CN2809654Y - Double-jaw ground resistance tester - Google Patents
Double-jaw ground resistance tester Download PDFInfo
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- CN2809654Y CN2809654Y CN 200520096881 CN200520096881U CN2809654Y CN 2809654 Y CN2809654 Y CN 2809654Y CN 200520096881 CN200520096881 CN 200520096881 CN 200520096881 U CN200520096881 U CN 200520096881U CN 2809654 Y CN2809654 Y CN 2809654Y
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Abstract
The utility model relates to a double-jaw grounded resistance tester. The utility model has the structure that the utility model is provided with a liquid crystal display LCD and a power supply circuit. The utility model is also characterized in that the utility model is also provided with an emission jaw circuit which is composed of a central processing unit MCU, a square wave generator and a power amplifier, a receiving jaw circuit which is composed of an analogue-to-digital converter, an A/D, a frequency selection amplifier and wave detecting device, a memory circuit which is composed of an integrated circuit U10, an automatic range converting circuit which is composed of an integrated circuit U7, and a keyboard circuit which is composed of an integrated circuit U15 and keys, wherein the integrated circuit U7 is an analog switch in the automatic rang converting circuit and eight channels of the analog switch are respectively connected with a first foot of a gain control end of an integrated circuit U 8 by a resistor. A U 7 foot 3 is connected with a U8 foot 8, a U7 foot 9, 10, and 11 are connected with an MCU, and the integrated circuit U 8 is a high-accuracy instrumentation amplifier. The utility model has the advantages of strong anti-interference ability, high test precision, a plurality of functions, simple operation, etc.
Description
Technical field
The utility model relates to electronic measuring instrument, particularly two jaw earth resistance testers.
Background technology
At present, the instrument of measurement of Grounding Resistance mainly contains hand-rail type earth resistance tester and digital earth resistance tester, and two kinds of instruments respectively have relative merits.Hand-rail type earth resistance tester measuring accuracy is not high, must beat pile and measure complicated operation.Digital earth resistance tester constant current source is less, and signal to noise ratio (S/N ratio) is low, and anti-power frequency and high-frequency ability are poor, must beat pile and measure complicated operation.
Summary of the invention
Problem to be solved in the utility model is: the two jaw earth resistance testers that a kind of superior performance are provided and have multiple function, and to overcome the deficiency of above-mentioned two kinds of instrument.
The technical scheme that the utility model adopted is as follows:
Be provided with LCD LCD and power circuit, also be provided with the emission jaw circuit that constitutes by central processor MCU, square-wave generator and power amplifier, the reception jaw circuit that constitutes by analog to digital converter, A/D, frequency-selecting amplification and detection, by the memory circuit that comprises that integrated circuit U10 constitutes, by the Automatic Range-changing Circuit that comprises that integrated circuit U7 constitutes, and constitute keyboard circuit by integrated circuit U15 and button.
In the Automatic Range-changing Circuit: integrated circuit U7 is an analog switch, and each gain control end the 1st pin through resistance and integrated circuit U8 of its 8 passages joins; U7 pin 3 connects U8 pin 8, and U7 pin 9,10,11 links to each other with MCU; Integrated circuit U8 is the high precision instrument amplifier.
Principle of the present utility model is: abandoned the method that measurement of Grounding Resistance in the past must be beaten pile, adopted the two-jawed non-contact measurement, i.e. and emission jaw, one receives jaw.Calculate the size of stake resistance by the size that detect to receive the signal that jaw receives, on liquid crystal display LCD, demonstrate the stake resistance of tested grounding body at last.
The utility model compared with prior art has following major advantage:
The one, be fit to any test condition, antijamming capability is strong, can avoid power frequency and high frequency interference effectively.
The 2nd, the measuring accuracy height, its minimum resolution is 0.01 Ω.
The 3rd, multi-functional: as, to have four-wire method measurement of Grounding Resistance function and measured soil resistivity function by software processes owing to adopted integrated circuit U14 (89C55 series monolithic).
The 4th, power unit adopts the power supply of high-performance power module, and all power supplies separately of the working power of the power supply of radiating portion and other chip, has improved stability.
The 5th, simple to operate.
Description of drawings
Fig. 1 is the utility model circuit block diagram.
Fig. 2 is the utility model circuit theory diagrams.
Fig. 3 is the active filter circuit schematic diagram of the band enlarging function that is made of integrated circuit U11 and peripheral circuit among Fig. 2.
Fig. 4 is the keyboard circuit schematic diagram.
Embodiment.
The utility model is described in further detail below in conjunction with embodiment and accompanying drawing.
Structure of the present utility model is as depicted in figs. 1 and 2: be provided with LCD LCD (7) and power circuit (9), also be provided with the radiating circuit that constitutes by central processor MCU, square-wave generator (1) and power amplifier (6), amplify the receiving circuit that (4) constitute by modulus converter A/D (2), detection (3) and frequency-selecting, by comprising the memory circuit that integrated circuit U10 constitutes (8), by comprising the Automatic Range-changing Circuit that integrated circuit U7 constitutes (5), and constitute keyboard circuit by integrated circuit U15 and button.
In the Automatic Range-changing Circuit: integrated circuit U7 is an analog switch, and each gain control end the 1st pin through resistance and integrated circuit U8 of its 8 passages joins, and these resistance are respectively R19～R26, and its resistance is that 100 Ω to 50K Ω do not wait.U7 pin 3 connects U8 pin 8, and U7 pin 9,10,11 is that single-chip microcomputer links to each other with central processor MCU.
Integrated circuit U8 can select the high precision instrument amplifier of INA128 or INA129 model for use.
Above-mentioned central processor MCU is single-chip microcomputer U14, square-wave generator and peripheral circuit, and the modulus converter A/D that is provided with integrated circuit U13, its annexation is: single-chip microcomputer U14, the two ends of its pin 18,19 cross-over connection 24M crystal oscillators and respectively through capacitor C 17, C18 ground connection, its pin 37,38,39 is connected to the pin 5,6,7 of integrated circuit U13 respectively, and its pin 31 and pin 1 connect power Vcc altogether; The pin 3 of U13 and 4 is ground connection altogether.
Above-mentioned power amplifier is provided with integrated circuit U12 and peripheral circuit, its annexation is: integrated circuit U12 is an operational amplifier, its in-phase end is through resistance R 10 ground connection, join through capacitor C 7 and resistance R 13,14 1 ends again, the other end of resistance R 13,14 joins with the collector of triode Q5, Q6 respectively; Its end of oppisite phase joins through the collector of resistance R 8, R9 and push-pull amplifier Q3, Q4 respectively; Its output pin joins with the positive pole of voltage stabilizing diode D2, the negative pole of D3 respectively through resistance R 7, and the negative pole of D2 connects the Q3 base stage, and the positive pole of D3 connects the Q4 base stage; The emitter of a Q3 and Q4 capacitor C 6 in parallel output to the emission jaw.Push-pull amplifier Q3, Q4 constitute the radiating portion of emission jaw circuit, and its transmission frequency can be selected 1697Hz.
Above-mentioned detecting circuit is provided with integrated circuit U9, selective frequency amplifier circuit is provided with integrated circuit U11 and U8 and peripheral circuit thereof, its annexation is: integrated circuit U9, its output pin (the 6th pin) joins through an end and the integrated circuit U13 pin 2 of detector diode D4 negative pole and capacitor C 16, the output pin (the 7th pin) of its homophase termination U11, its end of oppisite phase and output pin join, the other end ground connection of capacitor C 16.
Integrated circuit U8, its pin 5 ground connection, its pin 2 joins through an end of serial connection capacitor C 8, C9 and reception jaw, and its pin 3 joins through the other end of serial connection capacitor C 10, C11 and reception jaw, and its pin 2 and pin 3 are again respectively through resistance R 16, R17 ground connection.
As shown in Figure 3, integrated circuit U11 and peripheral circuit thereof constitute the active filter circuit of a band enlarging function, specifically: integrated circuit U11, its pin 1 and pin 2 cross-over connection capacitor C 15; Its pin 2 and pin 7 cross-over connections have resistance R 32; Its pin 3 and pin 5 ground connection; Its pin 6 connects its pin 8 through resistance R 40, and pin 6 and pin 7 cross-over connections have capacitor C 16; Its pin 7 connects its pin 9 through resistance R 38, connects its pin 10 through resistance R 39 again; Its pin 8 and pin 9 cross-over connections have resistance R 37; Its pin 9 and pin 1 cross-over connection have resistance R 33; Its pin 11 and pin 4 connect positive-negative power respectively; Its pin 12 ground connection; Its pin 13 joins through resistance R 36 and pin 8, and connects its pin 1 through resistance R 34; Its pin 14 connects its pin 13 through resistance R 35.
The integrated circuit U10 of above-mentioned memory circuit, its pin 3 and pin 8 connect altogether with power Vcc, direct earth capacitance C15, resistance R 18 1 ends, its pin 4 ground connection, its pin 7 joins with resistance R 18 other ends.
As shown in Figure 4, the annexation of keyboard circuit is: integrated circuit U15, and its pin 1,2,3 and pin 11,12,13 are connected to a button respectively; Its pin 5,10 and 14 ground connection; Its A, B, C pin link to each other with central processor MCU by connector; Its pin 15 meets power vd D.
The integrated circuit U that is adopted in the present embodiment, wherein: U 7 can adopt 8 tunnels analogy switches of CD4051 model; U9 can adopt model chips such as TL081, OP07; U10 can adopt the X5045 cake core; U11 can adopt TL084 or adopt four model chips such as single amplifier TL081, OP07; U12 can adopt model chips such as TL081, OP07; U13 can adopt model chips such as TL1549; U14 can adopt the 89C55 family chip; U15 can adopt 74LS148 etc.
Brief description principle of work of the present utility model once.
Guaranteeing that tested grounding body constitutes under the situation of a loop, by central processor MCU is the square wave that single-chip microcomputer produces a characteristic frequency, give power amplifier (exporting square wave through Q5 when four-wire system is measured) through power discharging transistor Q5 or Q6, give the emission jaw after amplifying by push-pull amplifier Q3, Q4 again, in tested grounding body loop, produce certain induced electromotive force this moment, thereby in loop, form certain induced current, and receiving the certain induced potential of jaw generation thus, this induced potential changes along with the size of loop resitance.Then, select the useful signal that becomes certain relation with loop resitance that receives from the reception jaw, and give the 2nd pin, the 3rd pin of instrumentation amplifier U8 by the filtering circuit that C8, C9, C10, C11, R16, R17 form.Amplify by giving selective frequency amplifier circuit after the U8 amplification, and detect the amplitude of the signal that receives through detecting circuit, give the single-chip microcomputer processing after converting thereof into digital signal by modulus converter A/D again, on liquid crystal display LCD, demonstrate the stake resistance of tested grounding body at last.
The principle of work of Automatic Range-changing Circuit is: U8 adopts high precision instrument amplifier INA128/INA129.Because its gain G=1+50K Ω/R (R is connected on 1 pin of U8 and the resistance between 8 pin), therefore as long as just can control the gain of U8 by the size of controlling R.This example is connected on R19～R26 (its resistance is that 100 Ω to 50K Ω do not wait) respectively on 8 passages of analog switch U7, receives gain control end the 1st pin, the 8th pin of instrumentation amplifier U8 then, and 9,10,11 pin of U7 link to each other with single-chip microcomputer.Control the break-make of 8 passages of analog switch U7 according to the signal magnitude that receives through 9,10,11 pin of U7 by single-chip microcomputer, promptly connect different resistances.And the gain of control instrument amplifier U8 thus, thereby reach the purpose that range is changed.
Claims (8)
1. two jaw earth resistance tester, be provided with LCD LCD and power circuit, it is characterized in that also being provided with: the emission jaw circuit that constitutes by central processor MCU, square-wave generator and power amplifier, the reception jaw circuit that constitutes by analog to digital converter, A/D, frequency-selecting amplification and detection, by the memory circuit that comprises that integrated circuit U10 constitutes, by the Automatic Range-changing Circuit that comprises that integrated circuit U7 constitutes, and by comprising that integrated circuit U15 and button constitute keyboard circuit
In the Automatic Range-changing Circuit: integrated circuit U7 is an analog switch, and each gain control end the 1st pin through resistance and integrated circuit U8 of its 8 passages joins; U7 pin 3 connects U8 pin 8, and U7 pin 9,10,11 links to each other with MCU; Integrated circuit U8 is the high precision instrument amplifier.
2. jaw earth resistance tester according to claim 1, it is characterized in that central processor MCU is single-chip microcomputer U14, square-wave generator and peripheral circuit, and the modulus converter A/D that is provided with integrated circuit U13, its annexation is: single-chip microcomputer U14, the two ends of its pin 18,19 cross-over connection 24M crystal oscillators and respectively through capacitor C 17, C18 ground connection, its pin 37,38,39 is connected to the pin 5,6,7 of integrated circuit U13 respectively, and its pin 31 and pin 1 connect power Vcc altogether; The pin 3 of U13 and 4 is ground connection altogether.
3. jaw earth resistance tester according to claim 1, it is characterized in that power amplifier is provided with integrated circuit U12 and peripheral circuit, its annexation is: integrated circuit U12 is an operational amplifier, its in-phase end is through resistance R 10 ground connection, join through capacitor C 7 and resistance R 13,14 1 ends again, the other end of resistance R 13,14 joins with the collector of triode Q5, Q6 respectively; Its end of oppisite phase joins through the collector of resistance R 8, R9 and push-pull amplifier Q3, Q4 respectively; Its output pin joins with the positive pole of voltage stabilizing diode D2, the negative pole of D3 respectively through resistance R 7, and the negative pole of D2 connects the Q3 base stage, and the positive pole of D3 connects the Q4 base stage; The emitter of a Q3 and Q4 capacitor C 6 in parallel output to the emission jaw.
4. jaw earth resistance tester according to claim 3 is characterized in that push-pull amplifier Q3, Q4 constitute the radiating portion of emission jaw circuit, and its transmission frequency is 1697Hz.
5. jaw earth resistance tester according to claim 1 is characterized in that in the keyboard circuit, and its annexation is: integrated circuit U15, and its pin 1,2,3 and pin 11,12,13 are connected to a button respectively; Its pin 5,10 and 14 ground connection; Its A, B, C pin link to each other with central processor MCU by connector; Its pin 15 meets power vd D.
6. jaw earth resistance tester according to claim 1 is characterized in that detecting circuit is provided with integrated circuit U9, and selective frequency amplifier circuit is provided with integrated circuit U11 and U8 and peripheral circuit thereof, and its annexation is:
Integrated circuit U9, its output pin joins through an end and the integrated circuit U13 pin 2 of detector diode D4 negative pole and capacitor C 16, the output pin of its homophase termination U11, its end of oppisite phase and output pin join, the other end ground connection of capacitor C 16,
Integrated circuit U11 and peripheral circuit thereof constitute the active filter circuit of a band enlarging function,
Integrated circuit U8, its pin 5 ground connection, its pin 2 joins through an end of serial connection capacitor C 8, C9 and reception jaw, and its pin 3 joins through the other end of serial connection capacitor C 10, C11 and reception jaw, and its pin 2, pin 3 are again respectively through resistance R 16, R17 ground connection.
7. jaw earth resistance tester according to claim 6 is characterized in that integrated circuit U11 and peripheral circuit thereof constitute the active filter circuit of a band enlarging function, specifically: integrated circuit U11, its pin 1 and pin 2 cross-over connection capacitor C 15; Its pin 2 and pin 7 cross-over connections have resistance R 32; Its pin 3 and pin 5 ground connection; Its pin 6 connects its pin 8 through resistance R 40, and pin 6 and pin 7 cross-over connections have capacitor C 16; Its pin 7 connects its pin 9 through resistance R 38, connects its pin 10 through resistance R 39 again; Its pin 8 and pin 9 cross-over connections have resistance R 37; Its pin 9 and pin 1 cross-over connection have resistance R 33; Its pin 11 and pin 4 connect positive-negative power respectively; Its pin 12 ground connection; Its pin 13 joins through resistance R 36 and pin 8, and connects its pin 1 through resistance R 34; Its pin 14 connects its pin 13 through resistance R 35.
8. jaw earth resistance tester according to claim 1, it is characterized in that: the integrated circuit U10 of memory circuit, its pin 3 and pin 8 connect altogether with power Vcc, direct earth capacitance C15, resistance R 18 1 ends, its pin 4 ground connection, and its pin 7 joins with resistance R 18 other ends.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200520096881 CN2809654Y (en) | 2005-06-24 | 2005-06-24 | Double-jaw ground resistance tester |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200520096881 CN2809654Y (en) | 2005-06-24 | 2005-06-24 | Double-jaw ground resistance tester |
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| Publication Number | Publication Date |
|---|---|
| CN2809654Y true CN2809654Y (en) | 2006-08-23 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200520096881 Expired - Lifetime CN2809654Y (en) | 2005-06-24 | 2005-06-24 | Double-jaw ground resistance tester |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101526560B (en) * | 2009-03-19 | 2013-04-17 | 优利德科技(中国)有限公司 | Electronic measuring method based on electromagnetic induction principle and measuring multimeter |
| CN104749444A (en) * | 2013-12-31 | 2015-07-01 | 孙巍巍 | Grounding resistance measuring device |
| CN104931792A (en) * | 2015-06-23 | 2015-09-23 | 中山市木易万用仪器仪表有限公司 | Clamp-shaped insulation resistance test device |
| CN105738703A (en) * | 2016-03-31 | 2016-07-06 | 南京信息工程大学 | On-line measurement device and measurement method of grounding resistor |
| CN109839563A (en) * | 2019-01-09 | 2019-06-04 | 国网江苏省电力有限公司检修分公司 | A kind of intelligent line connector conduction detecting system and method |
| CN110208604A (en) * | 2019-05-10 | 2019-09-06 | 湖南科技大学 | A kind of electrode earth-return circuit impedance measurement device and measurement method |
-
2005
- 2005-06-24 CN CN 200520096881 patent/CN2809654Y/en not_active Expired - Lifetime
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101526560B (en) * | 2009-03-19 | 2013-04-17 | 优利德科技(中国)有限公司 | Electronic measuring method based on electromagnetic induction principle and measuring multimeter |
| CN104749444A (en) * | 2013-12-31 | 2015-07-01 | 孙巍巍 | Grounding resistance measuring device |
| CN104931792A (en) * | 2015-06-23 | 2015-09-23 | 中山市木易万用仪器仪表有限公司 | Clamp-shaped insulation resistance test device |
| CN105738703A (en) * | 2016-03-31 | 2016-07-06 | 南京信息工程大学 | On-line measurement device and measurement method of grounding resistor |
| CN105738703B (en) * | 2016-03-31 | 2018-09-04 | 南京信息工程大学 | A kind of the on-line measurement device and measurement method of ground resistance |
| CN109839563A (en) * | 2019-01-09 | 2019-06-04 | 国网江苏省电力有限公司检修分公司 | A kind of intelligent line connector conduction detecting system and method |
| CN110208604A (en) * | 2019-05-10 | 2019-09-06 | 湖南科技大学 | A kind of electrode earth-return circuit impedance measurement device and measurement method |
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Legal Events
| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CX01 | Expiry of patent term |
Expiration termination date: 20150624 Granted publication date: 20060823 |