Digital density meter and communication module

Abstract

The utility model discloses a communication module, belongs to the technical field of digital density meters, and particularly relates to a digital density meter and a communication module, and in order to improve the stability, the communication module is additionally provided with a lightning protection circuit, an optical coupler isolation circuit and other multi-stage protection circuits. The first-stage circuit is composed of six phase inverters, a pull-up resistor, an input resistor and an optical coupler isolation circuit, and aims to achieve the purposes of isolation protection, waveform shaping and improvement of load capacity. The second-stage circuit is composed of an RS485 chip and a lightning protection circuit, the RS485 chip converts TTL level into RS485 level, and high-speed data transmission is achieved. In addition, the lightning protection circuit is composed of two stages of circuits. And the primary protection circuit realizes lightning protection between wires and between wires and the ground. And the secondary protection quickly limits the overhigh voltage within a safety range to protect the rear circuit.

Description

Technical Field

[0001] The utility model discloses a digital density meter and a communication module, belonging to the technical field, and specifically relates to a digital density meter and a communication module. Background Art

[0002] A digital density meter is an instrument capable of measuring the density of a gas, and is a density measurement device with digital display and modern functions. These devices can usually provide high-precision measurement results and are widely used in industrial and scientific laboratories.

[0003] The main characteristics of a digital density meter include:

[0004] Digital display: Using a digital display screen or digital monitor, the measurement results are intuitively displayed, reducing the possibility of reading errors.

[0005] High-precision measurement: Usually able to provide relatively high-precision density measurement, suitable for application scenarios with high density requirements.

[0006] Automation functions: With functions such as automatic temperature compensation and automatic calibration, improving the accuracy and repeatability of measurement.

[0007] Versatility: Supports density representation in multiple units (such as g / cm 3 、kg / m 3 etc.), and may have functions such as saving measurement data, data transmission, and printing.

[0008] Easy to operate: Simple in design and convenient to operate, suitable for various working environments and user levels.

[0009] Durability and reliability: The design usually takes into account the requirements of the industrial environment, has strong durability and reliability, and can operate stably for a long time.

[0010] Digital density meters are widely used in fields such as chemistry, pharmaceuticals, food processing, and materials research, and are one of the indispensable measurement tools in modern laboratories and industrial process control.

[0011] In the existing technology, for a digital density meter, in case of an emergency power outage, the time is not allowed to exceed a few milliseconds. Therefore, the stability and reliability requirements for the sampling circuit and communication circuit of the system are extremely high. Content of the Utility Model

[0012] Utility model purpose: To provide a digital density meter and a communication module to solve the problems mentioned above.

[0013] First aspect: A communication module of a digital density meter, which is composed of an RS-485 interface circuit and is used for communicating with external control devices, PLCs, ARMs, and computers;

[0014] The RS-485 interface circuit consists of a first-stage circuit, a second-stage circuit, and three ports: TXD0 transmission port, RXD0 reception port, and RecSend reception and transmission control port.

[0015] In a further embodiment, the first-stage circuit consists of an inverter 74HC14, a pull-up resistor, an input resistor, and an opto-isolation circuit;

[0016] The second-stage circuit consists of an RS-485 chip and a lightning protection circuit.

[0017] In a further embodiment, the first-stage circuit includes: inverter U1A, inverter U1B, inverter U1C, inverter U1D, inverter U1E, inverter U1F, opto-isolator U2, opto-isolator U3, opto-isolator U4, resistor R1, resistor R2, resistor R3, resistor R4, resistor R5, resistor R6;

[0018] The 2nd pin of the inverter U1A is connected to the RXD0 reception port, and the 1st pin is simultaneously connected to one end of the resistor R1 and the 6th pin of the opto-isolator U2. The 7th and 8th pins of the opto-isolator U2 are connected to the other end of the resistor R1 and input voltage VCC1. The 2nd pin of the opto-isolator U2 inputs voltage VCC2. The 3rd pin of the opto-isolator U2 is connected to one end of the resistor R4, and the other end of the resistor R4 is connected to the 2nd pin of the inverter U1D. The 1st pin of the inverter U1D is connected to the RXD0 reception port;

[0019] The 2nd pin of the inverter U1E is connected to the TXD0 transmission port, and the 1st pin is simultaneously connected to one end of the resistor R5 and the 6th pin of the opto-isolator U3. The 7th and 8th pins of the opto-isolator U3 are connected to the other end of the resistor R5 and input voltage VCC2. The 2nd pin of the opto-isolator U3 inputs voltage VCC1. The 3rd pin of the opto-isolator U3 is connected to one end of the resistor R2, and the other end of the resistor R2 is connected to the 2nd pin of the inverter U1B. The 1st pin of the inverter U1B is connected to the TXD0 transmission port;

[0020] The second pin of the inverter U1F is connected to the RecSend receive and transmit control port. The first pin is simultaneously connected to one end of the resistor R6 and the sixth pin of the opto-isolator U4. The seventh and eighth pins of the opto-isolator U4 are connected to the other end of the resistor R6 and input the voltage VCC2. The second pin of the opto-isolator U4 inputs the voltage VCC1. The third pin of the opto-isolator U4 is connected to one end of the resistor R3. The other end of the resistor R3 is connected to the second pin of the inverter U1C. The first pin of the inverter U1C is connected to the RecSend receive and transmit control port.

[0021] In a further embodiment, the second-stage circuit includes: an RS-485 chip, a capacitor C1, a voltage regulator diode D1, a voltage regulator diode D2, a diode D3, a diode D4, a diode D5, a resistor R7, a resistor R8, and an interface J1;

[0022] The first pin of the RS-485 chip is connected to the RXD0 receive port. The second and third pins are connected to the RecSend receive and transmit control port. The fourth pin is connected to the TXD0 transmit port. The seventh pin of the RS-485 chip is simultaneously connected to one end of the resistor R7 and the negative electrode of the voltage regulator diode D1. The eighth pin of the RS-485 chip is connected to one end of the capacitor C1 and receives the voltage VCC2. The sixth pin of the RS-485 chip is simultaneously connected to the negative electrode of the voltage regulator diode D2 and one end of the resistor R8. The fifth pin of the RS-485 chip is simultaneously connected to the positive electrode of the voltage regulator diode D1 and the positive electrode of the voltage regulator diode D2 and is grounded. The other end of the capacitor C1 is grounded. The negative electrode of the diode D3 is simultaneously connected to the other end of the resistor R7, the negative electrode of the diode D5, and is connected to the first pin of the interface J1. The positive electrode of the diode D3 is simultaneously connected to the other end of the resistor R8, the negative electrode of the diode D4, and is connected to the second pin of the interface J1. The positive electrodes of the diode D4, the diode D5, and the third pin of the interface J1 are grounded.

[0023] In a second aspect, a digital density meter is characterized by comprising a density meter body, a main control chip, a power supply circuit, a voltage sampling circuit, a frequency sampling circuit, a control and display circuit, a monitoring circuit, an alarm circuit, and the communication module arranged in the density meter body.

[0024] Beneficial effects: In order to improve the stability of the communication module of the present utility model, multiple protection circuits such as a lightning protection circuit and an optocoupler isolation circuit are additionally added. The first-stage circuit consists of six inverters, a pull-up resistor, an input resistor, and an optocoupler isolation circuit, and its purpose is isolation protection, waveform shaping, and improvement of the load-carrying capacity. The second-stage circuit consists of an RS485 chip and a lightning protection circuit. The RS485 chip converts the TTL level into the RS485 level to achieve high-speed data transmission. In addition, the lightning protection circuit is composed of two-stage circuits. The primary protection circuit realizes lightning protection between lines and between line and ground. The secondary protection quickly limits the excessive voltage within a safe range to protect the subsequent circuit. Brief description of the drawings

[0025] Figure 1 is a schematic diagram of the present utility model.

[0026] Figure 2 is a schematic diagram of the first-stage circuit of the present utility model.

[0027] Figure 3 is a schematic diagram of the second-stage circuit of the present utility model. Specific implementation manners

[0028] The technical solutions of the present utility model will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present utility model, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without making creative efforts shall fall within the protection scope of the present utility model.

[0029] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present utility model. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0030] In the description of the present utility model, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances. In addition, the technical features involved in different embodiments of the present utility model described below can be combined with each other as long as they do not conflict with each other.

[0031] Embodiment 1:

[0032] A communication module of a digital density meter, the communication module is composed of an RS-485 interface circuit and is used for communicating with external control devices, PLCs, ARMs, and computers;

[0033] The RS-485 interface circuit is composed of a first-stage circuit, a second-stage circuit, and three ports, namely a TXD0 transmission port, an RXD0 reception port, and a RecSend reception and transmission control port.

[0034] In one embodiment, as Figures 2 to 3 shown, the first-stage circuit is composed of an inverter 74HC14, a pull-up resistor, an input resistor, and an opto-isolation circuit;

[0035] The second-stage circuit is composed of an RS-485 chip and a lightning protection circuit.

[0036] In one embodiment, as Figure 2 shown, the first-stage circuit includes: inverters U1A, U1B, U1C, U1D, U1E, U1F, opto-isolators U2, U3, U4, resistors R1, R2, R3, R4, R5, R6;

[0037] The 2nd pin of the inverter U1A is connected to the RXD0 reception port, and the 1st pin is simultaneously connected to one end of the resistor R1 and the 6th pin of the opto-isolator U2. The 7th and 8th pins of the opto-isolator U2 are connected to the other end of the resistor R1 and input the voltage VCC1. The 2nd pin of the opto-isolator U2 inputs the voltage VCC2. The 3rd pin of the opto-isolator U2 is connected to one end of the resistor R4. The other end of the resistor R4 is connected to the 2nd pin of the inverter U1D. The 1st pin of the inverter U1D is connected to the RXD0 reception port;

[0038] The 2nd pin of the inverter U1E is connected to the TXD0 sending port, and the 1st pin is simultaneously connected to one end of the resistor R5 and the 6th pin of the opto-isolator U3. The 7th and 8th pins of the opto-isolator U3 are connected to the other end of the resistor R5 and input the voltage VCC2. The 2nd pin of the opto-isolator U3 inputs the voltage VCC1. The 3rd pin of the opto-isolator U3 is connected to one end of the resistor R2, and the other end of the resistor R2 is connected to the 2nd pin of the inverter U1B. The 1st pin of the inverter U1B is connected to the TXD0 sending port;

[0039] The 2nd pin of the inverter U1F is connected to the RecSend receive and send control port, and the 1st pin is simultaneously connected to one end of the resistor R6 and the 6th pin of the opto-isolator U4. The 7th and 8th pins of the opto-isolator U4 are connected to the other end of the resistor R6 and input the voltage VCC2. The 2nd pin of the opto-isolator U4 inputs the voltage VCC1. The 3rd pin of the opto-isolator U4 is connected to one end of the resistor R3, and the other end of the resistor R3 is connected to the 2nd pin of the inverter U1C. The 1st pin of the inverter U1C is connected to the RecSend receive and send control port.

[0040] In one embodiment, as Figure 3 shown, the second-stage circuit includes: an RS-485 chip, a capacitor C1, a voltage regulator diode D1, a voltage regulator diode D2, a diode D3, a diode D4, a diode D5, a resistor R7, a resistor R8, and an interface J1;

[0041] The 1st pin of the RS-485 chip is connected to the RXD0 receive port, the 2nd and 3rd pins are connected to the RecSend receive and send control port, and the 4th pin is connected to the TXD0 sending port; the 7th pin of the RS-485 chip is simultaneously connected to one end of the resistor R7 and the negative electrode of the voltage regulator diode D1. The 8th pin of the RS-485 chip is connected to one end of the capacitor C1 and receives the voltage VCC2. The 6th pin of the RS-485 chip is simultaneously connected to the negative electrode of the voltage regulator diode D2 and one end of the resistor R8. The 5th pin of the RS-485 chip is simultaneously connected to the positive electrode of the voltage regulator diode D1 and the positive electrode of the voltage regulator diode D2 and is grounded. The other end of the capacitor C1 is grounded. The negative electrode of the diode D3 is simultaneously connected to the other end of the resistor R7, the negative electrode of the diode D5, and is connected to the 1st pin of the interface J1. The positive electrode of the diode D3 is simultaneously connected to the other end of the resistor R8, the negative electrode of the diode D4, and is connected to the 2nd pin of the interface J1. The positive electrode of the diode D4, the positive electrode of the diode D5, and the 3rd pin of the interface J1 are grounded.

[0042] Embodiment 2:

[0043] As Figure 1 shown, a digital density meter, characterized in that it comprises a density meter body, a main control chip arranged in the density meter body, a power supply circuit, a voltage sampling circuit, a frequency sampling circuit, a control display circuit, a monitoring circuit, an alarm circuit and the communication module.

[0044] Working principle: The communication module of the present utility model enhances the anti-interference ability of the system by adding multi-stage lightning protection circuits, isolation circuits, etc. When common power supply failures such as loss of voltage, under-voltage, over-voltage, phase loss, abnormal power frequency, etc. occur, the system can cut off the power supply within a few milliseconds, replace it with a backup power supply, and give an alarm, thus ensuring the normal power supply. Thereby ensuring the stability and continuity of the power consumption of various devices. During communication, the main control chip sends a control signal through the RecSend port. The control signal is inverted and then output through an opto-isolator, and is inverted again and then added to the RE and DE ports of the RS485 chip. When the control signal is at a low level, it is in the receiving state, and when it is at a high level, it is in the sending state. TXD0 is responsible for data transmission, and RXD0 is responsible for signal reception. A conversion chip with strong anti-interference ability is selected in the communication module, and at the same time, the anti-interference ability of the system is enhanced by adding multi-stage protection circuits such as lightning protection circuits and isolation circuits. Thereby ensuring the stability and continuity of the power consumption of various devices.

[0045] Obviously, the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present utility model.

Claims

1. A communication module of a digital density meter, characterized in that, The communication module is composed of an RS-485 interface circuit and is used for communicating with external control devices, PLCs, the main control chip, and computers; The RS-485 interface circuit consists of a first-stage circuit, a second-stage circuit, and three ports: the TXD0 transmission port, the RXD0 reception port, and the RecSend receive-transmit control port; The first-stage circuit consists of an inverter 74HC14, pull-up resistors, input resistors, and an opto-isolation circuit; The second-stage circuit consists of an RS-485 chip and a lightning protection circuit.

2. The communication module of a digital density meter according to claim 1, characterized in that, The first-stage circuit includes: inverters U1A, U1B, U1C, U1D, U1E, U1F, opto-isolators U2, U3, U4, resistors R1, R2, R3, R4, R5, R6; The 2nd pin of the inverter U1A is connected to the RXD0 reception port, and the 1st pin is simultaneously connected to one end of the resistor R1 and the 6th pin of the opto-isolator U2. The 7th and 8th pins of the opto-isolator U2 are connected to the other end of the resistor R1 and input the voltage VCC1. The 2nd pin of the opto-isolator U2 inputs the voltage VCC2. The 3rd pin of the opto-isolator U2 is connected to one end of the resistor R4, and the other end of the resistor R4 is connected to the 2nd pin of the inverter U1D. The 1st pin of the inverter U1D is connected to the RXD0 reception port; The 2nd pin of the inverter U1E is connected to the TXD0 transmission port, and the 1st pin is simultaneously connected to one end of the resistor R5 and the 6th pin of the opto-isolator U3. The 7th and 8th pins of the opto-isolator U3 are connected to the other end of the resistor R5 and input the voltage VCC2. The 2nd pin of the opto-isolator U3 inputs the voltage VCC1. The 3rd pin of the opto-isolator U3 is connected to one end of the resistor R2, and the other end of the resistor R2 is connected to the 2nd pin of the inverter U1B. The 1st pin of the inverter U1B is connected to the TXD0 transmission port; The 2nd pin of the inverter U1F is connected to the RecSend receive-transmit control port, and the 1st pin is simultaneously connected to one end of the resistor R6 and the 6th pin of the opto-isolator U4. The 7th and 8th pins of the opto-isolator U4 are connected to the other end of the resistor R6 and input the voltage VCC2. The 2nd pin of the opto-isolator U4 inputs the voltage VCC1. The 3rd pin of the opto-isolator U4 is connected to one end of the resistor R3, and the other end of the resistor R3 is connected to the 2nd pin of the inverter U1C. The 1st pin of the inverter U1C is connected to the RecSend receive-transmit control port.

3. The communication module of a digital density meter according to claim 1, characterized in that, The second-stage circuit includes: an RS-485 chip, a capacitor C1, voltage regulator diodes D1, D2, diodes D3, D4, D5, resistors R7, R8, and an interface J1; The 1st pin of the RS-485 chip is connected to the RXD0 receiving port, the 2nd and 3rd pins are connected to the RecSend receiving and sending control port, and the 4th pin is connected to the TXD0 sending port; the 7th pin of the RS-485 chip is simultaneously connected to one end of the resistor R7 and the negative electrode of the voltage stabilizing diode D1, the 8th pin of the RS-485 chip is connected to one end of the capacitor C1 and is connected to the voltage VCC2, the 6th pin of the RS-485 chip is simultaneously connected to the negative electrode of the voltage stabilizing diode D2 and one end of the resistor R8, the 5th pin of the RS-485 chip is simultaneously connected to the positive electrodes of the voltage stabilizing diode D1 and the voltage stabilizing diode D2 and is grounded, the other end of the capacitor C1 is grounded, the negative electrode of the diode D3 is simultaneously connected to the other end of the resistor R7, the negative electrode of the diode D5 and is connected to the 1st pin of the interface J1, the positive electrode of the diode D3 is simultaneously connected to the other end of the resistor R8, the negative electrode of the diode D4 and is connected to the 2nd pin of the interface J1, and the positive electrodes of the diode D4, the diode D5 and the 3rd pin of the interface J1 are grounded.

4. A digital density meter, characterized in that, It consists of a density meter body, a main control chip arranged in the density meter body, a power supply circuit, a voltage sampling circuit, a frequency sampling circuit, a control and display circuit, a monitoring circuit, an alarm circuit and the communication module according to any one of claims 1 to 3.

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