺明志 | Electric wire and cable AC resistance tester |
| CN2689246Y (en) * | 2004-04-29 | 2005-03-30 | 董长富 | Circuit alarming devices |
| CN1838191A (en) * | 2006-02-24 | 2006-09-27 | 南京联宏自动化系统工程有限公司 | Anti-theft alarm for electric power cable |
| CN2924549Y (en) * | 2006-06-15 | 2007-07-18 | 杭州瑞琦信息技术有限公司 | Lighting cable power-off stealing detection device |
| CN101604924B (en) * | 2008-05-30 | 2011-04-20 | 北京利德华福电气技术有限公司 | Isolation buffer tri-level inversion circuit |
| CN101853558B (en) * | 2009-04-01 | 2011-12-21 | 大连现代高技术发展有限公司 | Cable burglar alarm wireless monitoring system |
| CN103051163B (en) * | 2011-10-17 | 2015-06-03 | 中国北车股份有限公司 | Output signal conversion equipment of pulse width modulation rectifier and electric locomotive |
| CN202372576U (en) * | 2011-11-25 | 2012-08-08 | 比亚迪股份有限公司 | Resistance measurement system for cable |
| CN102841259B (en) * | 2012-09-24 | 2015-06-03 | 冶金自动化研究设计院 | Device and method for detecting insulation resistance of direct current system |
| CN202904793U (en) * | 2012-11-22 | 2013-04-24 | 浙江方大智控科技有限公司 | Cable antitheft system based on combination of impedance test and GSM communication |
| US10281939B2 (en) * | 2014-02-17 | 2019-05-07 | Commscope Technologies Llc | Methods and equipment for reducing power loss in cellular systems |
| CN204008808U (en) * | 2014-07-15 | 2014-12-10 | 国家电网公司 | Alternating current is scurried into the detection of straight-flow system and is compeled to jump device |
| CN205003216U (en) * | 2015-09-22 | 2016-01-27 | 浙江方大智控科技有限公司 | Cable impedance detection circuitry |
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