CN205262543U

CN205262543U - Many detection of water level system based on conversion of RC oscillator RF

Info

Publication number: CN205262543U
Application number: CN201520556343.6U
Authority: CN
Inventors: 张立远
Original assignee: Haining Zhien Electronic Technology Co Ltd
Current assignee: Haining Zhien Electronic Technology Co Ltd
Priority date: 2015-07-28
Filing date: 2015-07-28
Publication date: 2016-05-25
Anticipated expiration: 2025-07-28

Abstract

The utility model discloses a many detection of water level system based on conversion of RC oscillator RF, including water level detection circuit and controller, water level detection circuit is equipped with level sensor, forms resistance R1 between the level sensor electrode after switching on through water, level sensor couples with controller, oscillation circuit respectively, and oscillation circuit's output and controller are connected, because the level sensor who arranges the aquatic in is equipped with NULL and according to the water level height and other electrodes that set up will arouse that sensor output resistance changes when switching on after between two electrodes of level sensor, the change of sensor resistance can arouse oscillator "Frequency"'s change, the output frequence of controller through detecting the oscillator, again with reference frequency relatively later on alright accuracy detect out the water level, this designs simple structure, be of value to enhance product performance, reduction in production cost.

Description

A kind of many water level detecting systems based on RC oscillator R/F conversion

Technical field

The utility model relates to solar energy heat collection engineering water level detecting field, especially a kind of many water level detecting systems based on RC oscillator R/F conversion.

Background technology

Along with social development, people more and more pursue high-quality, low cost, free of contamination hot water supply option, and therefore solar water water supply scheme arises. At first, solar water heating system is comparatively simple, and its majority applies to family, small-sized hotel etc. Along with popularizing of industry development and solar water, people are more and more higher to the requirement of solar energy hot water supply, more hotel, school, factory's dormitory, government department etc. are all considering that solar energy uses the economic benefit of bringing, therefore engineering is more and more diversified, and it is beyond one's ability that traditional single system scheme more and more shows under the diversified background of engineering. The system of multisystem combination or the combination of many water tanks is more and more universal, has proposed a new difficult problem to control and the test section of heat collecting engineering simultaneously. The water level that how to use detection scheme reliable detection more cheaply to go out multisystem or many water tanks becomes the common difficulty that whole industry faces. In the past, conventional method had:

1: on original single cistern device, integrate, such as the system of two water tanks is just installed the controller of two cover list water tanks, its shortcoming is: 1) cost increases considerably, and it controls cost double-water-tank system and will on the basis of single water tank, double; 2) between water tank, control logic is difficult to realize coordination, although its water tank quantity of the even many cistern systems of double-water-tank system increases, but after all or a system, utilize this scheme to realize, its each other logic be difficult to reach a rational level; 3) complex operation, will operate two controllers when arranging or operate, the cost that has been tantamount to strengthen debugging and has safeguarded; 4) be unfavorable for system full-automation, intelligent management; 5) user experience is poor.

2: utilize the principle of pressure to detect, the detection of pressure has very high reliability and resolution ratio, but pressure sensor itself has very high cost, and its testing circuit has increased the cost of controller greatly.

Utility model content

For the problem of above-mentioned existence, the utility model has designed a kind of many water level detecting systems based on RC oscillator R/F conversion, through RC oscillator R/F conversion, realize the conversion of level sensor resistance R to oscillator frequency of oscillation F, through the final value that obtains tested water level of outer interruption of single-chip microcomputer, this project organization is simple, is of value to and enhances product performance, reduces production costs.

The utility model solves the technical scheme that its technical problem adopts: a kind of many water level detecting systems based on RC oscillator R/F conversion, due to other electrodes that are placed in the level sensor of water and are provided with public electrode and arrange according to water level height, when causing after conducting between level sensor two electrodes that sensor output resistance changes, the variation of sensor resistance can cause the variation of oscillator frequency of oscillation, controller passes through to detect the output frequency of oscillator, more just can accurately detect water level with reference frequency relatively later;

Related content in such scheme is explained as follows:

Described a kind of water level detecting system based on RC oscillator R/F conversion, is provided with water level detection circuit and controller; Described water level detection circuit is provided with level sensor, between water level sensor electrode, forms resistance R 1 afterwards by water conducting; Described level sensor is provided with 4 grades, is respectively 20%, 50%, 80%, 100% electrode; Described level sensor connects with controller, oscillating circuit respectively, and the output of oscillating circuit is connected with controller; Described water level detection circuit is provided with capacitor, and the capacitor C of capacitor is fixed value; Described water level detection circuit is provided with an other fixed resistance R2, and resistance R 2 is in parallel with water level sensor electrode output resistance R 1, in the time that minor variations occurs water level sensor electrode output resistance R 1, all can cause that the total prevention in circuit changes; In described water level detection circuit, be provided with phase inverter, phase inverter forms RC oscillating circuit with conduct electricity resistance R1, resistance R 2 and capacitor; It is the Arm single-chip microcomputer LPC1114 based on CortcxM3 core that described controller is selected kernel control chip; The core that described single-chip microcomputer LPC1114 is controller, detects and carries out error correction and compensation from hardware and software aspect level sensor signal.

The beneficial effects of the utility model are:

1. cost advantage: sensor and the measuring circuit of measuring water level are all very simple, so greatly reduce the cost of original (pressure signal etc.) scheme using, but its measurement result is not quite meticulous, but its utilization aspect solar thermal collection system is completely enough.

2. thermometric lead-in wire is long: it is finally to detect the frequency of input Transistor-Transistor Logic level (binary digital logic level) that R/F surveys water level scheme. And in general 5V digital circuit, test side thinks that the level that is greater than 2.4V is high level, be low level lower than the level of 0.4V. Therefore its signal itself has very strong tolerance and anti-interference antidamping ability. Therefore in remote survey water level, change circuit and there is advantage clearly, and often in solar energy heat collection engineering most survey water level point distance detection device all far, therefore this programme has advantage and operability clearly in solar energy heat collection engineering industry.

3. can be found out by detection waveform, the transmission of signal in wire is to present periodically, causes that detection sensitivity reduces like this with regard to the sensor scaling of having avoided the long-time energising of direct current signal to cause.

Brief description of the drawings

Below in conjunction with drawings and Examples, the utility model is further illustrated.

Fig. 1 is the utility model structured flowchart.

Fig. 2 is electrical block diagram of the present utility model.

Fig. 3 is the utility model embodiment middle water level sensor construction schematic diagram.

Fig. 4 is the signal waveforms that in the utility model embodiment, single-chip microcomputer detects.

Fig. 5 be the utility model level sensor resistance value can measuring-signal to single-chip microcomputer change-over circuit figure.

In figure: 1, controller, 2, level sensor, 3, oscillating circuit, 4, capacitor, 5, phase inverter.

Detailed description of the invention

As Figure 1-5, the utility model has designed a kind of many water level detecting systems based on RC oscillator R/F conversion, is provided with water level detection circuit and controller 1.

Described water level detection circuit is provided with level sensor 2, between water level sensor electrode, forms resistance R 1 afterwards by water conducting. Described level sensor 2 is provided with 4 grades, is respectively 20%, 50%, 80%, 100% electrode, and road as shown in Figure 3 all changes the resistance value that causes sensor output after any one water level point and common segment are by water conducting. Described level sensor 2 is connected with controller 1, oscillating circuit 3 respectively, and the output of oscillating circuit 3 is connected with controller 1. Described water level detection circuit is provided with capacitor 4, and the capacitor C of capacitor 4 is fixed value. Described water level detection circuit is provided with an other fixed resistance R2, resistance R 2 is in parallel with level sensor 2 electrode output resistance R 1, in the time there is minor variations in level sensor 2 electrode output resistance R 1, capital causes that the total prevention in circuit changes, NAND gate output cycle parameter directly depends on the numerical value of Resistor-Capacitor Unit RC in circuit as shown in Figure 3, and its cycle can be expressed as T=(1.414～2.2) RC. In the time that capacitor C is fixed value, the output of RC oscillator changes with resistance of sensor cycle of oscillation. In described circuit, be provided with phase inverter 5, described phase inverter 5 is 74HC04, and phase inverter 5 forms RC oscillating circuit 3 with resistance R 1, resistance R 2 and capacitor 4. It is the Arm single-chip microcomputer LPC1114 based on CortcxM3 core that described controller 1 is selected kernel control chip. Described single-chip microcomputer LPC1114 is the core of controller 1, and level sensor signal is detected and carries out error correction and compensation from hardware and software aspect, as shown in Figure 4, can simply calculate water level in which gear by the variation of its waveform frequency.

Due to other electrodes that are placed in the level sensor of water and are provided with public electrode and arrange according to water level height, when causing after conducting between level sensor two electrodes that sensor output resistance changes, the variation of sensor resistance can cause the variation of oscillator frequency of oscillation, controller passes through to detect the output frequency of oscillator, more just can accurately detect water level with reference frequency relatively later.

Further, as shown in Figure 5, a channel Temperature Measuring needs three not gates to form, and a slice 74HC04 comprises six road not gates, can complete the detection of two-way temperature. In the time of needs multi-route measuring temperature, only need in circuit, RC oscillating circuit 3 be set as required and 74HC04 can complete, therefore, embody the price advantage of R/F thermometric scheme completely.

The above is only preferred embodiment of the present utility model, for those skilled in the art, not departing under the prerequisite of the utility model principle, can also make some improvement, and these improve and also should be considered as protection domain of the present utility model.

Claims

1. the many water level detecting systems based on RC oscillator R/F conversion, is characterized in that: comprise water level detection circuit and controller, water level detection circuit is provided with level sensor, between water level sensor electrode, form resistance R 1 afterwards by water conducting; Described level sensor is provided with 4 grades, is respectively 20%, 50%, 80%, 100% electrode; Described level sensor is connected with controller, oscillating circuit respectively, and the output of oscillating circuit is connected with controller; Described water level detection circuit is provided with capacitor, and the capacitor C of capacitor is fixed value; Described water level detection circuit is provided with an other fixed resistance R2, resistance R 2 is in parallel with water level sensor electrode output resistance R 1, in described water level detection circuit, be provided with phase inverter (5), described phase inverter is 74HC04, forms RC oscillating circuit with resistance R 1, resistance R 2 and capacitor.

2. a kind of many water level detecting systems based on RC oscillator R/F conversion according to claim 1, is characterized in that: it is the Arm single-chip microcomputer LPC1114 based on CortcxM3 core that described controller (1) is selected kernel control chip.