Micro-positive pressure environment monitoring system

Abstract

The utility model belongs to the technical field of monitoring systems, and particularly relates to a micro-positive pressure environment monitoring system. The utility model provides a circuit hardware foundation of a micro-positive pressure environment monitoring system, which has a good use effect. The system comprises a micro-positive voltage acquisition circuit, a noise acquisition circuit, a temperature and humidity acquisition circuit, a controller circuit, a storage circuit, an RS485 communication circuit and a power supply circuit. The system is characterized in that an acquisition signal input port of the controller circuit is respectively connected with an acquisition signal output port of the micro-positive voltage acquisition circuit, an acquisition signal output port of the noise acquisition circuit and an acquisition signal output port of the temperature and humidity acquisition circuit; and a signal transmission port of the controller circuit is respectively connected with a signal transmission port of the storage circuit and a signal transmission port of the RS485 communication circuit.

Description

TECHNICAL FIELD

[0001] The utility model belongs to monitoring system technical field, especially relate to a micro positive pressure environment monitoring system. BACKGROUND

[0002] For some important space area, such as the room with precision equipment, the operating environment is required to be higher. The environmental quality problems such as pressure, temperature and humidity, noise can cause the precision equipment to work with low accuracy or shorten the service life of equipment, and affect the reliability of system operation. Therefore, it has very important value to design a circuit hardware basis of micro positive pressure environment monitoring system with good use effect, so as to better monitor the environment of precision equipment workspace. The existing micro positive pressure environment monitoring equipment only has the micro positive pressure monitoring function, and the monitoring data is not comprehensive enough. INVENTION CONTENTS

[0003] The utility model is just in view of above -mentioned problem, provide a circuit hardware basis of micro positive pressure environment monitoring system with good use effect.

[0004] In order to achieve the above object, the utility model adopts the following technical scheme, the utility model discloses a micro positive pressure acquisition circuit, noise acquisition circuit, temperature and humidity acquisition circuit, controller circuit, storage circuit, RS485 communication circuit and power supply circuit, and its characterized in that the acquisition signal input port of controller circuit is connected with the acquisition signal output port of micro positive pressure acquisition circuit, the acquisition signal output port of noise acquisition circuit, the acquisition signal output port of temperature and humidity acquisition circuit respectively, the signal transmission port of controller circuit is connected with the signal transmission port of storage circuit, the signal transmission port of RS485 communication circuit respectively, and the electric energy output port of power supply circuit is connected with the power port of micro positive pressure acquisition circuit, the power port of noise acquisition circuit, the power port of temperature and humidity acquisition circuit, the power port of controller circuit, the power port of storage circuit, the power port of RS485 communication circuit respectively.

[0005] As a preferred scheme, the micro positive pressure acquisition circuit of the utility model adopts BMP180-SHUTL chip U1, the 2 feet of U1 are connected with +3.3V, the 3 feet of U1 are connected with inductance L1, one end of capacitor C1, one end of capacitor C2, one end of resistance R1 and one end of resistance R2 respectively, the other end of L1 is connected with +3.3V, and the other end of C1 is connected with the other end of C2 and GNDD respectively;The 5 feet of U1 are connected with the other end of R2 and SCL1 respectively, the 6 feet of U1 are connected with the other end of R1 and SCA1 respectively, and the 7 feet of U1 are connected with GND.

[0006] As another preferred scheme, the noise acquisition circuit adopts INMP441 chip U4, the 1, 2, 4, 8, 3 pins of U4 are respectively connected with IIS_SCK, IIS_SD, GNDD, +3.3V, IIS_WS in correspondence, the 5, 6, 9 pins of U4 are respectively connected with one end of capacitor C4, one end of capacitor C5, the 7 pin of U4 is respectively connected with the other end of C4, the other end of C5 and +3.3V.

[0007] As another preferred scheme, the temperature and humidity acquisition circuit adopts SHT30-DIS-B10KS chip U5, the 1 pin of U5 is respectively connected with SDA2 and one end of resistor R6, the other end of R6 is connected with +3.3V, the 2 pin of U5 is connected with GNDD, the 4 pin of U5 is respectively connected with SCL2 and one end of resistor R7, the other end of R7 is connected with +3.3V, the 5, 6 pins of U5 are respectively connected with one end of capacitor C6, one end of capacitor C7 and +3.3V, the 7, 8 pins of U5 are respectively connected with the other end of C6, the other end of C7 and GNDD.

[0008] As another preferred scheme, the controller circuit adopts STM32F103RCT6 chip U2, the 14, 15 pins of U2 are respectively connected with SDA1 and SCL1 in correspondence, the 46, 49 pins of U2 are respectively connected with the 3, 2 pins of connector P1 in correspondence, the 1, 4 pins of P1 are respectively connected with GNDD and +3.3V in correspondence, the 54 pin of U2 is connected with PD2, the 60 pin of U2 is connected with GNDD through resistor R5, the 7 pin of U2 is connected with RESET, the 1, 32, 48, 64, 19, 13 pins of U2 are connected with +3.3V, +3.3V is respectively connected with RESET and one end of capacitor C8 through resistor R8, the other end of C8 is connected with GNDD, the 31, 47, 63, 18, 12 pins of U2 are connected with GNDD, the 39, 40 pins of U2 are respectively connected with SDA2 and SCL2 in correspondence, the 8-11, 24, 25, 37, 38 pins of U2 are respectively connected with PC0-PC7 in correspondence, the 26, 27, 28, 61, 62, 29, 30, 33, 34, 36 pins of U2 are respectively connected with SCL3, SDA3, GNDD, PB8, PB9, PB10, PB11, IIS_WS, IIS_SCK, IIS_SD in correspondence.

[0009] As another preferred scheme, the storage circuit adopts AT24C1024W-10SI-2.7 chip U3, the 2, 4 pins of U3 are connected with GND, the 5 pin of U3 is respectively connected with SDA3 and one end of resistor R4, the other end of R4 is connected with +3.3V, the 6 pin of U3 is respectively connected with SCL3 and one end of resistor R3, the other end of R3 is connected with +3.3V, the 7 pin of U3 is respectively connected with one end of capacitor C3 and GNDD, the other end of C3 is respectively connected with the 8 pin of U3 and +3.3V.

[0010] As another preferred, the utility model discloses RS485 communication circuit includes AMD2483 chip U6 and B0505S module U8, and the 1, 2, 3 foot of U6 is connected with + 3.3V, GNDD, PB11 corresponding respectively, and the 4, 5 foot of U6 is connected with PB9, and the 6, 7, 8 foot of U6 is connected with PB10, + 3.3V, GNDD corresponding respectively, and the 9, 15, 16 foot of U6 is connected with GND3, GND3, + 5V2 corresponding respectively, and the 13 foot of U6 is connected with the one end of resistance R11, the one end of P6SMB6.8CA tube TVS1, the one end of P6SMB6.8CA tube TVS3, the 1 foot of RS485 communication connector P2 respectively, and the 2 foot of P2 is connected with GND3, and the 3 foot of P2 is connected with the 12 foot of U6, the other end of R11, the other end of TVS1, the one end of P6SMB6.8CA tube TVS2 respectively, and the other end of TVS2 is connected with GND3, the other end of TVS3 respectively.

[0011] Secondly, the utility model discloses power supply circuit includes connector P3, and the 2 foot of P3 is connected with FG, and the 3 foot of P3 is connected with the one end of capacitor C13, the one end of common mode inductance U7 first coil respectively, and the 1 foot of P3 is connected with the other end of C13, the one end of U7 second coil respectively, and the other end of U7 first coil is connected with the one end of capacitor C14, the one end of capacitor C10, the anode of diode BD1, the cathode of diode BD2 respectively, and the other end of U7 second coil is connected with the other end of C14, the one end of capacitor C16, the anode of diode BD4, the cathode of diode BD5 respectively, and the other end of C10 and C16 is connected with FG;

[0012] The cathode of BD1 is connected with the cathode of BD4, the positive pole of capacitor C12, the one end of resistance R10, the one end of capacitor C11, the one end of transformer T1 primary side T1-A respectively, and the anode of BD5 is connected with the cathode of BD2, the negative pole of C12, GND1 respectively, and the other end of R10 is connected with the other end of C11, the cathode of diode D1 respectively, and the anode of D1 is connected with the other end of T1-A, the 8 foot of SDH8634 chip U9, the 7 foot of U9, the 6 foot of U9 respectively, and the 1 foot of U9 is connected with GND1, and the 3 foot of U9 is connected with the one end of capacitor C26, the cathode of voltage stabilizing tube ZD2, the cathode of diode D75 respectively, and the anode of D75 is connected with GND1, the anode of ZD2, the other end of C26, the one end of capacitor C27, the emitter of PC817 chip U11 output end respectively through T1 second secondary side T1-C, and the collector of U11 output end is connected with the 4 foot of U9, the other end of C27 respectively;

[0013] T1-B other end, GNDD are connected in series; the other end of R13 is connected with the anode of U11 input end through the zener diode ZD1, the cathode of U11 input end is connected with GNDD and the one end of R14 in series, the other end of R14 is connected with the other end of C21.

[0014] The Vin port of AMS1117-3.3 module U10 is connected with +5V and the one end of C22 and C23 in series, the Vout port of U10 is connected with +3.3V and the one end of C25 and C24 in series, the other end of C22, the negative pole of C23, the other end of C25 and the negative pole of C24 are connected with GNDD.

[0015] In addition, the number of turns of T1-A is 346, the number of turns of T1-B is 8, and the number of turns of T1-C is 11, and the magnetic core of transformer T1 is EI25.

[0016] The utility model discloses beneficial effects.

[0017] The utility model discloses can carry out high accuracy measurement to the temperature and humidity, micro positive pressure and noise in specific space.

[0018] The utility model discloses adopt the centralized mode design structure, adopt a singlechip (namely controller circuit) to each sensor data are gathered, then, through RS485 bus transmission to host end.

[0019] The utility model discloses through a singlechip and each sensor communication, equipment integration degree is high, and the equipment needed element is few, and the failure rate is low, and the installation is convenient. ACCURACY

[0020] The utility model makes further explanation to the utility model below combining with the drawings and specific embodiment. The utility model protection scope is not only limited to the following content's expression.

[0021] Figure 1 It is micro positive pressure acquisition circuit principle diagram of the utility model.

[0022] Figure 2 It is noise acquisition circuit principle diagram of the utility model.

[0023] Figure 3 It is temperature and humidity acquisition circuit principle diagram of the utility model.

[0024] Figure 4 It is controller circuit principle diagram of the utility model.

[0025] Figure 5 The utility model storage circuit schematic diagram is.

[0026] Figure 6 The utility model RS485 communication circuit schematic diagram is.

[0027] Figure 7 The utility model power supply circuit schematic diagram is. DETAILED DESCRIPTION

[0028] As shown in the figure, the utility model includes micro positive pressure acquisition circuit, noise acquisition circuit, temperature and humidity acquisition circuit, controller circuit, storage circuit, RS485 communication circuit and power supply circuit, and the acquisition signal input port of controller circuit is connected with the acquisition signal output port of micro positive pressure acquisition circuit, the acquisition signal output port of noise acquisition circuit, the acquisition signal output port of temperature and humidity acquisition circuit respectively, the signal transmission port of controller circuit is connected with the signal transmission port of storage circuit, the signal transmission port of RS485 communication circuit respectively, and the electric energy output port of power supply circuit is connected with the power port of micro positive pressure acquisition circuit, the power port of noise acquisition circuit, the power port of temperature and humidity acquisition circuit, the power port of controller circuit, the power port of storage circuit, the power port of RS485 communication circuit respectively.

[0029] The micro positive pressure acquisition circuit adopts BMP180-SHUTL chip U1, and the 2 pin of U1 is connected with + 3.3V, and the 3 pin of U1 is connected with inductance L1, one end of capacitor C1, one end of capacitor C2, one end of resistance R1 and one end of resistance R2 respectively, and the other end of L1 is connected with + 3.3V, and the other end of C1 is connected with the other end of C2 and GNDD respectively;The 5 pin of U1 is connected with the other end of R2 and SCL1 respectively, the 6 pin of U1 is connected with the other end of R1 and SCA1 respectively, and the 7 pin of U1 is connected with GND.

[0030] The micro positive pressure acquisition circuit is connected with U2 through IIC interface (SCA1, SCL1). L1 is magnetic bead, and the role is to filter interference.

[0031] SDA1 is data signal. SCL1 is clock signal, and is used for synchronizing U1 and U2 communication data signal synchronization.

[0032] The noise acquisition circuit adopts INMP441 chip U4, and the 1, 2, 4, 8, 3 pin of U4 is connected with IIS_SCK, IIS_SD, GNDD, + 3.3V, IIS_WS respectively, and the 5, 6, 9 pin of U4 is connected with one end of capacitor C4 and one end of capacitor C5 respectively, and the 7 pin of U4 is connected with the other end of C4, the other end of C5 and + 3.3V respectively.

[0033] Noise acquisition circuit acquires noise value through IIS communication interface (IIS_SCK, IIS_SD, IIS_WS) and sends to U2.

[0034] IIS_SCK: continuous serial clock signal.

[0035] IIS_WS: word selection signal of IIS communication.

[0036] IIS_SD: serial data signal.

[0037] The temperature and humidity acquisition circuit adopts SHT30-DIS-B10KS chip U5, the 1 pin of U5 is connected with SDA2 and one end of resistor R6 respectively, the other end of R6 is connected with +3.3V, the 2 pin of U5 is connected with GNDD, the 4 pin of U5 is connected with SCL2 and one end of resistor R7 respectively, the other end of R7 is connected with +3.3V; the 5 and 6 pins of U5 are connected with one end of capacitor C6, one end of capacitor C7 and +3.3V respectively, the 7 and 8 pins of U5 are connected with the other end of C6, the other end of C7 and GNDD respectively.

[0038] The temperature and humidity acquisition circuit acquires temperature value and humidity value through U5 and sends the collected information to U2 through IIC interface (SDA2, SCL2).

[0039] SDA2: data signal.

[0040] SCL2: clock signal.

[0041] The controller circuit adopts STM32F103RCT6 chip U2, the 14 and 15 pins of U2 are connected with SDA1 and SCL1 respectively, the 46 and 49 pins of U2 are connected with the 3 and 2 pins of connector P1 respectively, the 1 and 4 pins of P1 are connected with GNDD and +3.3V respectively, the 54 pin of U2 is connected with PD2, the 60 pin of U2 is connected with GNDD through resistor R5, the 7 pin of U2 is connected with RESET, the 1, 32, 48, 64, 19 and 13 pins of U2 are connected with +3.3V, +3.3V is connected with RESET and one end of capacitor C8 through resistor R8, the other end of C8 is connected with GNDD; the 31, 47, 63, 18 and 12 pins of U2 are connected with GNDD, the 39 and 40 pins of U2 are connected with SDA2 and SCL2 respectively, the 8-11, 24, 25 and 37-38 pins of U2 are connected with PC0-PC7 respectively, the 26, 27, 28, 61, 62, 29, 30, 33, 34 and 36 pins of U2 are connected with SCL3, SDA3, GNDD, PB8, PB9, PB10, PB11, IIS_WS, IIS_SCK and IIS_SD respectively.

[0042] P1: source program download port of single-chip microcomputer.

[0043] TMS: data interface.

[0044] TCK: clock interface.

[0045] RESET is a signal issued by the single-chip microcomputer for normal power-on start. When the voltage of the RESET pin is lower than 0.8V, the single-chip microcomputer will enter the reset state. When the RESET pin recovers to high level (usually higher than 1.2V), the single-chip microcomputer will exit the reset state and restart.

[0046] The storage circuit adopts AT24C1024W-10SI-2.7 chip U3, the 2 and 4 pins of U3 are connected with GND, the 5 pin of U3 is connected with SDA3 and one end of resistor R4 respectively, the other end of R4 is connected with +3.3V, the 6 pin of U3 is connected with SCL3 and one end of resistor R3 respectively, the other end of R3 is connected with +3.3V, the 7 pin of U3 is connected with one end of capacitor C3 and GNDD respectively, the other end of C3 is connected with the 8 pin of U3 and +3.3V respectively.

[0047] The AT24C1024W-10SI-2.7 chip U3 is used for saving data and generating time stamp after communication failure, and the single such chip is limited by read-write life, the EEPROM chip provides 1,000,000 times of write / erase cycles, in order to protect the read-write life, the EasyFlash (a kind of public technology) control strategy is added in the single-chip microcomputer, which can maximize the life of the chip by controlling the uniformity of writing (balance the number of each writing sector).

[0048] After U2 collects data, the collected values of each sensor are filtered, and after 30 consecutive values are collected, two maximum values and two minimum values can be removed, and after the remaining values are averaged, they are saved after being bound with the current time stamp.

[0049] After U2 collects data, it can be set that if the data is not successfully read by the host on the RS485 communication bus within 5 minutes, the data and time stamp will be saved in U3. After the communication is restored, the host reads and re-uploads the data in U3. The hardware design structure of this circuit can ensure that the data is not lost, and when viewing the data curve, the data will not be 0 due to the loss of data, which will affect the data processing of the host.

[0050] The above detection whether the data is successfully read by the host on the RS485 communication bus can be realized in the following way:

[0051] Through the agreed communication protocol of RS485, the host collects each micro-positive pressure environment monitoring system (attached Figure 1 ~ attached Figure 7The detection value of the micro-positive pressure environment monitoring system circuit diagram) is detected through two ways. 1. If the host does not collect U2 data of the system within 5 minutes, it means that the system fails to communicate with the host. 2. If the host collects U2 data of the system three times in succession, it also means that the communication fails. Because in the judgment process, if the host fails to collect, it will collect again. If it fails to collect for three times (within 2 minutes), the host judges that the micro-positive pressure environment monitoring system has a problem. Therefore, when the micro-positive pressure environment monitoring system is collected by the host for three times in succession, it is judged that the micro-positive pressure environment monitoring system fails to communicate with the host.

[0052] The RS485 communication circuit includes an AMD2483 chip U6 and a B0505S module U8. The 1, 2 and 3 pins of U6 are respectively connected with +3.3V, GNDD and PB11, the 4 and 5 pins of U6 are connected with PB9, the 6, 7 and 8 pins of U6 are respectively connected with PB10, +3.3V and GNDD, the 9, 15 and 16 pins of U6 are respectively connected with GND3, GND3 and +5V2, the 13 pin of U6 is connected with one end of resistor R11, one end of P6SMB6.8CA tube TVS1, one end of P6SMB6.8CA tube TVS3 and the 1 pin of RS485 communication connector P2, the 2 pin of P2 is connected with GND3, the 3 pin of P2 is respectively connected with the 12 pin of U6, the other end of R11, the other end of TVS1 and one end of P6SMB6.8CA tube TVS2, the other end of TVS2 is respectively connected with GND3 and the other end of TVS3.

[0053] As shown in Figure 6 TVS1-TVS3: transient suppression diode, transient suppression diode (Transient Voltage Suppressor, TVS) is used to protect the circuit from the influence of transient voltage (such as surge and voltage peak). It plays a role in overvoltage protection in the circuit. When the RS485 bus has a transient overvoltage phenomenon (voltage exceeds 6.8V), the TVS diode will quickly conduct, and the excess current will be conducted to the ground to prevent the voltage from exceeding the safety threshold of the circuit. The voltage between RS485 bus and A to GND and B to GND will not exceed 6.8V.

[0054] The RS485 communication circuit of the application has an isolation function (U6 is an RS485 special isolation communication chip)

[0055] RS485 communication module. The AMD2483 chip U6 can convert the TTL communication signal of the U2 single-chip microcomputer into RS485 communication. U8 is an isolation power supply with 5V input and output (+5V, +5V2). The AMD2483 chip U6 requires two power supplies, the 1 pin of U6 is the primary side power supply, and the 3 pin of U6 is the receiving port of TTL. The 4 and 5 pins of U6 are in high level to enter the sending mode, and in low level to enter the receiving mode. The 6 pin of U6 is the TTL sending pin. The 16 pin of U6 is the secondary side power supply. The secondary side and the primary side of the AMD2483 chip U6 have an isolation voltage of more than 1000V, which can effectively avoid the possibility of damaging the single-chip microcomputer U2 connected to the primary side of U6 by radiation interference and high voltage or static breakdown of the communication line connected to the secondary side of U6.

[0056] R11 is a 120-ohm resistor used for terminal matching to reduce signal reflection and ensure signal integrity. RS485 is a differential signal transmission method. In long-distance and high-speed communication, without proper terminal matching, the signal at the end of the transmission line may be reflected back, causing signal distortion and communication errors. By adding a 120-ohm terminal resistor at both ends of the bus, the characteristic impedance of the bus is matched, thereby absorbing the reflection of the signal. This ensures that the amplitude and shape of the signal remain stable when it propagates on the bus, effectively improving the reliability and stability of communication.

[0057] The power supply circuit includes a connector P3, the 2 pin of P3 is connected to FG, the 3 pin of P3 is connected to one end of capacitor C13 and one end of common mode inductor U7 first coil respectively, the 1 pin of P3 is connected to the other end of C13 and one end of U7 second coil respectively; the other end of U7 first coil is connected to one end of capacitor C14, one end of capacitor C10, anode of diode BD1 and cathode of diode BD2 respectively, the other end of U7 second coil is connected to the other end of C14, one end of capacitor C16, anode of diode BD4 and cathode of diode BD5 respectively; the other end of C10 and the other end of C16 are connected to FG;

[0058] The BD1 cathode is connected with the BD4 cathode, the capacitor C12 positive electrode, the resistor R10 one end, the capacitor C11 one end and the transformer T1 primary side T1-A one end respectively, the BD5 anode is connected with the BD2 cathode, the C12 negative electrode and the GND1 respectively, the R10 other end is connected with the C11 other end and the diode D1 cathode respectively, the D1 anode is connected with the T1-A other end, the 8th pin of the SDH8634 chip U9, the 7th pin of the U9 and the 6th pin of the U9 respectively, the 1st pin of the U9 is connected with the GND1, the 3rd pin of the U9 is connected with the capacitor C26 one end, the stabilizing tube ZD2 cathode and the diode D75 cathode respectively, the D75 anode is connected with the GND1, the ZD2 anode, the C26 other end, the capacitor C27 one end and the PC817 chip U11 output end emitter respectively through the T1 second secondary side T1-C, the U11 output end collector is connected with the 4th pin of the U9 and the C27 other end respectively;

[0059] The T1 first secondary side T1-B one end is connected with the resistor R9 one end and the diode BD3 anode respectively, the R9 other end is connected with the BD3 cathode and the inductor L2 one end respectively through the capacitor C9, the L2 other end is connected with the resistor R13 one end, the capacitor C21 one end, the capacitor C15 positive electrode, the resistor R12 one end and the +5V respectively, the R12 other end is connected with the C15 negative electrode, the T1-B other end and the GNDD respectively; the R13 other end is connected with the U11 input end anode through the stabilizing diode ZD1, the U11 input end cathode is connected with the GNDD and the resistor R14 one end respectively, the R14 other end is connected with the C21 other end;

[0060] The Vin port of the AMS1117-3.3 module U10 is connected with the +5V, the capacitor C22 one end and the capacitor C23 positive electrode respectively, the Vout port of the U10 is connected with the +3.3V, the capacitor C25 one end and the capacitor C24 positive electrode respectively, the C22 other end, the capacitor C23 negative electrode, the C25 other end and the capacitor C24 negative electrode are connected with the GNDD.

[0061] The number of turns of T1-A is 346, the number of turns of T1-B is 8, and the number of turns of T1-C is 11. The transformer T1 uses an EI25 magnetic core. Through experiments, it is verified that the transformer T1 with the magnetic core and the number of turns can control the copper loss and the iron loss to be approximately the same, and can reduce the transformer temperature and the power consumption to the minimum. When the loss of the magnetic core is reduced by increasing the number of turns of the primary side, the number of turns of the primary side is larger, and the disadvantage is that the primary current passes through the longer primary winding enameled wire, and the copper loss of the enameled wire is higher. If the primary side winding ratio is reduced while the primary side winding ratio is unchanged, the copper loss can be greatly reduced, but the maximum magnetic flux is increased, the problem of magnetic core saturation is prone to occur, and the magnetic hysteresis loop area is larger. The best selection method is that the copper loss is equal to the iron loss, the best ratio effect is obtained by adjusting the primary side winding ratio, the best efficiency of the power supply is achieved, the lowest loss is achieved, and the working magnetic flux is below the saturation magnetic flux density of the magnetic core 0.35 tesla (3500 gauss) at the highest voltage or the highest working temperature.

[0062] P3 is used to connect the mains L, N, and ground. The mains is filtered through C13, common mode inductor U7, C14, C10, and C16. The mains is filtered through X capacitors (C13 and C14) (the capacity of the capacitors is different, and the filtering frequency is different. The higher the capacity of the capacitor, the lower the frequency), and filtered to the ground through Y capacitors C10 and C16. Then the mains is rectified through four diodes (BD1-BD4) and filtered through C12. The mains is supplied to the built-in switch tube power supply chip of SDH8634 chip U9 through T1-A. The 3-pin of U9 is a chip power supply interface, and the chip is supplied through the T1-C winding. The 4-pin of U9 is a feedback winding, which detects the voltage of T1-B, adjusts the opening and closing duty cycle of the built-in switch tube of U9, changes the voltage of T1-B, and achieves constant voltage output. T1-B is rectified through BD3, filtered through L2 to reduce the ripple, and a stable 5V voltage is generated through capacitor C15.

[0063] The output voltage of T1-B is input to the anode of U11 through R13 and ZD1. The +5V secondary side voltage is introduced to supply power to the primary side of U11, and the 4-pin of U9. When the output voltage of T1-B is low, the primary side current of U11 decreases, the secondary side conduction of U11 decreases, and the resistance of the 4-pin of U9 to the ground increases. After U9 detects the change of the pin, the duty cycle is adjusted to control the constant voltage of the output end 5V, and the output voltage of T1-B is not affected by the load change.

[0064] In the design, the power supply is a single-ended flyback switching power supply, when the main winding works (the internal switch tube of U9 is turned on), the magnetic core stores energy, when the main winding is turned off (the internal switch tube of U9 is turned off), due to the existence of external parasitic inductance, the storage of switching capacitor and the existence of external parasitic energy storage element, a higher oscillation interference voltage is applied to the off tube, and the direction is the antiphase end relationship of T1-A, part of the interference can be filtered out through R10, C11 and D1, so that the internal switch of U9 is not damaged by high voltage oscillation.

[0065] R9, C9 are used for eliminating the oscillation of BD3 due to parasitic inductance and BD3 junction capacitance, and protecting BD3 from being damaged.

[0066] R14 and C21 are used as compensation of the sampling comparison circuit, so as to prevent the instantaneous change of sampling comparison caused by sudden change, and cause the instability of the whole feedback loop.

[0067] The micro-positive pressure acquisition circuit, the noise acquisition circuit, the temperature and humidity acquisition circuit, the controller circuit, the storage circuit, the RS485 communication circuit and the power supply circuit can be arranged in the shell, and the acquisition head of the micro-positive pressure acquisition circuit, the acquisition head of the noise acquisition circuit and the acquisition head of the temperature and humidity acquisition circuit can be arranged outside the shell. Hooks or mounting supports can be arranged on the shell, so that the shell is conveniently mounted and arranged.

[0068] It can be understood that the above specific description of the utility model is only used for illustrating the utility model and is not limited to the technical scheme described in the utility model embodiment, and those skilled in the art should understand that the utility model can still be modified or replaced equivalently to achieve the same technical effect, as long as the use needs are met, which is within the protection scope of the utility model.

Claims

1. A micro-positive pressure environment monitoring system, comprising a micro-positive pressure acquisition circuit, a noise acquisition circuit, a temperature and humidity acquisition circuit, a controller circuit, a storage circuit, an RS485 communication circuit and a power supply circuit, characterized in that The signal collection input ports of the controller circuit are connected with the signal collection output ports of the micro-positive pressure collection circuit, the signal collection output ports of the noise collection circuit and the signal collection output ports of the temperature and humidity collection circuit respectively, the signal transmission ports of the controller circuit are connected with the signal transmission ports of the storage circuit and the signal transmission ports of the RS485 communication circuit respectively, and the power output ports of the power supply circuit are connected with the power ports of the micro-positive pressure collection circuit, the power ports of the noise collection circuit, the power ports of the temperature and humidity collection circuit, the power port of the controller circuit, the power port of the storage circuit and the power port of the RS485 communication circuit respectively. The micro-positive pressure collection circuit adopts a BMP180-SHUTL chip U1, the 2th pin of U1 is connected with +3.3V, the 3th pin of U1 is connected with the inductor L1, one end of the capacitor C1, one end of the capacitor C2, one end of the resistor R1 and one end of the resistor R2 respectively, the other end of L1 is connected with +3.3V, and the other end of C1 is connected with the other end of C2 and GNDD respectively; the 5th pin of U1 is connected with the other end of R2 and SCL1 respectively, the 6th pin of U1 is connected with the other end of R1 and SCA1 respectively, and the 7th pin of U1 is connected with GND. The controller circuit adopts an STM32F103RCT6 chip U2, the 14th and 15th pins of U2 are connected with SDA1 and SCL1 respectively, the 46th and 49th pins of U2 are connected with the 3rd and 2nd pins of the connector P1 respectively, the 1st and 4th pins of P1 are connected with GNDD and +3.3V respectively, the 54th pin of U2 is connected with PD2, the 60th pin of U2 is connected with GNDD through the resistor R5, the 7th pin of U2 is connected with RESET, the 1st, 32nd, 48th, 64th, 19th and 13th pins of U2 are connected with +3.3V, +3.3V is connected with RESET and one end of the capacitor C8 through the resistor R8, and the other end of C8 is connected with GNDD; the 31st, 47th, 63rd, 18th and 12th pins of U2 are connected with GNDD, the 39th and 40th pins of U2 are connected with SDA2 and SCL2 respectively, the 8th-11th, 24th, 25th, 37th and 38th pins of U2 are connected with PC0-PC7 respectively, and the 26th, 27th, 28th, 61st, 62nd, 29th, 30th, 33rd, 34th and 36th pins of U2 are connected with SCL3, SDA3, GNDD, PB8, PB9, PB10, PB11, IIS_WS, IIS_SCK and IIS_SD respectively.

2. The micro-positive pressure environment monitoring system according to claim 1, wherein The noise collection circuit adopts an INMP441 chip U4, the 1st, 2nd, 4th, 8th and 3rd pins of U4 are connected with IIS_SCK, IIS_SD, GNDD, +3.3V and IIS_WS respectively, the 5th and 6th pins of U4 are connected with one end of the capacitor C4 and one end of the capacitor C5 respectively, and the 7th pin of U4 is connected with the other end of C4, the other end of C5 and +3.3V.

3. The micro-positive pressure environment monitoring system of claim 1, wherein The temperature and humidity acquisition circuit adopts SHT30-DIS-B10KS chip U5, the pin 1 of U5 is connected with SDA2 and one end of resistor R6 respectively, the other end of R6 is connected with +3.3V, the pin 2 of U5 is connected with GNDD, the pin 4 of U5 is connected with SCL2 and one end of resistor R7 respectively, the other end of R7 is connected with +3.3V; the pin 5 and 6 of U5 are connected with one end of capacitor C6, one end of capacitor C7 and +3.3V respectively, the pin 7 and 8 of U5 are connected with the other end of C6, the other end of C7 and GNDD respectively.

4. The micro-positive pressure environment monitoring system of claim 1, wherein The storage circuit adopts AT24C1024W-10SI-2.7 chip U3, the pin 2 and 4 of U3 are connected with GND, the pin 5 of U3 is connected with SDA3 and one end of resistor R4 respectively, the other end of R4 is connected with +3.3V, the pin 6 of U3 is connected with SCL3 and one end of resistor R3 respectively, the other end of R3 is connected with +3.3V, the pin 7 of U3 is connected with one end of capacitor C3 and GNDD respectively, the other end of C3 is connected with the pin 8 of U3 and +3.3V respectively.

5. The micro-positive pressure environment monitoring system of claim 1, wherein The RS485 communication circuit includes AMD2483 chip U6 and B0505S module U8, the pin 1, 2 and 3 of U6 are connected with +3.3V, GNDD and PB11 respectively, the pin 4 and 5 of U6 are connected with PB9, the pin 6, 7 and 8 of U6 are connected with PB10, +3.3V and GNDD respectively, the pin 9, 15 and 16 of U6 are connected with GND3, GND3 and +5V2 respectively, the pin 13 of U6 is connected with one end of resistor R11, one end of P6SMB6.8CA tube TVS1, one end of P6SMB6.8CA tube TVS3 and the pin 1 of RS485 communication connector P2 respectively, the pin 2 of P2 is connected with GND3, the pin 3 of P2 is connected with the pin 12 of U6, the other end of R11, the other end of TVS1, one end of P6SMB6.8CA tube TVS2 respectively, the other end of TVS2 is connected with GND3 and the other end of TVS3 respectively.

6. The micro-positive pressure environment monitoring system of claim 1, wherein The power supply circuit includes connector P3, the pin 2 of P3 is connected with FG, the pin 3 of P3 is connected with one end of capacitor C13 and one end of the first coil of common mode inductor U7 respectively, the pin 1 of P3 is connected with the other end of C13 and one end of the second coil of U7 respectively; the other end of the first coil of U7 is connected with one end of capacitor C14, one end of capacitor C10, anode of diode BD1 and cathode of diode BD2 respectively, the other end of the second coil of U7 is connected with the other end of C14, one end of capacitor C16, anode of diode BD4 and cathode of diode BD5 respectively; the other end of C10 and C16 is connected with FG; The BD1 cathode is connected with the BD4 cathode, the capacitor C12 positive pole, the resistor R10 one end, the capacitor C11 one end and the transformer T1 primary side T1-A one end respectively, the BD5 anode is connected with the BD2 cathode, the C12 negative pole and the GND1 respectively, the R10 other end is connected with the C11 other end and the diode D1 cathode respectively, the D1 anode is connected with the T1-A other end, the U9 8th pin of the SDH8634 chip U9, the U9 7th pin and the U9 6th pin respectively, the U9 1st pin is connected with the GND1, the U9 3rd pin is connected with the capacitor C26 one end, the ZD2 cathode and the diode D75 cathode respectively, the D75 anode is connected with the GND1, the ZD2 anode, the C26 other end, the capacitor C27 one end and the U11 output end emitter of the PC817 chip U11 respectively through the T1 second secondary side T1-C, the U11 output end collector is connected with the U9 4th pin and the C27 other end respectively; The T1 first secondary side T1-B one end is connected with the resistor R9 one end and the diode BD3 anode respectively, the R9 other end is connected with the BD3 cathode and the inductor L2 one end respectively through the capacitor C9, the L2 other end is connected with the resistor R13 one end, the capacitor C21 one end, the capacitor C15 positive pole, the resistor R12 one end and the +5V respectively, the R12 other end is connected with the C15 negative pole, the T1-B other end and the GNDD respectively; the R13 other end is connected with the U11 input end anode through the ZD1, the U11 input end cathode is connected with the GNDD and the resistor R14 one end respectively, the R14 other end is connected with the C21 other end; The Vin port of the AMS1117-3.3 module U10 is connected with the +5V, the capacitor C22 one end and the capacitor C23 positive pole respectively, the Vout port of the U10 is connected with the +3.3V, the capacitor C25 one end and the capacitor C24 positive pole respectively, the C22 other end, the capacitor C23 negative pole, the C25 other end and the capacitor C24 negative pole are connected with the GNDD.

7. The micro-positive pressure environment monitoring system of claim 6, wherein The number of turns of the T1-A is 346 turns, the number of turns of the T1-B is 8 turns, the number of turns of the T1-C is 11 turns, and the transformer T1 magnetic core adopts EI25.

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