CN102305656B - Liquid level indicating system and contact resistance washing circuit - Google Patents
Liquid level indicating system and contact resistance washing circuit Download PDFInfo
- Publication number
- CN102305656B CN102305656B CN 201110214505 CN201110214505A CN102305656B CN 102305656 B CN102305656 B CN 102305656B CN 201110214505 CN201110214505 CN 201110214505 CN 201110214505 A CN201110214505 A CN 201110214505A CN 102305656 B CN102305656 B CN 102305656B
- Authority
- CN
- China
- Prior art keywords
- resistance
- liquid level
- pulse
- comparer
- termination
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)
Abstract
The invention discloses a liquid level indicating system, which comprises a two-wire liquid level sensor, a liquid level instrument and a contact resistance washing circuit, wherein the washing signal end of the contact resistance washing circuit is connected with a liquid level signal end of the liquid level instrument; and when a periodic pulse falling edge generated by the liquid level instrument arrives, the washing signal end of the contact resistance washing circuit delays set pulse delay time to output a washing pulse. The invention also discloses the contact resistance washing circuit. In the liquid level indicating system, high direct-current voltage is led into the two-wire liquid level sensor to puncture contact resistance; and the two-wire liquid level sensor is washed by heavy current to improve the signal quality of the two-wire liquid level sensor, so that the corresponding relation of liquid level height and a resistance value is accurate, and the liquid level instrument can indicate liquid levels accurately.
Description
Technical field
The present invention relates to electronic technology, particularly a kind of liquid level indication system and contact resistance irrigation circuit.
Background technology
Common liquid level indication system such as the liquid level indication system of automobile fuel pump, comprises two-wire system liquid level sensor, liquid level instrument.As shown in Figure 1, the principle of two-wire system liquid level sensor is a slide rheostat, the liquid level signal end of the described liquid level instrument of conduction band one termination of described two-wire system liquid level sensor, described liquid level instrument arrives described two-wire system liquid level sensor through a series connection resistance R cons at described liquid level signal end output recurrent pulses voltage, the contact ground connection of described two-wire system liquid level sensor, when liquid level changes, described contact changes with the contact position of conduction band, described conduction band one end is changed with the resistance value Rx ratio between the contact, described liquid level instrument is according to the sampled voltage of described conduction band one end when producing pulse voltage, calculate corresponding conduction band one end with the resistance value between the contact, provide corresponding liquid level indication.
But owing to reasons such as corrosion, the contact resistance Rcontact of contact can increase, and the total resistance value of described two-wire system liquid level sensor output changes, and liquid level-resistance value corresponding relation is disorderly, causes the indication of liquid level instrument liquid level inaccurate.
In order to prevent causing the indication of liquid level instrument liquid level inaccurate because of the contact resistance Rcontact increase of contact, normally realize (as increasing the noble metal use amount of conduction band or contact) by improving material, but cost is higher.
Summary of the invention
The technical problem to be solved in the present invention is, prevents from that contact resistance because of the contact from increasing to cause the indication of liquid level instrument liquid level inaccurate, and cost is lower.
For solving the problems of the technologies described above, the invention provides a kind of liquid level indication system, liquid level indication system, comprise the two-wire system liquid level sensor, liquid level instrument, the liquid level signal end of the described liquid level instrument of conduction band one termination of described two-wire system liquid level sensor, described liquid level instrument arrives described two-wire system liquid level sensor through described liquid level signal end output recurrent pulses voltage, the contact ground connection of described two-wire system liquid level sensor, described liquid level instrument is according to the sampled voltage of described conduction band one end when producing pulse high level, calculate corresponding described conduction band one end with the resistance value between the contact, provide corresponding liquid level indication; Also comprise a contact resistance irrigation circuit;
The described liquid level signal end of the flush signal termination of described contact resistance irrigation circuit, described flush signal end are delayed a pulse delay time output of setting one flushing pulse after the recurrent pulses negative edge arrival that described liquid level instrument produces;
Ub1 〉=2Vp, Ub1 are the amplitude of described flushing pulse, and Vp is the pulse height of the recurrent pulses of described liquid level instrument generation;
T2＜(T-t1-Tr1), the pulse delay time of t2 for setting, Tr1 is the width of described flushing pulse, and T is the cycle of the recurrent pulses of described liquid level instrument generation, and t1 is the pulse width of the recurrent pulses of described liquid level instrument generation.
Described contact resistance irrigation circuit can comprise that flush signal end, pulse delay and transfer stretch circuit, gauge tap;
Described pulse is delayed and is transferred stretch circuit, the described flush signal end of input termination, the control end of the described gauge tap of output termination, described pulse are delayed and are transferred stretch circuit to delay the pulse delay time of setting after the recurrent pulses negative edge that described liquid level instrument produces arrives and export a pulse;
Described gauge tap is connected to a direct current voltage with between the described flush signal end, and by its its break-make of control end Control of Voltage, when described pulse was delayed and transfer stretch circuit output pulse, described gauge tap was connected;
Ub 〉=2Vp, Ub are described DC voltage;
T2＜(T-t1-Tr), Tr is the width that the pulse of stretch circuit output is delayed and transferred in described pulse, and T is the cycle of the recurrent pulses of described liquid level instrument generation.
Described gauge tap can be a triode, and the collector of described triode connects described DC voltage, and emitter connects described flush signal end, and base stage is as control end.
Described pulse is delayed and is transferred stretch circuit, can comprise the first comparer, the second comparer, the 3rd comparer, diode, the first electric capacity, the second electric capacity, the one one resistance, the one or two resistance, the one or three resistance, the one or four resistance, the one or five resistance, the one or six resistance, the one or seven resistance, the one or eight resistance, the one or nine resistance, the second zero resistance, the 21 resistance;
One end of the one one resistance is delayed as described pulse and is transferred stretch circuit to input the described flush signal end of termination, described the first comparer positive input terminal of another termination of the one one resistance;
One termination the 3rd reference voltage of the one or two resistance, the negative input end of described first comparer of another termination of the one or two resistance;
One end ground connection of the one or four resistance, the negative input end of described first comparer of another termination of the one or four resistance;
The described DC voltage of one termination of the one or five resistance, the output terminal of described first comparer of another termination of the one or five resistance;
The output terminal of described first comparer of positive termination of diode, negative terminal connects an end of the one or six resistance, the negative input end of another termination the second comparer of the one or six resistance;
The first electric capacity, the one or seven resistance are connected to the negative input end of the second comparer with between the ground;
The negative input end of one termination, second comparer of the one or eight resistance, the positive input terminal of another termination the 3rd comparer of the one or eight resistance;
One termination, first reference voltage of the one or nine resistance, the positive input terminal of another termination the second comparer of the one or nine resistance;
One end ground connection of the second electric capacity, the positive input terminal of another termination the 3rd comparer of the second electric capacity;
Negative input termination second reference voltage of the 3rd comparer;
The output terminal short circuit of same the 3rd comparer of the output terminal of the second comparer is as the 4th reference voltage output terminal;
Described the 4th reference voltage output terminal of one termination of the one or three resistance, another termination first comparer negative input end of the one or three resistance;
The described DC voltage of one termination of the second zero resistance, another termination the 4th reference voltage output terminal of the second zero resistance;
Described the 4th reference voltage output terminal of one termination of the 21 resistance, the other end of the 21 resistance delays and transfers the output terminal of stretch circuit as described pulse.
Described pulse is delayed and is transferred stretch circuit can also comprise the 31 resistance, the three or two resistance, the three or three resistance, the three or four resistance, the three or five resistance, the three or six resistance;
The 31 resistance is connected to described DC voltage with between the ground with the three or two resistance string, export the 3rd reference voltage, the three or three resistance is connected to described DC voltage with between the ground with the three or four resistance string, export the first reference voltage, the three or five resistance is connected to described DC voltage with between the ground with the three or six resistance string, exports the second reference voltage.
Described the 3rd reference voltage is less than the pulse height of the recurrent pulses of described liquid level instrument generation;
The first reference voltage is greater than the second reference voltage, and less than described DC voltage.
For solving the problems of the technologies described above, the present invention also provides a kind of contact resistance irrigation circuit, comprises that flush signal end, pulse delay and transfer stretch circuit, gauge tap;
Described pulse is delayed and is transferred stretch circuit, input termination flush signal end is used for the access period pulse, the control end of the described gauge tap of output termination, described pulse are delayed and are transferred stretch circuit to delay the pulse delay time of setting after described recurrent pulses negative edge arrives and export a pulse to the control end of described gauge tap;
Described gauge tap is connected to a direct current voltage with between the described flush signal end, and by its its break-make of control end Control of Voltage, when described pulse was delayed and transfer stretch circuit output pulse, described gauge tap was connected;
Ub 〉=2Vp, Ub are described DC voltage, and Vp is the pulse height of described recurrent pulses;
T2＜(T-t1-Tr), the pulse delay time of t2 for setting, Tr is the width that the pulse of stretch circuit output is delayed and transferred in described pulse, and T is the cycle of described recurrent pulses, and t1 is the pulse width of described recurrent pulses.
Described pulse is delayed and is transferred stretch circuit, can comprise the first comparer, the second comparer, the 3rd comparer, diode, the first electric capacity, the second electric capacity, the one one resistance, the one or two resistance, the one or three resistance, the one or four resistance, the one or five resistance, the one or six resistance, the one or seven resistance, the one or eight resistance, the one or nine resistance, the second zero resistance, the 21 resistance;
One end of the one one resistance is delayed as described pulse and is transferred stretch circuit input end, described the first comparer positive input terminal of another termination of the one one resistance;
One termination the 3rd reference voltage of the one or two resistance, the negative input end of described first comparer of another termination of the one or two resistance;
One end ground connection of the one or four resistance, the negative input end of described first comparer of another termination of the one or four resistance;
The described DC voltage of one termination of the one or five resistance, the output terminal of described first comparer of another termination of the one or five resistance;
The output terminal of described first comparer of positive termination of diode, negative terminal connects an end of the one or six resistance, the negative input end of another termination the second comparer of the one or six resistance;
The first electric capacity, the one or seven resistance are connected to the negative input end of the second comparer with between the ground;
The negative input end of one termination, second comparer of the one or eight resistance, the positive input terminal of another termination the 3rd comparer of the one or eight resistance;
One termination, first reference voltage of the one or nine resistance, the positive input terminal of another termination the second comparer of the one or nine resistance;
One end ground connection of the second electric capacity, the positive input terminal of another termination the 3rd comparer of the second electric capacity;
Negative input termination second reference voltage of the 3rd comparer;
The output terminal short circuit of same the 3rd comparer of the output terminal of the second comparer is as the 4th reference voltage output terminal;
Described the 4th reference voltage output terminal of one termination of the one or three resistance, another termination first comparer negative input end of the one or three resistance;
The described DC voltage of one termination of the second zero resistance, another termination the 4th reference voltage output terminal of the second zero resistance;
Described the 4th reference voltage output terminal of one termination of the 21 resistance, the other end of the 21 resistance delays and transfers the output terminal of stretch circuit as described pulse.
Described gauge tap can be a triode, and the collector of described triode connects described DC voltage, and emitter connects described flush signal end, and base stage is as control end.
Described pulse is delayed and is transferred stretch circuit can also comprise the 31 resistance, the three or two resistance, the three or three resistance, the three or four resistance, the three or five resistance, the three or six resistance;
The 31 resistance is connected to described DC voltage with between the ground with the three or two resistance string, export the 3rd reference voltage, the three or three resistance is connected to described DC voltage with between the ground with the three or four resistance string, export the first reference voltage, the three or five resistance is connected to described DC voltage with between the ground with the three or six resistance string, exports the second reference voltage;
Described the 3rd reference voltage is less than the pulse height of described recurrent pulses;
Described the first reference voltage is greater than the second reference voltage and less than described DC voltage.
Liquid level indication system of the present invention, enter a contact resistance irrigation circuit at liquid level instrument to the liquid level signal termination of two-wire system liquid level sensor, described contact resistance irrigation circuit utilizes the recurrent pulses negative edge of liquid level instrument generation as trigger pip, after delaying a setting-up time, DC voltage that will be higher is introduced the two-wire system liquid level sensor, thereby puncture contact resistance, the two-wire system liquid level sensor is carried out large electric current flushing, improve the signal quality of two-wire system liquid level sensor, make liquid level-resistance value corresponding relation accurate, and then make liquid level instrument can accurately indicate liquid level.Contact resistance irrigation circuit in the liquid level indication system of the present invention, delay time and flush time all can be adjusted as required, and what use is the analog devices such as analog comparator spare and resistance, electric capacity, have greatly saved cost.
Description of drawings
Below in conjunction with the drawings and the specific embodiments the present invention is described in further detail.
Fig. 1 is the schematic diagram of common liquid level indication system;
Fig. 2 is liquid level indication system one embodiment schematic diagram of the present invention;
Fig. 3 is contact resistance irrigation circuit one embodiment circuit diagram of the present invention.
Embodiment
Liquid level indication system one embodiment of the present invention comprises two-wire system liquid level sensor, liquid level instrument, contact resistance irrigation circuit as shown in Figure 2;
The liquid level signal end of the described liquid level instrument of conduction band one termination of described two-wire system liquid level sensor, described liquid level instrument arrives described two-wire system liquid level sensor through described liquid level signal end output recurrent pulses voltage, the contact ground connection of described two-wire system liquid level sensor, described liquid level instrument is according to the sampled voltage of described conduction band one end when producing pulse high level, calculate corresponding described conduction band one end with the resistance value between the contact, provide corresponding liquid level indication.
The recurrent pulses that the described liquid level signal end of the flush signal termination of described contact resistance irrigation circuit produces to access described liquid level instrument, described flush signal end are delayed a pulse delay time output of setting one flushing pulse after the recurrent pulses negative edge arrival that described liquid level instrument produces;
Ub1 〉=2Vp, Ub1 are the amplitude of described flushing pulse, and Vp is the pulse height of the recurrent pulses of described liquid level instrument generation;
T2＜(T-t1-Tr1), the pulse delay time of t2 for setting, Tr1 is the width of described flushing pulse, and T is the cycle of the recurrent pulses of described liquid level instrument generation, and t1 is the pulse width of the recurrent pulses of described liquid level instrument generation.
Described contact resistance irrigation circuit comprises that flush signal end, pulse delay and transfer stretch circuit, gauge tap;
Described pulse is delayed and is transferred stretch circuit, the recurrent pulses that the described flush signal end of input termination produces to access described liquid level instrument, the control end of the described gauge tap of output termination, described pulse are delayed and are transferred stretch circuit to delay the pulse delay time of setting after the recurrent pulses negative edge that described liquid level instrument produces arrives and export a pulse;
Described gauge tap is connected to a direct current voltage with between the described flush signal end, and by its its break-make of control end Control of Voltage, when described pulse was delayed and transfer stretch circuit output pulse, described gauge tap was connected;
Ub 〉=2Vp, Ub are described DC voltage;
T2＜(T-t1-Tr), Tr is the width that the pulse of stretch circuit output is delayed and transferred in described pulse, and T is the cycle of the recurrent pulses of described liquid level instrument generation.
Described gauge tap can be a triode, and the collector of described triode connects described DC voltage, and emitter connects described flush signal end, and base stage is as control end.
Described contact resistance irrigation circuit one embodiment as shown in Figure 3, described gauge tap is a triode Q1, the collector of described triode Q1 meets DC voltage Ub, emitter connects the flush signal end, base stage is as control end;
Described pulse is delayed and is transferred stretch circuit, comprises the first comparer U1, the second comparer U2, the 3rd comparer U3, diode D1, the first capacitor C 1, the second capacitor C 2, the one one resistance R 11, the one or two resistance R 12, the one or three resistance R 13, the one or four resistance R 14, the one or five resistance R 15, the one or six resistance R 16, the one or seven resistance R 17, the one or eight resistance R 18, the one or nine resistance R 19, the second zero resistance R20, the 21 resistance R 21, the 31 resistance R 31, the three or two resistance R 32, the three or three resistance R 33, the three or four resistance R 34, the three or five resistance R 35, the three or six resistance R 36;
The 31 resistance R 31 is serially connected with described DC voltage Ub with between the ground with the three or two resistance R 32, export the 3rd reference voltage ref3, the three or three resistance R 33 is serially connected with described DC voltage Ub with between the ground with the three or four resistance R 34, export the first reference voltage ref1, the three or five resistance R 35 is serially connected with described DC voltage Ub with between the ground with the three or six resistance R 36, exports the second reference voltage ref2; Described the 3rd reference voltage ref3 is less than the pulse height of the recurrent pulses of described liquid level instrument generation; Described the first reference voltage ref1 is greater than described the second reference voltage ref2, and less than described DC voltage Ub.
One end of the one one resistance R 11 is delayed as described pulse and is transferred stretch circuit input end pulse to connect the flush signal end, described the first comparer U1 positive input terminal of another termination of the one one resistance R 11;
One termination the 3rd reference voltage ref3 of the one or two resistance R 12, described the first comparer U1 negative input end of another termination of the one or two resistance R 12;
One end ground connection of the one or four resistance R 14, described the first comparer U1 negative input end of another termination of the one or four resistance R 14;
One termination DC voltage Ub of the one or five resistance R 15, the output terminal of the described first comparer U1 of another termination of the one or five resistance R 15;
The output terminal of described the first comparer U1 of positive termination of diode D1, negative terminal connects an end of the one or six resistance R 16, the negative input end of another termination second comparer U2 of the one or six resistance R 16;
Described the first capacitor C 1, the one or seven resistance R 17 are connected to the negative input end of the second comparer U2 with between the ground;
The negative input end of one termination, the second comparer U2 of the one or eight resistance R 18, the positive input terminal of another termination the 3rd comparer U3 of the one or eight resistance R 18;
One termination, the first reference voltage ref1 of the one or nine resistance R 19, the positive input terminal of another termination second comparer U2 of the one or nine resistance R 19;
One end ground connection of the second capacitor C 2, the positive input terminal of another termination the 3rd comparer U3 of the second capacitor C 2;
Negative input termination the second reference voltage ref2 of the 3rd comparer U3; The output terminal short circuit of same the 3rd comparer U3 of the output terminal of the second comparer U2 is as the 4th reference voltage ref4 output terminal;
One termination the 4th reference voltage ref4 output terminal of the one or three resistance R 13, another termination first comparer U1 negative input end of the one or three resistance R 13;
The termination DC voltage Ub of the second zero resistance R20, another termination the 4th reference voltage ref4 output terminal of the second zero resistance R20;
One termination the 4th reference voltage ref4 output terminal of the 21 resistance R 21, the output terminal of stretch circuit is delayed and transferred to the other end of the 21 resistance R 21 as described pulse, connects the base stage of described triode Q1.
Above-mentioned contact resistance irrigation circuit, by adjusting the size of described the first capacitor C 1, the one or seven resistance R 17, the first reference voltage ref1, the second reference voltage ref2, can set accurately that described pulse delays and transfer pulse delay time T r, the pulse width of stretch circuit output pulse is t2, pulse delay and pulse width all are to realize by the RC charge-discharge characteristic, so that cost reduces greatly; Since used output and design, the pulsewidth time is depended on voltage threshold voltage scope, for the process that prevents from charging also produces output pulse width, the second capacitor C 2, the one or eight resistance R 18 have been increased in the circuit as secondary RC circuit to the three comparer U3, thereby avoided the threshold scope, so that charging process can not produce additional pulse; Also become the trigger pip that stretch circuit is delayed and transferred in described pulse for what prevent described pulse is delayed and the voltage of transferring stretch circuit initiatively to generate is higher output pulse, thereby so that whole circuit enters vibration, added FEEDBACK CONTROL in the circuit, with the output terminal of the second comparer U2 with the output terminal short circuit of the 3rd comparer U3 as the 4th reference voltage ref4 output terminal, access the negative input end of the first comparer U1, be optimized with the threshold values to the first comparer U1, avoided whole circuit to enter vibration.Because the virtual impedance scope of liquid level sensor is 36ohm～300ohm, thereby needs are considered the current limit under the different conditions, guarantee that liquid level sensor can not damage, utilized the triode amplification characteristic in the circuit, by optimizing base resistance the 21 resistance R 21, the control base current, thus reach the current limliting purpose.
Described contact resistance irrigation circuit only needs three extension lines, and an extension line is used for ground connection, and an extension line is used for connecing DC voltage (as it is anodal to connect the oil pump storage battery), and an extension line is used for connecing the liquid level signal end of liquid level instrument as the flush signal end; Use the analog devices such as analog comparator spare and resistance, electric capacity in the circuit, greatly saved cost; The printing board PCB area of described contact resistance irrigation circuit is as far as possible little, can be integrated in oil pump bracket flange upper surface, as the part of oil pump bracket assembly.
Liquid level indication system of the present invention, enter a contact resistance irrigation circuit at liquid level instrument to the liquid level signal termination of two-wire system liquid level sensor, described contact resistance irrigation circuit utilizes the recurrent pulses negative edge of liquid level instrument generation as trigger pip, after delaying a setting-up time, DC voltage that will be higher is introduced the two-wire system liquid level sensor, thereby puncture contact resistance, the two-wire system liquid level sensor is carried out large electric current flushing, improve the signal quality of two-wire system liquid level sensor, make liquid level-resistance value corresponding relation accurate, and then make liquid level instrument can accurately indicate liquid level.Contact resistance irrigation circuit in the liquid level indication system of the present invention, delay time and flush time all can be adjusted as required, and what use is the analog devices such as analog comparator spare and resistance, electric capacity, have greatly saved cost.
Claims (9)
1. liquid level indication system, comprise two-wire system liquid level sensor, liquid level instrument, the liquid level signal end of the described liquid level instrument of conduction band one termination of described two-wire system liquid level sensor, described liquid level instrument arrives described two-wire system liquid level sensor through described liquid level signal end output recurrent pulses voltage, the contact ground connection of described two-wire system liquid level sensor, described liquid level instrument is according to the sampled voltage of described conduction band one end when producing pulse high level, calculate corresponding described conduction band one end with the resistance value between the contact, provide corresponding liquid level indication; It is characterized in that, also comprise a contact resistance irrigation circuit;
The described liquid level signal end of the flush signal termination of described contact resistance irrigation circuit, described flush signal end are delayed a pulse delay time output of setting one flushing pulse after the recurrent pulses negative edge arrival that described liquid level instrument produces;
Ub1 〉=2Vp, Ub1 are the amplitude of described flushing pulse, and Vp is the pulse height of the recurrent pulses of described liquid level instrument generation;
T2＜(T-t1-Tr1), the pulse delay time of t2 for setting, Tr1 is the width of described flushing pulse, and T is the cycle of the recurrent pulses of described liquid level instrument generation, and t1 is the pulse width of the recurrent pulses of described liquid level instrument generation;
Described contact resistance irrigation circuit comprises that flush signal end, pulse delay and transfer stretch circuit, gauge tap;
Described pulse is delayed and is transferred stretch circuit, the described flush signal end of input termination, the control end of the described gauge tap of output termination, described pulse are delayed and are transferred stretch circuit to delay the pulse delay time of setting after the recurrent pulses negative edge that described liquid level instrument produces arrives and export a pulse;
Described gauge tap is connected to a direct current voltage with between the described flush signal end, and by its its break-make of control end Control of Voltage, when described pulse was delayed and transfer stretch circuit output pulse, described gauge tap was connected;
Ub 〉=2Vp, Ub are described DC voltage;
T2＜(T-t1-Tr), Tr is the width that the pulse of stretch circuit output is delayed and transferred in described pulse, and T is the cycle of the recurrent pulses of described liquid level instrument generation.
2. liquid level indication system according to claim 1 is characterized in that,
Described gauge tap is a triode, and the collector of described triode connects described DC voltage, and emitter connects described flush signal end, and base stage is as control end.
3. liquid level indication system according to claim 1 is characterized in that,
Described pulse is delayed and is transferred stretch circuit, comprises the first comparer, the second comparer, the 3rd comparer, diode, the first electric capacity, the second electric capacity, the one one resistance, the one or two resistance, the one or three resistance, the one or four resistance, the one or five resistance, the one or six resistance, the one or seven resistance, the one or eight resistance, the one or nine resistance, the second zero resistance, the 21 resistance;
One end of the one one resistance is delayed as described pulse and is transferred stretch circuit to input the described flush signal end of termination, described the first comparer positive input terminal of another termination of the one one resistance;
One termination the 3rd reference voltage of the one or two resistance, the negative input end of described first comparer of another termination of the one or two resistance;
One end ground connection of the one or four resistance, the negative input end of described first comparer of another termination of the one or four resistance;
The described DC voltage of one termination of the one or five resistance, the output terminal of described first comparer of another termination of the one or five resistance;
The output terminal of described first comparer of positive termination of diode, negative terminal connects an end of the one or six resistance, the negative input end of another termination the second comparer of the one or six resistance;
The first electric capacity, the one or seven resistance are connected to the negative input end of the second comparer with between the ground;
The negative input end of one termination, second comparer of the one or eight resistance, the positive input terminal of another termination the 3rd comparer of the one or eight resistance;
One termination, first reference voltage of the one or nine resistance, the positive input terminal of another termination the second comparer of the one or nine resistance;
One end ground connection of the second electric capacity, the positive input terminal of another termination the 3rd comparer of the second electric capacity;
Negative input termination second reference voltage of the 3rd comparer;
The output terminal short circuit of same the 3rd comparer of the output terminal of the second comparer is as the 4th reference voltage output terminal;
Described the 4th reference voltage output terminal of one termination of the one or three resistance, another termination first comparer negative input end of the one or three resistance;
The described DC voltage of one termination of the second zero resistance, another termination the 4th reference voltage output terminal of the second zero resistance;
Described the 4th reference voltage output terminal of one termination of the 21 resistance, the other end of the 21 resistance delays and transfers the output terminal of stretch circuit as described pulse.
4. liquid level indication system according to claim 3 is characterized in that,
Described pulse is delayed and is transferred stretch circuit also to comprise the 31 resistance, the three or two resistance, the three or three resistance, the three or four resistance, the three or five resistance, the three or six resistance;
The 31 resistance is connected to described DC voltage with between the ground with the three or two resistance string, export the 3rd reference voltage, the three or three resistance is connected to described DC voltage with between the ground with the three or four resistance string, export the first reference voltage, the three or five resistance is connected to described DC voltage with between the ground with the three or six resistance string, exports the second reference voltage.
5. liquid level indication system according to claim 3 is characterized in that,
Described the 3rd reference voltage is less than the pulse height of the recurrent pulses of described liquid level instrument generation;
The first reference voltage is greater than the second reference voltage, and less than described DC voltage.
6. a contact resistance irrigation circuit is characterized in that, comprises that flush signal end, pulse delay and transfer stretch circuit, gauge tap;
Described pulse is delayed and is transferred stretch circuit, input termination flush signal end is used for the access period pulse, the control end of the described gauge tap of output termination, described pulse are delayed and are transferred stretch circuit to delay the pulse delay time of setting after described recurrent pulses negative edge arrives and export a pulse to the control end of described gauge tap;
Described gauge tap is connected to a direct current voltage with between the described flush signal end, and by its its break-make of control end Control of Voltage, when described pulse was delayed and transfer stretch circuit output pulse, described gauge tap was connected;
Ub 〉=2Vp, Ub are described DC voltage, and Vp is the pulse height of described recurrent pulses;
T2＜(T-t1-Tr), the pulse delay time of t2 for setting, Tr is the width that the pulse of stretch circuit output is delayed and transferred in described pulse, and T is the cycle of described recurrent pulses, and t1 is the pulse width of described recurrent pulses.
7. contact resistance irrigation circuit according to claim 6 is characterized in that,
Described pulse is delayed and is transferred stretch circuit, comprises the first comparer, the second comparer, the 3rd comparer, diode, the first electric capacity, the second electric capacity, the one one resistance, the one or two resistance, the one or three resistance, the one or four resistance, the one or five resistance, the one or six resistance, the one or seven resistance, the one or eight resistance, the one or nine resistance, the second zero resistance, the 21 resistance;
One end of the one one resistance is delayed as described pulse and is transferred stretch circuit input end, described the first comparer positive input terminal of another termination of the one one resistance;
One termination the 3rd reference voltage of the one or two resistance, the negative input end of described first comparer of another termination of the one or two resistance;
One end ground connection of the one or four resistance, the negative input end of described first comparer of another termination of the one or four resistance;
The described DC voltage of one termination of the one or five resistance, the output terminal of described first comparer of another termination of the one or five resistance;
The output terminal of described first comparer of positive termination of diode, negative terminal connects an end of the one or six resistance, the negative input end of another termination the second comparer of the one or six resistance;
The first electric capacity, the one or seven resistance are connected to the negative input end of the second comparer with between the ground;
The negative input end of one termination, second comparer of the one or eight resistance, the positive input terminal of another termination the 3rd comparer of the one or eight resistance;
One termination, first reference voltage of the one or nine resistance, the positive input terminal of another termination the second comparer of the one or nine resistance;
One end ground connection of the second electric capacity, the positive input terminal of another termination the 3rd comparer of the second electric capacity;
Negative input termination second reference voltage of the 3rd comparer;
The output terminal short circuit of same the 3rd comparer of the output terminal of the second comparer is as the 4th reference voltage output terminal;
Described the 4th reference voltage output terminal of one termination of the one or three resistance, another termination first comparer negative input end of the one or three resistance;
The described DC voltage of one termination of the second zero resistance, another termination the 4th reference voltage output terminal of the second zero resistance;
Described the 4th reference voltage output terminal of one termination of the 21 resistance, the other end of the 21 resistance delays and transfers the output terminal of stretch circuit as described pulse.
8. contact resistance irrigation circuit according to claim 6 is characterized in that,
Described gauge tap is a triode, and the collector of described triode connects described DC voltage, and emitter connects described flush signal end, and base stage is as control end.
9. contact resistance irrigation circuit according to claim 7 is characterized in that,
Described pulse is delayed and is transferred stretch circuit also to comprise the 31 resistance, the three or two resistance, the three or three resistance, the three or four resistance, the three or five resistance, the three or six resistance;
The 31 resistance is connected to described DC voltage with between the ground with the three or two resistance string, export the 3rd reference voltage, the three or three resistance is connected to described DC voltage with between the ground with the three or four resistance string, export the first reference voltage, the three or five resistance is connected to described DC voltage with between the ground with the three or six resistance string, exports the second reference voltage;
Described the 3rd reference voltage is less than the pulse height of described recurrent pulses;
Described the first reference voltage is greater than the second reference voltage and less than described DC voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201110214505 CN102305656B (en) | 2011-07-29 | 2011-07-29 | Liquid level indicating system and contact resistance washing circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201110214505 CN102305656B (en) | 2011-07-29 | 2011-07-29 | Liquid level indicating system and contact resistance washing circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN102305656A CN102305656A (en) | 2012-01-04 |
| CN102305656B true CN102305656B (en) | 2013-02-06 |
Family
ID=45379539
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201110214505 Active CN102305656B (en) | 2011-07-29 | 2011-07-29 | Liquid level indicating system and contact resistance washing circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN102305656B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104833705A (en) * | 2014-10-27 | 2015-08-12 | 北汽福田汽车股份有限公司 | Automobile, and fuel oil monitoring device |
| CN106205380A (en) * | 2016-08-31 | 2016-12-07 | 无锡市万里实业发展有限公司 | Online health department display device |
| CN109798951B (en) * | 2017-11-17 | 2020-10-20 | 厦门雅迅网络股份有限公司 | Self-correction circuit and method for vehicle-mounted oil level detection |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4117050A1 (en) * | 1991-05-24 | 1992-11-26 | Vdo Schindling | METHOD FOR LEVEL MEASUREMENT |
| JP3370855B2 (en) * | 1996-07-11 | 2003-01-27 | 株式会社山武 | Level detection circuit and combustion control device |
| JP3555136B2 (en) * | 2000-07-31 | 2004-08-18 | 日本精機株式会社 | Resistance type liquid level measuring device |
| CN101813507A (en) * | 2010-04-27 | 2010-08-25 | 联合汽车电子有限公司 | Sensor used for detecting vehicle oil level |
| CN202195855U (en) * | 2011-07-29 | 2012-04-18 | 联合汽车电子有限公司 | Liquid level indication system and contact resistor flushing circuit |
-
2011
- 2011-07-29 CN CN 201110214505 patent/CN102305656B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN102305656A (en) | 2012-01-04 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102305656B (en) | Liquid level indicating system and contact resistance washing circuit | |
| CN103066989B (en) | Single power electric level shift circuit with digital filtering function | |
| CN102375625A (en) | Sensing circuit and method for capacitance type touch control panel | |
| CN103440073B (en) | Get rid of the capacitance sensing circuit of effect of parasitic capacitance | |
| CN102185604A (en) | Differential detection circuit for capacitive touch | |
| CN201947233U (en) | High-precision time-lapse synchronous machine based on high-performance interpolation digital compensation circuit | |
| CN202421440U (en) | Circuit delay time measurement device | |
| CN202195855U (en) | Liquid level indication system and contact resistor flushing circuit | |
| CN104459338A (en) | Capacitor capacitance value measuring device and measuring method | |
| CN207691759U (en) | A kind of tension measuring circuit | |
| CN202998029U (en) | Special signal edge detection device | |
| CN203849614U (en) | Gray scale sensor for automatically calculating average gray-value | |
| CN202268860U (en) | Driving pulse signal delay circuit | |
| CN202533494U (en) | High-accuracy peak detector | |
| CN110456783A (en) | Intelligent terminal and grey scale tracking sensing module and grey scale sensor thereof | |
| CN201732110U (en) | Multimeter | |
| CN204128572U (en) | A kind of inductance induction type data collector | |
| CN210520104U (en) | High accuracy constant temperature electron cigarette based on dual supply | |
| CN204461543U (en) | A kind of liquid level detection device | |
| CN203519728U (en) | Differential capacitance type sensor detection circuit | |
| CN201926699U (en) | Low-voltage circuit for power failure detection | |
| CN204154857U (en) | Integrated transporting discharging chip high speed detector | |
| CN204905963U (en) | Formula of putting environmental protection charger is filled in pulse | |
| CN204347145U (en) | A kind of circuit structure of capacitor's capacity measurement mechanism and measurement mechanism | |
| CN103389404A (en) | High-precision peak value detector |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |