CN107402053B - Two-wire contact type electronic material level meter - Google Patents
Two-wire contact type electronic material level meter Download PDFInfo
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- CN107402053B CN107402053B CN201710665393.1A CN201710665393A CN107402053B CN 107402053 B CN107402053 B CN 107402053B CN 201710665393 A CN201710665393 A CN 201710665393A CN 107402053 B CN107402053 B CN 107402053B
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- 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
- G01F23/24—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 resistance of resistors due to contact with conductor fluid
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Abstract
The invention discloses a two-wire system contact type electronic material level instrument, wherein two incoming wires J1 and J2 are respectively connected to a bridge rectifier BD1, the output of the bridge rectifier BD1 is connected with an electric energy storage electronic module (2), the electric energy storage electronic module outputs a stabilized voltage power supply VCC1, and the stabilized voltage power supply VCC1 supplies power to a central controller electronic module (1) and a high-frequency generator electronic module (3); the central controller electronic module is connected with the high-frequency generator electronic module, receives the output signal of the sensor electronic module (4), outputs the signal to control the electric energy storage electronic module through the working mode converter (5), and outputs the signal to a remote central control room through two incoming lines; the output of the high-frequency generator electronic module is connected with the input end of the isolation transformer, and the output voltage V2 of the isolation transformer is connected with the sensor electronic module; the sensor electronic module comprises a detection sensor, and after the detection sensor detects the material level or the liquid level of the material, an output signal is processed by the sensor electronic module and then output to the central controller electronic module.
Description
Technical Field
The invention relates to an electronic material level instrument, in particular to a two-wire system contact type electronic material level instrument.
Background
Level meters currently used in the market are classified into two major categories, namely contact type and non-contact type. The contact level meter is divided into mercury type, rotation resistance type, capacitance type, permanent magnet type, weight type and the like; non-contact level gauges are also classified into ultrasonic, radar, laser, and the like. The various level meters have advantages and disadvantages according to different application environments and different measured substances. When the mercury type level gauge is used for powder ore materials, the faults of hammer burying, no alarm and hammer breakage exist. The rotation-resisting material level meter has poor precision and is not durable. The capacitance level gauge has poor reliability. The hammer type has the problems of hammer breakage, hammer burying and rope disorder. The permanent magnet must be mounted vertically. Non-contact material level instruments, such as ultrasonic material level instruments, are affected by dust, concave-convex surfaces and noise. The radar level gauge is influenced by dust and concave-convex surfaces and has requirements on dielectric constant. The laser material level meter is affected by dust and concave-convex surfaces.
Due to the harsh use environment, factors such as the shape, temperature, dust, medium concentration, signal interference and the like of the measured substance influence the precision and effect of the detection, and even the production accident can occur to influence the normal production order. Therefore, the user must select a proper level meter according to the use environment and occasion, so as to improve the detection precision and effect, otherwise, the production is affected and the cost is increased.
Disclosure of Invention
The invention aims to provide a two-wire contact type electronic level meter which is long in service life, high in detection precision, safe, reliable and good in stability.
In order to achieve the technical purpose, the invention adopts the following technical scheme:
a two-wire system contact type electronic level meter comprises: the system comprises a central controller electronic module, an electric energy storage electronic module, a high-frequency generator electronic module, a sensor electronic module and a working mode converter;
the two incoming wires J1 and J2 are respectively connected to a pin 1 and a pin 3 of a bridge rectifier BD1, a pin 4 of the bridge rectifier BD1 is grounded, a pin 2 of the bridge rectifier BD1 is connected with an electric energy storage electronic module, the electric energy storage electronic module outputs a stabilized voltage power supply VCC1, and the stabilized voltage power supply VCC1 supplies power to a central controller electronic module and a high-frequency generator electronic module;
the central controller electronic module is connected with the high-frequency generator electronic module, the central controller electronic module is connected with the sensor electronic module to receive output signals of the sensor electronic module, the output of the central controller electronic module is connected with the electric energy storage electronic module through the working mode converter, and the electric energy storage electronic module outputs signals to a remote central control room through two incoming lines;
the output of the high-frequency generator electronic module is connected with the input end of the isolation transformer, and the output voltage V2 of the isolation transformer is connected with the sensor electronic module;
the sensor electronic module comprises a detection sensor, the detection sensor detects the material level or the liquid level of the material, and the output signal of the detection sensor is processed by the sensor electronic module and then is output to the central controller electronic module.
The input ends of the two incoming wires are connected with a coil output wire and a ground wire of a central control room or an intermediate relay of the central control room or a PLC, and the output ends of the two incoming wires are respectively connected with a pin 1 and a pin 3 of a bridge rectifier BD 1.
The electric energy storage electronic module comprises a triode T1, a field effect transistor T4, a voltage stabilizing diode DV, a resistor and a capacitor; a pin 2 of the rectifier circuit device BD1 is connected in parallel with an emitter of a triode T1, one end of a resistor R2, a cathode of a voltage stabilizing diode DV2 and one end of a variable resistor RW1, a base of a triode T1 is connected in parallel with the other end of a resistor R2 and one end of a resistor R3, a collector of a triode T1 is connected with one end of a resistor R4, and the other end of the resistor R4 is connected in parallel with the other end of a resistor R3 and an anode of a; the other end of the variable resistor RW1 and the third pin are connected with one end of a resistor R1 in parallel, the cathode of the voltage stabilizing diode DV1 is connected with the other end of the resistor R1 and the source of the field effect transistor T4 in parallel, and the anode of the voltage stabilizing diode DV1 is grounded; the grid of the field effect transistor T4 is connected with the other end of the resistor R4 and one end of the capacitor C1 in parallel, the other end of the capacitor C1 is grounded, the grid of the field effect transistor T4 is connected with the output end VCC1, one end of the variable resistor RW2 is connected with the third pin in parallel and then connected with the output end VCC1, the other end of the variable resistor RW2 is connected with the resistor R7 in series, the other end of the resistor R7 is connected with the drain of the field effect transistor T4, one end of the capacitor C2 is connected with; the cathode of the voltage stabilizing diode DV3 is connected in series with the light emitting diode LD2 and then connected with the output end VCC1, the anode of the voltage stabilizing diode DV3 is grounded, one end of the capacitor C3 is connected with the output end VCC1, and the other end of the capacitor C3 is grounded.
The central controller electronic module comprises a triode, a voltage stabilizing diode and an integrated block U2A, wherein an emitter of a triode T2 is connected with a base electrode of a triode T3, a collector of a triode T2 and a collector of a triode T3 are connected in parallel and then connected with an anode of a voltage stabilizing diode DV2, a cathode of the voltage stabilizing diode DV2 is connected with a pin 2 output by the bridge rectifier BD1, a base electrode of a triode T2 is connected with a resistor R6 and then connected with a pin 2 and a pin 4 of an output end of a working mode converter, the pin 2 and the pin 4 of the output end of the working mode converter are connected in; the cathode and the anode of the voltage-stabilizing diode DV2 are connected with a resistor R5 in series with the light-emitting diode LD 1; the input end 5 of the integrated block U2A is connected with the output signal Text of the sensor electronic module, the input end 3 of the integrated block U2A is connected with the high-frequency pulse signal of the high-frequency generator electronic module, the pins U2A 4 and 6 of the integrated block are grounded, the pin 1 of the output end 1 of the integrated block U2A outputs a forward signal, the pin 2 of the output end 2 of the integrated block U2A outputs a reverse signal, and the pin 1 and the pin 2 of the output end of the integrated block U2A are respectively connected with the pin 1 and the pin 3 of the input end of the working mode converter.
The operating mode switching module is a switch JP 1.
The electronic module of the high-frequency generator comprises an inverter, an integrated block, a triode and a bridge rectifier, wherein the output end of the inverter U1A is connected with the input end of the inverter U1B through a capacitor C4, the input end of the inverter U1A and the output end of the inverter U1B are connected with a capacitor C5 in parallel, the input end and the output end of the inverter U1A are connected with a resistor R9 in parallel, the input end and the output end of the inverter U1B are connected with a resistor R10 in parallel, the inverters U1A and U1B, resistors R9 and R10, a capacitor C4 and a capacitor C5 form the high-frequency generator, and the; the output of the phase inverter U1B is connected with the pin 11 of the input end of the integrated block U2B, the pin 9 of the input end of the integrated block U2B is connected with the pin 12 of the output end, the pin 12 of the output end of the integrated block U2B outputs a reverse signal, the pins U2B and 10 of the integrated block are grounded, the pin 13 of the output end of the integrated block U2B outputs a forward signal, and the pin 13 of the output end of the integrated block U2B is connected with the base electrode of a triode T4 after being connected with a resistor; an emitter of the triode T4 is connected with a power VCC1, a collector of the triode T4 is connected with a resistor R15 and then is grounded, the capacitor C12 is connected with an emitter and a ground of the triode T4 in parallel, an output of a collector of the triode T4 is connected with an input end of an isolation transformer TRAN, the other end of the input end of the isolation transformer TRAN is grounded, an output end of the isolation transformer TRAN is respectively connected with a pin 1 and a pin 3 of the bridge rectifier BD2, a pin 2 of the bridge rectifier BD2 is connected with an anode of a diode D2, a cathode of the diode D2 is used as a power supply V2, an anode of the capacitor C6 is connected with a cathode of a diode D82.
The sensor electronic module comprises an inverter, a photoelectric coupler, a resistor, a capacitor and a detection sensor, wherein the inverter U4A, the inverter U4B and the inverter U4C are connected in series and then are connected with the input end of the photoelectric coupler U5, the other end of the input end of the photoelectric coupler U5 is connected with the ground E, the input end of the inverter U4A is connected with the detection sensor, the input end of the inverter U4A is connected with a resistor R11, a resistor R12, a capacitor C8 and a capacitor C9 in parallel, the other end of the resistor R11 is connected with a power supply V2, the other end of the resistor R12 is connected with the ground E, the other end of the capacitor C8 is connected; the positive end of the output end of a photoelectric coupler U5 is connected with a central controller electronic module as a detection sensor signal output line Text, the positive end of the output end of a photoelectric coupler U5 is connected with a capacitor C11, a resistor R16 and a resistor R13 in parallel, the other end of the resistor R13 is connected with a power VCC1, the other ends of the capacitor C11 and the resistor R16 are grounded, and the negative end of the output end of a photoelectric coupler U5 is grounded.
The two-wire system contact type electronic material level comprises a central controller electronic module, an electric energy storage electronic module, a high-frequency generator electronic module and a sensor electronic module. The central controller electronic module controls the electric energy storage electronic module to store electric energy and is responsible for processing signals of the sensor electronic module, and if the sensor detects a material level or a liquid level, an alarm signal is output to a central control room or an electric control room through a PLC or an intermediate relay. The electric energy storage electronic module provides voltage for stable operation of the high-frequency generator electronic module. The high-frequency generator electronic module drives an isolation transformer to work, so that the sensor electronic module obtains normal working voltage. The sensor electronic module detects the material level or the liquid level through the detection device, and once the material level or the liquid level is detected, a signal is immediately transmitted to the central controller electronic module, and the central controller electronic module sends out an alarm signal.
Compared with the prior art, the invention has the beneficial effects that:
because the invention adopts the two-wire system technology, the power supply part in the conventional electronic product is saved, thereby achieving the energy-saving effect on one hand and reducing the failure rate of the product on the other hand. The invention can detect solid substances, powdery substances and liquid substances.
The two-wire contact type electronic level meter is not influenced by the shape, temperature, dust, medium concentration and signal interference of a measured substance, and effectively improves the safety, reliability, stability, detection precision and service life of the contact type level meter. When the level gauge is installed and used, the level gauge can be divided into a weight type and a wall-hanging type according to the requirements of users.
Drawings
FIG. 1 is an electrical block diagram of a two-wire contact electronic level gauge according to the present invention;
FIG. 2 is a schematic circuit diagram of a two-wire contact electronic level gauge according to the present invention;
FIG. 3 is a schematic diagram of an electrical energy storage electronic module circuit;
FIG. 4 is a schematic circuit diagram of the central controller electronics module;
FIG. 5 is a schematic circuit diagram of the high frequency generator electronic module;
fig. 6 is a schematic diagram of the sensor electronics module circuit.
In the figure: the system comprises a central controller electronic module 1, an electric energy storage electronic module 2, a high-frequency generator electronic module 3, a sensor electronic module 4 and a working mode converter 5.
Detailed Description
The invention is further described with reference to the following figures and specific examples.
Referring to fig. 1 and 2, a two-wire system contact type electronic level gauge includes: the system comprises a central controller electronic module 1, an electric energy storage electronic module 2, a high-frequency generator electronic module 3, a sensor electronic module 4 and a working mode converter 5.
The two incoming wires J1 and J2 are respectively connected to a pin 1 and a pin 3 of a bridge rectifier BD1, a pin 4 of the bridge rectifier BD1 is grounded, a pin 2 of the bridge rectifier BD1 is connected with an electric energy storage electronic module 2, the electric energy storage electronic module 2 outputs a regulated power supply VCC1, and the regulated power supply VCC1 supplies power to the central controller electronic module 1 and the high-frequency generator electronic module 3.
The central controller electronic module 1 is connected with the high-frequency generator electronic module 3, the central controller electronic module 1 is connected with the sensor electronic module 4 to output signals, the output of the central controller electronic module 1 is connected with the electric energy storage electronic module 2 through the working mode converter 5 to control the loop current formed by the two inlet wires J1 and J2 to be increased or reduced instantly, and the signals are output to a remote central control room through the two inlet wires to enable the intermediate relay to be closed or opened.
The output of the high-frequency generator electronic module 3 is connected with the input end of the isolation transformer, and the output voltage V2 of the isolation transformer is connected with the sensor electronic module 4. The sensor electronic module 4 comprises a detection sensor, the detection sensor detects the material level or the liquid level of the material, and the output signal of the detection sensor is processed by the sensor electronic module 4 and then is output to the central controller electronic module 1.
The input ends of the two incoming wires are connected with a coil output wire and a ground wire of a central control room or an intermediate relay of the central control room or a PLC, and the output ends of the two incoming wires are respectively connected with a pin 1 and a pin 3 of a bridge rectifier BD 1.
The central controller electronic module 1, the electric energy storage electronic module 2, the high-frequency generator electronic module 3, the sensor electronic module 4 and the working mode converter 5 have independent functions and are effectively connected with each other to form a complete circuit diagram and are installed on a printed circuit board.
The printed circuit board is arranged in the circular metal box, covered by the metal cover and fixed by four stainless steel screws. The metal box and the metal cover are sealed by a sealing ring, so that the waterproof and dustproof effects are achieved; the middle of the metal box is transversely provided with a round hole for two wires to pass through, and the metal box is fixedly sealed by a chuck, and the bottom of the metal box is fixed with a flange by a connecting piece. The center of the flange is provided with a hole which is convenient for placing a metal rod or a steel wire rope, an insulating sleeve is sleeved outside the metal rod or the steel wire rope, the length of the insulating sleeve can be adjusted according to needs, one end of the metal rod or the steel wire rope is connected with a wiring terminal in the metal box, and the other end of the metal rod or the steel wire rope is connected with the hammer head. The hammer head is used as a probe of the detection sensor.
The following describes each module of the two-wire contact electronic level meter in detail.
The two-wire system is that the coil output and the ground wire of an intermediate relay (or PLC) of a central control room or an electric control room are only needed to be connected with the input end of the two-wire system contact type electronic level instrument, namely two incoming wires are respectively connected to a pin 1 and a pin 3 of a bridge rectifier BD1, a pin 2 and a pin 4 of the bridge rectifier are connected with an electric energy storage electronic module 2, see figure 3, and a power supply is not needed to be provided for the two-wire system contact type electronic level instrument independently, even if the intermediate relay or the PLC is in a normally open state, the voltage for maintaining the normal work of the electronic level instrument can be obtained by using the micro leakage current of the coil to.
Referring to fig. 3, the electric energy storage electronic module 2 includes a transistor T1, a field effect transistor T4, a voltage regulator diode DV, a resistor, and a capacitor; a pin 2 of the rectifier circuit device BD1 is connected in parallel with an emitter of a triode T1, one end of a resistor R2, a cathode of a voltage stabilizing diode DV2 and one end of a variable resistor RW1, a base of a triode T1 is connected in parallel with the other end of a resistor R2 and one end of a resistor R3, a collector of a triode T1 is connected with one end of a resistor R4, and the other end of the resistor R4 is connected in parallel with the other end of a resistor R3 and an anode of a; the other end of the variable resistor RW1 and the third pin are connected with one end of a resistor R1 in parallel, the cathode of the voltage stabilizing diode DV1 is connected with the other end of the resistor R1 and the source of the field effect transistor T4 in parallel, and the anode of the voltage stabilizing diode DV1 is grounded; the grid of the field effect transistor T4 is connected with the other end of the resistor R4 and one end of the capacitor C1 in parallel, the other end of the capacitor C1 is grounded, the grid of the field effect transistor T4 is connected with the output end VCC1, one end of the variable resistor RW2 is connected with the third pin in parallel and then connected with the output end VCC1, the other end of the variable resistor RW2 is connected with the resistor R7 in series, the other end of the resistor R7 is connected with the drain of the field effect transistor T4, one end of the capacitor C2 is connected with; the cathode of the voltage stabilizing diode DV3 is connected in series with the light emitting diode LD2 and then connected with the output end VCC1, the anode of the voltage stabilizing diode DV3 is grounded, one end of the capacitor C3 is connected with the output end VCC1, and the other end of the capacitor C3 is grounded.
The function of the electrical energy storage electronic module 2 is: 1. under the action of the voltage difference between two ends of the voltage stabilizing diode DV2, the triode T1 is conducted to work through the biasing and current limiting of the resistors R2, R3 and R4; under the voltage stabilizing effect of the voltage stabilizing diode DV1, a constant current loop is formed by the variable resistor RW1, the resistor R1, the field effect transistor T4, the variable resistor RW2, the resistor R7, the light emitting diode LD2 and the voltage stabilizing diode DV3, and then energy is stored continuously through the electrolytic capacitors C1 and C2, so that stable voltage VCC1 is obtained and is supplied to the central controller electronic module 1 and the high-frequency generator electronic module 3 for power supply, the light emitting diode LD2 is a power supply indicator lamp, and the light emitting diode is turned on as long as stable voltage is provided at the VCC1 end. 2. The variable resistors RW1 and RW2 are used for regulating voltage and current, when the intermediate relay or PLC is in a normally open state, the variable resistors RW1 and RW2 are regulated to enable the constant-current loop current to be added with loop current formed by the pin 2 of the bridge rectifier BD1 through the variable resistor RW1, the resistor R1 and the voltage-stabilizing diode DV1, and loop merging current formed by the two wires J1 and J2 is controlled between 200uA and 900uA, so that the intermediate relay or PLC is guaranteed not to generate misoperation. 3. In order to adapt to the use requirements of intermediate relays with different voltage levels, the intermediate relays with voltage levels of direct current 24V, 48V, 110V and alternating current 220V can be suitable by adjusting the resistance values of the variable resistors RW1 and RW2 and the resistors R1 and R7. 4. In this circuit diagram, VCC1 is positive and GND is negative.
Referring to fig. 4, the electronic module of the central controller includes a triode, a zener diode, and an integrated block U2A, wherein an emitter of the triode T2 is connected to a base of the triode T3, a collector of the triode T2 is connected in parallel with a collector of the triode T3 and then connected to an anode of the zener diode DV2, a cathode of the zener diode DV2 is connected to an output pin 2 of the bridge rectifier BD1, a base of the triode T2 is connected to a resistor R6 and then connected to output pins 2 and 4 of the operating mode converter, the output pins 2 and 4 of the operating mode converter are connected in parallel, and an emitter of the triode T3; the cathode and the anode of the voltage-stabilizing diode DV2 are connected with a resistor R5 in series with the light-emitting diode LD 1; the input end 5 of the integrated block U2A is connected with the output signal Text of the sensor electronic module 4, the input end 3 of the integrated block U2A is connected with the high-frequency pulse signal of the high-frequency generator electronic module 3, the pins U2A 4 and 6 of the integrated block are grounded, the pin 1 of the output end 1 of the integrated block U2A outputs a forward signal, the pin 2 of the output end 2 of the integrated block U2A outputs a reverse signal, and the pin 1 and the pin 2 of the output end of the integrated block U2A are respectively connected with the pin 1 and the pin 3 of the input end 5 of the working mode converter. The operating mode switching module 5 is a switch JP 1.
The 3-pin of the integrated block U2A (D flip-flop) in the central controller electronic module 1 is connected with the 4-pin input high-frequency pulse signal of the integrated block U1B (inverter) in the high-frequency generator electronic module 3; once the sensor electronic module 4 sends a signal for detecting the material level or the liquid level to the central controller electronic module 1, the central controller electronic module 1 outputs a high level or a low level through a working mode converter in a circuit to enable the triodes T2 and T3 to be switched on or switched off, so that the loop current formed by the two inlet wires J1 and J2 is increased or reduced instantly, an intermediate relay or a PLC is switched on or off instantly, and the requirement of the alarm purpose of the material level or the liquid level is met; the light emitting diode LD1 in the circuit diagram is lit to indicate that the intermediate relay or PLC is closed, whereas the light is not lit to indicate that the intermediate relay or PLC is open.
Referring to fig. 5, the electronic module 3 of the high frequency generator includes an inverter, an integrated block, a triode, and a bridge rectifier, wherein an output terminal of the inverter U1A is connected to an input terminal of the inverter U1B through a capacitor C4, an input terminal of the inverter U1A and an output terminal of the inverter U1B are connected to the capacitor C5 in parallel, an input terminal and an output terminal of the inverter U1A are connected to the resistor R9 in parallel, an input terminal and an output terminal of the inverter U1B are connected to the resistor R10 in parallel, the inverters U1A and U1B, the resistors R9 and R10, the capacitors C4 and C5 constitute the high frequency generator, and the; the output of the phase inverter U1B is connected with the pin 11 of the input end of the integrated block U2B, the pin 9 of the input end of the integrated block U2B is connected with the pin 12 of the output end, the pin 12 of the output end of the integrated block U2B outputs a reverse signal, the pins U2B and 10 of the integrated block are grounded, the pin 13 of the output end of the integrated block U2B outputs a forward signal, and the pin 13 of the output end of the integrated block U2B is connected with the base electrode of a triode T4 after being connected with a resistor; an emitter of the triode T4 is connected with a power VCC1, a collector of the triode T4 is connected with a resistor R15 and then is grounded, the capacitor C12 is connected with an emitter and a ground of the triode T4 in parallel, an output of a collector of the triode T4 is connected with an input end of an isolation transformer TRAN, the other end of the input end of the isolation transformer TRAN is grounded, an output end of the isolation transformer TRAN is respectively connected with a pin 1 and a pin 3 of the bridge rectifier BD2, a pin 2 of the bridge rectifier BD2 is connected with an anode of a diode D2, a cathode of the diode D2 is used as a power supply V2, an anode of the capacitor C6 is connected with a cathode of a diode D82.
The high-frequency generator electronic module 3 comprises an inverter U1A, an inverter U1B, resistors R9 and R10, capacitors C4 and C5, has a frequency of about 8Khz, and has two functions: 1. the 4-pin pulse output end of the inverter U1B is connected with the 3 pins of the integrated block U2A (D flip-flop) in the central controller electronic module 1; 2. the 4-pin pulse output of the inverter U1B is divided by two by an integrated block U2B (D flip-flop), and then drives the primary coil of the isolation transformer TRAN through a resistor R14, R15, a transistor T4 and a capacitor C12, and the secondary coil of the isolation transformer TRAN is rectified by a bridge rectifier BD2 and a rectifier diode D2, and then continuously stores energy through an electrolytic capacitor C6 to obtain a stable voltage V2, which is supplied to the sensor electronic module 4 for use.
Referring to fig. 6, the sensor electronic module 4 includes an inverter, a photocoupler, a resistor, a capacitor, and a detection sensor, the inverter U4A, the inverter U4B, and the inverter U4C are connected in series and then connected to the input end of the photocoupler U5, the other end of the input end of the photocoupler U5 is connected to the ground E, the input end of the inverter U4A is connected to the detection sensor, the input end of the inverter U4A is connected to the resistor R11, the resistor R12, the capacitor C8, and the capacitor C9 in parallel, the other end of the resistor R11 is connected to the power supply V2, the other end of the resistor R12 is connected to the ground E, the other end of the capacitor C36; the positive end of the output end of a photoelectric coupler U5 is connected with the electronic module 1 of the central controller as a detection sensor signal output line Text, the positive end of the output end of the photoelectric coupler U5 is connected with a capacitor C11, a resistor R16 and a resistor R13 in parallel, the other end of the resistor R13 is connected with a power VCC1, the other ends of the capacitor C11 and the resistor R16 are grounded, and the negative end of the output end of the photoelectric coupler U5 is grounded.
The sensor electronic module 4 comprises a detection sensor (probe for short), a detection signal processing circuit and a detection signal photoelectric isolation output circuit, and the output signal of the detection sensor is sent to the central controller electronic module 1 through an output line Text. Wherein 1, V2 represents the positive power supply in the circuit diagram; e represents that the power supply is negative and is communicated with the ground; at the moment, the bottom of the material stack is communicated with the ground, the material surface is used as a measured point, and similarly, if the liquid level is measured, the metal container for storing the liquid is communicated with the ground, and the surface of the liquid is used as the measured point. In the circuit diagram, VCC1 and GND represent the positive power supply and the negative power supply of another group, and are shared by the electric energy storage electronic module 2, the central controller electronic module 1 and the high-frequency generator electronic module 3, and the two groups of power supplies are isolated by an isolation transformer TRAN and a photoelectric coupler U5. The detection signal processing circuit consists of resistors R11 and R12, capacitors C6, C8, C9, inverters U4A, U4B, U4C and light emitting diodes of a photoelectric coupler U5, when the detection sensor does not detect the material level or the liquid level, the logic of a pin 1 of the inverter U4A is high level '1', the logic of a pin 6 of the inverter U4C is low level '0', and the light emitting diodes of the photoelectric coupler U5 are not conducted; when the detection sensor detects the material level or the liquid level, the logic of pin 1 of the inverter U4A is low level "0", so that the logic of pin 6 of the inverter U4C is high level "1", and the light emitting diode of the photoelectric coupler U5 is conducted. 2. The resistances of the resistors R11 and R12 are synchronously adjusted to adjust the sensitivity of the detection signal, when the resistances of the resistors R11 and R12 are larger, the photoelectric isolation output circuit of the sensitivity of the detection signal is composed of a phototriode of the optoelectronic coupler U5, a capacitor C11, a resistor R13 and R16, when the detection sensor does not detect the material level or the liquid level, the logic of the collector output end of the phototriode of the optoelectronic coupler U5 is high level "1", when the detection sensor detects the material level or the liquid level, the logic of the collector output end of the phototriode of the optoelectronic coupler U5 is low level "0", and the signal is connected to the 5-pin input end of the integrated block U2A (D flip-flop) of the electronic module 1 of the central controller.
The two-wire system contact type electronic material level instrument only needs to utilize the coil output line and the ground wire of the intermediate relay (or PLC) of the central control room or the electric control room to be connected with the input end of the two-wire system contact type electronic material level instrument, and solves the following technical problems under the condition that a power supply is not required to be independently provided for the two-wire system contact type electronic material level instrument:
1. the energy storage and control of the contact type electronic material level instrument and the effective detection of the sensor are realized by using two lines.
2. The method solves the problem that the detection of the material level or the liquid level is not influenced by the shape, the concentration, the temperature and the dust of the material by measuring the conductivity of the material (or the liquid), and improves the detection precision.
3. Due to the adoption of the principle method of detecting the conductivity of the material (or liquid), the alarm time after the material level or the liquid level is detected is very short (compared with a rotation resistance type material level instrument, a mercury type material level instrument, a permanent magnet type material level instrument and the like which are used in the current market).
4. In order to adapt to the use requirements of intermediate relays with different voltage levels, the intermediate relays with voltage levels of direct current 24V, 48V, 110V and alternating current 220V can be suitable at present by adjusting the resistance values of the variable resistors RW1 and RW2 and the resistors R1 and R7.
The two-wire contact type electronic level meter has the advantages of long service life, high detection precision, short alarm time, low cost, electric energy saving and the like, and is not influenced by the shape, temperature, dust, medium concentration and the like of a measured substance through tests.
The present invention is not limited to the above embodiments, and any modifications, equivalent replacements, improvements, etc. within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (5)
1. A two-wire system contact type electronic material level instrument is characterized in that: the method comprises the following steps: the system comprises a central controller electronic module (1), an electric energy storage electronic module (2), a high-frequency generator electronic module (3), a sensor electronic module (4) and a working mode converter (5);
the two incoming wires J1 and J2 are respectively connected to a pin 1 and a pin 3 of a bridge rectifier BD1, a pin 4 of the bridge rectifier BD1 is grounded, a pin 2 of the bridge rectifier BD1 is connected with an electric energy storage electronic module (2), the electric energy storage electronic module (2) outputs a stabilized voltage power supply VCC1, and the stabilized voltage power supply VCC1 supplies power to the central controller electronic module (1) and the high-frequency generator electronic module (3);
the central controller electronic module (1) is connected with the high-frequency generator electronic module (3), the central controller electronic module (1) receives an output signal of the sensor electronic module (4), the output of the central controller electronic module (1) is connected with the control electric energy storage electronic module (2) through the working mode converter (5), and the signal is output to a remote central control room or an electric control room through two incoming wires;
the output of the high-frequency generator electronic module (3) is connected with the input end of an isolation transformer, and the output voltage V2 of the isolation transformer is connected with the sensor electronic module (4);
the sensor electronic module (4) comprises a detection sensor, the detection sensor detects the material level or the liquid level of the material, and the output signal of the detection sensor is processed by the sensor electronic module (4) and then is output to the central controller electronic module (1);
the input ends of the two incoming wires are connected with an output line of a central control room and a ground wire, or the input ends of the two incoming wires are connected with an intermediate relay of an electric control room or a coil output line of a PLC (programmable logic controller) and the ground wire, and the output ends of the two incoming wires are respectively connected with a pin 1 and a pin 3 of a bridge rectifier BD 1.
2. The two-wire contact electronic level meter according to claim 1, wherein: the electric energy storage electronic module (2) comprises a triode T1, a field effect transistor T4, a voltage stabilizing diode, a resistor and a capacitor; a pin 2 of the bridge rectifier BD1 is connected with an emitter of a triode T1, one end of a resistor R2, a cathode of a voltage stabilizing diode DV2 and one end of a variable resistor RW1 in parallel, a base of a triode T1 is connected with the other end of a resistor R2 and one end of a resistor R3 in parallel, a collector of a triode T1 is connected with one end of a resistor R4, and the other end of the resistor R4 is connected with the other end of a resistor R3 and an anode of a voltage stabilizing; the other end of the variable resistor RW1 and the third pin are connected with one end of a resistor R1 in parallel, the cathode of the voltage stabilizing diode DV1 is connected with the other end of the resistor R1 and the source of the field effect transistor T4 in parallel, and the anode of the voltage stabilizing diode DV1 is grounded; the grid of the field effect transistor T4 is connected with the other end of the resistor R4 and one end of the capacitor C1 in parallel, the other end of the capacitor C1 is grounded, the grid of the field effect transistor T4 is connected with the output end VCC1, one end of the variable resistor RW2 is connected with the third pin in parallel and then connected with the output end VCC1, the other end of the variable resistor RW2 is connected with the resistor R7 in series, the other end of the resistor R7 is connected with the drain of the field effect transistor T4, one end of the capacitor C2 is connected with; the cathode of the voltage stabilizing diode DV3 is connected in series with the light emitting diode LD2 and then connected with the output end VCC1, the anode of the voltage stabilizing diode DV3 is grounded, one end of the capacitor C3 is connected with the output end VCC1, and the other end of the capacitor C3 is grounded.
3. The two-wire contact electronic level meter according to claim 1, wherein: the central controller electronic module (1) comprises a triode, a voltage stabilizing diode and an integrated block U2A, wherein an emitter of a triode T2 is connected with a base electrode of a triode T3, a collector of a triode T2 and a collector of a triode T3 are connected in parallel and then connected with an anode of a voltage stabilizing diode DV2, a cathode of the voltage stabilizing diode DV2 is connected with a pin 2 output by the bridge rectifier 1, a base electrode of a triode T2 is connected with a resistor R6 and then connected with a pin 2 and a pin 4 of an output end of the working mode converter (5), a pin 2 and a pin 4 of the output end of the working mode converter (5) are connected in parallel; the cathode and the anode of the voltage-stabilizing diode DV2 are connected with a resistor R5 in series with the light-emitting diode LD 1; the input end 5 of the integrated block U2A is connected with the output signal Text of the sensor electronic module (4), the input end 3 of the integrated block U2A is connected with the high-frequency pulse signal of the high-frequency generator electronic module (3), the pins U2A 4 and 6 of the integrated block are grounded, the pin 1 of the output end of the integrated block U2A outputs a forward signal, the pin 2 of the output end of the integrated block U2A outputs a reverse signal, and the pin 1 and the pin 2 of the output end of the integrated block U2A are respectively connected with the pin 1 and the pin 3 of the input end of the working mode converter (5);
the working mode converter (5) is a change-over switch JP 1;
the integrated block U2A is a D flip-flop, and the ports of the D flip-flop correspond to the pins of the integrated block U2A as follows: the D end corresponds to the 5 pins, the Q end corresponds to the 1 pin,the end corresponds to 2 feet, the CLK end corresponds to 3 feet, the R end corresponds to 4 feet, and the S end corresponds to 6 feet.
4. The two-wire contact electronic level meter according to claim 1, wherein: the high-frequency generator electronic module (3) comprises an inverter, an integrated block, a triode and a bridge rectifier, wherein the output end of an inverter U1A is connected with the input end of an inverter U1B through a capacitor C4, the input end of an inverter U1A and the output end of the inverter U1B are connected with a capacitor C5 in parallel, the input end and the output end of the inverter U1A are connected with a resistor R9 in parallel, the input end and the output end of the inverter U1B are connected with a resistor R10 in parallel, the inverter U1A and U1B, resistors R9 and R10 and capacitors C4 and C5 form a high-frequency generator, and the inverter U1B; the output of the phase inverter U1B is connected with the pin 11 of the input end of the integrated block U2B, the pin 9 of the input end of the integrated block U2B is connected with the pin 12 of the output end, the pin 12 of the output end of the integrated block U2B outputs a reverse signal, the pins U2B and 10 of the integrated block are grounded, the pin 13 of the output end of the integrated block U2B outputs a forward signal, and the pin 13 of the output end of the integrated block U2B is connected with the base electrode of a triode T4 after being connected with a resistor; an emitter of the triode T4 is connected with a power supply VCC1, a collector of the triode T4 is connected with a resistor R15 and then is grounded, the capacitor C12 is connected with an emitter and a ground of the triode T4 in parallel, an output of a collector of the triode T4 is connected with an input end of an isolation transformer TRAN, the other end of the input end of the isolation transformer TRAN is grounded, an output end of the isolation transformer TRAN is respectively connected with a pin 1 and a pin 3 of a bridge rectifier BD2, a pin 2 of the bridge rectifier BD2 is connected with an anode of a diode D2, a cathode of the diode D2 is used as a power supply V2, an anode of the capacitor C6 is connected with a cathode of a diode D;
the integrated block U2B is a D flip-flop, and the ports of the D flip-flop correspond to the pins of the integrated block U2B as follows: the D end corresponds to 9 feet, the Q end corresponds to 13 feet,the end corresponds to 12 pins, the CLK end corresponds to 11 pins, the R end corresponds to 10 pins, and the S end corresponds to 8 pins.
5. The two-wire contact electronic level meter according to claim 1, wherein: the sensor electronic module (4) comprises an inverter, a photoelectric coupler, a resistor, a capacitor and a detection sensor, wherein the inverter U4A, the inverter U4B and the inverter U4C are connected in series and then are connected with the input end of the photoelectric coupler U5, the other end of the input end of the photoelectric coupler U5 is connected with the ground E, the input end of the inverter U4A is connected with the detection sensor, the input end of the inverter U4A is connected with one end of a resistor R11, a resistor R12, a capacitor C8 and a capacitor C9 in parallel, the other end of the resistor R11 is connected with a power supply V2, the other end of the resistor R12 is connected with the ground E, the other end of the capacitor C8 is; the positive end of the output end of a photoelectric coupler U5 is connected with the central controller electronic module (1) as a detection sensor signal output line Text, the positive end of the output end of the photoelectric coupler U5 is connected with one end of a capacitor C11, a resistor R16 and a resistor R13 in parallel, the other end of a resistor R13 is connected with a power supply VCC1, the other ends of the capacitor C11 and the resistor R16 are grounded, and the negative end of the output end of the photoelectric coupler U5 is grounded; one end of the capacitor C6 is connected with the power supply V2, and the other end of the capacitor C6 is connected with the ground E.
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