CN205384340U - Cable joins conversely and short circuit detection circuitry - Google Patents
Cable joins conversely and short circuit detection circuitry Download PDFInfo
- Publication number
- CN205384340U CN205384340U CN201620205355.9U CN201620205355U CN205384340U CN 205384340 U CN205384340 U CN 205384340U CN 201620205355 U CN201620205355 U CN 201620205355U CN 205384340 U CN205384340 U CN 205384340U
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- communication chip
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Abstract
The utility model discloses a cable joins conversely and short circuit detection circuitry, including main control chip MCU and nonpolarity RS485 communication chip U2, main control chip MCU's 1 foot is connected with operational amplifier U5, and operational amplifier U5 is connected with the reverse bias circuit, main control chip MCU's 2 feet are connected with electronic switch S, main control chip MCU's 3 feet and nonpolarity RS485 communication chip U2's 1 foot link to each other, and main control chip MCU's 4 feet link to each other with nonpolarity RS485 communication chip U2's 2 feet and 3 feet respectively, and main control chip MCU's 5 feet link to each other with nonpolarity RS485 communication chip U2's 4 feet, and nonpolarity RS485 communication chip U2's 6 feet and 7 feet are connected with the outside protection circuit that can effectively avoid the external interference and bias circuit in advance. Has following advantage: effectively detect the electric energy meter and be qualified for the next round of competitions that circuit wiring has nonpolarity transposition, short circuit phenomenon between side and the user's block terminal, guarantee single high -efficient the operation.
Description
Technical field
This utility model belongs to electric instrument field, particularly a kind of cable reversal connection and short-circuit detecting circuit.
Background technology
Along with the quickening of urbanization process, the heavy construction such as high residential building, Tall Office Building increases day by day, and electrical problem is the main problem concerning life of people.Research Work of Power Transmission Line state in these heavy constructions how, the problem such as zero live wire whether reversal connection annoying the power quality of people.
Current detection method is that the mode adopting and manually adding circuit tester carries out on-the-spot judgement: by double cooperation, a people in ammeter side by short circuit, separate the modes such as Live line Zero line and operate, another people carries circuit tester and registers one's residence investigation.There is following defect in this detection method:
1, there is potential safety hazard, when the situation that user's other exterior power supplies of indoor existence access, once empty opening and closing is closed, it is possible to cause on-the-spot short circuit phenomenon；
2, artificial judgment easily causes careless omission, this line mode is depended on artificial judgment, once there is careless omission general idea in operating process, causes under-enumeration most probably；
3, to on-the-spot error-polarity connection situation None-identified, this scheme depends on circuit tester, it is impossible to carry out error-polarity connection judgement.
Utility model content
Technical problem to be solved in the utility model is to provide a kind of cable reversal connection and short-circuit detecting circuit, and between effective detection electric energy meter outgoing line side and user's distribution box, connections is with or without error-polarity connection, short circuit phenomenon, it is ensured that single efficient operation.
For solving above-mentioned technical problem, the cable reversal connection of this utility model offer and short-circuit detecting circuit, it includes 1 foot of main control chip MCU and nonpolarity RS485 communication chip U2, main control chip MCU and is connected to operational amplifier U5, and operational amplifier U5 is connected to reverse bias circuitry；2 feet of main control chip MCU are connected to electrical switch S；3 feet of main control chip MCU are connected with 1 foot of nonpolarity RS485 communication chip U2; 4 feet of main control chip MCU are connected with 2 feet of nonpolarity RS485 communication chip U2 and 3 feet respectively; 5 feet of main control chip MCU are connected with 4 feet of nonpolarity RS485 communication chip U2, and 6 feet of nonpolarity RS485 communication chip U2 and 7 feet are connected to the outer protection circuit and pre-biased circuit that can be prevented effectively from external disturbance.
As preferably, described reverse circuits includes resistance R22, R23 and R25, and one end of described resistance R22 is connected with resistance R23, other end ground connection；The other end of resistance R23 is connected with resistance R25, another termination+3V3 voltage of resistance R25；It is provided with resistance R21 between node and the positive input of operational amplifier U5 between resistance R22 and resistance R23, it is provided with between 1 foot and the outfan of operational amplifier U5 of resistance R24, main control chip MCU between node and the reverse input end of operational amplifier U5 between resistance R23 and resistance R25 and is provided with resistance R26.
As preferably, described protection circuit includes critesistor PTC1, and one end of critesistor PTC1 is connected with 6 feet of nonpolarity RS485 communication chip U2, and the other end is connected with output terminals A；6 feet of described nonpolarity RS485 communication chip U2 and 7 feet are connected to the diode TVS1 that can effectively suppress the high pressure between output terminals A, B, and output terminals A is connected with 1 foot of nonpolarity RS485 interface J2, and 2 feet of outfan B and nonpolarity RS485 interface J2 are connected.
As preferably, described pre-biased circuit includes resistance R2, R6, R8, and the node between resistance R2 one end and 1 foot of output terminals A and nonpolarity RS485 interface J2 is connected, and another terminates+3V3 voltage；The two ends of resistance R6 are connected with 6 feet of nonpolarity RS485 communication chip U2 and 7 feet respectively；Node between resistance R8 one end and 2 feet of outfan B and nonpolarity RS485 interface J2 is connected, other end ground connection.
As preferably, being provided with resistance R28 between node and the positive input of operational amplifier U5 between diode TVS1 and critesistor PTC1, between node and the reverse input end of operational amplifier U5 between diode TVS1 and outfan B, it is provided with resistance R27.
As preferably, one end of electrical switch S is connected to electric capacity C12, and the other end is connected to electric capacity C9；One termination+3V3 the voltage of electric capacity C12, other end ground connection；The one termination external power supply of electric capacity C9, other end ground connection；Node between electrical switch S and electric capacity C9 is connected to resistance R1, the other end of resistance R1 is connected to power supply V485 end, node between resistance R1 and power supply V485 end is connected to electric capacity C1, the other end ground connection of electric capacity C1, electric capacity C1 is parallel with electric capacity C2, node between electric capacity C1 and electric capacity C2 is connected with 8 feet of nonpolarity RS485 communication chip U2, the 5 foot ground connection of nonpolarity RS485 communication chip U2.
As preferably, the node being provided with between 1 foot of resistance R4, resistance R4 and nonpolarity RS485 communication chip U2 between 3 feet and 1 foot of nonpolarity RS485 communication chip U2 of main control chip MCU is connected to resistance R3, and the other end of resistance R3 is connected to power supply V485 end；Node between 4 feet and 2 feet and 3 feet of nonpolarity RS485 communication chip U2 of main control chip MCU is connected between 5 feet of resistance R5, main control chip MCU and 4 feet of nonpolarity RS485 communication chip U2 and is provided with resistance R7.
After adopting above structure, cable reversal connection of the present utility model and short-circuit detecting circuit are compared with prior art, have the advantage that the pre-biased circuit adding resistance R2, R6, R8 composition at nonpolarity RS485 interface, when without communication, AB port has the individual forward bias more than 200mV, it is possible to avoid the nondeterministic statement that chip occurs when static state.Access the reverse bias circuitry being made up of resistance R22, R23, R25 simultaneously at the input of operational amplifier U5, its objective is the short trouble for RS485 network can be detected reliably and reversal connection fault.Positive bias voltage is higher than reverse bias voltage in normal state, and operational amplifier U5 exports high level, represents that port is normal.When circuit-under-test short circuit (owing to critesistor PTC1 resistance is only small, can ignore at this) 6, the 7 foot voltages of nonpolarity RS485 communication chip U2 trend towards 0V, namely the forward bias of circuit disappears, the input of operational amplifier U5 is then in negative bias, cause being output as low level, and circuit cannot communication, the main communicating circuit of opposite side at test cable has a stronger positive bias.When reversal connection occurs in circuit, the strong positively biased of main communicating circuit becomes strong negative bias, and the input also resulting in operational amplifier U5 is in negative bias, and it is output as low level.Can effectively detect between electric energy meter outgoing line side and user's distribution box connections with or without error-polarity connection, short circuit phenomenon, it is ensured that single efficient operation.
Accompanying drawing explanation
Fig. 1 is this utility model circuit theory diagrams.
Detailed description of the invention
In conjunction with accompanying drawing, the utility model will be further described by the examples below.
As it is shown in figure 1, the cable reversal connection of the present embodiment offer and short-circuit detecting circuit, it includes 1 foot of main control chip MCU and nonpolarity RS485 communication chip U2, main control chip MCU and is connected to operational amplifier U5, and operational amplifier U5 is connected to reverse bias circuitry；2 feet of main control chip MCU are connected to electrical switch S；3 feet of main control chip MCU are connected with 1 foot of nonpolarity RS485 communication chip U2; 4 feet of main control chip MCU are connected with 2 feet of nonpolarity RS485 communication chip U2 and 3 feet respectively; 5 feet of main control chip MCU are connected with 4 feet of nonpolarity RS485 communication chip U2, and 6 feet of nonpolarity RS485 communication chip U2 and 7 feet are connected to the outer protection circuit and pre-biased circuit that can be prevented effectively from external disturbance.
Described reverse bias circuitry includes resistance R22, R23 and R25, and one end of described resistance R22 is connected with resistance R23, other end ground connection；The other end of resistance R23 is connected with resistance R25, another termination+3V3 voltage of resistance R25；It is provided with resistance R21 between node and the positive input of operational amplifier U5 between resistance R22 and resistance R23, it is provided with between 1 foot and the outfan of operational amplifier U5 of resistance R24, main control chip MCU between node and the reverse input end of operational amplifier U5 between resistance R23 and resistance R25 and is provided with resistance R26.
Described protection circuit includes critesistor PTC1, and one end of critesistor PTC1 is connected with 6 feet of nonpolarity RS485 communication chip U2, and the other end is connected with output terminals A；6 feet of described nonpolarity RS485 communication chip U2 and 7 feet are connected to the diode TVS1 that can effectively suppress the high pressure between output terminals A, B, and output terminals A is connected with 1 foot of nonpolarity RS485 interface J2, and 2 feet of outfan B and nonpolarity RS485 interface J2 are connected.
Described pre-biased circuit includes resistance R2, R6, R8, and the node between resistance R2 one end and 1 foot of output terminals A and nonpolarity RS485 interface J2 is connected, and another terminates+3V3 voltage；The two ends of resistance R6 are connected with 6 feet of nonpolarity RS485 communication chip U2 and 7 feet respectively；Node between resistance R8 one end and 2 feet of outfan B and nonpolarity RS485 interface J2 is connected, other end ground connection.
It is provided with resistance R28 between node and the positive input of operational amplifier U5 between diode TVS1 and critesistor PTC1, between node and the reverse input end of operational amplifier U5 between diode TVS1 and outfan B, is provided with resistance R27.
One end of electrical switch S is connected to electric capacity C12, and the other end is connected to electric capacity C9；One termination+3V3 the voltage of electric capacity C12, other end ground connection；The one termination external power supply of electric capacity C9, other end ground connection；Node between electrical switch S and electric capacity C9 is connected to resistance R1, the other end of resistance R1 is connected to power supply V485 end, node between resistance R1 and power supply V485 end is connected to electric capacity C1, the other end ground connection of electric capacity C1, electric capacity C1 is parallel with electric capacity C2, node between electric capacity C1 and electric capacity C2 is connected with 8 feet of nonpolarity RS485 communication chip U2, the 5 foot ground connection of nonpolarity RS485 communication chip U2.
The node being provided with between 1 foot of resistance R4, resistance R4 and nonpolarity RS485 communication chip U2 between 3 feet and 1 foot of nonpolarity RS485 communication chip U2 of main control chip MCU is connected to resistance R3, and the other end of resistance R3 is connected to power supply V485 end；Node between 4 feet and 2 feet and 3 feet of nonpolarity RS485 communication chip U2 of main control chip MCU is connected between 5 feet of resistance R5, main control chip MCU and 4 feet of nonpolarity RS485 communication chip U2 and is provided with resistance R7.
This wireline inspection adopts 3.7V chargeable lithium cell to power, 3.3V be exported to system power supply after low-power consumption LDO voltage stabilizing, for there being minimum stand-by power consumption then the nonpolarity RS485 communication chip U2 that power consumption is bigger to be carried out power supply control when system resting state, simultaneously controlled also have show part (because being not directed to then be not drawn in FIG).The switch S of power supply adopts electrical switch to constitute, and its extremely low conducting resistance can reduce the power consumption of complete machine further.In the selection of operational amplifier U5, additionally also use the product of extremely low power dissipation, its operating current only 13uA.So when system resting state, nonpolarity RS485 communication chip U2 and display part independent power source are turned off, and operational amplifier U5 still can continue detection line status, can wake system at any time up according to line conditions and carry out wireline inspection.
The operation principle of this circuit is as communication line using tested cable, wire size or family number transmission to this device is detected wiring whether correct.Numerous communication standards is selected the communication standard interface of RS485 technical grade, its interface adopts half-duplex balance transmission mode, there is strong anti-interference performance, the characteristic that communication distance is remote, its the longest communication distance can arrive 1000 meters, the standard definition of RS485 is the communication interface of polarized, in the application of circuit detector, circuit is possible to reversal connection, for also can carry out communication when reversal connection, the design have employed the nonpolarity communication chip of up-to-date RS485, to guarantee also to complete communication detection work when line reversal.Owing to this circuit is for the detection of electric power cable; damage is very likely caused because maloperation is accessed civil power; for avoiding the circuit caused because of maloperation to damage; communication port line adds critesistor PTC1 and diode TVS1; when communication interface has forceful electric power to access; 6,7 pins of nonpolarity RS485 communication chip U2 are by diode TVS1 clamper in safe voltage, and bigger absorption electric current causes that critesistor PTC1 quickly enters high resistant guard mode, effectively avoids the damage of internal circuit.When port voltage recovers normal and recovers just to be returned to its original resistance after room temperature until critesistor PTC1, then this circuit can recover original detection function.
Line status testing circuit is mainly made up of the capacitance resistance ware of operational amplifier U5 and periphery, standard RS485 circuit circuit when communication is in high-impedance state, both 6, the 7 pin no-voltages of nonpolarity RS485 communication chip U2, so cannot judge circuit whether reversal connection and short circuit.Therefore the pre-biased circuit being made up of resistance R2, R6, R8 is added at 485 ports, when without communication, A, B port has the individual forward bias more than 200mV, it is possible to avoid the nondeterministic statement that chip occurs when static state.Add, at the input of operational amplifier U5, the reverse bias circuitry being made up of resistance R22, R23, R25 simultaneously, its objective is the short trouble for 485 networks can be detected reliably and reversal connection fault.In normal state, positive bias voltage is higher than reverse bias voltage, and operational amplifier U5 exports high level, represents that port is normal, responds circuit normal information.When circuit-under-test short circuit (owing to PTC1 resistance is only small, can ignore at this) 6,7 pin voltage of nonpolarity RS485 communication chip U2 trend towards 0V, namely the forward bias of circuit disappears, the input of operational amplifier U5 is in negative bias, cause being output as low level, and circuit cannot communication, the main communicating circuit of opposite side at test cable has a stronger positive bias.When there is reversal connection in circuit, the strong positively biased of main communicating circuit becomes strong negative bias, the input also resulting in operational amplifier U5 is in negative bias, it is output as low level, owing to have employed non-polarity communication circuit, now circuit communication is normal, and host computer side is still able to correct line information be passed to circuit detector.
Claims (7)
1. cable reversal connection and a short-circuit detecting circuit, it includes main control chip MCU and nonpolarity RS485 communication chip U2, it is characterised in that: 1 foot of main control chip MCU is connected to operational amplifier U5, and operational amplifier U5 is connected to reverse bias circuitry；2 feet of main control chip MCU are connected to electrical switch S；3 feet of main control chip MCU are connected with 1 foot of nonpolarity RS485 communication chip U2; 4 feet of main control chip MCU are connected with 2 feet of nonpolarity RS485 communication chip U2 and 3 feet respectively; 5 feet of main control chip MCU are connected with 4 feet of nonpolarity RS485 communication chip U2, and 6 feet of nonpolarity RS485 communication chip U2 and 7 feet are connected to the outer protection circuit and pre-biased circuit that can be prevented effectively from external disturbance.
2. cable reversal connection according to claim 1 and short-circuit detecting circuit, it is characterised in that: described reverse bias circuitry includes resistance R22, R23 and R25, and one end of described resistance R22 is connected with resistance R23, other end ground connection；The other end of resistance R23 is connected with resistance R25, another termination+3V3 voltage of resistance R25；It is provided with resistance R21 between node and the positive input of operational amplifier U5 between resistance R22 and resistance R23, it is provided with between 1 foot and the outfan of operational amplifier U5 of resistance R24, main control chip MCU between node and the reverse input end of operational amplifier U5 between resistance R23 and resistance R25 and is provided with resistance R26.
3. cable reversal connection according to claim 2 and short-circuit detecting circuit, it is characterised in that: described protection circuit includes critesistor PTC1, and one end of critesistor PTC1 is connected with 6 feet of nonpolarity RS485 communication chip U2, and the other end is connected with output terminals A；6 feet of described nonpolarity RS485 communication chip U2 and 7 feet are connected to the diode TVS1 that can effectively suppress the high pressure between output terminals A, B, and output terminals A is connected with 1 foot of nonpolarity RS485 interface J2, and 2 feet of outfan B and nonpolarity RS485 interface J2 are connected.
4. cable reversal connection according to claim 3 and short-circuit detecting circuit, it is characterized in that: described pre-biased circuit includes resistance R2, R6, R8, node between resistance R2 one end and 1 foot of output terminals A and nonpolarity RS485 interface J2 is connected, and another terminates+3V3 voltage；The two ends of resistance R6 are connected with 6 feet of nonpolarity RS485 communication chip U2 and 7 feet respectively；Node between resistance R8 one end and 2 feet of outfan B and nonpolarity RS485 interface J2 is connected, other end ground connection.
5. cable reversal connection according to claim 3 and short-circuit detecting circuit, it is characterized in that: between node and the positive input of operational amplifier U5 between diode TVS1 and critesistor PTC1, be provided with resistance R28, between node and the reverse input end of operational amplifier U5 between diode TVS1 and outfan B, be provided with resistance R27.
6. cable reversal connection according to claim 1 and short-circuit detecting circuit, it is characterised in that: one end of electrical switch S is connected to electric capacity C12, and the other end is connected to electric capacity C9；One termination+3V3 the voltage of electric capacity C12, other end ground connection；The one termination external power supply of electric capacity C9, other end ground connection；Node between electrical switch S and electric capacity C9 is connected to resistance R1, the other end of resistance R1 is connected to power supply V485 end, node between resistance R1 and power supply V485 end is connected to electric capacity C1, the other end ground connection of electric capacity C1, electric capacity C1 is parallel with electric capacity C2, node between electric capacity C1 and electric capacity C2 is connected with 8 feet of nonpolarity RS485 communication chip U2, the 5 foot ground connection of nonpolarity RS485 communication chip U2.
7. cable reversal connection according to claim 1 and short-circuit detecting circuit, it is characterized in that: between 3 feet and 1 foot of nonpolarity RS485 communication chip U2 of main control chip MCU, be provided with resistance R4, node between 1 foot of resistance R4 and nonpolarity RS485 communication chip U2 is connected to resistance R3, and the other end of resistance R3 is connected to power supply V485 end；Node between 4 feet and 2 feet and 3 feet of nonpolarity RS485 communication chip U2 of main control chip MCU is connected between 5 feet of resistance R5, main control chip MCU and 4 feet of nonpolarity RS485 communication chip U2 and is provided with resistance R7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620205355.9U CN205384340U (en) | 2016-03-17 | 2016-03-17 | Cable joins conversely and short circuit detection circuitry |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620205355.9U CN205384340U (en) | 2016-03-17 | 2016-03-17 | Cable joins conversely and short circuit detection circuitry |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN205384340U true CN205384340U (en) | 2016-07-13 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201620205355.9U Withdrawn - After Issue CN205384340U (en) | 2016-03-17 | 2016-03-17 | Cable joins conversely and short circuit detection circuitry |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN205384340U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105676054A (en) * | 2016-03-17 | 2016-06-15 | 杭州普安科技有限公司 | Cable reversal connection and short-circuit detection circuit |
| CN106569084A (en) * | 2016-11-15 | 2017-04-19 | 杭州普安科技有限公司 | Controllable characteristic load used for cable cabling accuracy detection |
-
2016
- 2016-03-17 CN CN201620205355.9U patent/CN205384340U/en not_active Withdrawn - After Issue
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105676054A (en) * | 2016-03-17 | 2016-06-15 | 杭州普安科技有限公司 | Cable reversal connection and short-circuit detection circuit |
| CN105676054B (en) * | 2016-03-17 | 2018-08-14 | 杭州普安科技有限公司 | Cable reversal connection and short-circuit detecting circuit |
| CN106569084A (en) * | 2016-11-15 | 2017-04-19 | 杭州普安科技有限公司 | Controllable characteristic load used for cable cabling accuracy detection |
| CN106569084B (en) * | 2016-11-15 | 2019-04-02 | 杭州普安科技有限公司 | A kind of controllable characteristics load for the detection of cable wiring accuracy |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20160713 Effective date of abandoning: 20180814 |
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| AV01 | Patent right actively abandoned |