Signal conversion circuit for electrode type liquid level detection and water storage tank liquid level measurement and control device

Abstract

The utility model relates to the technical field of liquid level detection equipment, in particular to an electrode type liquid level detection device which is reasonable in structure, low in cost, reliable in work and capable of rapidly and accurately converting output signals of a traditional electrode type liquid level detection device. The electrode type signal conversion circuit for liquid level detection and the water storage tank liquid level measurement and control device are provided with a chip at least provided with two paths of 2-input NOR gates, each path of NOR gate of the chip is provided with two signal input ends and one path of signal output end, and the two NOR gate chips are respectively marked as IC1A and IC1E, two signal input ends of the NOR gate chip IC1A are connected with the high liquid level wiring terminal E1, and the high liquid level wiring terminal E1 is connected with the adjustable resistor R1, so that the low-cost electrode type liquid level detection can be widely applied.

Description

TECHNICAL FIELD

[0001] The utility model relates to liquid level detection equipment technical field, and specifically is a structure is reasonable, cost is low, reliable work, can with traditional electrode formula liquid level detection device's output signal carries out fast accurate conversion, in order to facilitate the system subsequent processing and the signal conversion circuit for electrode formula liquid level detection and water storage tank liquid level control device of execution control. BACKGROUND

[0002] The electrode formula liquid level detection device and its corresponding control switch can cooperatively complete liquid level detection and control, and are widely applied due to low cost. The working principle of the electrode formula liquid level detection device is to detect the liquid level by using the conductivity of the liquid, and the structure is simple and convenient to use. The corresponding control switch can control the pump or valve to discharge the liquid to lower the liquid level or control the pump or valve to supplement the liquid to raise the liquid level when detecting the high or low liquid level, so as to achieve the purpose of controlling the stable liquid level.

[0003] In actual application, the point detection of the electrode formula liquid level detection device is only used for the control of the pump or valve, and there is no feedback of the electrode on-off state, so the liquid level change cannot be observed from the control device. In addition, the liquid level detection may fail due to the scaling on the surface of the electrode and other reasons, and further lead to the problem of out-of-control liquid level. If the electrode formula liquid level detection device is directly connected to the PLC control device, the intelligent control device such as PLC cannot accurately detect the on-off state of the electrode due to different conductivity of the liquid and different impurity content.

[0004] In order to overcome the above-mentioned defects, a liquid level conversion device is needed, which can convert the liquid level signal detected by the electrode into a signal that can be input into the intelligent control device such as PLC, so as to judge and give corresponding measures by using the intelligent program. SUMMARY

[0005] The utility model discloses a structure is reasonable, cost is low, reliable work, can with traditional electrode formula liquid level detection device's output signal carries out fast accurate conversion, in order to facilitate the system subsequent processing and the signal conversion circuit for electrode formula liquid level detection and water storage tank liquid level control device of execution control.

[0006] The utility model reaches by the following measures:

[0007] The utility model discloses a signal conversion circuit for electrode type liquid level detection, characterized in that it comprises at least two 2-input NAND gate chips, each of which has two signal input terminals and one signal output terminal, and the two NAND gate chips are respectively marked as IC1A and IC1E, wherein the two signal input terminals of the NAND gate chip IC1A are connected with a high liquid level terminal E1, the high liquid level terminal E1 is connected with an adjustable resistor R1, the other end of the adjustable resistor R1 is connected with a positive terminal A1, and the output terminal of the NAND gate chip IC1A is connected with a high liquid level signal output terminal X1; the two signal input terminals of the NAND gate chip IC1E are both connected with a low liquid level terminal E2, the low liquid level terminal E2 is connected with one end of an adjustable resistor R2, the other end of the adjustable resistor R2 is connected with the positive terminal A1, and the signal output terminal of the NAND gate chip IC1E is connected with a low liquid level signal output terminal X2.

[0008] In the utility model, the high liquid level terminal E1 is connected with a high liquid level detection electrode in the electrode type liquid level detection device, the low liquid level terminal E2 is connected with a low liquid level detection electrode in the electrode type liquid level detection device, the high liquid level signal output terminal X1 and the low liquid level signal output terminal X2 can be directly connected with the signal input terminal of the PLC programmable logic controller, and the signal of the electrode type liquid level detection device can be transmitted.

[0009] The adjustable resistor R1 and the adjustable resistor R2 have the same resistance range of 10-100kΩ, and the sensitivity of the liquid level detection can be increased or decreased by reducing or increasing the resistance and increasing or reducing the current flowing through the electrode.

[0010] In the utility model, the NAND gate chip is a four-way 2-input NAND gate chip 74HC02D,653 or a five-way 2-input NAND gate chip 74LS02, and the GND terminal is connected with a power input terminal A2.

[0011] In the utility model, the high liquid level signal output terminal X1 and the low liquid level signal output terminal X2 are directly connected with the PLC programmable logic controller, the high and low level signals output by X1 and X2 can be used to display the detection state of the electrode type liquid level detection device in real time on the man-machine interface computer in real-time communication with the PLC programmable logic controller.

[0012] The utility model discloses still further be equipped with liquid level detection control circuit, in order to facilitate with the water storage tank's water replenishing pump or water pump linkage, realize according to liquid level information and carry out the automatic control of water replenishing or drainage, liquid level detection control circuit is equipped with three-way or non-gate, respectively are recorded as IC1B, IC1C, IC1D, still contain a light emitting diode D1 for indicating lamp and a NPN triode Q1.

[0013] The utility model discloses still further be equipped with liquid level detection control circuit, in order to facilitate with the water storage tank's water replenishing pump or water pump linkage, realize according to liquid level information and carry out the automatic control of water replenishing or drainage, liquid level detection control circuit is equipped with three-way or non-gate, respectively are recorded as IC1B, IC1C, IC1D, still contain a light emitting diode D1 for indicating lamp and a NPN triode Q1.

[0014] The utility model discloses still further be equipped with liquid level detection control circuit, in order to facilitate with the water storage tank's water replenishing pump or water pump linkage, realize according to liquid level information and carry out the automatic control of water replenishing or drainage, liquid level detection control circuit is equipped with three-way or non-gate, respectively are recorded as IC1B, IC1C, IC1D, still contain a light emitting diode D1 for indicating lamp and a NPN triode Q1.

[0015] The utility model discloses still further be equipped with liquid level detection control circuit, in order to facilitate with the water storage tank's water replenishing pump or water pump linkage, realize according to liquid level information and carry out the automatic control of water replenishing or drainage, liquid level detection control circuit is equipped with three-way or non-gate, respectively are recorded as IC1B, IC1C, IC1D, still contain a light emitting diode D1 for indicating lamp and a NPN triode Q1.

[0016] Compared with the prior art, this utility model has significant advantages such as reasonable structure, low construction cost, and reliable operation. Attached image description:

[0017] Appendix Figure 1 This is a schematic diagram of the signal conversion circuit for electrode-type liquid level detection in this utility model.

[0018] Appendix Figure 2 This is a schematic diagram of the signal conversion and liquid level detection control circuit in this utility model.

[0019] Figure labels: 1. Signal conversion circuit for electrode-type liquid level detection; 2. Water storage tank; 3. Signal conversion and liquid level detection control circuit. Detailed implementation method:

[0020] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0021] Example 1:

[0022] As attached Figure 1 As shown, this example provides a signal conversion circuit for electrode-type liquid level detection, and provides a device for applying the signal conversion circuit for electrode-type liquid level detection to liquid level detection in a water storage tank;

[0023] In this example, a chip with at least two 2-input NOR gates is provided. Each NOR gate of the chip has two signal input terminals and one signal output terminal. The two NOR gate chips are denoted as IC1A and IC1E, respectively. The two signal input terminals of NOR gate chip IC1A are connected to the high liquid level terminal E1. The high liquid level terminal E1 is connected to the adjustable resistor R1. The other end of the adjustable resistor R1 is connected to the positive power supply terminal A1. The output terminal of NOR gate chip IC1A is connected to the high liquid level signal output terminal X1. The two signal input terminals of NOR gate chip IC1E are both connected to the low liquid level terminal E2. The low liquid level terminal E2 is connected to one end of the adjustable resistor R2. The other end of the adjustable resistor R2 is connected to the positive power supply terminal A1. The signal output terminal of NOR gate chip IC1E is connected to the low liquid level signal output terminal X2.

[0024] In this invention, the high liquid level terminal E1 is used to connect to the high liquid level detection electrode in the electrode-type liquid level detection device, and the low liquid level terminal E2 is used to connect to the low liquid level detection electrode in the electrode-type liquid level detection device. The terminal E0 is used to connect to the water tank body and the negative terminal A2 of the power supply. The high liquid level signal output terminal X1 and the low liquid level signal output terminal X2 can be directly connected to the signal input terminal of the PLC programmable logic controller to complete the transmission of the signal of the electrode-type liquid level detection device.

[0025] The adjustable resistance R1 and the adjustable resistance R2 have the same resistance range of 10-100kΩ, and the sensitivity of liquid level detection can be increased or decreased by reducing or increasing the resistance, and increasing or reducing the current flowing through the electrode.

[0026] The NOR gate chip of the electrode type liquid level detection signal conversion circuit is a four-way 2-input NOR gate chip 74HC02D,653 or a five-way 2-input NOR gate chip 74LS02, and the GND end is connected with the power negative terminal A2.

[0027] In the use process of the example, the high liquid level signal output end X1 and the low liquid level signal output end X2 are directly connected with the PLC programmable logic controller, high and low level signals are output through X1 and X2, and the detection data of the electrode type liquid level detection device can be displayed in real time, specifically: when the liquid level in the water storage tank is lower than the low liquid level detection electrode, X1 and X2 both output low level; when the liquid level in the water storage tank gradually rises to the low liquid level detection electrode after water replenishment, X1 outputs low level signal and X2 outputs high level signal, that is, the external operator can know that the current low liquid level detection electrode successfully collects liquid level data; when the liquid level further rises but has not reached the high liquid level detection electrode, X1 outputs low level and X2 outputs high level; when the liquid level further rises to the high liquid level detection electrode, X1 outputs high level and X2 outputs high level.

[0028] The potential signals output through X1 and X2 can be received by the external PLC control mechanism and help the whole system to further perform related actions, the device quantity of the example scheme is small, the construction is simple, the cost is low, and the work is reliable.

[0029] Embodiment 2:

[0030] As shown in the accompanying Figure 2 The example provides a water storage tank liquid level measurement and control device, which is provided with a water storage tank, the tank body of the water storage tank is a metal tank body, and is provided with an electrode type liquid level detection component and an electrode type liquid level detection signal conversion circuit as described in embodiment 1, the electrode type liquid level detection component comprises a high liquid level detection electrode and a low liquid level detection electrode, the high liquid level detection electrode is installed above the low liquid level detection electrode, and the low liquid level detection electrode is installed at the middle part of the tank body of the water storage tank.

[0031] The example is further provided with a liquid level detection control circuit, so as to be linked with a water replenishing pump or a water discharging pump of the water storage tank, and automatic control of water replenishing or water discharging according to liquid level information is realized, the liquid level detection control circuit is provided with three NOR gates, which are respectively marked as IC1B, IC1C and IC1D, further comprises a light emitting diode D1 used as an indicator lamp and an NPN triode Q1.

[0032] The utility model discloses a liquid level detection control circuit, or the one-way input end of NAND gate chip IC1B is connected with the output end of or NAND gate chip IC1A in electrode formula liquid level detection signal conversion circuit, and the other way input end of NAND gate chip IC1B is connected with the output end of or NAND gate chip IC1C and the two-way input end of or NAND gate chip IC1D, and the single pole double throw switch SW1 is connected, and the single pole double throw switch SW1 is connected with the B electrode of triode Q1 through resistance R3, and the output end of NAND gate chip IC1B is connected with the one-way input end of or NAND gate chip IC1C, and the other way input end of or NAND gate chip IC1C is connected with low liquid level terminal E2, and the GND end of or NAND gate chip IC1C is connected with ground, and the output end of or NAND gate chip IC1D is connected with single pole double throw switch SW1, and the C electrode of triode Q1 is connected with the negative pole of emitting diode D1 through resistance R4, and the positive pole of emitting diode D1 is connected with power supply positive pole, and the E electrode of triode Q1 is connected with power supply negative pole terminal A2, and the C electrode of triode Q1 is connected with terminal C2, and the terminal C2 is used for connecting the negative pole of the control coil of drainage pump or drainage valve, and the positive pole of emitting diode D1 is also connected with terminal C1, and the terminal C1 is used for connecting the positive pole of the control coil of drainage valve or drainage pump.

[0033] In the example, R3 is 10kΩ, and R4 is 1kΩ.

[0034] The signal conversion and liquid level detection control circuit uses a five-way 2-input NAND gate chip 74LS02, and the GND end is connected with the power supply input terminal A2.

[0035] In the example, when working, the high and low liquid level detection electrodes of the water storage tank and the conductive tank body are connected to the terminal E1, E2 and E0 through wires, and the power supply is connected to the terminal A1 and A2 according to the polarity, then according to the liquid level change in the water storage tank 2, the terminal X1, X2, C1, C2 and emitting diode D1 respectively obtain the following results:

[0036] When the liquid level is below the low liquid level detection electrode, both the terminals X1 and X2 output low level, both the terminals C1 and C2 output high level, and the light emitting diode D1 is extinguished; when the liquid level reaches the low liquid level detection electrode, the terminal X1 keeps low level, the terminal X2 outputs high level, both the terminals C1 and C2 output high level, and the light emitting diode D1 keeps extinguished; when the liquid level reaches the high liquid level detection electrode, both the terminals X1 and X2 output high level, the terminal C1 outputs high level, the terminal C2 outputs low level, and the light emitting diode D1 is lighted; when the liquid level gradually decreases and is below the high liquid level detection electrode, the terminal X1 outputs low level, the terminal X2 outputs high level, the terminal C1 outputs high level, the terminal C2 keeps low level, and the light emitting diode D1 keeps lighted; when the liquid level continues to gradually decrease and is below the low liquid level detection electrode, both the terminals X1 and X2 output low level, both the terminals C1 and C2 output high level, and the light emitting diode D1 is extinguished;

[0037] After the single-pole double-throw switch SW1 is toggled, according to the liquid level change in the water storage tank 2, the output results of the terminals X1 and X2 are the same as the above process, and the output results of the terminals C1 and C2 and the light emitting diode D1 are opposite to the above results.

[0038] When the terminals C1 and C2 are connected with the control coils of the drainage pump or the drainage valve respectively, the water storage tank can be controlled according to the liquid level when the single-pole double-throw switch SW1 keeps the state as shown in the figure, and the water storage tank can be controlled for water replenishment after the single-pole double-throw switch SW1 is toggled; through the light emitting diode D1, the control signal of the pump or the valve can be displayed, and the operator can intuitively understand. Figure 2

[0039] In the example, since the low liquid level detection electrode is arranged at the middle part of the condensate water storage tank, the drainage mode always keeps a certain water level at the bottom of the condensate water storage tank.

[0040] Compared with the prior art, the utility model discloses a liquid level conversion control switch which can independently control and provide a liquid level signal to an intelligent control device such as PLC, and then uses an intelligent program to judge and give corresponding measures, so that the electrode type liquid level detection with low cost is widely applied.​

Claims

1. A signal conversion circuit for electrode type liquid level detection, characterized by comprising: The chip has at least two 2-input NOR gates, each of which has two signal input terminals and one signal output terminal, and the two NOR gate chips are respectively marked as IC1A and IC1E, wherein the two signal input terminals of the NOR gate chip IC1A are connected with a high liquid level terminal E1, the high liquid level terminal E1 is connected with an adjustable resistor R1, the other end of the adjustable resistor R1 is connected with a positive terminal A1, and the output terminal of the NOR gate chip IC1A is connected with a high liquid level signal output terminal X1; the two signal input terminals of the NOR gate chip IC1E are both connected with a low liquid level terminal E2, the low liquid level terminal E2 is connected with one end of an adjustable resistor R2, the other end of the adjustable resistor R2 is connected with the positive terminal A1, and the signal output terminal of the NOR gate chip IC1E is connected with a low liquid level signal output terminal X2.

2. The signal conversion circuit for electrode type liquid level detection according to claim 1, characterized in that, The high liquid level terminal E1 is connected with a high liquid level detection electrode in the electrode type liquid level detection device, the low liquid level terminal E2 is connected with a low liquid level detection electrode in the electrode type liquid level detection device, and the high liquid level signal output terminal X1 and the low liquid level signal output terminal X2 can be directly connected with signal input terminals of a PLC programmable logic controller to complete signal transmission of the electrode type liquid level detection device.

3. The signal conversion circuit for electrode type liquid level detection according to claim 1, characterized in that, The adjustable resistor R1 and the adjustable resistor R2 have a resistance range of 10-100kΩ.

4. The signal conversion circuit for electrode type liquid level detection according to claim 1, characterized in that, The NOR gate chip adopts a four-way 2-input NOR gate chip 74HC02D653 or a five-way 2-input NOR gate chip 74LS02.

5. A water storage tank liquid level measuring and controlling device, provided with a water storage tank, the tank body of the water storage tank is a metal tank body, characterized in that, The electrode type liquid level detection device comprises a high liquid level detection electrode and a low liquid level detection electrode, the high liquid level detection electrode is installed above the low liquid level detection electrode, the low liquid level detection electrode is installed at a middle or lower part of the water storage tank body, and the tank body is connected with a power input terminal A2 of the electrode type liquid level detection signal conversion circuit.

6. The water storage tank liquid level measuring and controlling device according to claim 5, characterized in that, The liquid level detection control circuit is provided with three NOR gates, which are respectively marked as IC1B, IC1C and IC1D, and further comprises a light emitting diode D1 used as an indicator lamp and an NPN triode Q1.

7. The water storage tank liquid level measuring and controlling device according to claim 6, characterized in that, The liquid level detection control circuit, or the input end of the NOR gate chip IC1B is connected with the output end of the signal conversion circuit of the electrode type liquid level detection in the NOR gate chip IC1A, the other input end of the NOR gate chip IC1B is connected with the output end of the NOR gate chip IC1C and the two input ends of the NOR gate chip IC1D are connected with the single-pole double-throw switch SW1, the single-pole double-throw switch SW1 is connected with the B electrode of the transistor Q1 through the resistor R3, the output end of the NOR gate chip IC1B is connected with the input end of the NOR gate chip IC1C, the other input end of the NOR gate chip IC1C is connected with the low liquid level terminal E2, the GND end of the NOR gate chip IC1C is grounded, the output end of the NOR gate chip IC1D is connected with the single-pole double-throw switch SW1, the C electrode of the transistor Q1 is connected with the negative electrode of the light emitting diode D1 through the resistor R4, the positive electrode of the light emitting diode D1 is connected with the positive electrode of the power supply, the E electrode of the transistor Q1 is grounded, the C electrode of the transistor Q1 is connected with the terminal C2, the terminal C2 is used for connecting the negative electrode of the control coil of the drain pump or the drain valve, the positive electrode of the light emitting diode D1 is also connected with the terminal C1, and the terminal C1 is used for connecting the positive electrode of the control coil of the drain valve or the drain pump.

Images