CN203414136U

CN203414136U - Liquid-level sensor circuit

Info

Publication number: CN203414136U
Application number: CN201320538480.8U
Authority: CN
Inventors: 杨腊平
Original assignee: GUODA ELECTRIC EQUIPMENT Co Ltd WENZHOU CITY
Current assignee: GUODA ELECTRIC EQUIPMENT Co Ltd WENZHOU CITY
Priority date: 2013-08-30
Filing date: 2013-08-30
Publication date: 2014-01-29
Anticipated expiration: 2023-08-30

Abstract

The utility model relates to a sensor circuit, in particular to a liquid-level sensor circuit. The liquid-level sensor circuit comprises a pair of metal electrodes, a power supply circuit, a vibration generation and detection unit adopting a single chip microprocessor as a core, and an alarm signal amplification unit. Through the vibration generation and detection unit adopting the single chip microprocessor as the core and by utilizing the remarkable variation of electric capacitance under two statuses that medium is charged between the two electrodes and the medium is not charged between the two electrodes, whether the liquid-level sensor is contacted with a liquid surface is judged by detecting the amplitude of the vibration voltage on the electrodes, so that the purpose of detecting the liquid level can be realized. Meanwhile, the vibration generation and detection unit of the liquid-level sensor circuit adopts the universal single chip microprocessor as the core, so that the price is low, and the procurement is convenient, and the popularization is easy.

Description

A kind of liquid level sensor circuit

Technical field

The utility model relates to a kind of sensor circuit, specifically a kind of liquid level sensor circuit.

Background technology

The control of using widely water level in existing production and life, as all needed to use liquid level sensor for water tower, solar water heater, steam generator and radiator etc., the water level in equipment is monitored, the reliability of liquid level sensor is to the normal operation of equipment and safeguard most important.Current liquid level sensor has mechanical type and electronic type, mechanical type generally includes ball float and tongue tube, ball float is provided with magnetic, by tongue tube, the induction of magnetic position is monitored to liquid level, with low cost, but precision is not high, and ball float is easily blocked or sticks by foreign matter, carbon is easily tied in the contact of tongue tube, causes cisco unity malfunction.Electronic type is typically provided with special circuit, is imported product substantially at present, and precision is higher, but complex circuit, element is difficult for buying, and price is higher, is difficult to popularize in an all-round way.

Summary of the invention

The purpose of this utility model is to provide a kind of precision higher in order to overcome the defect of prior art, but the liquid level sensor circuit of reasonable price.

To achieve these goals, the utility model discloses a kind of liquid level sensor circuit, it is characterized in that: comprise pair of metal electrodes, power circuit, single-chip microcomputer is vibration generation and detecting unit and the alerting signal amplifying unit that core forms, the oscillation output end of described vibration generation and detecting unit is connected with the first electrode in described pair of metal electrodes, described the first electrode is connected with the oscillation test input end of described vibration generation and detecting unit after rectification circuit through a shunt capacitance, the input end of described alerting signal amplifying unit is connected with the controlling alarm end of described vibration generation and detecting unit, the second electrode in described pair of metal electrodes through an isolation capacitance and power supply be connected, described the first electrode and the second electrode are isolated setting mutually, while being full of measured medium between described the first electrode and the second electrode, the electric capacity forming between described the first electrode and the second electrode and total equivalent electric capacity of the isolation capacitance at least large order of magnitude of comparing with described shunt capacitance, described power circuit occurs for vibrating and detecting unit provides working power.

This liquid level sensor circuit take by arranging vibration generation and the detecting unit that single-chip microcomputer forms as core, and utilize the marked change that whether is filled with electric capacity under medium two states between two electrodes, detection by the oscillating voltage amplitude on electrode judges whether liquid level sensor has touched liquid level, reaches the object that liquid level detects.Because vibration generation and the detecting unit of this liquid level sensor circuit be take general single-chip microcomputer as core formation, price is low simultaneously, and buying is convenient, is easy to promote.

Below in conjunction with drawings and the specific embodiments, the utility model is described in further detail.

Accompanying drawing explanation

Accompanying drawing 1 is the utility model specific embodiment schematic block circuit diagram;

Accompanying drawing 2 is the utility model specific embodiment circuit theory diagrams.

Embodiment

As shown in Figure 1, liquid level sensor circuit comprises that pair of metal electrodes, power circuit, single-chip microcomputer are vibration generation and detecting unit and the alerting signal amplifying unit that core forms.The oscillation output end of described vibration generation and detecting unit is connected with the first electrode A in described pair of metal electrodes, described the first electrode A is connected with the oscillation test input end of described vibration generation and detecting unit after rectification circuit through a shunt capacitance, the input end of described alerting signal amplifying unit is connected with the controlling alarm end of described vibration generation and detecting unit, the second electrode B in described pair of metal electrodes through an isolation capacitance and power supply be connected, described the first electrode A and the second electrode B are isolated setting mutually, while being full of measured medium between described the first electrode and the second electrode, the electric capacity forming between described the first electrode A and the second electrode B and total equivalent electric capacity of the isolation capacitance at least large order of magnitude of comparing with described shunt capacitance, conventionally with 10-50, be doubly advisable, described power circuit occurs for vibrating and detecting unit provides working power.In this specific embodiment, as shown in Figure 2, power circuit selects three terminal regulator U1 and filter capacitor C1 and C2 to form, and can certainly form with discrete component; Described vibration generation and detecting unit be take single-chip microcomputer U2 as core formation, in this specific embodiment, select PIC12F675(also can select other like products), the first output terminal of single-chip microcomputer PIC12F675 (pin 3) is connected with the first electrode A, described alerting signal amplifying unit consists of amplifying triode Q1, and the second output terminal of single-chip microcomputer PIC12F675 (pin 7) is connected with amplifying triode Q1 base stage through current-limiting resistance; The RC parallel filtering branch road that described rectification circuit comprises commutation diode D2 and is comprised of resistance R 4 and capacitor C 5, described RC parallel filtering branch road is connected between the first input end (pin 5) and power supply ground of single-chip microcomputer PIC12F675, described shunt capacitance C3 one end is connected A with the first electrode, the other end is connected with commutation diode D2 is anodal, and described commutation diode D2 negative pole is connected with the first input end (pin 5) of single-chip microcomputer PIC12F675.

The principle of work of this liquid level sensor circuit is as follows: described vibration generation and detecting unit are set from the first output terminal (pin 3) output oscillating voltage signal to the first electrode A by internal processes in the situation that having working power, if now the first electrode A of liquid level sensor circuit and the second electrode B not with tested liquid medium contact, the electric capacity forming between the first electrode A and the second electrode B is very little, most of oscillating voltage signal is transported to the oscillation test input end (pin 5) of described vibration generation and detecting unit after shunt capacitance and rectification circuit, vibration occurs and detecting unit detects larger vibration voltage signal, the first electrode A and the second electrode B and tested liquid medium contact when liquid level sensor circuit, the electric capacity forming between the first electrode A and the second electrode B increases, the at least large order of magnitude of more described shunt capacitance, now, most of oscillating voltage signal has arrived power supply ground through electric capacity and the capacitor C 4 forming between the first electrode A and the second electrode B, only have a very little part after shunt capacitance and rectification circuit, to transport to the oscillation test input end of described vibration generation and detecting unit (pin 5), vibration occurs and detecting unit can only detect very little oscillating voltage signal, vibration occurs and detecting unit can judge according to the size of the oscillating voltage signal detecting whether liquid level touches Liquid level test probe.

Claims

1. a liquid level sensor circuit, it is characterized in that: comprise pair of metal electrodes, power circuit, single-chip microcomputer is vibration generation and detecting unit and the alerting signal amplifying unit that core forms, the oscillation output end of described vibration generation and detecting unit is connected with the first electrode in described pair of metal electrodes, described the first electrode is connected with the oscillation test input end of described vibration generation and detecting unit after rectification circuit through a shunt capacitance, the input end of described alerting signal amplifying unit is connected with the controlling alarm end of described vibration generation and detecting unit, the second electrode in described pair of metal electrodes through an isolation capacitance and power supply be connected, described the first electrode and the second electrode are isolated setting mutually, while being full of measured medium between described the first electrode and the second electrode, the electric capacity forming between described the first electrode and the second electrode and total equivalent electric capacity of the isolation capacitance at least large order of magnitude of comparing with described shunt capacitance, described power circuit occurs for vibrating and detecting unit provides working power.

2. liquid level sensor circuit according to claim 1, it is characterized in that: described vibration generation and detecting unit be take single-chip microcomputer PIC12F675 as core formation, the first output terminal of single-chip microcomputer PIC12F675 is connected with the first electrode, described alerting signal amplifying unit consists of amplifying triode, and the second output terminal of single-chip microcomputer PIC12F675 is connected with amplifying triode base stage through current-limiting resistance; Described rectification circuit comprises commutation diode and RC parallel filtering branch road, described RC parallel filtering branch road is connected between the first input end and power supply ground of single-chip microcomputer PIC12F675, described shunt capacitance one end is connected with the first electrode, the other end is connected with commutation diode is anodal, and described commutation diode negative pole is connected with the first input end of single-chip microcomputer PIC12F675.