Dielectric moisture meter

FIELD: measuring engineering.

SUBSTANCE: dielectric moisture meter comprises two frequency dividers, recording pulse generators, and AND/OR elements. The output of the reference generator is connected with the first input of the AND/OR element, input of the recording pulse generator, and input of the first frequency divider. The first output of the first divider is connected with the input of the pulse generator. The second output is connected with the second input of the AND/OR element through the phase frequency self-adjusting unit, automatic controllable generator and second frequency divider and input of the recording pulse generator. The first output of the pulse recording generator is connected to the input of the digital voltmeter through the cadence input of the pulse generator. The output of the subtracting device is connected with the second output. The cadence output of the subtracting device of scaling is connected with the outputs of the digital voltmeter through the subtracting device. The cadence input of the subtracting device is connected with the output of the AND/NOT element. The outputs of the scaling device are connected with the inputs of the digital voltmeter through subtracting device.

EFFECT: enhanced accuracy.

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The invention relates to measuring technique and can be used in automatic control and measurement of moisture content pochvogruntov environments in the field of reclamation, humidity leguminous crops agricultural production, and concentration of impurities, the two-phase liquid media, for example the concentration of dry ingredients when cooking syrup in the food industry.

It is known device electric hygrometer (Berliner M.A. humidity Measurement. - M.: Energy, 1973. - 400 C.), based on the principle of differential measuring circuits containing the generator frequency, the findings of which are connected to the exemplary capacitor and the capacitor sensing element of the sensor, the findings of which are additionally connected with a pointing device.

A disadvantage of this device is the low accuracy of the measurements (2-3%) in the end regions of the measuring range due to the low sensitivity of the device.

The closest in technical essence to the invention is an electric hygrometer (RF Patent No. 2045053, MKI G 01 N 27/22. Electric hygrometer. /Andrievsky, A.// Opening. Of the invention. - 27.09.95, Bulletin No. 27), a digital voltmeter, device scaling, subtractive device, reference generator block phase-locked loop in about the position of the two control circuits, as well as automatic driven generators, channels conversion which contain interconnected generators managed voltages and capacitive sensors, respectively, with the reference and the measuring sensors, the output of an automatic reference controlled oscillator, which is the output of the generator is controlled voltage connected to the first input of the control circuit, which is the input of the phase comparator, the output of which is connected to the integrator, and the output of the latter is the output of the first control circuit and connected to the generator of the controlled voltage and the first input of subtractive device, the output of which through device scaling is connected to the input of the digital voltmeter, measuring automatic controlled oscillator connected to the first input of the second control circuit, the output which is connected to the measuring input of the controlled oscillator and the second subtractive input device, and the output of the reference oscillator with the second inputs of the control circuits.

The low accuracy of moisture measurements in this device due to the total error from temperature instability serially connected channels conversion of the reference oscillator unit, a phase-locked loop, subtractive device masshtabiv the deposits and digital voltmeter. The use of a large number of circuit elements of the device leads to low reliability, a large amount of energy (about 50-70 mA at a supply voltage ±5), as well as to the complexity in setting up and calibrating.

Towards the realization of this technical solution, the author of the known device for measuring the concentration of impurities indirect method (for example, calculated using the total density of the medium) in the physico-mechanical class of devices (Civilis S. Densitometers. - M.: Energy, 1980. - 279 S.). The principle of operation of such devices based on the change in resonant frequency of oscillation of a rod (plate) depending on changes in the density of the medium. The disadvantages of such devices include the dependence of the output signals from changing cavitation regimes applicable to the research streams of the mixed liquids. In addition, the bulky design of the sensing elements, as well as the requirements of the high cost of supply for their vibrations do not give the opportunity to realize the principle of autonomy and portability of the developed devices.

The objective of the invention is the improvement of measurement accuracy and reliability of the device.

This object is achieved in that in the known device electric hygrometer, containing auto is eticheski controllable oscillator, unit phase-locked loop frequency reference generator device scaling, subtractive device and a digital voltmeter, additionally introduced two frequency divider pulse, pulse shapers account and setup, and the element AND-NOT output of the reference oscillator connected to the first input element AND-NOT, the clock input of the pulse shaper recording and input of the first frequency divider pulse, the first output of which is connected to the set input of the pulse shaper setup, and the second output through the unit phase-locked loop, automatic controlled oscillator and a second frequency divider pulse to the second input element AND-NOT and installation the input of the shaper pulse recording, the first output of which through the clock input of the pulse shaper unit are connected to the synchronization input of the digital voltmeter, and the second output to the input of the preset subtractive device, the clock input of which is connected to the output element AND-NOT, bit outputs of the device scaling through subtractive device is connected to the bit inputs of the digital voltmeter.

Comparative analysis of the invention with the prototype shows that the proposed device is different from the known introduction of two frequency dividers pulse, fo is Miravalle pulse recording and installation as well as the logical element AND-NOT that allows you to get new properties in independence measurement accuracy of the total error caused by temperature instability serially connected composite channels transformations, and thereby to improve the accuracy of measurement with readout of moisture content of the studied environments, the terms of measurable physical quantities. In addition, new functional relationships provide a phase locked loop measuring and reference generators with full coverage of the feedbacks between the component channels transformation, which allows to conclude that significant differences of the proposed device.

Thus, the claimed object meets the criterion of "novelty". The applicant unknown solutions containing similar features distinguishing the claimed solution to the prototype that allows to make a conclusion on the conformity of the proposed solutions to the criterion of "Inventive step".

The drawing shows the device electric hygrometer.

The block diagram of the electric hygrometer consists of a reference oscillator 1, the first frequency divider pulse 2, block a phase-locked loop 3, automatic controlled oscillator 4, a second frequency divider pulse 5, the element AND NOT 6, the pulse shapers Zap the si 7 and pulses installation 8, device scaling 9, subtractive device 10 and the digital voltmeter 11.

Reference oscillator 1 is implemented in the base of the quartz resonator frequency is about 1 MHz and inverters (IC type CLN). The first frequency divider pulse 2 in connection with the reference oscillator 1 is designed for power conversion cycle, the digital display and synchronization, the length of time which is of the order of 100 mS. It is implemented as counting decades on the basis of IMS type C IE. Moreover, the first output formed bit output of one of the components of decades, the second output is formed by the successive connection of the bit output of the counting decade to the shaper short pulses in a single level. Therefore, the second output is connected through the block phase-locked loop 3 to the input of the automatic controlled oscillator 4.

Automatic driven generator 4 performs the function of measuring generator, adjust the phase to the phase of the reference oscillator. It is implemented as interconnected in a self-oscillating circuit of the comparator and integrator, as an integrating capacitance which uses the sensor capacitor type. For process measurements of granular media (soil moisture in the field of reclamation and leguminous crops in agro-industry) the data device is implemented as a portable device in the casing with dimensions 120× 60×20 mm with cord connection with the sensor element up to 1.5-2 meters In the implementation of the sensor in the form of double-vane blades and powered by rechargeable batteries (type 7D-0.125) voltage 9 V supply current is 10 mA. When measuring the moisture content of the syrup during cooking sensitive sensor elements made in the form of isolated capacitor plates with an effective area of 100 cm²other plate of which is the metal wall of the reactor.

The high deviation of the generated frequencies (up to 300 kHz and above) is achieved using a precision IC type KUA. Therefore, the output of the generator 4 is connected via a second frequency divider pulse to the second input of the logical element AND-NOT 6 and mounting the input of the shaper pulse recording 7, the clock input of which together with the first input of the logical element AND-NOT connected to the output of the reference oscillator 1. The first output of the pulse shaper record 7 is connected to the clock input of the pulse shaper setup 8.

The second frequency divider pulse 5 is designed to convert the deviations of the measured frequencies in a time interval and is implemented on the IC type CIE. As a logical element AND-NOT 6 used IC type CLA.

The pulse shapers Zap the si 7 and 8 installation are designed to generate short single series of pulses in the cycle of transformations and implemented in the form of update schemes for single decades distributors pulses (IC type CIE or CIE). The first output of the first frequency divider pulse 2 is connected to the set input of the pulse shaper setup 8, the output of which is connected to the synchronization input of the digital voltmeter 11, the output of element AND-NOT 6 connected to the clock input of subtractive device 10, the input set which is connected to the second output of the pulse shaper record 7. Bit outputs of the device scaling 9 through subtractive device 10 is connected to the bit inputs digital voltmeter 11.

Device scaling 9 is a four decade typesetting fields binary units. Subtractive device 10 is designed to convert the measurement data of the moisture from the frequency of the waveform in digital and represents a serially connected decade hundredths, tenths, units and tens of percents digital scale, implemented in decimal counters with preset (IC type CIE).

Digital voltmeter 11 is designed to convert BCD code information in the seven-segment code for digital (liquid crystal or semiconductor) indicators. Therefore, it is implemented on the input decoders (IC type KID) for direct connection to digital indicators.

The principle of operation of the device, the implementation of which is as follows.

When the humidity of the studied environment in the local volume of the sensing element of the sensor is carried out in a corresponding change in its dielectric constant, and hence a corresponding change in the frequency of automatic controlled oscillator 4. The measured frequency from generator 4 is supplied to the second frequency divider 5 for converting the time interval of the unit level. When the pulse duration of these intervals is then converted into the corresponding number of reference pulses from the generator 1 through a logical element AND-NOT 6 for recording in the accounts of the decade subtractive device 10.

At the end of each significant information pulse shaper pulse recording 7 produces first with the first output pulse to start the pulse shaper setup 8, and with a delay of one clock cycle of the reference frequency, it produces a pulse from the second output pulse recording preset value code mask scalable device 9. Moreover, the pulse setup allows you to synchronize the operation of the digital voltmeter for subsequent decryption and digital display of measurement data.

Initial setup (calibration) electric moisture meter as follows. For setting the hygrometer is necessary to have two of the sample environment with different humidity. For example, for a range of measurement from 0 to 50% of the sample with minimal humidity W_min=5% and with a maximum humidity W_max=45%that define exemplary difference in ΔW_arr=40%. Initially, all the weights of device scaling 9 selects zero values, and the sensor (measuring automatic controlled oscillator) 4 is immersed in an environment with a humidity of W_min. After this is fixed digital value of the minimum moisture content using a digital voltmeter 11. Then the sensor is placed in an environment with ideal humidity W_maxenvironment to determine its relative value in digital form. If the measured range of humidities ΔW_ISMcoincides with the model (ΔW_arr=ΔW_ISM) if not their relative indications, it is necessary to make the relative offset it by the value of the calibration weight ΔW_castledetermined by the difference between one model and the measured values. In this case, the calibration mask ΔW_castlerecorded stacked field in the device scale 9, which is then calculated in a parallel manner using a subtractive device 9 to obtain the true values of the measured parameters.

The discrepancy between the measured range humidity with exemplary (ΔW_arr≠ΔW_{var/sub> means lack of sensitivity of the measuring automatic controlled oscillator 4 (or exceed it). In this case, the device scaling 9 must be translated into a value of zero. When the weak sensitivity of the hygrometer in the beginning of the first cycle calibration using the trimmer element (resistor) measurement automatic controlled oscillator 4. Then the sensor is immersed in the sample of Wminto measure this value (Wmpis). The sensor is immersed in the sample of Wmaxsubsequent measurement values (Wmachismand the definition of the measured humidity ΔWISM. This ends the first cycle settings. If no goal due to the weak sensitivity of the hygrometer these cycles are repeated. In the case of the high sensitivity of the hygrometer using the trimmer element measuring automatic controlled oscillator 4 is reducing the frequency of self-oscillations and followed by one or more of the above cycles settings. Moreover, the configuration process is considered complete upon receipt of equality ΔWarr=ΔWISM. With specified accuracy metrics, and subsequent relative displacement range of transformations by weight of the mask ΔWcastleas was shown above.}

When metering the research Institute of the moisture content of dry food during cooking syrups measurement error was 0.01% in the range from 0 to 48% when the temperature changes from +20 ^°C to +150^°With and feeding device stresses within ±20%.

Changing the moisture content of the soil environments and legumes measurement error was 0.1% in the range of humidities from 0 to 48%due to the effect of changes in density of the studied environments (soil densities and dispersion of particles of grain for different crops in the local zone sensor element of the sensor (made in the shape of the shoulder). While the accuracy achieved zero at 0.01%.

Technical appraisal and economic benefits of the proposed facility compared to the known can improve the accuracy of measurements in 2-3 times in a considerable simplification of the circuit implementation. The use of the proposed electric hygrometer allows you to increase resolution of the measurement of the moisture content of the two-phase environments and to increase its reliability by reducing the circuit design and reduce power consumption.

Electric hygrometer, containing automatic driven generator, the unit phase-locked loop frequency reference generator device scaling, subtractive device and a digital voltmeter, characterized in that it has two frequency dividers pulse shaper pulse recording and installation and element AND-NOT output of the reference General the RA connected to the first input element AND-NOT, clock input of the pulse shaper recording and input of the first frequency divider pulse, the first output of which is connected to the set input of the pulse shaper setup, and the second output through the unit phase-locked loop, automatic controlled oscillator and a second frequency divider pulse to the second input element AND-NOT and set the input of the shaper pulse recording, the first output of which through the clock input of the pulse shaper unit are connected to the synchronization input of the digital voltmeter, and the second output to the input of the preset subtractive device, the clock input of which is connected to the output element AND-NOT, bit outputs of the device scaling through subtractive the device is connected to the bit inputs of the digital voltmeter.