CN107796482A

CN107796482A - Liquid-level detecting method and liquid level detection device

Info

Publication number: CN107796482A
Application number: CN201610803047.0A
Authority: CN
Inventors: 何世娴; 李奇峰; 杨云
Original assignee: BYD Co Ltd
Current assignee: BYD Semiconductor Co Ltd
Priority date: 2016-09-05
Filing date: 2016-09-05
Publication date: 2018-03-13
Anticipated expiration: 2036-09-05
Also published as: CN107796482B

Abstract

The invention discloses a kind of liquid-level detecting method and liquid level detection device, the described method comprises the following steps：Comprise the following steps：The capacitance present value of each capacitance detector in N number of capacitance detector is detected, wherein, N number of capacitance detector is configured to M group capacitance detection units, and every group of capacitance detection unit includes two capacitance detectors, and N, M are the integer more than 1；The capacitance change of each capacitance detector is obtained according to the capacitance present value of each capacitance detector, and the capacitance change difference of every group of capacitance detection unit is obtained according to the capacitance change of each capacitance detector；Liquid level information is generated according to the capacitance change difference of every group of capacitance detection unit, so as to, improve the accuracy of capacitance detecting, and then improve the accuracy of level sensing, and the change to environment has good anti-interference such as temperature drift, power jitter, PCB noises, is applicable to complex environment.

Description

Liquid-level detecting method and liquid level detection device

Technical field

The present invention relates to observation and control technology field, more particularly to a kind of liquid-level detecting method and a kind of liquid level detection device.

Background technology

Correlation technique proposes a kind of capacitive liquid level survey meter of intelligence, and the program is by capacitive frequency change-over circuit by electricity Hold change and be converted to frequency change, then CPU changes according to frequency and calculates liquid level by software formula, so as to Measurement liquid level indirectly.

But correlation technique the problem of existing is, between electric capacity during by comparing no liquid and electric capacity when having liquid Difference judge liquid level, electric capacity during because of no liquid is a fixed reference, thus fixed reference not in time with When the change of upper environment such as environment does temperature rise, it is easy to cause difference mistake, cause liquid level judgment disturbance.

The content of the invention

It is contemplated that at least solves one of technical problem in correlation technique to a certain extent.Therefore, the present invention One purpose is to propose a kind of liquid-level detecting method, this method can the change of accurate judgement liquid level, effectively suppress environment to liquid The interference of position detection.

It is another object of the present invention to propose a kind of liquid level detection device.

To reach above-mentioned purpose, one aspect of the present invention embodiment proposes a kind of liquid-level detecting method, comprised the following steps： The capacitance present value of each capacitance detector in N number of capacitance detector is obtained, wherein, N number of capacitance detector is configured to M groups Capacitance detection unit, every group of capacitance detection unit include two capacitance detectors, and N, M are the integer more than 1；According to each electric capacity The capacitance present value of detector obtains the capacitance change of each capacitance detector, and is become according to the electric capacity of each capacitance detector Change amount obtains the capacitance change difference of every group of capacitance detection unit；According to the capacitance change of every group of capacitance detection unit Difference generates liquid level information.

The liquid-level detecting method proposed according to embodiments of the present invention, obtain each capacitance detector in N number of capacitance detector Capacitance present value, N number of capacitance detector is configured to M group capacitance detection units, and every group of capacitance detection unit includes two electric capacity Detector, the capacitance change of each capacitance detector is then obtained, and obtained according to the capacitance change of each capacitance detector The capacitance change difference of every group of capacitance detection unit is taken, and is generated according to the capacitance change difference of every group of capacitance detection unit Liquid level information, so as to, the accuracy of capacitance detecting is improved, and then the accuracy of level sensing is improved, and to environment Change has good anti-interference such as temperature drift, power jitter, PCB noises, is applicable to complex environment.

To reach above-mentioned purpose, another aspect of the present invention embodiment proposes a kind of liquid level detection device, including：N number of electricity Hold detector, N number of capacitance detector is configured to M group capacitance detection units, and every group of capacitance detection unit includes two electric capacity Detector, N, M are the integer more than 1；Controller, the controller are respectively connected with N number of capacitance detector, the control Device is used for the capacitance present value for obtaining each capacitance detector in N number of capacitance detector, and working as according to each capacitance detector Preceding capacitance obtains the capacitance change of each capacitance detector, and is obtained according to the capacitance change of each capacitance detector The capacitance change difference of every group of capacitance detection unit, and the capacitance change difference according to every group of capacitance detection unit Generate liquid level information.

The liquid level detection device proposed according to embodiments of the present invention, N number of capacitance detector is configured to M group capacitance detecting lists Member, every group of capacitance detection unit include two capacitance detectors, and controller obtains each capacitance detector in N number of capacitance detector Capacitance present value, and obtain according to the capacitance present value of each capacitance detector the capacitance change of each capacitance detector, And the capacitance change difference of every group of capacitance detection unit, Yi Jigen are obtained according to the capacitance change of each capacitance detector Liquid level information is generated according to the capacitance change difference of every group of capacitance detection unit, so as to improve the accurate of capacitance detecting Property, and then the accuracy of level sensing is improved, and the change to environment has very such as temperature drift, power jitter, PCB noises Good anti-interference, is applicable to complex environment.

Brief description of the drawings

Fig. 1 is the flow chart of liquid-level detecting method according to embodiments of the present invention；

Fig. 2 is the flow chart of liquid-level detecting method according to an embodiment of the invention；

Fig. 3 is the flow chart of liquid-level detecting method in accordance with another embodiment of the present invention；

Fig. 4 is the block diagram of liquid level detection device according to embodiments of the present invention；

Fig. 5 is the structural representation of liquid level detection device according to an embodiment of the invention；And

Fig. 6 is the scheme of installation of liquid level detection device according to an embodiment of the invention.

Embodiment

Embodiments of the invention are described below in detail, the example of the embodiment is shown in the drawings, wherein from beginning to end Same or similar label represents same or similar element or the element with same or like function.Below with reference to attached The embodiment of figure description is exemplary, it is intended to for explaining the present invention, and is not considered as limiting the invention.

Below with reference to the accompanying drawings come describe the embodiment of the present invention proposition liquid-level detecting method and liquid level detection device.

Fig. 1 is the flow chart of liquid-level detecting method according to embodiments of the present invention.As shown in figure 1, the embodiment of the present invention Liquid-level detecting method comprises the following steps：

S1：The capacitance present value of each capacitance detector in N number of capacitance detector is obtained, wherein, N number of capacitance detector structure M group capacitance detection units are caused, every group of capacitance detection unit includes two capacitance detectors, and N, M are the integer more than 1.

Specifically, after start-up capacitance detection, the capacitance present value of each capacitance detector, capacitance present value be can detect It can be the real-time capacitance of capacitance detector.

Wherein, in every group of capacitance detection unit, a capacitance detector can be as the effective electricity for providing effective capacitance value Hold detector, another capacitance detector can be as the reference capacitance detector for providing reference capacitance value.For example, every group of electricity Two capacitance detectors held in detection unit are set according to upper-lower position formula, can be using the capacitance detector below position as having Capacitance detector is imitated, and using capacitance detector above as reference capacitance detector.

It should be noted that N number of capacitance detector can be combined in any way forms M group capacitance detection units, no Limit form one group of capacitance detection unit two capacitance detectors between interval number, can be 0,1,2 ..., N-1.

Moreover, not limiting number of any one capacitance detector as effective capacitance detector, any one electricity is not limited yet Hold number of the detector as reference capacitance detector, that is, say, same capacitance detector can be in different capacitance detection units Middle to be used as effective capacitance detector, same capacitance detector can also be examined in different capacitance detection units as reference capacitance Device is surveyed, for example, first capacitance detector can form capacitance detection unit, while first electric capacity with second capacitance detector Detector can also form capacitance detection unit with the 3rd capacitance detector, and first capacitance detector can also be with the 4th electric capacity Detector forms capacitance detection unit, and first capacitance detector is single as effective capacitance detection in above-mentioned capacitance detection unit Member, second capacitance detector, the 3rd capacitance detector and the 4th capacitance detector detect single respectively as reference capacitance Member.

Also, same capacitance detector can be used as effective capacitance detector in one group of capacitance detection unit, and another Reference capacitance detector is used as in one group of capacitance detection unit, for example, first capacitance detector can be with the 3rd capacitance detecting Device forms capacitance detection unit, and now first capacitance detector is made as effective capacitance detector, the 3rd capacitance detector For reference capacitance detector, while the 3rd capacitance detector can also form capacitance detection unit with the 5th capacitance detector, Now the 3rd capacitance detector is as effective capacitance detector, and the 5th capacitance detector is as reference capacitance detector.

In the specific example of the present invention, N number of capacitance detector can be brought into close contact with container, such as gluing by 3M Patch, it should be appreciated that the set-up mode of N number of capacitance detector and container is not limited to laminating type.Also, N number of capacitance detecting Device can be arranged in order according to ascent direction of the liquid in container, such as N number of capacitance detector can be in the vertical of the bottom of container It is arranged in order on direction, will be changed by the quantity of the capacitance detection unit of liquid level covering with the change of liquid level.

S2：The capacitance change of each capacitance detector, and root are obtained according to the capacitance present value of each capacitance detector The capacitance change difference of every group of capacitance detection unit is obtained according to the capacitance change of each capacitance detector.

According to one embodiment of present invention, obtaining the capacitance change difference of every group of capacitance detection unit includes：To every The capacitance present value of individual capacitance detector carries out computing to obtain the capacitance change of each capacitance detector with predetermined capacitance； The difference between the capacitance change of two capacitance detectors in every group of capacitance detection unit is calculated, to obtain every group of capacitance detecting The capacitance change difference of unit.

It should be noted that predetermined capacitance can not be covered with the liquid the electricity i.e. in container during no liquid for capacitance detector Capacitance, the predetermined capacitance of each capacitance detector can be stored in advance in the memory of control unit, such as MCU (Micro Control Unit, microprocessor) EEPROM ((Electrically Erasable Programmable Read-Only Memory, EEPROM) in.After power-up initializing, each capacitance detector can be read from memory Predetermined capacitance.

Specifically, capacitance present value can be subtracted to predetermined capacitance to obtain the capacitance variations of each capacitance detector Amount, after the capacitance change of each capacitance detector is obtained, the capacitance change of effective capacitance detector can be subtracted ginseng The capacitance change of capacitance detector is examined to obtain the capacitance change difference of every group of capacitance detection unit.Or it will can also join The capacitance change for examining capacitance detector subtracts the capacitance change of effective capacitance detector to obtain every group of capacitance detection unit Capacitance change difference.

Thus, the capacitance change of each capacitance detector is being obtained, you can obtain every group of capacitance detecting list by calculating The capacitance change difference of member.

S3：Liquid level information is generated according to the capacitance change difference of every group of capacitance detection unit.

Specifically, in embodiments of the present invention, each effective capacitance detector can be given to match a reference capacitance detection Device, or, can also all effective detection capacitors share a reference capacitance detector, such as n-th capacitance detector. When carrying out level sensing every time, the capacitance change of each capacitance detector can be got, then, by effective capacitance detector Capacitance change difference of the capacitance change of capacitance change and reference capacitance detector as every group of capacitance detection unit, this Sample, after the capacitance change difference for obtaining every group of capacitance detection unit, you can become according to the electric capacity of every group of capacitance detection unit Change amount difference judges liquid level.

Thus, by calculating the capacitance change difference of every group of capacitance detection unit, ambient compensation can be achieved, reject environment Such as the influence to capacitance detecting such as temperature drift, power jitter, PCB noises, capacitance detecting follow environmental change, greatly improved in real time The accuracy of capacitance detecting, and then improve the accuracy of level sensing, it is applicable to complex environment.

According to one embodiment of present invention, a capacitance detector may be present in N number of capacitance detector and is arranged on liquid level Above the upper limit, and at least one group of capacitance detection unit in M group capacitance detection units be present including being arranged on above the liquid level upper limit Capacitance detector.In addition, it is to be understood that in some embodiments of the invention, N number of capacitance detector can be also respectively mounted Below the liquid level upper limit.

Specifically, liquid level information is generated according to the capacitance change difference of every group of capacitance detection unit, including：Judge every group Whether the capacitance change difference of capacitance detection unit is more than the first predetermined threshold value；If there is at least one set of capacitance detection unit Capacitance change difference be more than the first predetermined threshold value, then according to capacitance change difference be more than the first predetermined threshold value electric capacity examine Survey unit and obtain liquid level information.

That is, when judging liquid level, can be according to preset order successively by the capacitance change of M group capacitance detection units Difference compared with the first predetermined threshold value, wherein, if to be more than first default for the capacitance change difference of capacitance detection unit Threshold value, then judge that liquid reaches the first predeterminated position corresponding to effective capacitance detector in the capacitance detection unit, such as first Predeterminated position can be the height residing for effective capacitance detector upper edge；If it is determined that the capacitance variations of M group capacitance detection units Amount difference is respectively less than the first predetermined threshold value, then illustrates that capacitance variations caused by liquid level change are little, now keep the liquid obtained Position Information invariability, the liquid level information that will be obtained the last time is as current level information.

Further, it is respectively less than or equal to the first default threshold in the capacitance change difference for judging every group of capacitance detection unit After being worth or being more than the capacitance detection unit acquisition liquid level information of the first predetermined threshold value according to capacitance change difference, method is also Including：Judge whether the capacitance change difference of every group of capacitance detection unit is more than the second predetermined threshold value, wherein, the second default threshold Value is less than the first predetermined threshold value；It is more than the second default threshold if there is the capacitance change difference of at least one set of capacitance detection unit Value, the then capacitance detection unit for being more than the second predetermined threshold value according to capacitance change difference adjust liquid level information；If every group of electricity The capacitance change difference for holding detection unit is respectively less than or equal to the second predetermined threshold value, then keeps the liquid level information of acquisition constant.

That is, the capacitance change difference of M group capacitance detection units is being compared with the first predetermined threshold value successively , can also be according to preset order successively again by the capacitance change difference of M group capacitance detection units and the second predetermined threshold value after relatively Judged, wherein, if the capacitance change difference of capacitance detection unit is more than the second predetermined threshold value, judge that liquid level has reached The second predeterminated position corresponding to effective capacitance detector into the capacitance detection unit, such as the second predeterminated position can be effectively electric Hold the height residing for detector centre position；If the capacitance change difference of M group capacitance detection units is respectively less than or equal to the Two predetermined threshold values, then illustrate that capacitance variations caused by liquid level change are smaller, the liquid level information for now keeping having obtained for example passes through The liquid level information of acquisition is constant compared with the first predetermined threshold value, and the liquid level information that will be obtained the last time is believed as current level Breath.

Thus, can be only by the capacitance change difference of every group of capacitance detection unit and the in the method for the embodiment of the present invention One predetermined threshold value is compared to judge liquid level, also can be by the capacitance change difference of every group of capacitance detection unit respectively with first Predetermined threshold value and the second predetermined threshold value are compared to judge liquid level, so as to lift the precision of level sensing.

By that analogy, using with previous embodiment identical mode, can also be by the capacitance variations of every group of capacitance detection unit Difference is measured compared with other predetermined threshold values, further to lift level sensing precision.

In addition, before whether the capacitance change difference for judging every group of capacitance detection unit is more than the first predetermined threshold value, Also include：Judge whether the capacitance change difference of every group of capacitance detection unit meets empty level conditions, if every group of electric capacity inspection The capacitance change difference for surveying unit meets empty level conditions, then liquid level information is empty liquid level.

Further, if the capacitance change difference of every group of capacitance detection unit is unsatisfactory for sky level conditions, judge Whether the capacitance change difference of every group of capacitance detection unit meets level conditions, if the electric capacity of every group of capacitance detection unit Variable quantity difference meets full level conditions, then liquid level information is full liquid level.

Specifically, that a capacitance detector is arranged on above the liquid level upper limit in N number of capacitance detector be present Under, it can judge whether liquid level information is sky liquid level according only to default empty level conditions, and by by M group capacitance detection units Capacitance change difference and the first predetermined threshold value be compared to judge whether liquid level information is to expire liquid level.Now, in this hair In a bright specific example, it is pre- that empty level conditions can be respectively less than the 3rd for the capacitance change difference of M group capacitance detection units If threshold value, the 3rd predetermined threshold value can be the numerical value close to zero.

In the case where N number of capacitance detector is installed in below the liquid level upper limit, can first according to default empty level conditions, Judge whether liquid level information is sky liquid level, and can judge whether liquid level information is full liquid further according to default full level conditions Position.Now, in the specific example of the present invention, empty level conditions can be that the capacitance change of M group capacitance detection units is poor Value is respectively less than the 3rd predetermined threshold value and the capacitance change of N number of capacitance detector is respectively less than the 4th predetermined threshold value, the 3rd default threshold Value and the 4th predetermined threshold value can be the numerical value close to zero；Full level conditions can be that the capacitance change of M group capacitance detection units is poor Value is respectively less than the 3rd predetermined threshold value and the capacitance change of N number of capacitance detector is all higher than the 5th predetermined threshold value, the 3rd default threshold Value can be the numerical value close to zero, and the 5th predetermined threshold value is more than the 4th predetermined threshold value.

In one embodiment of the invention, N number of capacitance detector may be provided on same PCB printed circuit board (PCB)s.

The liquid-level detecting method of the embodiment of the present invention is described with specific embodiment below.Assuming that N number of capacitance detecting N-th capacitance detector is arranged on the top of the liquid level upper limit in device, more specifically, n-th capacitance detector can be higher than on container Edge.In N number of capacitance detector the 1st to the N-1 capacitance detector be arranged on the liquid level upper limit lower section and the 1st to N-1 Individual capacitance detector is sequentially set up successively from liquid level lower limit, wherein, N number of capacitance detector is configured to N-1 group capacitance detectings Unit, and i-th of capacitance detector and the i-th+2 capacitance detectors are configured to i-th group of capacitance detection unit, the N-1 electric capacity Detector is configured to N-1 group capacitance detection units, i=1 to N-2 with n-th capacitance detector.

The operation principle of the liquid-level detecting method of the embodiment of the present invention is as follows：If the electric capacity of N-1 group capacitance detection units Variable quantity difference is respectively less than the 3rd predetermined threshold value, and the 3rd predetermined threshold value is close to zero, then judges liquid level information for empty liquid level；If The 1st group of capacitance change difference to N-3 group capacitance detection units be less than the 3rd predetermined threshold value i.e. close to zero and N-2 groups to N- The capacitance change difference of 1 group of capacitance detection unit is all higher than the first predetermined threshold value, then judges liquid level information for full liquid level；If The capacitance change difference that jth group capacitance detection unit be present is more than the first predetermined threshold value and the group capacitance detection unit of jth+1 Capacitance change difference is less than the 3rd predetermined threshold value i.e. close to zero, then jth in judging liquid level information for jth group capacitance detection unit First predeterminated position corresponding to individual capacitance detector, j=1,2 ..., N-3.

In addition, if the capacitance change difference that jth group capacitance detection unit be present be more than the first predetermined threshold value and jth+ The capacitance change difference of 1 group of capacitance detection unit is more than the second predetermined threshold value and is less than the first predetermined threshold value, then judges liquid level Information be the group capacitance detection unit of jth+1 in the second predeterminated position corresponding to+1 capacitance detector of jth, j=1,2 ..., N-3.

It should be appreciated that not having liquid during empty liquid level in container completely, N number of capacitance detector is not all entirely flooded by liquid, The capacitance change difference of N-1 group capacitance detection units is close to zero, therefore, when the electric capacity for judging N-1 group capacitance detection units When variable quantity difference is respectively less than three predetermined threshold values, judgement is now empty liquid level, exports liquid level information.

Liquid is loaded with container during full liquid level, now the 1st to the N-1 capacitance detector is entirely flooded by liquid, n-th Capacitance detector is not entirely flooded by liquid, therefore is worked as and judged that the 1st group of capacitance change difference to N-3 group capacitance detection units is small The first predetermined threshold value is all higher than in the 3rd predetermined threshold value and N-2 groups to the capacitance change difference of N-1 group capacitance detection units When, judge now to export liquid level information for full liquid level.

Partially full of liquid in container during the liquid level of part, the now part in the 1st to the N-1 capacitance detector Capacitance detector is entirely flooded by liquid, and another part capacitance detector is not entirely flooded by liquid, and n-th capacitance detector is not flooded by liquid Not yet.The continuity of capacitance detector is flooded in view of liquid, therefore when the capacitance change that jth group capacitance detection unit be present is poor When value is less than three predetermined threshold values more than the capacitance change difference of the first predetermined threshold value and the group capacitance detection unit of jth+1, i.e., It can determine that now liquid level is the location of j-th capacitance detector upper edge i.e. the first predeterminated position, output liquid level information；And It is more than the electricity of the first predetermined threshold value and the group capacitance detection unit of jth+1 in the capacitance change difference of jth group capacitance detection unit When holding variable quantity difference more than the second predetermined threshold value and being less than the first predetermined threshold value, it can determine that now liquid level is+1 electric capacity of jth The location of detector centre position is the second predeterminated position, exports liquid level information.

The liquid-level detecting method of the embodiment of the present invention, i.e. five capacitance detectings are described by taking N==5, M=4 as an example below Device is configured to 4 groups of capacitance detection units.

Wherein, first capacitance detector is arranged on the bottom of bottom such as container, and second capacitance detector is set Above first capacitance detector, the 3rd capacitance detector is arranged on above second capacitance detector, the 4th electric capacity Detector is arranged on above the 3rd capacitance detector, and the 5th capacitance detector is arranged on above the 4th capacitance detector, And the 5th capacitance detector is arranged on the top of the liquid level upper limit, the 4th capacitance detector is arranged on the lower section of the liquid level upper limit.

Also, first capacitance detector and the 3rd capacitance detector can be used as first group of capacitance detection unit, second Individual capacitance detector and the 4th capacitance detector can be used as second group of capacitance detection unit, the 3rd capacitance detector and the 5th Individual capacitance detector can be used as the 3rd group of capacitance detection unit, and the 4th capacitance detector and the 5th capacitance detector can conducts 4th group of capacitance detection unit.In every group of capacitance detection unit, underlying capacitance detector is effective capacitance detector, Capacitance detector above is reference capacitance detector, such as in first group of capacitance detection unit, first electric capacity inspection It is effective capacitance detector to survey device, and the 3rd capacitance detector is reference capacitance detector.

The present invention a specific embodiment, as shown in Fig. 2 liquid-level detecting method specifically includes following steps：

S101：After power-up initializing, the capacitance of each capacitance detector under no liquid state is read to be used as each electricity Hold detector predetermined capacitance, i.e., first predetermined capacitance to the 5th capacitance detector be respectively C10, C20, C30, C40 and C50.

S102：Start-up capacitance detects, and detects the real-time capacitance of each capacitance detector to be used as each capacitance detector Capacitance present value, i.e., the first capacitance present value to the 5th capacitance detector is respectively C11, C21, C31, C41, C51.

S103：Calculate the capacitance change of each capacitance detector, i.e., first electric capacity to the 5th capacitance detector Variable quantity difference is respectively：D1=| C11-C10 |, D2=| C21-C20 |, D3=| C31-C30 |, D4=| C41-C40 |, D5= |C51-C50|。

S104：Judge | D1-D3 |, | D2-D4 |, | D3-D5 | and | D4-D5 | whether it is respectively less than the 3rd predetermined threshold value.

If it is, perform step S105；If it is not, then perform step S106.

S105：It is judged as sky liquid level, performs step S110.

It should be appreciated that not having liquid during empty liquid level in container completely, first to the 5th capacitance detector is all not It is entirely flooded by liquid, first group of capacitance change difference to the 4th group of capacitance detection unit works as condition close to zero | D1- D3|<Vref3；|D2-D4|<Vref3；|D3-D5|<Vref3；|D4-D5|<Vref3 meets simultaneously when, judgement is now empty liquid Position, export liquid level information.

S106：Judge | D1-D3 | and | D2-D4 | whether be respectively less than the 3rd predetermined threshold value and | D3-D5 | and | D4-D5 | whether More than the first predetermined threshold value.

If it is, perform step S107；If it is not, then perform step S108.

S107：It is judged as full liquid level, that is, reaches the height residing for the 4th capacitance detector upper edge, performs step S110。

S108：Judge whether the capacitance change difference of every group of capacitance detection unit is more than the first predetermined threshold value successively, i.e., Successively | D1-D3 | whether more than Vref1, | D2-D4 | whether more than Vref1, | D3-D5 | whether more than Vref1 and | D4-D5 | Whether Vref1 is more than.

If it is, i.e. | D1-D3 | more than Vref1 or | D2-D4 | more than Vref1 or | D3-D5 | more than Vref1 or | D4-D5 | more than Vref1, then perform step S109 and step S110；If not, i.e. | D1-D3 | less than or equal to Vref1 and | D2-D4 | Less than or equal to Vref1 and | D3-D5 | less than or equal to Vref1 and | D4-D5 | less than or equal to Vref1, then perform step S109。

S109：Judge whether the capacitance change difference of every group of capacitance detection unit is more than the second predetermined threshold value successively, i.e., Successively | D1-D3 | whether more than Vref2, | D2-D4 | whether more than Vref2, | D3-D5 | whether more than Vref2 and | D4-D5 | Whether Vref2 is more than.

If it is, i.e. | D1-D3 | more than Vref2 or | D2-D4 | more than Vref2 or | D3-D5 | more than Vref2 or | D4-D5 | more than Vref2, then perform step S110；If not, i.e. | D1-D3 | less than or equal to Vref2 and | D2-D4 | be less than or equal to Vref2 and | D3-D5 | less than or equal to Vref2 and | D4-D5 | less than or equal to Vref2, then return to step S101.

S110：Export liquid level information, return to step S101.

For example, when liquid level is between first capacitance detector and the 3rd capacitance detector, the inspection of the first electric capacity The capacitance change difference for surveying unit is more than Vref1, i.e., | D1-D3 | more than Vref1, it now can determine that liquid level reaches first electricity Hold the height residing for detector upper edge；Afterwards, if detecting that the capacitance change difference of second group of capacitance detection unit is big In Vref1, i.e., | D2-D4 | more than Vref1, then liquid level is adjusted to the height residing for second capacitance detector upper edge；Such as Fruit detects that the capacitance change difference of the 3rd group of capacitance detection unit is more than Vref1, i.e., | D3-D5 | more than Vref1, then by liquid Position is adjusted to the height residing for the 3rd capacitance detector upper edge；If detect that the electric capacity of the 4th group of capacitance detection unit becomes Change amount difference is more than Vref1, i.e., | D4-D5 | more than Vref1, then liquid level is adjusted to residing for the 4th capacitance detector upper edge Height.

Further, carried out by the capacitance change difference of every group of capacitance detection unit and the first predetermined threshold value Vref1 After comparing, then by the capacitance change difference of every group of capacitance detection unit compared with the second predetermined threshold value Vref2.Such as Fruit detects that the capacitance change difference of first group of capacitance detection unit is more than Vref2, i.e., | D1-D3 | more than Vref2, now may be used Judge that liquid level reaches the height residing for the centre position of first capacitance detector；If detect second group of capacitance detection unit Capacitance change difference be more than Vref2, i.e., | D2-D4 | more than Vref2, then liquid level is adjusted to second capacitance detector Height residing for centre position；If detecting that the capacitance change difference of the 3rd group of capacitance detection unit is more than Vref2, i.e., | D3-D5 | more than Vref2, then liquid level is adjusted to the height residing for the centre position of the 3rd capacitance detector；If detection Capacitance change difference to the 4th group of capacitance detection unit is more than Vref2, i.e., | D4-D5 | more than Vref2, then liquid level is adjusted For the height residing for the centre position of the 4th capacitance detector.

The present invention another specific embodiment, as shown in figure 3, liquid-level detecting method specifically includes following steps：

S201：After power-up initializing, the capacitance of each capacitance detector under no liquid state is read to be used as each electricity Hold detector predetermined capacitance, i.e., first predetermined capacitance to the 5th capacitance detector be respectively C10, C20, C30, C40 and C50.

S202：Start-up capacitance detects, and detects the real-time capacitance of each capacitance detector to be used as each capacitance detector Capacitance present value, i.e., the first capacitance present value to the 5th capacitance detector is respectively C11, C21, C31, C41, C51.

S203：Calculate the capacitance change of each capacitance detector, i.e., first electric capacity to the 5th capacitance detector Variable quantity difference is respectively：D1=| C11-C10 |, D2=| C21-C20 |, D3=| C31-C30 |, D4=| C41-C40 |, D5= |C51-C50|。

S204：Judge | D1-D3 |, | D2-D4 |, | D3-D5 | and | D4-D5 | whether it is respectively less than the 3rd predetermined threshold value Vref3.

If it is, perform step S205；If it is not, then perform step S206.

S205：It is judged as sky liquid level, performs step S222.

S206：Judge | D1-D3 | and | D2-D4 | whether less than the 3rd predetermined threshold value Vref3 and | D3-D5 | and | D4-D5 | Whether the first predetermined threshold value is more than.

If it is, perform step S207；If it is not, then perform step S208.

S207：It is judged as full liquid level, that is, reaches the height residing for the 4th capacitance detector, performs step S222.

It should be appreciated that be loaded with liquid in container during full liquid level, now first to the 4th capacitance detector quilt Liquid is flooded, and the 5th capacitance detector is not entirely flooded by liquid, therefore works as condition | D1-D3 |<Vref3；|D2-D4|<Vref3；| D3-D5|>Vref1；|D4-D5|>Vref1 meets simultaneously when, judge now to export liquid level information for full liquid level.

S208：Judge | D1-D3 | whether more than the first predetermined threshold value Vref1 and | D2-D4 |, | D3-D5 | and | D4-D5 | be It is no to be less than the 3rd predetermined threshold value Vref3.

If it is, perform step S209；If it is not, then perform step S210.

S209：Liquid level is judged for the height residing for first capacitance detector upper edge, performs step S222.

S210：Judge | D1-D3 | whether more than the second predetermined threshold value Vref2 and it is less than the first predetermined threshold value Vref1.

If it is, i.e. | D1-D3 | more than the second predetermined threshold value Vref2 and less than the first predetermined threshold value Vref1 and | D2-D4 |, | D3-D5 | and | D4-D5 | less than the 3rd predetermined threshold value Vref3, then perform step S211；If it is not, then perform step S212.

S211：Liquid level is judged for the height residing for first capacitance detector centre position, performs step S222.

S212：Judge | D1-D3 | and | D2-D4 | whether more than the first predetermined threshold value and | D3-D5 | and | D4-D5 | it is whether small In the 3rd predetermined threshold value Vref3.

If it is, perform step S213；If it is not, then perform step S214.

S213：Liquid level is judged for the height residing for second capacitance detector upper edge, performs step S222.

S214：Judge | D2-D4 | whether more than the second predetermined threshold value Vref2 and it is less than the first predetermined threshold value Vref1.

If it is, i.e. | D1-D3 | more than the first predetermined threshold value Vref1, | D2-D4 | more than the second predetermined threshold value Vref2 and Less than the first predetermined threshold value Vref1 and | D3-D5 | and | D4-D5 | less than the 3rd predetermined threshold value Vref3, then perform step S215； If it is not, then perform step S216.

S215：Liquid level is judged for the height residing for second capacitance detector centre position, performs step S222.

S216：Judge D1-D3 |, | D2-D4 | and | D3-D5 | whether more than the first predetermined threshold value Vref1 and | D4-D5 | be It is no to be less than the 3rd predetermined threshold value Vref3.

If it is, perform step S217；If it is not, then perform step S218.

S217：Liquid level is judged for the height residing for the 3rd capacitance detector upper edge, performs step S222.

S218：Judge | D1-D3 | and | D3-D5 | whether more than the second predetermined threshold value Vref2 and it is less than the first predetermined threshold value Vref1。

If it is, i.e. | D1-D3 | and | D3-D5 | more than the second predetermined threshold value Vref2 and it is less than the first predetermined threshold value Vref1, | D2-D4 | more than the first predetermined threshold value Vref1 and | D4-D5 | less than the 3rd predetermined threshold value Vref3, then perform step S219；If it is not, then perform step S220.

S219：Liquid level is judged for the height residing for the 3rd capacitance detector centre position, performs step S222.

S220：Judge | D1-D3 | whether less than the 3rd predetermined threshold value Vref3 and | D2-D4 | and | D4-D5 | whether be more than Second predetermined threshold value Vref2 and less than the first predetermined threshold value Vref1 and | D3-D5 | whether more than the first predetermined threshold value Vref1.

If it is, perform step S221；If it is not, then return to step S201.

S221：Judge liquid level for the height residing for the 4th capacitance detector centre position.S222：Export liquid level information, Return to step S201.

It should be appreciated that partially full of liquid, now first to the 4th electric capacity inspection in container during the liquid level of part The partition capacitance detector surveyed in device is entirely flooded by liquid, and the 5th capacitance detector is not entirely flooded by liquid.Assuming that liquid level is flooded First capacitance detector and second capacitance detector, then condition | D1-D3 |>Vref1；|D2-D4|>Vref1；|D3-D5 |<Vref3；|D4-D5|<Vref3 meets that judgement is now part liquid level, and liquid reaches residing for second capacitance detector simultaneously Height, export liquid level information.

Wherein, it is contemplated that liquid floods the continuity of capacitance detector, is judging | D3-D5 |<After Vref3, without sentencing It is disconnected | D4-D5 |<Vref3 can correctly draw liquid height, therefore aforementioned four Rule of judgment need not in the case of the liquid level of part All judge correctly identify liquid level.

In addition, it should be noted that, in above-mentioned steps S201-S222, it can also remove and judge whether liquid level is examined in electric capacity The judgment step in device centre position is surveyed, i.e., judges liquid level institute according only to the first predetermined threshold value Vref1 and the 3rd predetermined threshold value Vref3 The height at place.

To sum up, the liquid-level detecting method proposed according to embodiments of the present invention, each electric capacity inspection in N number of capacitance detector is obtained The capacitance present value of device is surveyed, N number of capacitance detector is configured to M group capacitance detection units, and every group of capacitance detection unit includes two Capacitance detector, the capacitance change of each capacitance detector is then obtained, and according to the capacitance variations of each capacitance detector Amount obtains the capacitance change difference of every group of capacitance detection unit, and according to the capacitance change difference of every group of capacitance detection unit Liquid level information is generated, so as to, the accuracy of capacitance detecting is improved, and then the accuracy of level sensing is improved, and to ring The change in border has good anti-interference such as temperature drift, power jitter, PCB noises, is applicable to complex environment.

Fig. 4 is the block diagram of liquid-detecting according to embodiments of the present invention.As shown in figure 4, the liquid detecting Device includes N number of capacitance detector 100 and controller 200.

Wherein, N number of capacitance detector 100 is configured to M group capacitance detection units, and every group of capacitance detection unit includes two electricity Hold detector, N, M are the integer more than 1；Controller 200 is respectively connected with N number of capacitance detector 100, and controller 200 is used to obtain The capacitance present value of each capacitance detector in N number of capacitance detector 100 is taken, and according to the capacitance present of each capacitance detector Value obtains the capacitance change of each capacitance detector, and obtains every group of electricity according to the capacitance change of each capacitance detector Hold the capacitance change difference of detection unit, and according to the capacitance change difference generation liquid level letter of every group of capacitance detection unit Breath.

It should be noted that N number of capacitance detector 100 can be combined in any way forms M group capacitance detection units, Do not limit form one group of capacitance detection unit two capacitance detectors between interval number, can be 0,1,2 ..., N-1.

Specifically, in embodiments of the present invention, each effective capacitance detector can be given to match a reference capacitance detection Device, or, can also all effective detection capacitors share a reference capacitance detector, such as n-th capacitance detector. When carrying out level sensing every time, controller 200 can obtain the capacitance present value of every group of capacitance detection unit, and according to each electric capacity The capacitance present value of detector obtains the capacitance change of each capacitance detector, and then, controller 200 detects effective capacitance The capacitance change of the capacitance change of device and reference capacitance detector is poor as the capacitance change of every group of capacitance detection unit Value, so, controller 200 is obtained after the capacitance change difference of every group of capacitance detection unit, you can is examined according to every group of electric capacity The capacitance change difference for surveying unit judges liquid level.

According to one embodiment of present invention, controller 200 is further used for, to the capacitance present of each capacitance detector Value carries out computing to obtain the capacitance change of each capacitance detector with predetermined capacitance, and calculates every group of capacitance detection unit In two capacitance detectors capacitance change between difference, it is poor to obtain the capacitance change of every group of capacitance detection unit Value.

It should be noted that predetermined capacitance can not be covered with the liquid the electricity i.e. in container during no liquid for capacitance detector Capacitance, the predetermined capacitance of each capacitance detector can be stored in advance in the memory of controller 200, such as MCU (Micro Control Unit, microprocessor) EEPROM ((Electrically Erasable Programmable Read-Only Memory, EEPROM) in.After power-up initializing, controller 200 can read each electricity from memory Hold the predetermined capacitance of detector.

Specifically, controller 200 can subtract capacitance present value predetermined capacitance to obtain each capacitance detector Capacitance change, after the capacitance change of each capacitance detector is obtained, controller 200 can be by effective capacitance detector The capacitance change that capacitance change subtracts reference capacitance detector is poor to obtain the capacitance change of every group of capacitance detection unit Value.Or controller 200 can also subtract the capacitance change of reference capacitance detector the capacitance variations of effective capacitance detector Measure to obtain the capacitance change difference of every group of capacitance detection unit.

Thus, the capacitance change of each capacitance detector is being obtained, controller 200 can obtain every group of electricity by calculating Hold the capacitance change difference of detection unit.

Further, according to one embodiment of present invention, controller 200 is further used for, and judges every group of capacitance detecting Whether the capacitance change difference of unit is more than the first predetermined threshold value, becomes if there is the electric capacity of at least one set of capacitance detection unit Change amount difference is more than the first predetermined threshold value, then the capacitance detection unit for being more than the first predetermined threshold value according to capacitance change difference obtains Take liquid level information.

That is, when judging liquid level, controller 200 can be according to preset order successively by M group capacitance detection units Capacitance change difference compared with the first predetermined threshold value, wherein, if the capacitance change difference of capacitance detection unit is big In the first predetermined threshold value, controller 200 then judges that liquid reaches in the capacitance detection unit corresponding to effective capacitance detector One predeterminated position, such as the first predeterminated position can be the height residing for effective capacitance detector upper edge；If it is determined that M group electric capacity The capacitance change difference of detection unit is respectively less than the first predetermined threshold value, then illustrates that capacitance variations caused by liquid level change are little, Now keep the liquid level information that has obtained constant, will the last liquid level information obtained as current level information.

Also, further, it is respectively less than or equal to first in the capacitance change difference for judging every group of capacitance detection unit Predetermined threshold value or according to capacitance change difference be more than the first predetermined threshold value capacitance detection unit obtain liquid level information after, Controller 200 is additionally operable to, and judges whether the capacitance change difference of every group of capacitance detection unit is more than the second predetermined threshold value, its In, the second predetermined threshold value is less than the first predetermined threshold value；If there is the capacitance change difference of at least one set of capacitance detection unit More than the second predetermined threshold value, controller 200 is then more than the capacitance detection unit of the second predetermined threshold value according to capacitance change difference Adjust liquid level information；If the capacitance change difference of every group of capacitance detection unit is respectively less than or equal to the second predetermined threshold value, control Device 200 processed then keeps the liquid level information of acquisition constant.

That is, the capacitance change difference of M group capacitance detection units is being compared with the first predetermined threshold value successively After relatively, controller 200 can also be according to preset order successively again by the capacitance change difference and second of M group capacitance detection units Predetermined threshold value judged, wherein, if the capacitance change difference of capacitance detection unit is more than the second predetermined threshold value, controller 200 judge that liquid level has reached the second predeterminated position corresponding to effective capacitance detector in the capacitance detection unit, such as second Predeterminated position can be the height residing for effective capacitance detector centre position；If the capacitance change of M group capacitance detection units Difference is respectively less than or equal to the second predetermined threshold value, then illustrates that capacitance variations caused by liquid level change are smaller, controller 200 is now protected It is constant to hold liquid level information of the liquid level information obtained for example by the acquisition compared with the first predetermined threshold value, will obtain the last time The liquid level information taken is as current level information.

Thus, can be only by the capacitance change difference of every group of capacitance detection unit and the in the device of the embodiment of the present invention One predetermined threshold value is compared to judge liquid level, also can be by the capacitance change difference of every group of capacitance detection unit respectively with first Predetermined threshold value and the second predetermined threshold value are compared to judge liquid level, so as to lift the precision of level sensing.

In addition, before whether the capacitance change difference for judging every group of capacitance detection unit is more than the first predetermined threshold value, Controller 200 is additionally operable to：Judge whether the capacitance change difference of every group of capacitance detection unit meets empty level conditions, if often The capacitance change difference of group capacitance detection unit meets empty level conditions, then liquid level information is empty liquid level.

Further, if the capacitance change difference of every group of capacitance detection unit is unsatisfactory for sky level conditions, controller Whether 200 capacitance change differences for judging every group of capacitance detection unit meet level conditions, if every group of capacitance detecting The capacitance change difference of unit meets full level conditions, and controller 200 then judges liquid level information for full liquid level.

Specifically, that a capacitance detector is arranged on above the liquid level upper limit in N number of capacitance detector be present Under, can be according only to default empty level conditions, controller 200 judges whether liquid level information is sky liquid level, and by by M group electric capacity The capacitance change difference of detection unit is compared to judge whether liquid level information is full liquid level with the first predetermined threshold value.This When, in the specific example of the present invention, empty level conditions can be that the capacitance change difference of M group capacitance detection units is small In the 3rd predetermined threshold value, the 3rd predetermined threshold value can be the numerical value close to zero.

In the case where N number of capacitance detector is installed in below the liquid level upper limit, controller 200 can be first according to default sky Level conditions, judge whether liquid level information is sky liquid level, and can judge that liquid level information is further according to default full level conditions No is full liquid level.Now, in the specific example of the present invention, empty level conditions can be the electric capacity of M group capacitance detection units Variable quantity difference is respectively less than the 3rd predetermined threshold value and the capacitance change of N number of capacitance detector is respectively less than the 4th predetermined threshold value, the Three predetermined threshold values and the 4th predetermined threshold value can be the numerical value close to zero；Full level conditions can be the electric capacity of M group capacitance detection units Variable quantity difference is respectively less than the 3rd predetermined threshold value and the capacitance change of N number of capacitance detector is all higher than the 5th predetermined threshold value, the Three predetermined threshold values can be the numerical value close to zero, and the 5th predetermined threshold value is more than the 4th predetermined threshold value.

The liquid-level detecting method of the embodiment of the present invention is described with specific embodiment below.

As it can be seen in figures 5 and 6, n-th capacitance detector is arranged on the top of the liquid level upper limit in N number of capacitance detector 100, more Specifically, n-th capacitance detector can be higher than edge on container.In N number of capacitance detector 100 the 1st to the N-1 capacitance detecting Device is arranged on the lower section of the liquid level upper limit and the 1st sequentially sets up successively to the N-1 capacitance detector from liquid level lower limit, its In, N number of capacitance detector 100 is configured to N-1 group capacitance detection units, and i-th of capacitance detector and the i-th+2 capacitance detectings Device is configured to i-th group of capacitance detection unit, and the N-1 capacitance detector is configured to N-1 group electric capacity with n-th capacitance detector Detection unit, i=1 to N-2.

Specifically, if the capacitance change difference of N-1 group capacitance detection units is respectively less than the 3rd predetermined threshold value and N number of electricity The capacitance change for holding detector is respectively less than the 4th predetermined threshold value, and the 3rd predetermined threshold value and the 4th predetermined threshold value are close to zero, control Device 200 processed then judges liquid level information for empty liquid level；If the 1st group of capacitance change difference to N-3 group capacitance detection units is equal The is all higher than less than the 3rd predetermined threshold value close to zero and N-2 groups to the capacitance change difference of N-1 group capacitance detection units One predetermined threshold value, controller 200 then judge liquid level information for full liquid level；If the capacitance change of jth group capacitance detection unit Difference is more than the first predetermined threshold value and the capacitance change difference of the group capacitance detection unit of jth+1 connects less than the 3rd predetermined threshold value Nearly zero, it is first pre- corresponding to j-th of capacitance detector during controller 200 then judges liquid level information for jth group capacitance detection unit If position, j=1,2 ..., N-3.

In addition, if the capacitance change difference that jth group capacitance detection unit be present be more than the first predetermined threshold value and jth+ The capacitance change difference of 1 group of capacitance detection unit is more than the second predetermined threshold value and is less than the first predetermined threshold value, and controller 200 is then Second predeterminated position corresponding to+1 capacitance detector of jth in judging liquid level information for the group capacitance detection unit of jth+1, j=1, 2、…、N-3。

It should be appreciated that not having liquid during empty liquid level in container completely, N number of capacitance detector is not all entirely flooded by liquid, The capacitance change difference of N-1 group capacitance detection units is close to zero, therefore, when the electric capacity for judging N-1 group capacitance detection units When variable quantity difference is respectively less than three predetermined threshold values, controller 200 judges to be now empty liquid level, and export liquid level information.

Liquid is loaded with container during full liquid level, now the 1st to the N-1 capacitance detector is entirely flooded by liquid, n-th Capacitance detector is not entirely flooded by liquid, therefore is worked as and judged that the 1st group of capacitance change difference to N-3 group capacitance detection units is small The first predetermined threshold value is all higher than in the 3rd predetermined threshold value and N-2 groups to the capacitance change difference of N-1 group capacitance detection units When, controller 200 is judged now for completely liquid level, and export liquid level information.

Partially full of liquid in container during the liquid level of part, the now part in the 1st to the N-1 capacitance detector Capacitance detector is entirely flooded by liquid, and another part capacitance detector is not entirely flooded by liquid, and n-th capacitance detector is not flooded by liquid Not yet.The continuity of capacitance detector is flooded in view of liquid, therefore when the capacitance change that jth group capacitance detection unit be present is poor When value is less than three predetermined threshold values more than the capacitance change difference of the first predetermined threshold value and the group capacitance detection unit of jth+1, control Device 200 processed can determine that now liquid level is the location of j-th capacitance detector upper edge i.e. the first predeterminated position, and exporting Liquid level information；And the capacitance change difference in jth group capacitance detection unit is more than the first predetermined threshold value and the group electric capacity of jth+1 When the capacitance change difference of detection unit is more than the second predetermined threshold value and is less than the first predetermined threshold value, controller 200 can determine that Now liquid level is the location of+1 capacitance detector centre position of jth i.e. the second predeterminated position, exports liquid level information.

In the specific example of the present invention, N number of capacitance detector 100 can be brought into close contact with container 600, such as be passed through 3M glues, it should be appreciated that the set-up mode of N number of capacitance detector 100 and container 600 is not limited to laminating type.Also, As shown in Figure 5 and Figure 6, N number of capacitance detector 100 can be arranged in order according to ascent direction of the liquid in container 600, such as N Individual capacitance detector 100 can be arranged in order in the vertical direction of the bottom of container, by the capacitance detection unit of liquid level covering Quantity will change with the change of liquid level.

In one embodiment of the invention, as shown in figure 5, N number of capacitance detector 100 and controller 200 are arranged on together On one PCB printed circuit board (PCB) 300.Also, PCB printed circuit board (PCB)s 300 can connect power panel by winding displacement 400.

The course of work of the liquid level detection device of the embodiment of the present invention described by taking N==5, M=4 as an example below, i.e., five Individual capacitance detector is configured to 4 groups of capacitance detection units.

Wherein, as it can be seen in figures 5 and 6, first capacitance detector 101 is arranged on the bottom of bottom such as container, second Individual capacitance detector 102 is arranged on first top of capacitance detector 101, and the 3rd capacitance detector 103 is arranged on second The top of capacitance detector 102, the 4th capacitance detector 104 are arranged on the 3rd top of capacitance detector 103, the 5th electric capacity Detector 105 is arranged on the 4th top of capacitance detector 104, and the 5th capacitance detector 105 is arranged on the liquid level upper limit Top, more specifically, the 5th capacitance detector 105 can be higher than edge on container 600, the 4th capacitance detector 104 is arranged on The lower section of the liquid level upper limit.

Also, first capacitance detector 101 and the 3rd capacitance detector 103 can be used as first group of capacitance detecting list Member, second capacitance detector 102 and the 4th capacitance detector 104 can be used as second group of capacitance detection unit, the 3rd electricity The 3rd group of capacitance detection unit, the 4th capacitance detector 104 can be used as by holding detector 103 and the 5th capacitance detector 105 The 4th group of capacitance detection unit can be used as with the 5th capacitance detector 105.It is underlying in every group of capacitance detection unit Capacitance detector is effective capacitance detector, and capacitance detector above is reference capacitance detector, such as at first group In capacitance detection unit, first capacitance detector 101 is effective capacitance detector, and the 3rd capacitance detector 103 is reference Capacitance detector.

In one embodiment of the invention, the course of work of the liquid level detection device of the embodiment of the present invention is as follows：

After power-up initializing, controller 200 reads the capacitance of each capacitance detector under no liquid state using as every The predetermined capacitance of individual capacitance detector, i.e., first predetermined capacitance to the 5th capacitance detector be respectively C10, C20, C30, C40 and C50.And after start-up capacitance detection, controller 200 obtain the real-time capacitance of each capacitance detector using as The capacitance present value of each capacitance detector, i.e., the first capacitance present value to the 5th capacitance detector be respectively C11, C21、C31、C41、C51。

Then controller 200 calculates the capacitance change of each capacitance detector, i.e., first to the 5th capacitance detecting The capacitance change difference of device is respectively：D1=| C11-C10 |, D2=| C21-C20 |, D3=| C31-C30 |, D4=| C41- C40 |, D5=| C51-C50 |.And judge | D1-D3 |, | D2-D4 |, | D3-D5 | and | D4-D5 | whether it is respectively less than the 3rd default threshold Value, if it is, being judged as sky liquid level；If not, judge | D1-D3 | and | D2-D4 | whether connect less than the 3rd predetermined threshold value Nearly zero and | D3-D5 | and | D4-D5 | whether more than the first predetermined threshold value, if it is, being judged as full liquid level, that is, reach the 4th Height residing for capacitance detector upper edge.

If it is not, then successively by the capacitance change difference of every group of capacitance detection unit compared with the first predetermined threshold value Or the capacitance change difference of every group of capacitance detection unit is compared with the first predetermined threshold value and the second predetermined threshold value successively Compared with.I.e. successively judge | D1-D3 | whether more than Vref1, | D2-D4 | whether more than Vref1, | D3-D5 | whether more than Vref1 with And | D4-D5 | whether more than Vref1.If it is, i.e. | D1-D3 | more than Vref1 or | D2-D4 | more than Vref1 or | D3-D5 | it is big In Vref1 or | D4-D5 | more than Vref1, controller 200 then exports liquid level information, and continues level sensing.

Also, can judge successively | D1-D3 | whether more than Vref2, | D2-D4 | whether more than Vref2, | D3-D5 | whether More than Vref2 and | D4-D5 | whether more than Vref2.If it is, i.e. | D1-D3 | more than Vref2 or | D2-D4 | more than Vref2 Or | D3-D5 | more than Vref2 or | D4-D5 | more than Vref2, controller 200 then exports liquid level information, and continues liquid level inspection Survey.

For example, when liquid level is between first capacitance detector 101 and the 3rd capacitance detector 103, first The capacitance change difference of group capacitance detection unit is more than Vref1, i.e., | D1-D3 | more than Vref1, controller 200 can now be sentenced Determine liquid level and reach height residing for first capacitance detector upper edge；Afterwards, if detecting second group of capacitance detection unit Capacitance change difference be more than Vref1, i.e., | D2-D4 | more than Vref1, liquid level is then adjusted to second electricity by controller 200 Hold the height residing for detector upper edge；If detect that the capacitance change difference of the 3rd group of capacitance detection unit is more than Vref1, i.e., | D3-D5 | more than Vref1, liquid level is then adjusted to residing for the 3rd capacitance detector upper edge by controller 200 Highly；If detecting that the capacitance change difference of the 4th group of capacitance detection unit is more than Vref1, i.e., | D4-D5 | it is more than Liquid level is then adjusted to the height residing for the 4th capacitance detector upper edge by Vref1, controller 200.

Further, carried out by the capacitance change difference of every group of capacitance detection unit and the first predetermined threshold value Vref1 After comparing, controller 200 is again carried out the capacitance change difference of every group of capacitance detection unit and the second predetermined threshold value Vref2 Compare.If detecting that the capacitance change difference of first group of capacitance detection unit is more than Vref2, i.e., | D1-D3 | it is more than Vref2, controller 200 now can determine that liquid level reaches the height residing for the centre position of first capacitance detector；If inspection The capacitance change difference for measuring second group of capacitance detection unit is more than Vref2, i.e., | D2-D4 | more than Vref2, controller 200 Liquid level is then adjusted to the height residing for the centre position of second capacitance detector；If detect the 3rd group of capacitance detecting list The capacitance change difference of member is more than Vref2, i.e., | D3-D5 | more than Vref2, liquid level is then adjusted to the 3rd by controller 200 Height residing for the centre position of capacitance detector；If detect that the capacitance change difference of the 4th group of capacitance detection unit is big In Vref2, i.e., | D4-D5 | more than Vref2, liquid level is then adjusted to the centre position of the 4th capacitance detector by controller 200 Residing height.

In another embodiment of the present invention, the course of work of the liquid level detection device of the embodiment of the present invention is as follows：

After power-up initializing, controller 200 reads the capacitance of each capacitance detector under no liquid state using as every The predetermined capacitance of individual capacitance detector, i.e., first predetermined capacitance to the 5th capacitance detector be respectively C10, C20, C30, C40 and C50.And detected in start-up capacitance, controller 200 obtains the real-time capacitance of each capacitance detector using as every The capacitance present value of individual capacitance detector, i.e., the first capacitance present value to the 5th capacitance detector be respectively C11, C21, C31、C41、C51。

Then controller 200 calculates the capacitance change of each capacitance detector, i.e., first to the 5th capacitance detecting The capacitance change difference of device is respectively：D1=| C11-C10 |, D2=| C21-C20 |, D3=| C31-C30 |, D4=| C41- C40 |, D5=| C51-C50 |.

Then judge | D1-D3 |, | D2-D4 |, | D3-D5 | and | D4-D5 | it is i.e. close whether to be respectively less than the 3rd predetermined threshold value Zero.If | D1-D3 |, | D2-D4 |, | D3-D5 | and | D4-D5 | the 3rd predetermined threshold value Vref3 is respectively less than, controller 200 is then sentenced Break as empty liquid level and export liquid level information.

It should be appreciated that there is no liquid during empty liquid level in container completely, first to the 5th capacitance detector 101 to 105 are not all entirely flooded by liquid, and first group of capacitance change difference to the 4th group of capacitance detection unit works as bar close to zero Part | D1-D3 |<Vref3；|D2-D4|<Vref3；|D3-D5|<Vref3；|D4-D5|<Vref3 meets simultaneously when, controller 200 Judgement is now empty liquid level, exports liquid level information.

If it is determined that | D1-D3 |, | D2-D4 |, | D3-D5 | and | D4-D5 | the 3rd predetermined threshold value Vref3 is not respectively less than, Controller 200 then judges | D1-D3 | and | D2-D4 | whether less than the 3rd predetermined threshold value Vref3 and | D3-D5 | and | D4-D5 | be It is no to be more than the first predetermined threshold value.If it is, controller 200 is then judged as full liquid level, that is, reach on the 4th capacitance detector 104 Height residing for edge, and export liquid level information.

It should be appreciated that be loaded with liquid in container during full liquid level, now first to the 4th capacitance detector quilt Liquid is flooded, and the 5th capacitance detector is not entirely flooded by liquid, therefore works as condition | D1-D3 | |<Vref3；|D2-D4||< Vref3；|D3-D5|>Vref1；|D4-D5|>Vref1 meets simultaneously when, controller 200 judges now to export liquid for full liquid level Position information.

If be unsatisfactory for | D1-D3 | and | D2-D4 | less than the 3rd predetermined threshold value Vref3 and | D3-D5 | and | D4-D5 | be more than First predetermined threshold value, then judge | D1-D3 | whether more than the first predetermined threshold value Vref1 and | D2-D4 |, | D3-D5 | and | D4-D5 | Whether the 3rd predetermined threshold value Vref3 is less than.If it is, controller 200 then judges liquid level for first top of capacitance detector 101 Along residing height, and export liquid level information.

If be unsatisfactory for | D1-D3 | more than the first predetermined threshold value Vref1 and | D2-D4 |, | D3-D5 | and | D4-D5 | be less than 3rd predetermined threshold value Vref3, controller 200 then judge | D1-D3 | it is whether more than the second predetermined threshold value Vref2 and pre- less than first If threshold value Vref1 and | D2-D4 |, | D3-D5 | and | D4-D5 | whether less than the 3rd predetermined threshold value Vref3.If it is, controller 200 judge liquid level for the height residing for first centre position of capacitance detector 101, and export liquid level information

If be unsatisfactory for | D1-D3 | more than the second predetermined threshold value Vref2 and less than the first predetermined threshold value Vref1 and | D2- D4 |, | D3-D5 | and | D4-D5 | whether then judge less than the 3rd predetermined threshold value Vref3, controller 200 | D1-D3 | and | D2-D4 | Whether be more than the first predetermined threshold value and | D3-D5 | and | D4-D5 | whether less than the 3rd predetermined threshold value Vref3.If it is, controller 200 judge liquid level for the height residing for second upper edge of capacitance detector 102, and export liquid level information.

If be unsatisfactory for | D1-D3 | and | D2-D4 be more than the first predetermined threshold value and | D3-D5 | and | D4-D5 | it is pre- less than the 3rd If threshold value Vref3, controller 200 then judges | D1-D3 | whether more than the first predetermined threshold value Vref1, | D2-D4 | whether more than Two predetermined threshold value Vref2 and less than the first predetermined threshold value Vref1 and | D3-D5 | and | D4-D5 | whether less than the 3rd predetermined threshold value Vref3, if it is, judging liquid level for the height residing for second centre position of capacitance detector 102, and export liquid level letter Breath.

If be unsatisfactory for | D1-D3 | whether more than the first predetermined threshold value Vref1, | D2-D4 | whether more than the second default threshold Value Vref2 and less than the first predetermined threshold value Vref1 and | D3-D5 | and | D4-D5 | whether less than the 3rd predetermined threshold value Vref3, control Device 200 processed then judges D1-D3 |, | D2-D4 | and | D3-D5 | whether more than the first predetermined threshold value Vref1 and | D4-D5 | it is whether small In the 3rd predetermined threshold value Vref3, if it is, liquid level is judged for the height residing for the 3rd upper edge of capacitance detector 103, and Export liquid level information.

If be unsatisfactory for D1-D3 |, | D2-D4 | and | D3-D5 | more than the first predetermined threshold value Vref1 and | D4-D5 | less than the Three predetermined threshold value Vref3, controller 200 then judge | D1-D3 | and | D3-D5 | whether more than the second predetermined threshold value Vref2 and small In the first predetermined threshold value Vref1, | D2-D4 | whether more than the first predetermined threshold value Vref1 and | D4-D5 | it is whether pre- less than the 3rd If threshold value Vref3, controller 200 then judges liquid level for the height residing for the 3rd centre position of capacitance detector 103.

If it is unsatisfactory for | D1-D3 | and | D3-D5 | more than the second predetermined threshold value Vref2 and it is less than the first predetermined threshold value Vref1, | D2-D4 | more than the first predetermined threshold value Vref1 and | D4-D5 | less than the 3rd predetermined threshold value Vref3, controller 200 is then Judge | D1-D3 | whether less than the 3rd predetermined threshold value Vref3 and | D2-D4 | and | D4-D5 | whether more than the second predetermined threshold value Vref2 and less than the first predetermined threshold value Vref1 and | D3-D5 | whether more than the first predetermined threshold value Vref1, if it is, judging Liquid level is the height residing for the 4th centre position of capacitance detector 104.

It should be appreciated that partially full of liquid, now first to the 4th electric capacity inspection in container during the liquid level of part The partition capacitance detector surveyed in device 101 to 104 is entirely flooded by liquid, and the 5th capacitance detector 105 is not entirely flooded by liquid.Assuming that Liquid level has flooded first capacitance detector 101 and second capacitance detector 102, then condition | D1-D3 |>Vref1；|D2- D4|>Vref1；|D3-D5|<Vref3；|D4-D5|<Vref3 meets simultaneously, and controller 200 judges to be now part liquid level, liquid Body reaches the height residing for second capacitance detector 102, exports liquid level information.

Wherein, it is contemplated that liquid floods the continuity of capacitance detector, and controller 200 is judging | D3-D5 |<Vref3 it Afterwards, without judging | D4-D5 |<Vref3 can correctly draw liquid height, therefore aforementioned four Rule of judgment is in the feelings of part liquid level Under condition liquid level can be correctly identified without all judging.

In addition, it should be noted that, in above-mentioned embodiment, it can also remove and judge whether liquid level is in capacitance detector Between position judgment step, i.e., the height residing for liquid level is judged according only to the first predetermined threshold value Vref1 and the 3rd predetermined threshold value Vref3 Degree.

To sum up, the liquid level detection device proposed according to embodiments of the present invention, N number of capacitance detector is configured to M group electric capacity Detection unit, every group of capacitance detection unit include two capacitance detectors, and controller obtains each electric capacity in N number of capacitance detector The capacitance present value of detector, and become according to the electric capacity of each capacitance detector of the capacitance present value of each capacitance detector acquisition Change amount, and the capacitance change difference according to the capacitance change of each capacitance detector every group of capacitance detection unit of acquisition, And liquid level information is generated according to the capacitance change difference of every group of capacitance detection unit, so as to improve capacitance detecting Accuracy, and then improve the accuracy of level sensing, and the change to environment such as temperature drift, power jitter, PCB noises Etc. there is good anti-interference, complex environment is applicable to.

In the description of the invention, it is to be understood that term " " center ", " longitudinal direction ", " transverse direction ", " length ", " width ", " thickness ", " on ", " under ", "front", "rear", "left", "right", " vertical ", " level ", " top ", " bottom " " interior ", " outer ", " up time The orientation or position relationship of the instruction such as pin ", " counterclockwise ", " axial direction ", " radial direction ", " circumference " be based on orientation shown in the drawings or Position relationship, it is for only for ease of and describes the present invention and simplify description, rather than indicates or imply that signified device or element must There must be specific orientation, with specific azimuth configuration and operation, therefore be not considered as limiting the invention.

In addition, term " first ", " second " are only used for describing purpose, and it is not intended that instruction or hint relative importance Or the implicit quantity for indicating indicated technical characteristic.Thus, define " first ", the feature of " second " can be expressed or Implicitly include at least one this feature.In the description of the invention, " multiple " are meant that at least two, such as two, three It is individual etc., unless otherwise specifically defined.

In the present invention, unless otherwise clearly defined and limited, term " installation ", " connected ", " connection ", " fixation " etc. Term should be interpreted broadly, for example, it may be fixedly connected or be detachably connected, or integrally；Can be that machinery connects Connect or electrically connect；Can be joined directly together, can also be indirectly connected by intermediary, can be in two elements The connection in portion or the interaction relationship of two elements, limited unless otherwise clear and definite.For one of ordinary skill in the art For, the concrete meaning of above-mentioned term in the present invention can be understood as the case may be.

In the present invention, unless otherwise clearly defined and limited, fisrt feature can be with "above" or "below" second feature It is that the first and second features directly contact, or the first and second features pass through intermediary mediate contact.Moreover, fisrt feature exists Second feature " on ", " top " and " above " but fisrt feature are directly over second feature or oblique upper, or be merely representative of Fisrt feature level height is higher than second feature.Fisrt feature second feature " under ", " lower section " and " below " can be One feature is immediately below second feature or obliquely downward, or is merely representative of fisrt feature level height and is less than second feature.

In the description of this specification, reference term " one embodiment ", " some embodiments ", " example ", " specifically show The description of example " or " some examples " etc. means specific features, structure, material or the spy for combining the embodiment or example description Point is contained at least one embodiment or example of the present invention.In this manual, to the schematic representation of above-mentioned term not Identical embodiment or example must be directed to.Moreover, specific features, structure, material or the feature of description can be with office Combined in an appropriate manner in one or more embodiments or example.In addition, in the case of not conflicting, the skill of this area Art personnel can be tied the different embodiments or example and the feature of different embodiments or example described in this specification Close and combine.

Although embodiments of the invention have been shown and described above, it is to be understood that above-described embodiment is example Property, it is impossible to limitation of the present invention is interpreted as, one of ordinary skill in the art within the scope of the invention can be to above-mentioned Embodiment is changed, changed, replacing and modification.

Claims

1. a kind of liquid-level detecting method, it is characterised in that comprise the following steps：

The capacitance present value of each capacitance detector in N number of capacitance detector is detected, wherein, N number of capacitance detector construction Into M group capacitance detection units, every group of capacitance detection unit includes two capacitance detectors, and N, M are the integer more than 1；

The capacitance change of each capacitance detector is obtained according to the capacitance present value of each capacitance detector, and according to each electricity The capacitance change for holding detector obtains the capacitance change difference of every group of capacitance detection unit；

Liquid level information is generated according to the capacitance change difference of every group of capacitance detection unit.

2. liquid-level detecting method according to claim 1, it is characterised in that the electricity for obtaining every group of capacitance detection unit Holding variable quantity difference includes：

Computing is carried out to obtain the electricity of each capacitance detector with predetermined capacitance to the capacitance present value of each capacitance detector Hold variable quantity；

The difference between the capacitance change of two capacitance detectors in every group of capacitance detection unit is calculated, to obtain every group of electric capacity The capacitance change difference of detection unit.

3. liquid-level detecting method according to claim 1, it is characterised in that described according to every group of capacitance detection unit Capacitance change difference generation liquid level information, including：Judging the capacitance change difference of every group of capacitance detection unit is It is no to be more than the first predetermined threshold value；

It is more than first predetermined threshold value if there is the capacitance change difference of at least one set of capacitance detection unit, then according to electricity Hold the capacitance detection unit acquisition liquid level information that variable quantity difference is more than first predetermined threshold value.

4. liquid-level detecting method according to claim 3, it is characterised in that judging every group of capacitance detection unit Capacitance change difference is respectively less than or is more than described first equal to first predetermined threshold value or according to capacitance change difference After the capacitance detection unit of predetermined threshold value obtains the liquid level information, in addition to：

Judge whether the capacitance change difference of every group of capacitance detection unit is more than the second predetermined threshold value, wherein, described Two predetermined threshold values are less than first predetermined threshold value；

It is more than second predetermined threshold value if there is the capacitance change difference of at least one set of capacitance detection unit, then according to electricity Hold the capacitance detection unit adjustment liquid level information that variable quantity difference is more than second predetermined threshold value；

If the capacitance change difference of every group of capacitance detection unit is respectively less than or equal to second predetermined threshold value, protect The liquid level information for holding acquisition is constant.

5. the liquid-level detecting method according to claim 3 or 4, it is characterised in that judging every group of capacitance detecting list Whether the capacitance change difference of member is more than before the first predetermined threshold value, in addition to：

Judge whether the capacitance change difference of every group of capacitance detection unit meets empty level conditions,

If the capacitance change difference of every group of capacitance detection unit meets the empty level conditions, the liquid level information For empty liquid level.

6. liquid-level detecting method according to claim 5, it is characterised in that

If the capacitance change difference of every group of capacitance detection unit is unsatisfactory for the empty level conditions, judge described every Whether the capacitance change difference of group capacitance detection unit meets level conditions,

If the capacitance change difference of every group of capacitance detection unit meets the full level conditions, the liquid level information For full liquid level.

7. liquid-level detecting method according to claim 1, it is characterised in that have one in N number of capacitance detector Capacitance detector is arranged on above the liquid level upper limit.

A kind of 8. liquid level detection device, it is characterised in that including：

N number of capacitance detector, N number of capacitance detector are configured to M group capacitance detection units, and every group of capacitance detection unit includes Two capacitance detectors, N, M are the integer more than 1；

Controller, the controller are respectively connected with N number of capacitance detector, and the controller is used to obtain N number of electric capacity inspection The capacitance present value of each capacitance detector in device is surveyed, and each electric capacity is obtained according to the capacitance present value of each capacitance detector The capacitance change of detector, and the electricity according to the capacitance change of each capacitance detector every group of capacitance detection unit of acquisition Hold variable quantity difference, and liquid level information is generated according to the capacitance change difference of every group of capacitance detection unit.

9. liquid level detection device according to claim 8, it is characterised in that the controller is further used for, to each The capacitance present value of capacitance detector carries out computing to obtain the capacitance change of each capacitance detector with predetermined capacitance, and The difference between the capacitance change of two capacitance detectors in every group of capacitance detection unit is calculated, to obtain every group of capacitance detecting The capacitance change difference of unit.

10. liquid level detection device according to claim 8, it is characterised in that the controller is used for,

Judge whether the capacitance change difference of every group of capacitance detection unit is more than the first predetermined threshold value, if there is at least The capacitance change difference of one group of capacitance detection unit is more than first predetermined threshold value, then is more than according to capacitance change difference The capacitance detection unit of first predetermined threshold value obtains the liquid level information.

11. liquid level detection device according to claim 10, it is characterised in that judging every group of capacitance detection unit Capacitance change difference be respectively less than or be more than described the equal to first predetermined threshold value or according to capacitance change difference After the capacitance detection unit of one predetermined threshold value obtains the liquid level information, the controller is additionally operable to,

It is more than second predetermined threshold value, the control if there is the capacitance change difference of at least one set of capacitance detection unit The capacitance detection unit that device is then more than second predetermined threshold value according to capacitance change difference adjusts the liquid level information；

If the capacitance change difference of every group of capacitance detection unit is respectively less than or equal to second predetermined threshold value, described Controller then keeps the liquid level information of acquisition constant.

12. the liquid level detection device according to claim 10 or 11, it is characterised in that judging every group of capacitance detecting Whether the capacitance change difference of unit is more than before the first predetermined threshold value, and the controller is additionally operable to：

13. liquid level detection device according to claim 12, it is characterised in that

If the capacitance change difference of every group of capacitance detection unit is unsatisfactory for the empty level conditions, the controller is then Judge whether the capacitance change difference of every group of capacitance detection unit meets level conditions,

If the capacitance change difference of every group of capacitance detection unit meets the full level conditions, the control then judges The liquid level information is full liquid level.

14. liquid level detection device according to claim 12, it is characterised in that wherein, deposited in N number of capacitance detector It is arranged in a capacitance detector above the liquid level upper limit.