Double-channel TDS data acquisition module of water dispenser

Abstract

The utility model relates to the technical field of water dispensers, and particularly discloses a double-channel TDS data acquisition module of a water dispenser, which is simple in circuit structure, capable of saving two A / D (analog / digital) input ports and low in TDS detection and signal transmission cost, and comprises a detection component, a TDS acquisition circuit and an isolating circuit, the detection assembly comprises a first TDS sensor and a second TDS sensor which are used for collecting TDS signals in a water body; the TDS acquisition circuit is electrically connected with the first TDS sensor and the second TDS sensor respectively; the isolation circuit comprises a first optical coupling isolator and a second optical coupling isolator which are electrically connected with the TDS acquisition circuit, an RS485 signal transceiver which is electrically connected with the first optical coupling isolator and the second optical coupling isolator, and a serial port connector which is electrically connected with the RS485 signal transceiver.

Description

Technical Field

[0001] The utility model relates to the technical field of water dispensers, in particular to a dual-channel TDS data acquisition module for water dispensers. Background Art

[0002] TDS (Total Dissolved Solids) content refers to the concentration of total dissolved substances in water, which mainly reflects the Ca 2+ MG 2+ 、Na + , K + The concentration of plasma has a good correspondence with the hardness and conductivity of water, and is an important indicator for evaluating the purity of drinking water. At present, most water dispensers on the market are equipped with TDS detection functions to monitor the total dissolved solid content in drinking water in real time to ensure the cleanliness and safety of drinking water. However, in traditional water dispensers with TDS detection functions, the TDS sensor detects that the input voltage of TDS data is 5V, and the output analog quantity is 0-2.3V, while the A / D analog quantity input required by the PLC controller is 0-10V. The two are incompatible, and the detected TDS data cannot be directly input into the PLC controller for processing. It is necessary to set up a conversion circuit and occupy two A / D input ports to transmit the TDS data to the PLC controller. The TDS detection circuit structure of the water dispenser is complex, and the number of occupied input ports is large, which increases the cost of TDS detection and signal transmission. Utility Model Content

[0003] Based on this, it is necessary to provide a dual-channel TDS data acquisition module for a water dispenser with a simple circuit structure, which can save two A / D input ports and has low TDS detection and signal transmission costs, in order to address the above shortcomings.

[0004] A dual-channel TDS data acquisition module for a water dispenser, comprising:

[0005] A detection component, the detection component comprising a first TDS sensor and a second TDS sensor for collecting TDS signals in water;

[0006] A TDS acquisition circuit, wherein the TDS acquisition circuit is electrically connected to the first TDS sensor and the second TDS sensor respectively; and

[0007] An isolation circuit includes a first optocoupler isolator and a second optocoupler isolator respectively electrically connected to the TDS acquisition circuit, an RS485 signal transceiver electrically connected to the first optocoupler isolator and the second optocoupler isolator, and a serial port connector electrically connected to the RS485 signal transceiver.

[0008] In one embodiment, the TDS acquisition circuit includes an MCU electrically connected to the first TDS sensor and the second TDS sensor, and a first filter circuit, a second filter circuit, and a third filter circuit electrically connected to the MCU.

[0009] In one embodiment, the first filtering circuit includes a first capacitor and a second capacitor electrically connected to the MCU and connected in parallel to the ground; the second filtering circuit includes a third capacitor electrically connected to the MCU and connected to the ground; and the third filtering circuit includes a fourth capacitor electrically connected to the MCU and connected to the ground.

[0010] In one of the embodiments, the TDS acquisition circuit further includes a photodiode connected to the first optocoupler isolator and the second optocoupler isolator.

[0011] In one embodiment, the isolation circuit further includes a first voltage divider circuit and a second voltage divider circuit for being electrically connected to an external power supply, the first voltage divider circuit being electrically connected to a first optocoupler isolator, and the second voltage divider circuit being electrically connected to a second optocoupler isolator.

[0012] In one embodiment, the isolation circuit further includes a fourth filtering circuit electrically connected to the RS485 signal transceiver.

[0013] The dual-channel TDS data acquisition module for a water dispenser of the utility model can convert the signals detected from the first TDS sensor and the second TDS sensor into RS485 signals by combining the TDS acquisition circuit with the isolation circuit, and output them through the serial port connector. Since the serial port connector can be connected to the RS485 port of the PLC controller, the dual-channel TDS data acquisition module for the water dispenser can be directly connected to the PLC controller without setting up related conversion circuits. The circuit structure is simple, and two A / D input ports can be saved, thereby reducing the occupancy of the input ports and reducing the cost of TDS detection and signal transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a structural diagram of a dual-channel TDS data acquisition module for a water dispenser in one embodiment of the utility model;

[0015] Figure 2 This is a circuit schematic diagram of a first TDS sensor in one embodiment of the utility model;

[0016] Figure 3 This is a circuit schematic diagram of a second TDS sensor in one embodiment of the utility model;

[0017] Figure 4 A circuit schematic diagram of a TDS acquisition circuit in one embodiment of the utility model;

[0018] Figure 5 The figure is a circuit schematic diagram of an isolation circuit in one embodiment of the utility model. DETAILED DESCRIPTION

[0019] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the utility model. However, the utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the utility model, so the utility model is not limited by the specific embodiments disclosed below.

[0020] Please combine Figure 1-5 The utility model discloses a dual-channel TDS data acquisition module for a water dispenser, which has a simple circuit structure, can save two A / D input ports, and has low TDS detection and signal transmission costs. The dual-channel TDS data acquisition module for a water dispenser is based on RS485-TTL communication to realize the transmission of TDS data. The dual-channel TDS data acquisition module for a water dispenser includes a detection component 100, a TDS acquisition circuit 200, and an isolation circuit 300, wherein the detection component 100 is used to collect information on the total dissolved solid content in the water body to be detected, and sends the collected information to the TDS acquisition circuit 200 for processing. The data processed by the TDS acquisition circuit 200 is further converted into an RS485 signal via the isolation circuit 300, so that the PLC controller can directly receive the RS485 signal and process it. Specifically, in this embodiment, the detection component 100 includes a first TDS sensor 110 and a second TDS sensor 120 for collecting TDS signals in the water body. By setting two TDS sensors, the first TDS sensor is used to detect the TDS value of the raw water in the water dispenser, and the second TDS sensor is used to detect the TDS value of the purified water in the water dispenser, so that the processed RS485 signal can be subsequently transmitted to the external processor to calculate the desalination rate of the RO membrane. The TDS acquisition circuit 200 is electrically connected to the first TDS sensor 110 and the second TDS sensor 120, respectively, for further processing the received TDS data. The isolation circuit 300 is used to process the signal transmitted by the TDS acquisition circuit 200 to obtain an RS485 signal that can be directly read by the PLC controller. The isolation circuit 300 includes a first optocoupler isolator 310 (i.e., a first optocoupler isolator 310) electrically connected to the TDS acquisition circuit 200. Figure 5 PC1 in the figure) and the second optical coupler isolator 320 (i.e. Figure 5 PC2 in the figure), an RS485 signal transceiver 330 (ie, an RS485 signal transceiver 330 electrically connected to the first optical coupler isolator 310 and the second optical coupler isolator 320) Figure 5IC1 in the figure), and a serial port connector 340 electrically connected to the RS485 signal transceiver 330.

[0021] Please combine Figure 1-3 In this embodiment, the two pins of the detection end of the first TDS sensor 110 form a loop after being connected to the water body. At this time, the output end of the first TDS sensor 110 outputs two TDS signals through two independent output pins, namely, the TDS1-1 output pin and the TDS1-2 output pin. Similarly, the two pins of the detection end of the second TDS sensor 120 form a loop after being connected to the water body. At this time, the output end of the second TDS sensor 120 outputs two TDS signals through two independent output pins, namely, the TDS2-1 and TDS2-2 output pins. Further, the acquisition range of the first TDS sensor 110 and the second TDS sensor 120 of this embodiment is 0-1000㎎ / L.

[0022] Please combine Figure 1-4 The TDS acquisition circuit 200 includes an MCU (i.e., Figure 4IC2 in, and the first filter circuit, the second filter circuit, and the third filter circuit electrically connected to the MCU. Among them, the MCU adopts the TDS detection chip of model BA012 produced by Shenzhen Bit Atom Company, and the TDS acquisition circuit 200 is the standard circuit of the BA012 TDS detection chip improved by the company. The TDS detection chip of model BA012 is internally integrated with a high-precision oscillation circuit, an analog-to-digital conversion circuit, and a floating-point operation unit, which can realize fast water quality TDS detection, and realize automatic temperature correction in a wide temperature range, reduce the measurement error caused by the change of TDS value with temperature, and improve the reliability of the water quality TDS detection result. Further, the first filter circuit includes a first capacitor C11 and a second capacitor C12 electrically connected to the MCU and connected to the ground in parallel; the second filter circuit includes a third capacitor C13 electrically connected to the MCU and grounded; the third filter circuit includes a fourth capacitor C14 electrically connected to the MCU and grounded. In the present embodiment, the TDS1-1 output pin of the first TDS sensor 110 is connected to the pin 10 of the MCU, and the TDS1-2 output pin of the first TDS sensor 110 is directly connected to the pin 12 of the MCU on the one hand, and is also connected to the pin 11 of the MCU through the voltage-dividing resistor R14 on the other hand. The TDS2-1 output pin of the second TDS sensor 120 is connected to the pin 7 of the MCU, and the TDS2-2 output pin of the second TDS sensor 120 is directly connected to the pin 5 of the MCU on the one hand, and is also connected to the pin 4 of the MCU through the voltage-dividing resistor R11 on the other hand. In addition, the TDS acquisition circuit 200 also includes a photodiode connected to the first optical coupler isolator 310 and the second optical coupler isolator 320, and the photodiode is also connected in series with a voltage-dividing resistor R15 to ensure the normal operation of the photodiode. Of course, in the present embodiment, the MCU of the TDS acquisition circuit 200 can also be replaced with other commercially available TDS detection chips, which will not be repeated here.

[0023] Please combine Figure 1-5In this embodiment, the RS485 signal transceiver 330 uses a transceiver of model MAX13487, the transistor of the first optocoupler isolator 310 is connected to pin 3 of the MCU, and the photodiode of the first optocoupler isolator 310 is connected to pin 1 of the RS485 signal transceiver 330; the photodiode of the second optocoupler isolator 320 is connected to pin 2 of the MCU, and the transistor of the second optocoupler isolator 320 is connected to pin 4 of the RS485 signal transceiver 330. In other words, the wiring directions of the first optocoupler isolator and the second optocoupler isolator are opposite. In this embodiment, an isolation circuit 300 is formed by providing a first photoelectric isolator and a second photoelectric isolator connected to the RS485 signal transceiver 330. The VCC and VDD of the isolation circuit 300 are two groups of power supplies that do not share a common ground, and an isolated DC-DC can be used to achieve power isolation. The first photoelectric isolator and the second photoelectric isolator are used to achieve isolated signal transmission, so that the RS485 signal transceiver 330 and the MCU of the TDS acquisition circuit 200 do not share a common ground, and are completely isolated to effectively suppress the generation of high common-mode voltage, greatly reduce the damage rate of the RS485 signal transceiver 330, and improve the stability of the system, so that the RS485 signal transceiver 330 can receive a common-mode voltage that exceeds its limit receiving voltage and still be able to work normally, and its output RS485 signal can be directly transmitted to the PLC controller, and the voltage is adapted to the input voltage required by the PLC controller.

[0024] In addition, the isolation circuit 300 also includes a first voltage divider circuit and a second voltage divider circuit for being electrically connected to an external power supply, the first voltage divider circuit being electrically connected to the first optocoupler isolator 310, and the second voltage divider circuit being electrically connected to the second optocoupler isolator 320. Specifically, the first voltage divider circuit includes a resistor R2 connected to the photodiode of the first optocoupler isolator 310, and the second voltage divider circuit includes a resistor R3 connected to the transistor of the second optocoupler isolator 320. The isolation circuit 300 also includes a fourth filter circuit electrically connected to the RS485 signal transceiver 330, and the fourth filter circuit includes a grounded capacitor C1 to prevent the RS485 signal transceiver 330 from being affected by sudden power fluctuations such as overcurrent or overvoltage.

[0025] In this embodiment, the model of the serial port connector 340 is DSub9, which has 9 interfaces No. 1-9, among which interface No. 3 and interface No. 8 are respectively connected to the RS485 signal transceiver 330 to constitute the positive and negative poles of the serial port connector 340, interface No. 5 of the serial port connector 340 is grounded, and interface No. 6 of the serial port connector 340 is connected to the external power supply voltage. In this way, when the serial port connector 340 is connected to the RS485 interface of the PLC controller, the RS485 signal can be directly transmitted to the PLC controller to realize the transmission of the signal detected by the TDS sensor to the PLC controller.

[0026] The dual-channel TDS data acquisition module for a water dispenser of the utility model can convert the signals detected from the first TDS sensor 110 and the second TDS sensor 120 into RS485 signals by combining the TDS acquisition circuit 200 with the isolation circuit 300, and output them through the serial port connector 340. Since the serial port connector 340 can be connected to the RS485 port of the PLC controller, the dual-channel TDS data acquisition module for the water dispenser can be directly connected to the PLC controller without setting up related conversion circuits. The circuit structure is simple, and two A / D input ports can be saved, thereby reducing the occupancy of the input ports and reducing the cost of TDS detection and signal transmission.

[0027] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0028] The above-mentioned embodiments only express several implementation methods of the utility model, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the utility model patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, which all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.

Claims

1. A dual-channel TDS data acquisition module for a water dispenser, characterized in that: include: A detection component, the detection component comprising a first TDS sensor and a second TDS sensor for collecting TDS signals in water; A TDS acquisition circuit, wherein the TDS acquisition circuit is electrically connected to the first TDS sensor and the second TDS sensor respectively; as well as An isolation circuit includes a first optocoupler isolator and a second optocoupler isolator respectively electrically connected to the TDS acquisition circuit, an RS485 signal transceiver electrically connected to the first optocoupler isolator and the second optocoupler isolator, and a serial port connector electrically connected to the RS485 signal transceiver.

2. The dual-channel TDS data acquisition module for water dispensers according to claim 1 is characterized in that: The TDS acquisition circuit includes an MCU electrically connected to the first TDS sensor and the second TDS sensor, and a first filter circuit, a second filter circuit, and a third filter circuit electrically connected to the MCU.

3. The dual-channel TDS data acquisition module for a water dispenser according to claim 2 is characterized in that: The first filter circuit includes a first capacitor and a second capacitor electrically connected to the MCU and connected in parallel to the ground; the second filter circuit includes a third capacitor electrically connected to the MCU and connected to the ground; the third filter circuit includes a fourth capacitor electrically connected to the MCU and connected to the ground.

4. The dual-channel TDS data acquisition module for a water dispenser according to claim 2 is characterized in that: The TDS acquisition circuit also includes a photodiode connected to the first optocoupler isolator and the second optocoupler isolator.

5. The dual-channel TDS data acquisition module for water dispensers according to claim 1 is characterized in that: The isolation circuit also includes a first voltage divider circuit and a second voltage divider circuit for being electrically connected to an external power supply, wherein the first voltage divider circuit is electrically connected to a first optocoupler isolator, and the second voltage divider circuit is electrically connected to a second optocoupler isolator.

6. The dual-channel TDS data acquisition module for a water dispenser according to claim 1, characterized in that: The isolation circuit also includes a fourth filtering circuit electrically connected to the RS485 signal transceiver.

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