CN202101785U - Intelligent wireless diffused silicon pressure transmitter - Google Patents

Abstract

The utility model discloses an intelligent wireless diffused silicon pressure transmitter. The intelligent wireless diffused silicon pressure transmitter comprises a three-way shell, a WIAPA-M1800 wireless adapter, a main controller circuit board, a display, a 3.3V power supply, and a WIA gateway. , Install the display and connect the power supply at the two larger openings of the shell, install the WIAPA-M1800 wireless adapter and the main controller circuit board inside the shell, install the wireless antenna at the smaller opening of the shell, and the liquid level sensor is directly connected to the main control The display is connected to the main controller circuit board through pins; the utility model is an intelligent wireless diffused silicon pressure transmitter with high precision and digital communication. This sensor uses the same pressure-sensitive chip to measure both static pressure and Temperature measurement, the transmitter is oriented to wireless communication of information between devices, especially suitable for use in harsh industrial field environments, with anti-interference ability, ultra-low power consumption, and real-time communication technology features.

Description

Smart Wireless Diffused Silicon Pressure Transmitter

technical field

The utility model relates to a transmitter, in particular to an intelligent wireless diffusion silicon pressure transmitter. the

Background technique

Since the introduction of the ST3000 intelligent pressure sensor (transmitter) by Honeywell in the United States in the late 1980s, major foreign instrument companies have developed and mass-produced their own intelligent sensors. These sensors all adopt HART communication technology and are compatible with a large number of analog transmitters currently used, and these transmitters have entered the Chinese market. Smart sensors (transmitters) have many advantages, such as high precision, high reliability, full-featured, remote calibration, adjustment, setting, etc., so they are more and more valued by the industrial sector, and their applications are gradually widespread. the

The analog diffused silicon pressure transmitters currently on the market have the advantages of low price and high sensitivity, but the diffused silicon sensor is quite sensitive to the influence of temperature, and it is difficult to achieve ideal temperature compensation using traditional methods, which greatly affects the transmitter. Accuracy, and limit the application of the transmitter. the

Contents of the invention

The purpose of this utility model is to provide an intelligent wireless diffused silicon pressure transmitter, which is an intelligent wireless diffused silicon pressure transmitter with high precision and wireless digital communication. This transmitter uses the same pressure-sensitive chip to measure Static pressure and temperature are measured again. The pressure and temperature signals are input to the single chip microcomputer after A/D conversion. After strict compensation and correction calculation, they are transmitted to the receiving end through wireless mode. The transmitter is based on the intelligent wireless network WIA technology system and complies with IEEE 802.15. 4 Wireless communication standards, mainly for wireless communication of information between devices, especially suitable for use in harsh industrial field environments, with strong anti-interference ability, ultra-low power consumption, real-time communication and other technical features. the

The technical solution of the utility model is: the intelligent wireless diffused silicon pressure transmitter includes a three-way shell, a WIAPA-M1800 wireless adapter, a main controller circuit board, a display, a 3.3V power supply, and a WIA gateway. Install the display and connect the power supply at the large opening, install the WIAPA-M1800 wireless adapter and the main controller circuit board inside the casing, install the wireless antenna at the small opening of the casing, the liquid level sensor is directly connected to the main controller circuit board, and the display is through the plug-in pins to the main controller circuit board. the

The measuring method of the utility model is: install the meter at the measuring point of the industrial equipment, install the WIA gateway in the coverage area of the WIA network, and connect with the upper computer through the RS232 serial port or Ethernet. the

When working, the upper computer downloads the calculation parameters corresponding to the sensor to the instrument through the WIA network, and the platinum thermal resistance measures the ambient temperature where the instrument is located; the signal conditioning circuit of the circuit board performs differential signal acquisition, amplification, and noise removal on the voltage signal generated by the sensor. processing; A/D converts the analog voltage signal into a digital signal, and the main controller combines the digital signal with the downloaded diffused silicon calculation parameters to obtain an accurate temperature value, and uploads the data in real time; both the WIAPA-M1800 wireless adapter and the main controller use The MSP430 single-chip microcomputer communicates between the two through the serial port; the display adopts 128-segment liquid crystal glass material, and the main controller drives it through the HT1621. the

The utility model has the following advantages: 1. Small size, light weight, the sensor can be integrated with the transmitter, good visualization, strong real-time performance, and convenient installation and use. 2. The analog-to-digital conversion chip adopts 16-bit A\D, which can make the nonlinear correction acquisition accuracy of Pt100 thermal resistance more than 0.1; 3. The data processing controller and communication controller adopt high-performance ultra-low Power consumption 16-bit MSP430 microprocessor, combined with the signal conditioning circuit, voltage stabilization circuit, anti-interference circuit and switching circuit on the circuit board, makes the whole instrument have low power consumption and high stability; 4. Applied intelligence Wireless network WIA technology is based on the short-range wireless communication IEEE 802.15.4 standard, using the free frequency band that complies with the regulations of the China Non-committee Committee, and solves the multipath caused by the reflection and scattering of wireless signals caused by various large-scale equipment and metal pipes distributed in harsh environments effect, as well as the interference of electromagnetic noise to wireless communication caused by motors and equipment running, providing highly reliable and real-time wireless communication services that can meet application requirements; 5. By using intelligent wireless network WIA technology, users can use lower investment and cost Realize the "ubiquitous perception" of the whole process, obtain important process parameters that cannot be monitored online due to cost reasons, and implement optimal control on this basis to achieve the goal of improving product quality and saving energy; 6. Based on WIA network It not only has all the advantages of intelligent transmitters, but also can compensate the temperature drift of the sensor through software to achieve high precision in the full temperature and pressure range, so that the diffused silicon transmitter has a greater Scope of use; 7. On the basis of meeting the industrial measurement range and accuracy requirements, it is a wireless pressure acquisition instrument that can adjust parameters in real time according to different types of sensors; 8. The instrument is based on the measurement principle of diffused silicon sensors, combined with nonlinear temperature compensation circuits. And high-precision analog-to-digital conversion devices, download the corresponding calculation coefficients of diffused silicon from the remote host computer through the WIA network to accurately calculate the pressure data, and upload the data in real time, while using the power consumption control characteristics of the microcontroller itself and the peripheral analog switch circuit , so that the entire instrument has better energy consumption performance. the

Description of drawings

Fig. 1 is a schematic diagram of the intelligent wireless diffused silicon pressure transmitter of the present invention. the

FIG. 2 is a schematic diagram of the controller and its peripheral circuits in FIG. 1 . the

Figure 3 is the data acquisition and temperature compensation circuit of Figure 1. the

FIG. 4 is an interface diagram of wireless communication and power consumption control in FIG. 1 . the

FIG. 5 is a data processing circuit diagram of FIG. 1 . the

In the figure: 1. antenna, 2. liquid crystal display, 3. diffused silicon probe, 4. shell. the

Detailed ways

The technical solutions of the present utility model will be further described below in conjunction with the accompanying drawings and embodiments, and the embodiments should not be construed as limitations on the technical solutions. the

As shown in Figure 1-4, the circuit connection of the intelligent wireless diffused silicon pressure transmitter is as follows:

Power supply: 3.3V lithium battery power supply, the main controller circuit board uses a 3.3V to 3V controllable switch chip to provide the required power for the analog part and digital part, and the 3.3V power supply is provided by C3, C14, C15, C16, C20, C21 , C22, C24 filter, 3V power supply is filtered by C1, C9, C10, C18;

16-bit A/D: use the ADS1110 chip of Texas Electric Company, using the I2C interface, the 1 pin of ADS1110 is connected to the output terminal of the second operational amplifier OP2, the 3 pins and 4 pins of ADS1110 are connected to the pull-up resistors R37 and R38 The other end of R7, R8 and the 5 pin of ADS1110 are connected to the +3.3V power supply, and the 2 pin and 6 pin of ADS1110 are grounded;

MCU: MSP430F149 chip from Texas Electric Company is selected, the crystal oscillator is selected at 3.6264MHz, the program download uses the standard JTAG interface, XT2IN, XT2OUT are connected to the crystal oscillator, and the resistance R17 is connected between them, through C11 and C12 to the ground, 54, 55, 56 of the MCU , 57 pins are respectively connected with the 1, 3, 5, 7 pins of the double row seat JP2, the 12 and 22 pins of the MCU are respectively connected with the 2 pins and 6 pins of the JP2, and the 58 pins of the MCU are connected with the 11 pins of the JP2;

Sensor: R1, R2, R3, R4, R5 and diffused silicon form a sensor circuit. Pin 1 of diffused silicon is connected to -OUT and one end of R1, and the other end of R1 is connected to pin 2 of diffused silicon, one end of R2, one end of R5 and +IN, the other end of R2 is connected to pin 3 of diffused silicon, +OUT, the other end of R5 is connected to one end of R3, one end of R4, -I, the other end of R3 is connected to pin 3 of diffused silicon, and the other end of R4 is connected to diffused silicon Silicon pin 5;

Signal conditioning circuit: One end of the sensor, that is, a balance point of the bridge, is connected to one end of the resistor R45, and the other end of R45 is respectively connected to the non-inverting input end of the operational amplifier OP and the amplifying resistor R47, and the inverting input end of the OP is respectively connected to the resistor R46. One end is connected to the negative input end of the A/D, the other end of R46 is connected to the other balance point of the bridge, the other end of R47 is respectively connected to one end of the filter capacitor C42, the output end of the operational amplifier OP, and the filter resistor R40. The other end is connected to the positive input end of the A/D, the other end of the filter capacitor C42 and the negative power supply end of the operational amplifier are grounded, and the positive power supply end of the operational amplifier is connected to the +3.3V power supply;

EEPROM memory: The off-chip memory chip is 24LC64 chip of MicroChip Company, which adopts I2C interface and is powered by 3.3V power supply. Pins 5 and 6 are connected to P4.5 and P4.6 ports of MCU through R20 and R21 pull-up resistors. C25 is used for filtering, pins 1, 2, 3, and 4 are grounded to indicate the physical address;

Display: 48-pin HT1621B with SPI bus structure is used to drive the LCD screen, of which 24 pins SEG0~SEG23 and COM0~COM3 are connected to the LCD glass, and the DATA pin is connected to one end of the pull-up resistor R52 and then connected to P5.1 of the MCU. The CS pin is connected to one end of the pull-up resistor R53 and then connected to the P1.5 port of the MCU, the WR pin is connected to one end of the pull-up resistor R54 and then connected to the P1.6 port of the MCU, and the RD pin is connected to the pull-up resistor One end of R55 is connected to the P1.7 port of the MCU, the other end of the pull-up resistors R52, R53, R54, and R55 is connected to VDD, and the R51 variable resistor is connected between VDD and VLCD pins. VDD and VSS are respectively connected to the main control The 3.3V power supply on the circuit board of the circuit board is connected to the ground wire, and the rest of the pins are suspended;

Wireless communication: The P3.4 and P3.5 ports of the MCU are connected to the serial port of the WIAPA-M1800 wireless communication module.

Claims (2)

1. Intelligent wireless diffused silicon pressure transmitter, characterized in that: the intelligent wireless diffused silicon pressure transmitter includes a tee shell, WIAPA-M1800 wireless adapter, main controller circuit board, display, 3.3V power supply, WIA gateway, Install the display and connect the power supply at the two larger openings of the casing, install the WIAPA-M1800 wireless adapter and the main controller circuit board inside the casing, install the wireless antenna at the smaller opening of the casing, and connect the liquid level sensor directly to the main controller The circuit board and the display are connected to the main controller circuit board through pins; the circuit connection of the intelligent wireless diffused silicon pressure transmitter is as follows: Power supply: 3.3V lithium battery power supply, the main controller circuit board uses a 3.3V to 3V controllable switch chip to provide the required power for the analog and digital parts; 16-bit A/D: The ADS1110 chip of Texas Electric Company is selected, and the I2C interface is used. Because of the built-in low-noise programmable instrument amplifier with a gain of 1-8, it can amplify the voltage signal from the amplifying circuit and convert it into a sample Digital signal; MCU: Select to process the digital signal output by A/D, calculate the temperature, communicate with the remote PC through the wireless module, receive the thermal resistance calculation parameter table, upload the collected results to the PC and other real-time communications, and pass the working mode switch for energy consumption control; Constant voltage circuit: The diffused silicon pressure sensor selected is a constant current power supply type, the power supply current is 1.5mA, and the constant current power supply adopts the National Semiconductor Corporation of the United States. The three-terminal adjustable constant current source LM334 produced by the company has a wide dynamic voltage range of 1 to 40V. The establishment of the constant current source only needs an external resistor, and it is a true floating constant current source that does not need an independent power supply; due to the output of the LM334 The current has a sensitive characteristic that is proportional to the absolute temperature. The current is constant only when the temperature is constant, so it needs to be compensated. As long as a resistor and a diode are added to the basic circuit, the zero temperature that offsets the temperature drift of the LM334 can be formed. coefficient constant current source; Signal conditioning circuit: amplify and filter the signal collected by diffused silicon; EEPROM memory: Since different thermal resistances correspond to different calculation parameters during calculation, 64K EEPROM is used to store calculation parameters of various common thermal resistances; Display: display the pressure of the environment where the sensor probe is located, with a measurement accuracy of 0.01°C; Wireless communication: The collected data is sent to the WIAPA-M1800 wireless communication module through the serial port, and then connected to the WIAPA-GW1498 wireless gateway to display the data on the remote PC. At the same time, the PC will correspond to each sensor probe when the system is used for the first time. The index table is transmitted to the MCU through the wireless module and stored in the external memory. 2. The intelligent wireless diffused silicon pressure transmitter according to claim 1, characterized in that: the hardware connection and working methods are as follows: Power supply: 3.3V lithium battery power supply, the main controller circuit board uses a 3.3V to 3V controllable switch chip to provide the required power for the analog part and digital part, and the 3.3V power supply is provided by C3, C14, C15, C16, C20, C21 , C22, C24 filter, 3V power supply is filtered by C1, C9, C10, C18; 16-bit A/D: use the ADS1110 chip of Texas Electric Company, using the I2C interface, the 1 pin of ADS1110 is connected to the output terminal of the second operational amplifier OP2, the 3 pins and 4 pins of ADS1110 are connected to the pull-up resistors R37 and R38 The other end of R7, R8 and the 5 pin of ADS1110 are connected to the +3.3V power supply, and the 2 pin and 6 pin of DS1110 are grounded; MCU: Choose the MSP430F149 chip of Texas Electric Company in the United States, choose the crystal oscillator of 3.6264MHz, use the standard JTAG interface for program download, connect XT2IN, XT2OUT to the crystal oscillator, connect resistor R17 between them, and go to ground through C11 and C12; Pins 54, 55, 56, and 57 of the MCU are connected to pins 1, 3, 5, and 7 of the double-row seat JP2, pins 12 and 22 of the MCU are connected to pins 2 and 6 of JP2, and pin 58 of the MCU is connected to pins of JP2. The 11 pins are connected; Sensor: R1, R2, R3, R4, R5 and diffused silicon form a sensor circuit. Pin 1 of diffused silicon is connected to -OUT and one end of R1, and the other end of R1 is connected to pin 2 of diffused silicon, one end of R2, one end of R5 and +IN, the other end of R2 is connected to pin 3 of diffused silicon, +OUT, the other end of R5 is connected to one end of R3, one end of R4, -IN, the other end of R3 is connected to pin 3 of diffused silicon, and the other end of R4 is connected to diffused silicon Silicon pin 5; Signal conditioning circuit: One end of the sensor, that is, a balance point of the bridge, is connected to one end of the resistor R45, and the other end of R45 is respectively connected to the non-inverting input end of the operational amplifier OP and the amplifying resistor R47, and the inverting input end of the OP is respectively connected to the resistor R46. One end is connected to the negative input end of A/D; The other end of R46 is connected to the other balance point of the bridge, the other end of R47 is respectively connected to one end of the filter capacitor C42, the output end of the operational amplifier OP, and the filter resistor R40, and the other end of R40 is connected to the positive input end of the A/D , the other end of the filter capacitor C42 and the negative power supply terminal of the operational amplifier are grounded, and the positive power supply terminal of the operational amplifier is connected to the +3.3V power supply; EEPROM memory: the off-chip memory chip is 24LC64 chip from MicroChip Company, using I2C interface; Powered by a 3.3V power supply, pins 5 and 6 are connected to ports P4.5 and P4.6 of the MCU through R20 and R21 pull-up resistors, C25 is used for filtering, and pins 1, 2, 3 and 4 are grounded for indication physical address; Display: 48-pin HT1621B with SPI bus structure is used to drive the LCD screen, of which 24 pins SEG0~SEG23 and COM0~COM3 are connected to the LCD glass, and the DATA pin is connected to one end of the pull-up resistor R52 and then connected to P5.1 of the MCU. The CS pin is connected to one end of the pull-up resistor R53 and then connected to the P1.5 port of the MCU, the WR pin is connected to one end of the pull-up resistor R54 and then connected to the P1.6 port of the MCU, and the RD pin is connected to the pull-up resistor One end of R55 is connected to the P1.7 port of the MCU, the other end of the pull-up resistors R52, R53, R54, and R55 is connected to VDD, and the R51 variable resistor is connected between VDD and VLCD pins. VDD and VSS are respectively connected to the main control The 3.3V power supply on the circuit board of the circuit board is connected to the ground wire, and the rest of the pins are suspended; Wireless communication: The P3.4 and P3.5 ports of the MCU are connected to the serial port of the WIAPA-M1800 wireless communication module.

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