WO2012048471A1 - 数字式场感应水位智能传感系统及其实现方法 - Google Patents

数字式场感应水位智能传感系统及其实现方法 Download PDF

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WO2012048471A1
WO2012048471A1 PCT/CN2010/077789 CN2010077789W WO2012048471A1 WO 2012048471 A1 WO2012048471 A1 WO 2012048471A1 CN 2010077789 W CN2010077789 W CN 2010077789W WO 2012048471 A1 WO2012048471 A1 WO 2012048471A1
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water level
digital
module
voltage signal
analog
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PCT/CN2010/077789
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English (en)
French (fr)
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刘达樊
史为新
周志辉
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惠州市卓耐普智能技术有限公司
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Priority to PCT/CN2010/077789 priority Critical patent/WO2012048471A1/zh
Priority to US13/521,396 priority patent/US20120291541A1/en
Priority to CN2010800564362A priority patent/CN102713534B/zh
Publication of WO2012048471A1 publication Critical patent/WO2012048471A1/zh

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
    • G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
    • G01F23/26—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
    • G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
    • G01F23/26—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields
    • G01F23/261—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields for discrete levels

Definitions

  • the invention relates to the technical field of sensors, in particular to a digital field sensing water level intelligent sensing system and an implementation method thereof, which can be applied to various liquid level measurement, and is particularly suitable for water level measurement of a solar water heater.
  • a water level sensor is an instrument that senses the water level and converts the sensed water level into a changing electrical signal.
  • the water level sensor has always played a decisive role.
  • the intelligent and humanized water heater is inseparable from the water level sensor.
  • the water level measuring instrument is inseparable from the water level sensor.
  • the water level sensor works stably. The guarantee of intelligent control of water heaters.
  • the principle of the existing water level sensor is to calibrate different water level segments on the sensor, and place a conductive copper foil on each water level segment (some sensors are injection molded with a silicone gel, conductive copper foil portions are made of conductive silica gel), and each copper foil Each is connected to a (sometimes several) resistors that have a common end that is connected together and connected to the lowest point of the sensor probe.
  • a resistors that have a common end that is connected together and connected to the lowest point of the sensor probe.
  • the soaked copper foil is electrically connected to the copper foil at the lowest point, and the resistance between the two copper foils that are turned on is equivalent. Shorted, the resistance becomes smaller, which reduces the resistance of the entire sensor.
  • the host can know the water level by measuring the resistance of the entire sensor.
  • the shortcoming of the existing water level sensor is that the existing sensor uses the conductivity of water to judge the water level. Different water quality and different water tank sizes (which affect the amount of water) have different conductivity, which will affect the measurement accuracy of the sensor. , causing the existing sensor to measure the water level is not accurate. Moreover, since the existing sensor is in direct contact with water, it is very easy to form a layer of scale on the sensor. Since the scale is not conductive, the contact between the water and the sensor copper foil is affected, which has a serious impact on the existing water level measurement method. The water level measurement is inaccurate, which makes the existing water level sensing solution not conducive to large-scale popularization and application.
  • the object of the present invention is to overcome the deficiencies in the prior art and provide a digital field sensing water level intelligent sensing system, which utilizes digital intelligent field sensing technology to solve the application of the water level sensor in a harsh environment. In the formation of scale and high temperature and high humidity environment, it is easy to make the sensing system fail.
  • the field sensing technology is used to make the sensing system not need to detect the water level through electrical connection or mechanical connection, and avoid the sensor failure or water level caused by scale formation. Measuring inaccuracies.
  • Another object of the present invention is to provide an implementation method of the above digital field sensing water level intelligent sensing system.
  • a digital field sensing water level intelligent sensing system including a water level sensor probe and a main control module, the water level sensor probe is provided with a plurality of water level probes, and the main control module
  • the settings are:
  • Capacitor voltage acquisition and conversion analog module which is used for real-time acquiring the capacitance information of the water level probe point to calculate the analog voltage signal of the water level probe point;
  • An analog-to-digital conversion (A/D) module for converting an analog voltage signal transmitted from a capacitor voltage acquisition conversion analog module into a digital voltage signal;
  • Digital filtering module for real-time filtering of analog-to-digital conversion (A/D)
  • A/D analog-to-digital conversion
  • the water level analysis module is configured to compare the received digital voltage signal with a water level voltage threshold stored by the system, and when the digital voltage signal is less than the water level voltage threshold, determine the water level probe corresponding to the digital voltage signal No water, otherwise it is determined that the water level probe corresponding to the digital voltage signal has water, and then the water level detection point with the highest water is detected as the water level point;
  • a water level voltage threshold storage module for storing a stored water level voltage threshold
  • Capacitor voltage acquisition conversion analog module analog to digital conversion (A/D a module, a digital filter module and a water level analysis module, wherein the water level probe is connected to the capacitor voltage acquisition conversion analog module, and the capacitor voltage acquisition conversion analog module is followed by analog to digital conversion (A/D)
  • A/D analog to digital conversion
  • the module, the digital filtering module and the water level analyzing module are connected, and the water level voltage threshold storage module is connected with the water level analyzing module.
  • the main control module is further provided with an automatic update module for receiving the digital voltage signal filtered by the digital filtering module in real time, and analyzing each collected water level probe point in the digital voltage signal set in the water level analysis time period. , with or without a small time period of the digital voltage signal whose amplitude changes significantly, if any, calculate the average value of the digital voltage signal in the corresponding segment of the above small time period or directly take any digital voltage signal in the segment to replace the water level voltage
  • the water level voltage threshold stored by the threshold storage module; the automatic update module is interposed between the water level voltage threshold storage module and the digital filter module.
  • the water level probes are preferably four.
  • the water level sensor probe can be sealed or unsealed.
  • the capacitor voltage acquisition and conversion simulation module obtains the capacitance information of the water level probe point in real time to calculate the analog voltage signal of the water level probe point;
  • A/D analog to digital conversion
  • digital filtering module real-time filtering analog-to-digital conversion (A/D The interference signal in the digital voltage signal sent by the module, and then transmitting the filtered digital voltage signal to the water level analysis module;
  • the water level analysis module compares the received digital voltage signal with a water level voltage threshold stored by the system. When the digital voltage signal is less than the water level voltage threshold, it is determined that the water level probe corresponding to the digital voltage signal is waterless. Otherwise, it is determined that the water level probe corresponding to the digital voltage signal has water, and then the water level probe located at the highest position with water is detected as the water point.
  • the small time period is an empirical value, and is set according to actual conditions such as a water level probe and a container for performing water level measurement.
  • the step (3) The digital filtering module transmits the filtered digital voltage signal to the water level analysis module, and also transmits the filtered digital voltage signal to the automatic update module in real time, and the automatic update module analyzes each water level probe collected.
  • the digital voltage signal set in the water level analysis period there is a small time period of the digital voltage signal whose amplitude changes significantly, and if any, the average value of the digital voltage signal in the corresponding segment of the above small time period is calculated or directly taken Any one of the digital voltage signals inside replaces the water level voltage threshold stored by the water level voltage threshold storage module as a new water level voltage threshold.
  • the present invention has the following advantages and beneficial effects:
  • the digital intelligent field sensing technology solves the problem that the water level sensor is difficult to make the sensing system fail in the formation of scale in the harsh environment and the high temperature and high humidity environment.
  • the field sensing technology is used to make the sensing system not need to be electrically connected. Or mechanical connection to detect the water level, so the presence of scale in the probe does not affect the normal operation and accuracy of the sensor, thus avoiding the problem of sensor failure or inaccurate water level measurement caused by scale formation.
  • FIG. 1 is a schematic structural view of a digital field sensing water level intelligent sensing system of the present invention
  • Figure 2 is a schematic diagram of one of the forms of electric field in the embodiment
  • Figure 3 is a schematic diagram of another form of electric field in the embodiment.
  • Figure 4 is a schematic diagram of another form of electric field in the embodiment.
  • Figure 5 is a two-dimensional functional relationship diagram between the dielectric constant and the water level of the embodiment.
  • the digital field sensing water level intelligent sensing system includes a water level sensor probe and a main control module, and the water level sensor probe is provided with a plurality of water level probe points (probing points 1, 2, 3, 4) ), the main control module is set;
  • Capacitor voltage acquisition and conversion analog module which is used for real-time acquiring the capacitance information of the water level probe point to calculate the analog voltage signal of the water level probe point;
  • An analog-to-digital conversion (A/D) module for converting an analog voltage signal transmitted from a capacitor voltage acquisition conversion analog module into a digital voltage signal;
  • Digital filtering module for real-time filtering of analog-to-digital conversion (A/D)
  • A/D analog-to-digital conversion
  • the water level analysis module is configured to compare the received digital voltage signal with a water level voltage threshold stored by the system, and when the digital voltage signal is less than the water level voltage threshold, determine the water level probe corresponding to the digital voltage signal No water, otherwise it is determined that the water level probe corresponding to the digital voltage signal has water, and then the water level detection point with the highest water is detected as the water level point;
  • a water level voltage threshold storage module for storing a stored water level voltage threshold
  • the module, the digital filtering module and the water level analyzing module are connected, and the water level voltage threshold storage module is connected with the water level analyzing module.
  • the main control module is further provided with an automatic update module for receiving the digital voltage signal filtered by the digital filtering module in real time, and analyzing the collected digital water signal probes in the digital voltage signal set in the water level analysis time period, with or without A small time period of the digital voltage signal whose amplitude changes significantly, if any, calculates the average value of the digital voltage signal in the corresponding segment of the above small time period or directly takes any digital voltage signal in the segment, and replaces the water level voltage threshold storage
  • the water level voltage threshold stored by the module; the automatic update module is interposed between the water level voltage threshold storage module and the digital filter module.
  • the capacitor voltage acquisition and conversion simulation module obtains the capacitance information of the water level probe point in real time to calculate the analog voltage signal of the water level probe point;
  • A/D analog to digital conversion
  • the automatic update module analyzes the digital voltage signal set of each water level probe point in the water level analysis time period, whether there is a small time period of the digital voltage signal whose amplitude changes significantly, and if any, the calculation is small
  • the small time period is an empirical value, and is set according to actual conditions such as a water level probe and a container for performing water level measurement.
  • the electric field is a vector field whose direction is from a planar conductor that collects a positive charge to a planar conductor that collects a negative charge.
  • the electric field strength at this point is E. .
  • the electric field strength of space is referred to as field strength.
  • the electric field strength of a fixed point in space is related to the electric quantity Q and the dielectric constant ⁇ of the medium.
  • the dielectric constant of the medium is ⁇ 0 , and the field strength at that point is E0, as shown in Figure 3.
  • the dielectric constant of the medium is ⁇ ', and the field strength at this point is E', as shown in Figure 4, by detecting the field strength E The change can detect the presence of a conductor between the two planar conductors.
  • the problem of detecting the presence or absence of water is converted into the problem of detecting the change of the dielectric constant.
  • the change in the amount of electricity required between the lower two planar conductors, ie the capacitance By measuring the change in capacitance, it is possible to measure the change in dielectric constant and the change in field strength to determine the presence of water.
  • the present invention utilizes different position distributions to detect the presence or absence of water at different locations, thereby knowing the level of the water level.
  • the picture below is one of the situations;
  • the digital conversion technology of analog-to-digital conversion is to convert the analog quantity of the electric field intensity into a digital quantity through a circuit, and realize detection and intelligent correction through software, so that the sensing system adapts to changes in the environment, thereby achieving stable detection.
  • RC charge and discharge circuits there are many ways to measure the capacitor voltage, there are RC charge and discharge circuits, RC Oscillation circuit, voltage multiplying circuit (can be used as capacitor voltage acquisition analog conversion module), etc., through these circuits to convert the capacitance change into a voltage change, because the voltage is analog, in order to achieve accurate detection and intelligent correction, the voltage analog quantity conversion is required. It is a digital quantity, which is called analog-to-digital conversion. Detecting changes in capacitance in a relatively short period of time can satisfy the water level detection in a short period of time, but in a harsh environment, the sensing environment changes over time, especially the dielectric constant caused by the aging of the material of the sensor system. Changes can lead to false detection of water levels.
  • the invention adopts digital information after analog-to-digital conversion, and intelligently corrects the detected water level through data processing.
  • the specific method is as follows:
  • the change of the horizontal plane relative to the planar conductors of the sensing system is not abrupt, but continuously varies, that is, the average dielectric constant of the space is continuously changed, that is, the change of the capacitance is also continuous. But this change has a turning point under certain conditions, as shown in the figure. 5 As shown, through the data processing, the turning point, that is, the detection point of the presence or absence of the water level, can be obtained.
  • the advantage of detecting the turning point is that the change of the dielectric constant caused by environmental changes does not affect the detection of the existence of the turning, so the method can solve the problems of aging of the sensing system or environmental changes.
  • C Q / U, where Q is the amount of electricity, U is the potential difference;
  • C f 2 ( ⁇ ), where C is the capacitance, ⁇ is the dielectric constant, and f 2 is the relationship between the capacitance and the dielectric constant;
  • Y f 7 (L), where f 7 is a function of the voltage digital quantity as a function of the water level. In the case determined by the sensing system, f 7 is unchanged, and a one-to-one correspondence between the voltage digital quantity Y and the water level L can be obtained.

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  • Electromagnetism (AREA)
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Description

数字式场感应水位智能传感系统及其实现方法
技术领域
本发明涉及传感器技术领域，具体涉及一种数字式场感应水位智能传感系统及其实现方法，可应用于各种液体液位测量，尤其适用于太阳能热水器的水位测量。
背景技术
水位传感器是一种能够感受水位，并且将感受到的水位转变成变化的电信号的仪器。在太阳能及电热水器的发展史上，水位传感器一直起着举足轻重的作用，热水器的智能化、人性化都与水位传感器密不可分，水位测控仪更是离不开水位传感器，水位传感器工作稳定是对整个热水器智能控制的保障。
现有水位传感器多需要通过电气连接或机械连接检测水位，材料的变化和环境的变化是水位传感器的测量精度和工作稳定性的重要影响因素。
现有水位传感器原理是，在传感器上标定不同的水位段，在每一个水位段上放置一个导电铜箔（有些传感器注塑了硅胶封装，导电铜箔部分用的是导电硅胶），每一个铜箔都连接了一个（有时候是几个）电阻，这些电阻有一个公共端连接到一起并连接到传感器探头的最低点的铜箔。利用水的导电性原理，当有水浸泡到传感器标定的不同铜箔后，被浸泡的铜箔就和最低点的铜箔电气导通，被导通的两个铜箔之间的电阻相当于被短路，电阻变小，这样把整个传感器的电阻也变小了。主机通过测量整个传感器的电阻大小，就可以知道水位了。
现有水位传感器的不足是，现有传感器正是利用水的导电性进行水位判断，不同的水质，不同的水箱大小（影响水量多少）的导电能力不一样，都会对传感器的测量准确度有影响，造成现有传感器测量水位不准的问题。而且，由于现有传感器要和水直接接触，非常容易在传感器上形成一层水垢，由于水垢不导电，影响了水和传感器铜箔的接触，这对现有的水位测量方式产生了严重的影响，造成水位测量不准确，致使现有的水位传感方案不利于大规模的推广应用。
发明内容
本发明的目的是克服现有技术中的不足之处，提供一种数字式场感应水位智能传感系统，该传感系统利用数字化智能的场感应技术，解决了水位传感器在恶劣环境中的应用中水垢的形成和高温高湿的环境中容易使传感系统失效的问题，利用场感应技术使传感系统不需要通过电气连接或机械连接检测水位，避免了水垢形成导致的传感器工作失效或水位测量不准确的问题。
本发明目的还在于提供上述数字式场感应水位智能传感系统的实现方法。
本发明的目的是通过以下技术方案来实现的：数字式场感应水位智能传感系统，包括水位传感器探头和主控模块，所述水位传感器探头设置有若干个水位探点，所述主控模块设置有：
电容电压采集转换模拟模块，用于实时获取水位探点的电容信息以计算出水位探点的模拟电压信号；
模数转换（ A/D ）模块，用于将电容电压采集转换模拟模块传来的模拟电压信号转换为数字电压信号；
数字滤波模块，用于实时滤除模数转换（ A/D ）模块传来的数字电压信号中的干扰信号，然后将滤波后的数字电压信号传给水位分析模块；
所述水位分析模块，用于将接收到的数字电压信号与系统存储的水位电压阀值做对比，当该数字电压信号小于水位电压阀值时，则认定该数字电压信号所对应的水位探点无水，否则认定该数字电压信号所对应的水位探点有水，进而取检测到有水的位于最高位的水位探点作为水位点；
水位电压阀值存储模块，用于存储存储的水位电压阀值；
电容电压采集转换模拟模块、模数转换（ A/D ）模块、数字滤波模块和水位分析模块，所述水位探点与电容电压采集转换模拟模块相连接，而后电容电压采集转换模拟模块依次与模数转换（ A/D ）模块、数字滤波模块和水位分析模块相连接，所述水位电压阀值存储模块与水位分析模块相连接。
优选的，所述主控模块还设置有自动更新模块，用于实时接收数字滤波模块滤波后的数字电压信号，分析所采集的每个水位探点在水位分析时间段内的数字电压信号集合中，有无幅度显著变化的数字电压信号的小时间段，如有的话，计算有上述小时间段的对应段内数字电压信号均值或者直接取该段内的任意一个数字电压信号，替换水位电压阀值存储模块所存储的水位电压阀值；所述自动更新模块介接于水位电压阀值存储模块与数字滤波模块之间。
所述水位探点优选为 4 个。
所述水位传感器探头可为密封型或非密封型。
上述数字式场感应水位智能传感系统的实现方法，步骤如下：
（ 1 ）、系统启动后，电容电压采集转换模拟模块实时获取水位探点的电容信息以计算出水位探点的模拟电压信号；
（ 2 ）、模数转换（ A/D ）模块将电容电压采集转换模拟模块传来的模拟电压信号转换为数字电压信号；
（ 3 ）、数字滤波模块实时滤除模数转换（ A/D ）模块传来的数字电压信号中的干扰信号，然后将滤波后的数字电压信号传给水位分析模块；
（ 4 ）、水位分析模块将接收到的数字电压信号与系统存储的水位电压阀值做对比，当该数字电压信号小于水位电压阀值时，则认定该数字电压信号所对应的水位探点无水，否则认定该数字电压信号所对应的水位探点有水，进而取检测到有水的位于最高位的水位探点作为水位点。
所述小时间段为经验值，根据水位探头及其所进行水位测量的容器等实际情况进行设定。
上述方法中，步骤（ 3 ）所述数字滤波模块将滤波后的数字电压信号传给水位分析模块的同时，还将该滤波后的数字电压信号实时传至自动更新模块，自动更新模块分析所采集的每个水位探点在水位分析时间段内的数字电压信号集合中，有无幅度显著变化的数字电压信号的小时间段，如有的话，计算有上述小时间段的对应段内数字电压信号均值或者直接取该段内的任意一个数字电压信号，替换水位电压阀值存储模块所存储的水位电压阀值，作为新的水位电压阀值。
本发明相比现有技术具有以下优点及有益效果：
本传感器采用了 数字化智能的场感应技术，解决了水位传感器在恶劣环境中的应用中水垢的形成和高温高湿的环境中容易使传感系统失效的问题，利用场感应技术使传感系统不需要通过电气连接或机械连接检测水位，所以，及时探头存在水垢也不影响本传感器的正常工作及精度，从而避免了水垢形成导致的传感器工作失效或水位测量不准确的问题。
附图说明
图 1 是本发明 数字式场感应水位智能传感系统 的结构示意图；
图 2 是实施例中其中一种形式电场原理图；
图 3 是实施例中另一种形式电场原理图；
图 4 是实施例中再一种形式电场原理图；
图 5 是实施例中介电常数与水位之间的二维函数关系图。
具体实施方式
下面结合实施例及附图对本发明作进一步详细的描述，但本发明的实施方式不限于此。
如图 1 所示，数字式场感应水位智能传感系统，包括水位传感器探头和主控模块，所述水位传感器探头设置有若干个水位探点（探点 1 、 2 、 3 、 4 ），所述主控模块设置有；
电容电压采集转换模拟模块，用于实时获取水位探点的电容信息以计算出水位探点的模拟电压信号；
模数转换（ A/D ）模块，用于将电容电压采集转换模拟模块传来的模拟电压信号转换为数字电压信号；
数字滤波模块，用于实时滤除模数转换（ A/D ）模块传来的数字电压信号中的干扰信号，然后将滤波后的数字电压信号传给水位分析模块；
所述水位分析模块，用于将接收到的数字电压信号与系统存储的水位电压阀值做对比，当该数字电压信号小于水位电压阀值时，则认定该数字电压信号所对应的水位探点无水，否则认定该数字电压信号所对应的水位探点有水，进而取检测到有水的位于最高位的水位探点作为水位点；
水位电压阀值存储模块，用于存储存储的水位电压阀值；
电容电压采集转换模拟模块、模块转换（ A/D ）模块、数字滤波模块和水位分析模块，所述水位探点与电容电压采集转换模拟模块相连接，而后电容电压采集转换模拟模块依次与模数转换（ A/D ）模块、数字滤波模块和水位分析模块相连接，所述水位电压阀值存储模块与水位分析模块相连接。
所述主控模块还设置有自动更新模块，用于实时接收数字滤波模块滤波后的数字电压信号，分析所采集的每个水位探点在水位分析时间段内的数字电压信号集合中，有无幅度显著变化的数字电压信号的小时间段，如有的话，计算有上述小时间段的对应段内数字电压信号均值或者直接取该段内的任意一个数字电压信号，替换水位电压阀值存储模块所存储的水位电压阀值；所述自动更新模块介接于水位电压阀值存储模块与数字滤波模块之间。
上述数字式场感应水位智能传感系统的实现方法，步骤如下：
（ 1 ）、系统启动后，电容电压采集转换模拟模块实时获取水位探点的电容信息以计算出水位探点的模拟电压信号；
（ 2 ）、模数转换（ A/D ）模块将电容电压采集转换模拟模块传来的模拟电压信号转换为数字电压信号；
（ 3 ）、数字滤波模块实时滤除模数转换（ A/D ）模块传来的数字电压信号中的干扰信号，然后将滤波后的数字电压信号分别传给水位分析模块、自动更新模块，然后由同时进行分别进行步骤（ 4 ）、（ 5 ）操作；
（ 4 ）、用于将接收到的数字电压信号与系统存储的水位电压阀值做对比，当该数字电压信号小于水位电压阀值时，则认定该数字电压信号所对应的水位探点无水，否则认定该数字电压信号所对应的水位探点有水，进而取检测到有水的位于最高位的水位探点作为水位点；
（ 5 ）、自动更新模块分析所采集的每个水位探点在水位分析时间段内的数字电压信号集合中，有无幅度显著变化的数字电压信号的小时间段，如有的话，计算有上述小时间段的对应段内数字电压信号均值或者直接取该段内的任意一个数字电压信号，替换水位电压阀值存储模块所存储的水位电压阀值，作为新的水位电压阀值。
所述小时间段为经验值，根据水位探头及其所进行水位测量的容器等实际情况进行设定。
以下对 本发明 非接触电场感应式水温水位传感器 作进一步详细的原理描述，但本发明的实施方式不限于此。
基本原理：
根据电场概念，在两块平面导体（导电薄膜或导电片）上加载电势差 U ，两导体间会形成电场，电场是一个矢量场，其方向从聚集正电荷的平面导体指向聚集负电荷的平面导体，如图 2 所示，该点电场强度为 E 。空间的电场强度由简称场强，空间中某固定点的电场强度与电量 Q 、介质的介电常数ε等参数有关。
假设环境不变，当无水的时候介质的介电常数为ε 0 ，此时该点的场强为 E0 ，如图 3 所示；当有水的时候介质的介电常数为ε ' ，此时该点的场强为 E' ， 如图 4 所示，通过检测场强 E 的变化，就可以检测出该两块平面导体间是否存在导体。
这样检测水的存在与否的问题就转换为检测介电常数变化的问题，为了解决该问题，可以通过检测在不同电势差 U 下两平面导体间所需不同电量的变化，即电容。通过测量电容的变化，就可以测得介电常数的变化和场强的变化，即可测得水是否存在。
实际应用：
在实际测量水位的应用中，只检测水的存在与否是不能够代表水位的高低。当然，水量的大小是可以引起电容大小的变化的，但水量的变化所获得的绝对电容的变化是很微小，且系统的寄生电容会作为噪声掩盖这种变化。所以本发明利用不同位置分布检测不同位置的水是否存在，从而得知水位的高低。下图是其中一种情况；
2 、模数转换的数字化技术是，通过电路将电场强度的模拟量转换成数字量，并通过软件实现检测和智能矫正，使传感系统适应环境的变化，从而实现稳定检测。
测量电容电压的方法很多，有 RC 充放电路、 RC 振荡电路、电压倍增电路（均可作为电容电压采集模拟转换模块）等，通过这些电路将电容变化转换成电压变化，因为电压为模拟量，为了实现准确检测和智能矫正，需要将电压模拟量转换为数字量，即通常所说的模数转换。在相对短暂的时间内检测电容的变化可以满足短时期内的水位检测，但在恶劣环境里随着时间推移，传感的环境发生变化，特别是传感器系统的材料老化时引起的介电常数的变化，会导致水位的误检测。
本发明采用模数转换后的数字信息，通过数据处理，智能矫正检测的水位。具体方法如下：
当水位发生变化时，水平面相对于传感系统的各个平面导体的变化并不是突变的，而是连续变化的，即空间的平均介电常数是连续变化的，即电容的变化也是连续的。但这种变化在满足一定的条件下有转折点，如图 5 所示，通数据处理，可以得到该转折点，也就是水位存在与否的检测点。检测转折点的好处是，环境变化引起的介电常数发生变化并不影响转折的存在的检测，所以该方法可以解决传感系统老化或环境变化等问题。
以下为本发明场感应水位测量原理的基本公式推导：
1 、根据电场强度理论，电场强度E与介电常数ε存在函数关系f1，E=f1(ε)，
2 、根据电场强度定义，U=E*d， U为电势差，d为两导体的距离；
3 、根据电容定义，C=Q/U，其中Q为电量，U为电势差；
4 、根据以上公式，可得C=Q/( E*d)，联合E=f1(ε)，可得
C= f2( ε)，其中C为电容，ε为介电常数，f2为电容与介电常数的关系；
5 、通过电容-电压转换电路，如RC振荡电路，存在u= f3(C)，其中u为转换后的电压模拟量，f3为电容与电压模拟量的函数关系；
6 、通过模-数转换电路，如ADC集成电路，存在Y= f4(u)，其中Y为转换后的电压数字量，f4为电压模拟量与电压数字量的函数关系；
7 、水位的变化会引起空间的介电常数的平均值发生变化ε= f6(L) ，L为水位高度，f6为水位高度与介电常数的函数关系。
根据4、5、6、7可以得到，Y= f7(L)，其中f7为电压数字量与水位高度的函数关系。在传感系统确定的情况下，f7不变，也就可以得到电压数字量Y与水位L的一一对应关系。
上述实施例为本 发明 较佳的实施方式，但本 发明 的实施方式并不受上述实施例的限制，其他的任何未背离本发明的精神实质与原理下所作的改变、修饰、替代、组合、简化，均应为等效的置换方式，都包含在本 发明 的保护范围之内。

Claims (7)

  1. 数字式场感应水位智能传感系统， 其特征在于， 包括水位传感器探头和主控模块，所述水位传感器探头设置有若干个水位探点，所述主控模块设置有；
    电容电压采集转换模拟模块，用于实时获取水位探点的电容信息以计算出水位探点的模拟电压信号；
    模数转换模块，用于将电容电压采集转换模拟模块传来的模拟电压信号转换为数字电压信号；
    数字滤波模块，用于实时滤除模数转换模块传来的数字电压信号中的干扰信号，然后将滤波后的数字电压信号传给水位分析模块；
    所述水位分析模块，用于将接收到的数字电压信号与系统存储的水位电压阀值做对比，当该数字电压信号小于水位电压阀值时，则认定该数字电压信号所对应的水位探点无水，否则认定该数字电压信号所对应的水位探点有水，进而取检测到有水的位于最高位的水位探点作为水位点；
    水位电压阀值存储模块，用于存储存储的水位电压阀值；
    电容电压采集转换模拟模块、模数转换模块、数字滤波模块和水位分析模块，所述水位探点与电容电压采集转换模拟模块相连接，而后电容电压采集转换模拟模块依次与模数转换模块、数字滤波模块和水位分析模块相连接，所述水位电压阀值存储模块与水位分析模块相连接。
  2. 根据权利要求1所述的数字式场感应水位智能传感系统，其特征在于，所述主控模块还设置有自动更新模块，用于实时接收数字滤波模块滤波后的数字电压信号，分析所采集的每个水位探点在水位分析时间段内的数字电压信号集合中，有无幅度显著变化的数字电压信号的小时间段，如有的话，计算有上述小时间段的对应段内数字电压信号均值或者直接取该段内的任意一个数字电压信号，替换水位电压阀值存储模块所存储的水位电压阀值；所述自动更新模块介接于水位电压阀值存储模块与数字滤波模块之间。
  3. 根据权利要求1所述的数字式场感应水位智能传感系统，其特征在于，所述水位传感器探头为密封型或非密封型。
  4. 根据权利要求1所述的数字式场感应水位智能传感系统，其特征在于，所述水位探点为4个。
  5. 根据权利要求1所述的数字式场感应水位智能传感系统的实现方法，其特征在于，步骤如下：
    （1）、系统启动后，电容电压采集转换模拟模块实时获取水位探点的电容信息以计算出水位探点的模拟电压信号；
    （2）、模数转换模块将电容电压采集转换模拟模块传来的模拟电压信号转换为数字电压信号；
    （3）、数字滤波模块实时滤除模数转换模块传来的数字电压信号中的干扰信号，然后将滤波后的数字电压信号传给水位分析模块；
    （4）、水位分析模块将接收到的数字电压信号与系统存储的水位电压阀值做对比，当该数字电压信号小于水位电压阀值时，则认定该数字电压信号所对应的水位探点无水，否则认定该数字电压信号所对应的水位探点有水，进而取检测到有水的位于最高位的水位探点作为水位点。
  6. 据权利要求5所述的数字式场感应水位智能传感系统的实现方法，其特征在于，
    所述小时间段为经验值，根据水位探头及其所进行水位测量的容器的实际情况进行设定。
  7. 据权利要求5所述的数字式场感应水位智能传感系统的实现方法，其特征在于，
    步骤（3）所述数字滤波模块将滤波后的数字电压信号传给水位分析模块的同时，还将该滤波后的数字电压信号实时传至自动更新模块，自动更新模块分析所采集的每个水位探点在水位分析时间段内的数字电压信号集合中，有无幅度显著变化的数字电压信号的小时间段，如有的话，计算有上述小时间段的对应段内数字电压信号均值或者直接取该段内的任意一个数字电压信号，替换水位电压阀值存储模块所存储的水位电压阀值，作为新的水位电压阀值。
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