Temperature controller for gas delivery device

Abstract

This utility model discloses a temperature controller for a gas delivery device. The device comprises a microcontroller (MCU) and modules for temperature detection, human-machine interaction, output drive, power management, and external interfaces. Temperature detection uses an RTD (PT100) and an ADC with dual IDAC to achieve differential sampling and lead compensation, and SPI communication. The output drive is an NPN switch with a freewheeling diode, controlling the heater and multiple gas path actuators, and features timing / delay linkage. Power management includes surge / overvoltage protection and provides 5V and 3.3V. Interfaces include T-Port, AIR-Port, MainPort, and general-purpose inputs. The MCU implements closed-loop temperature control, open / short circuit diagnosis, and over-temperature protection. In case of abnormalities, power is reduced and cooling is assisted through an independent standby channel. This utility model's temperature controller for gas delivery devices features high accuracy, strong anti-interference capabilities, and reliable safety.

Description

Technical Field

[0001] This utility model relates to the field of gas transportation and temperature control technology, specifically to a temperature controller for gas transportation devices. Background Technology

[0002] In scenarios such as gas transportation, constant temperature insulation, dehumidification and anti-condensation, and stabilizing flow / viscosity, it is often necessary to precisely, stably and safely control the temperature inside the pipeline or cavity.

[0003] The shortcomings of existing technology:

[0004] 1) Insufficient accuracy and anti-interference capability in temperature measurement: Two-wire or RTD solutions without lead compensation are easily affected by lead resistance and electromagnetic noise, resulting in increased error and temperature drift in the low temperature range, making it difficult to meet the requirements of precision temperature control.

[0005] 2) Insufficient real-time performance and determinism in the sampling-control link: Some existing solutions lack hardware "data ready" handshakes and rely solely on polling for reading, which can easily cause sampling jitter and control delays.

[0006] 3) Lack of sequential / delay linkage mechanism for heating and gas supply actuators: Parallel or simple coupling drive strategies may lead to problems such as cold air blowing directly on the heat source, thermal shock, or condensation.

[0007] Therefore, existing technologies have shortcomings and need further improvement. Utility Model Content

[0008] In view of the problems existing in the prior art, this utility model provides a temperature controller for a gas conveying device.

[0009] To achieve the above objectives, the specific solution of this utility model is as follows:

[0010] This utility model provides a temperature controller for a gas conveying device, comprising:

[0011] Microcontroller (MCU) and its electrically connected temperature detection module, human-machine interface module, output driver module, power management module and external interface module;

[0012] The temperature detection module uses a resistive temperature sensing element (RTD) connected to an analog-to-digital converter (ADC). The ADC provides an excitation current to the RTD and performs differential sampling. The ADC is electrically connected to a microcontroller (MCU) via a serial peripheral interface (SPI).

[0013] The human-computer interaction module includes a display unit and function buttons that are electrically connected to a microcontroller (MCU);

[0014] The output drive module includes a drive channel for the heater and multiple drive channels for the pneumatic actuators.

[0015] The power management module provides operating voltage for the microcontroller (MCU), analog-to-digital converter (ADC), and display unit, and provides surge / overvoltage protection for external input power.

[0016] The external interface module is used to connect the resistance temperature sensing element (RTD), heater, gas actuator and general input / output (I / O) to this temperature controller;

[0017] The microcontroller (MCU) is configured to perform closed-loop temperature control based on the acquired temperature signal and to perform timing and delay control on the heater and gas path actuators.

[0018] Furthermore, the resistive temperature sensing element (RTD) is a three-wire PT100 temperature sensor, and the analog-to-digital converter (ADC) has dual constant current sources (IDAC) connected to the two leads of the PT100 temperature sensor to achieve lead resistance compensation; the two ends of the PT100 temperature sensor are connected to the differential input terminals (AIN0, AIN1) of the ADC, and the reference terminals (REFP, REFN) of the ADC are connected to a reference voltage source; an RC noise reduction filter network is provided on the input side of the PT100 temperature sensor.

[0019] Furthermore, the analog-to-digital converter (ADC) communicates with the serial peripheral interface (SPI) of the microcontroller (MCU) through chip select (CS), clock (CLK), master-input-slave-in (MOSI) and master-input-slave-out (MISO), and provides a sampling ready interrupt signal to the microcontroller (MCU) through the data ready (DRDY) pin.

[0020] Furthermore, the power management module includes: surge / transient suppression diodes for external DC input, and cascaded voltage regulator circuits to obtain 5V and 3.3V power supplies, and decoupling and energy storage capacitors are provided at the power supply pins of each voltage regulator stage and key components.

[0021] Furthermore, the output driving module includes several switching driving units composed of NPN transistors. Each driving unit includes a base current limiting resistor and a pull-up / pull-down resistor, and a freewheeling diode connected in parallel with the inductive load to protect the inductive load. The driving units are used for the on / off control of the heater, the first gas path actuator, and the second gas path actuator, and are equipped with a delay / edge shaping network composed of resistors, capacitors, and diodes to realize the timing linkage between the heater and the gas path actuator.

[0022] Furthermore, the external interface module is equipped with multiple general-purpose input conditioning channels, each of which includes a voltage divider / current limiting resistor and an RC filter, and is then connected to the digital input pin of the microcontroller (MCU) to achieve anti-interference acquisition of external switching or status quantities.

[0023] Furthermore, the human-machine interaction module includes a serially driven display unit and at least four function buttons. The display unit is connected to the microcontroller (MCU) via chip select, clock, and serial data line. The buttons are connected to the microcontroller (MCU) via an interface circuit to perform operations such as setting temperature, working mode, and calibration.

[0024] Furthermore, the external interface module is provided with a separate port (T-Port) for the resistance temperature sensing element (RTD), a port (AIR-Port) for connecting the gas path actuator, and a main port (MainPort) for external system connections, so as to quickly connect with the heating components and gas path components of the gas delivery device.

[0025] Furthermore, the thermostat is also equipped with an independent standby control output channel, which is used to automatically switch to standby / cooling mode when the system is abnormal or the temperature reaches the upper limit, thereby reducing the heating power and maintaining the safety of gas delivery.

[0026] Furthermore, the microcontroller (MCU) is further configured to: perform open and short circuit diagnosis and over-temperature protection of the resistance temperature detection element (RTD); when over-temperature, RTD disconnection or external abnormal input is detected, promptly shut down the heater drive channel and open the gas path actuator according to a preset delay to assist in cooling, while displaying alarm information on the display unit.

[0027] The technical solution of this utility model has the following beneficial effects:

[0028] 1) Improved temperature measurement accuracy and stability: The three-wire PT100 is used in conjunction with a high-precision ADC with constant current source (IDAC), differential sampling and reference terminal design can effectively compensate for lead resistance and suppress common mode interference, thereby improving measurement accuracy and repeatability.

[0029] 2) Enhanced real-time and deterministic performance of the sampling-control link: The ADC and MCU communicate via the SPI bus and set the Data Ready (DRDY) hardware handshake signal, enabling deterministic sampling under interrupt-driven conditions, reducing timing jitter and control delay.

[0030] 3) Sequential / delay linkage of actuators to suppress thermal shock: The heating and two-way air output are set with a "T_Delay+ / AIR1_Delay+ / AIR2_Delay+" delay / shaping network to achieve "first / last" linkage and soft switching, avoiding cold air blowing directly on the heat source and thermal shock. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the principle of this utility model;

[0032] Figure 2 This is the analog-to-digital converter circuit diagram of this utility model;

[0033] Figure 3 This is the temperature sensor circuit of the present invention;

[0034] Figure 4 This utility model relates to a microcontroller and its peripheral interface circuit.

[0035] Figure 5 This utility model relates to an NPN low-end switch / drive circuit.

[0036] Figure 6 This is the linear regulated power supply circuit of this utility model;

[0037] Figure 7 This utility model relates to a low-dropout linear voltage regulator.

[0038] Figure 8 This utility model includes a power-on reset circuit, a partial crystal oscillator circuit, and an SWD download / debugging interface;

[0039] Figure 9 This utility model relates to a microcontroller and external interface circuit that employs optocoupler isolation.

[0040] Figure 10 This is the pin definition diagram of the interface / port of this utility model. Detailed Implementation

[0041] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.

[0042] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0043] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0044] In the description of this embodiment, the terms "upper," "lower," "front," "rear," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0045] Combination Figures 1-10 As shown, this utility model provides a temperature controller for a gas conveying device, comprising:

[0046] Microcontroller (MCU) and its electrically connected temperature detection module, human-machine interface module, output driver module, power management module and external interface module;

[0047] The temperature detection module uses a resistive temperature sensing element (RTD) connected to an analog-to-digital converter (ADC). The ADC provides an excitation current to the RTD and performs differential sampling. The ADC is electrically connected to a microcontroller (MCU) via a serial peripheral interface (SPI).

[0048] The human-computer interaction module includes a display unit and function buttons that are electrically connected to a microcontroller (MCU);

[0049] The output drive module includes a drive channel for the heater and multiple drive channels for the pneumatic actuators.

[0050] The power management module provides operating voltage for the microcontroller (MCU), analog-to-digital converter (ADC), and display unit, and provides surge / overvoltage protection for external input power.

[0051] The external interface module is used to connect the resistance temperature sensing element (RTD), heater, gas actuator and general input / output (I / O) to this temperature controller;

[0052] The microcontroller (MCU) is configured to perform closed-loop temperature control based on the acquired temperature signal and to perform timing and delay control on the heater and gas path actuators.

[0053] The resistive temperature sensing element (RTD) is a three-wire PT100 temperature sensor. The analog-to-digital converter (ADC) has dual constant current sources (IDAC) and is connected to the two leads of the PT100 temperature sensor to achieve lead resistance compensation. The two ends of the PT100 temperature sensor are connected to the differential input terminals (AIN0, AIN1) of the ADC, and the reference terminals (REFP, REFN) of the ADC are connected to a reference voltage source. An RC noise reduction filter network is provided on the input side of the PT100 temperature sensor.

[0054] The analog-to-digital converter (ADC) communicates with the serial peripheral interface (SPI) of the microcontroller (MCU) through chip select (CS), clock (CLK), master output slave input (MOSI) and master input slave output (MISO), and provides a sampling ready interrupt signal to the microcontroller (MCU) through the data ready (DRDY) pin.

[0055] The power management module includes: surge / transient suppression diodes for external DC input, and cascaded voltage regulator circuits to obtain 5V and 3.3V power supplies, and decoupling and energy storage capacitors are provided at the power supply pins of each voltage regulator stage and key components.

[0056] The output drive module includes several switching drive units composed of NPN transistors. Each drive unit contains a base current limiting resistor and a pull-up / pull-down resistor, and a freewheeling diode connected in parallel with the inductive load to protect the inductive load. The drive units are used for the on / off control of the heater, the first gas path actuator and the second gas path actuator, and are equipped with a delay / edge shaping network composed of resistors, capacitors and diodes to realize the timing linkage between the heater and the gas path actuator.

[0057] The external interface module is equipped with multiple general-purpose input conditioning channels. Each channel includes a voltage divider / current limiter resistor and an RC filter, which is then connected to the digital input pin of the microcontroller (MCU) to achieve anti-interference acquisition of external switching or status quantities.

[0058] The human-machine interaction module includes a serially driven display unit and at least four function buttons. The display unit is connected to the microcontroller (MCU) via chip select, clock and serial data line. The buttons are connected to the microcontroller (MCU) via interface circuit to realize operations such as setting temperature, working mode and calibration.

[0059] The external interface module is equipped with a separate port (T-Port) for the resistance temperature sensing element (RTD), a port (AIR-Port) for connecting the gas path actuator, and a main port (MainPort) for external system connections, so as to quickly connect with the heating components and gas path components of the gas delivery device.

[0060] The thermostat also has an independent standby control output channel, which is used to automatically switch to standby / cooling mode when the system is abnormal or the temperature reaches the upper limit, thereby reducing the heating power and maintaining the safety of gas delivery.

[0061] The microcontroller (MCU) is further configured to: perform open and short circuit diagnosis and over-temperature protection of the resistance temperature detection element (RTD); when over-temperature, RTD disconnection or external abnormal input is detected, promptly shut down the heater drive channel and open the gas path actuator according to the preset delay to assist in cooling, and at the same time display alarm information on the display unit.

[0062] The principle of this utility model is as follows:

[0063] 1) Temperature Acquisition and Conversion: The temperature probe uses a three-wire PT100. The high-precision analog-to-digital converter (ADC) has a built-in dual constant current source (IDAC) to provide excitation current to the RTD and acquires the voltage at both ends in a differential manner; the reference and input terminals of the ADC are used in conjunction with an RC network for noise reduction and stabilization, thereby suppressing lead resistance and noise.

[0064] 2) Digital Interface and Data Readiness: The ADC communicates with the MCU via the SPI bus and sets the data ready pin (ADC_RDY). After the ADC completes a conversion, it prompts the MCU to read the data via DRDY, thus achieving deterministic sampling in an interrupt-driven manner.

[0065] 3) Human-Machine Interaction and Settings: The human-machine interaction section includes a serially driven display interface and at least four function buttons. Users set the target temperature and operating mode via the buttons, and the MCU reads the button signals and displays the parameters and status.

[0066] 4) Closed-loop control strategy: The MCU periodically reads the temperature value, compares it with the set value, and outputs a control quantity to coordinate the control of the heating and gas path actuators; when the temperature is near the set upper and lower limits, it reduces jitter according to threshold / hysteresis strategies, and combines external input quantity (G_INPUT×) to perform linkage and protection logic judgment.

[0067] 5) Execution Drive and Timing Linkage: The heating and two gas path actuators are driven by transistor switches, with Schottky diodes connected in parallel for freewheeling and protection. Delay / shaping networks such as "T_Delay+", "AIR1_Delay+", and "AIR2_Delay+" are set at the front end of each channel to realize start-stop sequence and soft switching. The corresponding external control terminals are HEATER_O, AIR1_O, and AIR2_O.

[0068] 6) Abnormal and standby safety control: When over-temperature, sensor abnormality or external abnormal input is detected, the MCU triggers the standby control channel, and switches to standby / power reduction state through the "Standby_Delay+" network and STANDBY_OUT / STANDBY_O port. At the same time, it can link the air circuit actuator to perform cooling or exhaust.

[0069] 7) Power supply and power-on stability: The external DC input is suppressed by TVS and then regulated to obtain 5V and 3.3V through staged voltage regulation; each stage is equipped with large / small capacity capacitors for decoupling and energy storage, providing a stable power supply for MCU, ADC, display and drive circuits.

[0070] 8) External Interfaces and System Integration: To facilitate field integration, the board is equipped with partitioned interfaces such as the MainPort, the Temperature Sensor Port (T-Port), and the Air Port (AIR-port), which enable quick docking of the heater, PT100, and air actuators on the application side.

[0071] 9) Typical operating sequence: After power-on, the power supply is regulated and self-test is completed; the ADC excites the PT100 and continuously samples, and the DRDY interrupt triggers the MCU to read; the MCU calculates the control quantity according to the set value: when the temperature is lower than the threshold, the heating channel is soft-started via "T_Delay+"; when approaching the target or when coordinated air supply is required, the air circuit actuators are driven in the set sequence of "AIR1_Delay+ / AIR2_Delay+"; if over-temperature or external abnormality occurs, the system immediately switches to standby through the STANDBY_OUT channel, and then performs safety handling according to the strategy of linkage with the air circuit, and the process status is displayed on the display.

[0072] 10) Signal flow summary: Temperature sensor (PT100) → ADC (differential sampling / IDAC / reference) → SPI / DRDY → MCU (closed-loop calculation / determination) → Driver stage (heating / gas path / standby, including delay network and freewheeling protection) → External port (HEATER_O / AIR1_O / AIR2_O / STANDBY_O). The entire link is guaranteed to be stable and interference-resistant by power supply regulation and input conditioning.

[0073] Example:

[0074] Temperature controller for gas delivery systems

[0075] like Figure 1 As shown:

[0076] Temperature measurement / display and external I / O control circuit with a microcontroller (MCU) at its core. Temperature is acquired by a PT100 platinum resistance thermometer and sent to the MCU via the "temperature detection" front end; the MCU is responsible for display, button interaction, and sending and receiving control / status signals through the external interface on the left.

[0077] Major electronic components (functional modules)

[0078] PT100: Platinum Resistance Temperature Sensor (RTD);

[0079] Temperature detection: Sensor front end / signal conditioning module (constant current source / bridge, amplification, filtering, ADC or sent to the MCU's internal ADC).

[0080] MCU: Microcontroller, responsible for sampling, calculation, logic control, display and key press processing, as well as communication / driving with external interfaces.

[0081] Display: Digital tube / LCD / OLED, etc., driven by MCU to display temperature and status.

[0082] Buttons: Human-machine input, connected to the digital input pins of the MCU (may have pull-up / pull-down).

[0083] External interface: External I / O port, including one "input" line and one "output" line, which is connected to the MCU's I / O (can be connected to relays / SSRs / alarms or host computer signals).

[0084] Connection relationships (in order of line direction)

[0085] PT100 → Temperature Detection → MCU (Input): The PT100 is connected to the temperature detection module; the analog / digital output of this module is connected to the "input" terminal of the MCU.

[0086] Button → MCU (Input): The button signal line is connected to the digital input of the MCU.

[0087] MCU (Output) → Display: The MCU's display interface cable is connected to the display module.

[0088] External Interface. Input → MCU (Input): The "Input" line of the left interface goes into the MCU (to allow the MCU to read external status / trigger signals).

[0089] MCU (Output) → External Interface. Output: One output line of the MCU is connected to the interface "Output" (for external drive / alarm / control).

[0090] Working principle (process)

[0091] 1. Temperature Measurement: The resistance of the PT100 changes nearly linearly with temperature (approximately 0.385% / ℃). The temperature detection module provides a small constant current to the PT100 and converts its resistance change into voltage; after amplification / filtering, the voltage is sent to the MCU's ADC (or the module's built-in ADC sends the voltage to the MCU in digital form).

[0092] 2. Calculation / calibration: The MCU periodically samples the temperature value according to the PT100R-T relationship and calibration parameters, and performs processing such as limiting / denoising / averaging.

[0093] 3. Human-computer interaction: Read button signals (such as setting target temperature, switching units / interfaces); refresh temperature / status through the display module.

[0094] 4. External I / O: Read external trigger / linkage signals from the interface input; drive the interface output (such as controlling relays, SSRs, buzzers, or sending the status back to the host computer) based on the logic or threshold comparison results.

[0095] 5. (Optional) Closed-loop control: If the external output is connected to a heating / cooling actuator, a simple constant temperature / threshold control is formed (such as dual-position on / off control or with hysteresis).

[0096] Key points and engineering recommendations

[0097] PT100 connection method: 3 or 4 wires are preferred to eliminate lead resistance error; constant current source is usually in the range of 0.5–1mA to avoid self-heating.

[0098] Front-end circuit: A Wheatstone bridge + instrumentation amplifier (such as the INA series) or a dedicated RTDADC (such as the MAX31865) can be used; 50 / 60Hz suppression and digital filtering are performed at the MCU end.

[0099] Interface driver / protection: For external "output", it is recommended to use optocouplers + transistors / relays, and add TVS, current limiting, reverse connection / surge protection; for "input", use optocouplers / voltage dividers and debouncing.

[0100] Buttons / Display: Buttons are hard / soft debouncing; displays can use I²C / SPI buses to reduce pin usage.

[0101] Power supply and EMC: Analog / digital partitioning, single-point connection; provide low-noise reference and filtering for the temperature measurement analog front end, and pay attention to wiring and shielding.

[0102] like Figure 2 As shown:

[0103] This is an ADC (Analog-to-Digital Converter) interface circuit. The core chip is a high-precision ADC (with SPI interface) used to convert external analog signals (such as sensor voltage) into digital signals and communicate with the MCU via the SPI bus.

[0104] II. Main Electronic Components

[0105] ADC chip (U1)

[0106] Pin functions:

[0107] SPI interface:

[0108] SCLK (Clock Input)

[0109] CS# (Chip Select, active low)

[0110] DIN (Data Input / MOSI)

[0111] DOUT / DRDY# (Data Output + Data Ready Signal / MISO)

[0112] DRDY# (Data ready signal, interrupt-enabled)

[0113] Power and Ground: DVDD (Digital Power), AVDD (Analog Power), DGND (Digital Ground), AVSS (Analog Ground)

[0114] Analog inputs: AIN0, AIN1, AIN2, AIN3 / REFN1

[0115] Reference voltages: REFP0, REFN0, AIN0 / REFP1

[0116] Current source outputs: IDAC1, IDAC2 (used to excite the sensor)

[0117] resistance

[0118] R4, R7, R65, R58, R49 (47Ω): Series resistors on the SPI channel, used to suppress reflections and improve signal integrity.

[0119] R6 (100kΩ): Pull-up resistor, which pulls the CS# pin high by default to avoid false triggering.

[0120] capacitance

[0121] C4 and C5 (0.1µF): ​​Decoupling capacitors, connected near AVDD and AIN0 / REFP0 respectively, used for filtering and noise reduction.

[0122] power supply

[0123] V3.3: Provides 3.3V power to the analog and digital sections of the chip.

[0124] III. Connection Relationships Between Components

[0125] SPI interface

[0126] The MCU's MOSI→DIN (connected in series via R4)

[0127] MCU's MISO←DOUT / DRDY# (connected via R58)

[0128] MCU's CLK → SCLK (connected in series via R7)

[0129] The MCU's CS to CS# pins are connected in series via R65, with pull-up resistor R6 maintaining the default high level.

[0130] MCU interrupt input ←DRDY# (connected via R49)

[0131] Power supply and filtering

[0132] V3.3 → AVDD, DVDD, and a decoupling capacitor C4 is connected to the chip's power supply terminal.

[0133] Connect AIN0 / REFP0 to 3.3V and connect a decoupling capacitor C5 in parallel.

[0134] REFP0 / REFN0 provides a reference voltage input.

[0135] Analog Input

[0136] AIN0 and AIN1 are differential input signal terminals.

[0137] AIN2, AIN3 / REFN1 can be used for additional input channels or references.

[0138] IDAC1 and IDAC2 can provide current source excitation for the sensor.

[0139] IV. Working Principle

[0140] 1. Initialization and Power Supply

[0141] The chip is powered by a 3.3V power supply, and the power supply port is filtered by a capacitor to ensure stability.

[0142] CS# is pulled high by R6 by default, and the chip is in an unselected state.

[0143] 2.SPI communication

[0144] The MCU pulls CS# low to select the ADC, uses SCLK to provide the clock, and writes the configuration to the register via MOSI (DIN).

[0145] The ADC outputs the sampling results through MISO (DOUT / DRDY#). The DRDY# pin generates a low-level signal when the data is ready, which the MCU can use to read the data.

[0146] 3. Analog-to-digital conversion process

[0147] External analog signals are input through AIN0 and AIN1 (differential mode).

[0148] The chip utilizes its internal Σ-Δ (Delta-Sigma) architecture to perform oversampling and digital filtering on the signal.

[0149] The conversion result is sent to the MCU in digital form via SPI.

[0150] 4. Reference voltage and current sources

[0151] REFP0 / REFN0 provides a reference voltage that determines the ADC's range and resolution.

[0152] IDAC1 and IDAC2 can output constant current to excite sensors (such as resistive sensors and RTDs).

[0153] Summarize:

[0154] This is a high-precision ADC circuit based on the SPI interface, featuring differential input, reference voltage input, and current source output. The peripheral circuitry includes pull-up resistors, series resistors, and decoupling capacitors. Its main function is to acquire analog signals (such as sensor voltage / current), convert them into digital signals, and transmit them to the MCU for high-precision measurement.

[0155] like Figure 3 As shown:

[0156] This is a three-wire PT100 temperature sensor circuit used in conjunction with an analog-to-digital converter (ADC) for temperature measurement. The PT100 is a platinum resistance temperature sensor whose resistance changes with temperature. The circuit achieves temperature detection through constant current source excitation and voltage measurement.

[0157] Circuit components and their connections

[0158] 1. Sensor section

[0159] PT100 (three-wire system): labeled as PT100A, B, and C terminals.

[0160] Terminal A is connected to ADCAIN1 via resistor R12, and is also connected to the constant current source (ADCIDAC1).

[0161] Terminal B → Connect to ADCAIN0 via resistor R10.

[0162] Terminal C → Connect to the reference voltage input (ADCREFP0 / REFN0) via a resistor network (R1, R2, R3).

[0163] 2. Resistor Networks

[0164] R1 (10k), R2 (3.16k), R3 (10k): form a voltage divider network, connected to PT100C, to generate a reference voltage for the ADC.

[0165] R10 (4.99k), R12 (4.99k): Current limiting / matching resistors, connecting the two ends of PT100A and B to ADCAIN0 and AIN1.

[0166] 3. Capacitor

[0167] C1 (0.1μF): Connected between ADCREFP0 and GND for decoupling of the reference voltage.

[0168] C2 (1nF), C7 (1nF), C3 (0.01μF): Differential input ADCAIN0 and AIN1 are filtered and grounded to provide anti-interference.

[0169] 4. Power Supply and Reference

[0170] ADCREFP0 / REFN0: A stable reference voltage is provided by R1, R2, R3 and C1.

[0171] ADCAIN0 / AIN1: Differential input channels, receiving the voltage across the PT100 terminals.

[0172] ADCIDAC1: Current source, providing constant current excitation to PT100.

[0173] Working principle

[0174] Constant current source excitation

[0175] The ADC's IDAC1 pin provides a constant current (e.g., 1mA) flowing through the PT100, thereby generating a voltage across its resistor.

[0176] Because the resistance of the PT100 changes with temperature, the output voltage also changes with temperature.

[0177] Differential measurement

[0178] The voltage between PT100A and B is fed into ADCAIN0 and AIN1 after being current-limited by R10 and R12, forming a differential input.

[0179] Differential measurement can offset some of the line resistance (three-wire compensation).

[0180] Reference voltage generation

[0181] R1, R2, and R3 form a voltage divider circuit to generate a reference voltage.

[0182] C1 is used for filtering to ensure the stability of the reference voltage.

[0183] The ADC uses this reference voltage as a quantization standard to ensure the accuracy of temperature measurement.

[0184] Filtering and anti-interference

[0185] C2, C3, and C7 form a low-pass filter to suppress high-frequency noise and interference.

[0186] It is particularly suitable for industrial environments with strong electromagnetic interference.

[0187] Summarize

[0188] This circuit is a temperature measurement front-end circuit based on a three-wire PT100:

[0189] The sensor is excited using the internal current source (IDAC1) of the ADC.

[0190] The voltage across the PT100 is accurately measured using differential inputs AIN0 / AIN1.

[0191] A stable reference voltage is provided using a resistor divider and a decoupling capacitor.

[0192] Filter capacitors improve anti-interference capability.

[0193] Ultimately, the ADC outputs a voltage signal proportional to the PT100 resistor, which, after calibration, yields the temperature value.

[0194] like Figure 4 As shown:

[0195] This is a peripheral interface circuit based on the A32F030L microcontroller. The A32F030L is a 48-pin ARM Cortex-M0 microcontroller. The figure mainly shows its pinout, external capacitors, power supply decoupling, and some peripheral interfaces.

[0196] Main electronic components

[0197] core chip

[0198] U5: A32F030L microcontroller (QFN-48 package).

[0199] It is responsible for processing input / output signals and controlling peripheral circuits.

[0200] capacitance

[0201] C13, C16, C17, C18: 0.1µF decoupling capacitors used for power supply filtering and stabilization.

[0202] They are distributed near different power supply / VDDIO pins.

[0203] resistance

[0204] R23: 100kΩ, connected in series between V5 and LED_CS, possibly as a pull-up resistor.

[0205] power supply

[0206] V3.3: Powered by a 3.3V power supply.

[0207] V5: 5V power supply, used for some LEDs or peripheral circuits.

[0208] GND: Earth.

[0209] Input / output interface

[0210] HEATER_IO, HEATER_O: Heater control I / O.

[0211] AIR1_IO, AIR2_IO, AIR1_O, AIR2_O: Interfaces for airflow / air-related sensors or actuators.

[0212] KEY1~KEY4: Key input interface.

[0213] MCU_XIN / MCU_XOUT: External crystal oscillator input / output (clock).

[0214] LED_CS, LED_CLK, LED_MOSI: LED driver interface (similar to SPI protocol).

[0215] MCU_IN1~MCU_IN12: Multiple input signals.

[0216] MCU_OUT1~MCU_OUT4: Multiple output signals.

[0217] ADC_CS, ADC_CLK, ADC_MOSI, ADC_RDY: SPI interfaces for external ADC chips.

[0218] Debugging interface

[0219] SWDIO, SWCLK: Debug download interface.

[0220] NRST: Reset pin.

[0221] Connection

[0222] Power supply and decoupling

[0223] The VDD, VDDA, and VDDIO pins are all connected to 3.3V, and a 0.1µF capacitor is connected nearby for decoupling to ground.

[0224] VSS, VSSA, and VSSIO are grounded.

[0225] Key input

[0226] Key1~Key4 are connected to PA5, PA6, PA7, and PA8 of the microcontroller.

[0227] External crystal oscillator

[0228] MCU_XIN and MCU_XOUT are connected to an external crystal to provide the system clock for the MCU.

[0229] LED control

[0230] LED_CS is pulled up to V5 via R23 (100kΩ).

[0231] LED_CLK and LED_MOSI are connected to the MCU's I / O (compatible with SPI interface).

[0232] Analog / Sensor Interface

[0233] MCU_IN1~IN12 are distributed across multiple pins and are used to acquire external signals.

[0234] ADC_CS, ADC_CLK, ADC_MOSI, and ADC_RDY indicate that there is an external ADC chip, and the MCU communicates with it via SPI.

[0235] Peripheral control

[0236] HEATER_IO, HEATER_O: Used for heaters.

[0237] AIR1_IO / AIR1_O, AIR2_IO / AIR2_O: Used for fan or gas sensing control.

[0238] MCU_OUT1~4: Digital outputs, which may drive actuators.

[0239] Communication interface

[0240] Pins PA9, PA10, PA13, and PA14 can also be reused for UART, I²C, and SPI interfaces.

[0241] The document displays identifiers such as U0_RX, U0_TX, IIC0_SCL, and IIC0_SDA.

[0242] Working principle

[0243] This is an MCU-based sensing / control system circuit, which may be used for air heating / fan control or similar applications.

[0244] Power supply and stability

[0245] The system is mainly powered by 3.3V, and capacitors are used for filtering and power supply stabilization.

[0246] R23 provides a pull-up for LED_CS.

[0247] Signal Acquisition

[0248] The MCU receives signals from sensors or external sources via MCU_IN1~12.

[0249] Higher precision analog-to-digital conversion can be achieved through an external ADC (SPI bus).

[0250] Peripheral control

[0251] MCU_OUT1~4, HEATER_O, AIR1_O, and AIR2_O drive external actuators (such as heaters and fans).

[0252] Human-computer interaction

[0253] Key1 to Key4 are used for key input.

[0254] LED_CS / CLK / MOSI serves as the driver interface for LED displays.

[0255] System Control

[0256] The MCU core ensures reliable operation through a clock circuit (crystal oscillator) and a reset circuit (NRST).

[0257] SWDIO / SWCLK provides interfaces for debugging and program downloading.

[0258] Summarize:

[0259] This is a control system circuit based on an A32F030L microcontroller, including a power supply decoupling circuit, key input, LED display control, external ADC interface, and heater / fan control interface. Its working principle is that the MCU acquires external input signals (keys, sensors, ADC) and controls the outputs (heater, fan, LED) through program logic, making it a typical embedded control system.

[0260] like Figure 5 As shown:

[0261] The three-way NPN low-side switch / drive circuit is used to drive external loads ("TDelay, AIR1Delay, AIR2" loads, relay coils or other inductive loads) by using three logic control signals (HEATER, AIR1, AIR2).

[0262] Each path uses an NPN transistor S8050 as a switch with its emitter grounded; an SS14 Schottky diode is connected in parallel across the load for freewheeling (absorbing the reverse induced voltage when turned off).

[0263] Main electronic components

[0264] Q1, Q2, Q3: S8050 (NPN transistor), low-side switch;

[0265] D2, D3, D4: SS14 Schottky diodes (1A / 40V), connected across the load for freewheeling;

[0266] R21, R28, R38: 1kΩ base series resistor (current limiting);

[0267] R24, R30, R42: 3.3kΩ base pull-down resistors (pull the base to 0V when turned off);

[0268] Power supply: The upper router is powered by V12 (12V); the middle and lower routers are powered by V5 (5V);

[0269] Terminals / Loads:

[0270] “TDelay+ / TDelay-” (corresponding to Q1)

[0271] “AIR1Delay+ / AIR1Delay-” (corresponding to Q2)

[0272] “AIR2Delay+ / AIR2Delay-” (corresponding to Q3)

[0273] Connection relationships (explained path by path)

[0274] Route 1 (HEATER→TDelay)

[0275] Input: HEATER is connected to the base of Q1 through R21=1kΩ; the base is then grounded through R24=3.3kΩ (pull-down);

[0276] Transistor: Q1 emitter grounded; collector connected to node TDelay-;

[0277] Load and power supply: V12 → (external load) → TDelay-;

[0278] Diode: D2 (SS14) is connected between TDelay+ (=V12) and TDelay-, with the cathode connected to + (V12 / TDelay+) and the anode connected to... (TDelay-).

[0279] Route 2 (AIR1→AIR1Delay)

[0280] Input: AIR1 → R28 = 1kΩ → Q2 base; R30 = 3.3kΩ base to ground;

[0281] Transistor: Q2 emitter grounded; collector → AIR1Delay-;

[0282] Load and power supply: V5 → (external load) → AIR1Delay-;

[0283] Diode: D3 (SS14) is connected between AIR1Delay+ (=V5) and AIR1Delay-, with the cathode at + and the anode at -. .

[0284] Route 3 (AIR2→AIR2Delay)

[0285] Input: AIR2 → R38 = 1kΩ → Q3 base; R42 = 3.3kΩ base to ground;

[0286] Transistor: Q3 emitter grounded; collector → AIR2Delay-;

[0287] Load and power supply: V5 → (external load) → AIR2Delay-;

[0288] Diode: D4 (SS14) is connected between AIR2Delay+ (=V5) and AIR2Delay-, with the cathode at + and the anode at -. .

[0289] In summary: The three circuits are identical low-side switches, except that the first circuit uses a 12V load and the latter two use a 5V load; the output terminals are brought out in pairs as "Delay+ / Delay-", where Delay- is grounded by a transistor and Delay+ is directly connected to the power supply.

[0290] Working principle

[0291] When the input is high (HEATER / AIR1 / AIR2): current flows through the 1kΩ base resistor into the base of the S8050, and the transistor is saturated and turned on; its collector (Delay-) is pulled to close to 0V, and a circuit is formed across the load (V12 / V5→load→Delay-→transistor→ground), and the load is powered on and works (relay energized / solenoid valve activated, etc.).

[0292] Input low / floating: 3.3kΩ pull-down pulls the base to 0V, and the transistor is cut off; Delay- is pulled to the power supply potential (approximately V12 / V5) through the load, and the load is de-energized.

[0293] Protection during shutdown: If the load is an inductive element (coil, etc.), a reverse induced voltage will be generated in the positive direction of the power supply during shutdown; the parallel SS14 provides a freewheeling path (from the load's...) (Returning the terminal to the + terminal) clamps spikes, protects transistors and upstream logic, and reduces electromagnetic interference.

[0294] Notes / Key Points

[0295] A 1kΩ base resistor is used for current limiting; a 3.3kΩ pull-down resistor ensures that the circuit is not turned on when the input is floating.

[0296] The S8050 is a low-power NPN transistor. When used as a low-side switch, it is sufficient to ensure that the load current matches the base drive current (and the saturation amplification factor).

[0297] "Delay+" is the positive power supply terminal (12V or 5V), and "Delay-" is the switching terminal; simply connect the load to these two terminals to use the device.

[0298] like Figure 6 As shown:

[0299] The linear regulated power supply circuit mainly consists of a low dropout linear regulator (LDO) MIC5209-3.3YS-TR.

[0300] Its function is to convert the input 5V power supply (V5) into a stable 3.3V power supply (V3.3) for use by subsequent circuits.

[0301] 2. Main electronic components

[0302] U4: MIC5209-3.3YS-TR

[0303] → An LDO regulator chip with a fixed output voltage of 3.3V.

[0304] Pin 1: VIN (Input voltage 5V)

[0305] Pins 2 and 4: GND (Ground)

[0306] Pin 3: VOUT (Regulated output 3.3V)

[0307] C12: Input capacitor

[0308] Capacitance: 0.1µF

[0309] Connection location: Between V5 and GND

[0310] Function: Decoupling, filtering out high-frequency noise from the input power supply, and ensuring stable operation of the LDO.

[0311] C11: Output capacitor

[0312] Capacitance: 22µF

[0313] Connection location: Between V3.3 and GND

[0314] Function: To ensure stable output voltage, improve transient response, and prevent oscillation.

[0315] 3. Connection relationships between components

[0316] Input section:

[0317] V5 (5V power supply) → grounded through capacitor C12 (0.1µF) for filtering.

[0318] At the same time, V5 is connected to the VIN pin (1) of the U4 regulator.

[0319] Inside the voltage regulator (U4):

[0320] VIN (5V input) → Regulated → VOUT output fixed at 3.3V.

[0321] GND pins (2, 4) → common ground.

[0322] Output section:

[0323] U4's VOUT (pin 3) → outputs V3.3.

[0324] V3.3 is grounded via C11 (22µF) for output filtering and stabilization.

[0325] 4. Working principle

[0326] When a 5V voltage is applied to the VIN pin, the LDO regulator will adjust the input voltage to a fixed 3.3V output.

[0327] The C12 capacitor at the input terminal is used to filter out high-frequency noise in the input power supply and improve power quality.

[0328] The C11 capacitor at the output end ensures the stability of the regulated output and prevents excessive voltage fluctuations.

[0329] Since the MIC5209 is a low dropout LDO, it only requires a small input-output voltage difference (usually <500mV) to regulate voltage normally, making it very suitable for battery-powered or 5V to 3.3V scenarios.

[0330] Summarize:

[0331] This circuit is a 5V to 3.3V linear voltage regulator circuit. It uses a MIC5209-3.3LDO voltage regulator and necessary input / output filter capacitors to achieve a stable 3.3V power output. It is commonly used for powering low-voltage digital circuits such as microcontrollers, sensors, and communication modules.

[0332] like Figure 7 As shown:

[0333] This is a power supply regulator circuit based on the LM2941 low-dropout linear regulator (LDO) that converts a 12V input DC voltage to a stable 5V output DC voltage. The circuit also includes overvoltage protection and an output indicator LED.

[0334] Main components

[0335] 1. U3 (LM2941S / TR) - Low Dropout Linear Regulator (Adjustable Output)

[0336] Pins:

[0337] -Pin1: ADJ (Adjustment)

[0338] -Pin2: ON / OFF (Enable Control)

[0339] -Pin3:GND (Ground)

[0340] -Pin4:IN (Input Voltage)

[0341] -Pin5:OUT (Output Voltage)

[0342] -Tab:GND (Ground)

[0343] 2. Resistance

[0344] -R15=2.7kΩ (used to set the output voltage)

[0345] -R19=10kΩ (forms a voltage divider resistor network with R15)

[0346] -R20=267Ω (Current-limiting resistor, used for LEDs)

[0347] 3. Capacitor

[0348] -C15=0.47µF (Input filtering, suppressing high-frequency noise)

[0349] -C14=470µF (Output filter capacitor to ensure voltage stability)

[0350] 4. Diode

[0351] -D1=SMBJ14A (TVS transistor, transient voltage suppressor, used to prevent overvoltage surges from damaging the circuit).

[0352] 5. LED

[0353] -LED2 (SZYY0805B): Serves as a power output indicator light.

[0354] 6. Connector

[0355] -P2: Input terminal, connected to 12V power supply and GND.

[0356] Component connection relationship

[0357] 1. Input section

[0358] -V12 input → C15 (0.47µF) decoupling → IN pin (LM2941 pin 4)

[0359] 2. Voltage stabilization section

[0360] R15 (2.7kΩ) and R19 (10kΩ) form a voltage divider network, connected between OUT (pin 5) and ADJ (pin 1), and are used to set the output voltage.

[0361] - Output voltage setting formula:

[0362] V_OUT=V_REF×(1+R15 / R19)=1.275V×(1+2700 / 10000)≈5V

[0363] 3. Output section

[0364] -LM2941OUT→C14 (470µF, large capacitor for filtering)→V5 (stable output)

[0365] -D1 (SMBJ14A) is connected in parallel between the output and ground as overvoltage protection.

[0366] -LED2 is connected in series with R20 and grounded from V5 to provide a power status indication.

[0367] Working principle

[0368] 1. The input 12V DC voltage is stepped down to a stable 5V output by the LM2941 regulator.

[0369] 2. The output voltage of the resistor divider network (R15+R19) is set according to the formula.

[0370] 3. C15 filters out high-frequency noise at the input, and C14 ensures stable output voltage.

[0371] 4. D1 (TVS diode) is used to protect the circuit from the effects of power surges or transient high voltages.

[0372] 5. LED2 and R20 are used to indicate the power output status. The LED will light up when the output is 5V.

[0373] Summarize

[0374] This is a 12V to 5V linear voltage regulator circuit. The core component is the LM2941S / TR. The circuit sets the 5V output through voltage divider resistors and adds filter capacitors and TVS protection. It is also equipped with a power indicator light.

[0375] like Figure 8 As shown:

[0376] This demonstrates three common peripheral circuits in a minimum MCU system:

[0377] Power-on reset circuit (RC reset, active low).

[0378] External crystal oscillator circuit (Pierce oscillator structure: MCU internal inverter + crystal + two load capacitors).

[0379] SWD download / debug interface (4 pins: V3.3, SWCLK, SWDIO, GND).

[0380] II. Electronic Components (BOM Summary)

[0381]

[0382] III. Join Relationships (Equivalent "Netlist")

[0383] 1. V3.3 → R13 → Node MCU_RST

[0384] 2. MCU_RST→C9→GND

[0385] 3.MCU_XIN Y1 MCU_XOUT (The two ends of the crystal are connected to XIN / XOUT)

[0386] 4. MCU_XIN→C8→GND

[0387] 5. MCU_XOUT→C10→GND

[0388] 6.P1-1 V3.3; P1-2 SWCLK; P1-3 SWDIO; P1-4 GND

[0389] IV. Working Principle

[0390] 1) Power-on reset (RC)

[0391] Upon power-up, C9 is treated as a short circuit, causing MCU_RST to be pulled to 0V; subsequently, C9 is charged through R13, and the MCU_RST potential rises exponentially, before being released and reset after a delay.

[0392] The delay constant τ = R × C ≈ 10 kΩ × 0.1 µF ≈ 1 ms (effective reset is usually taken as 3–5 times τ).

[0393] 2) External crystal oscillator (Pierce structure)

[0394] The internal inverter of the MCU, together with the external crystal Y1 and load capacitors C8 / C10, forms a Pierce oscillator. The equivalent parallel connection formula for C8 and C10 is as follows:

[0395] C_L≈(C8×C10) / (C8+C10)+C_parasite (common target is 12–20pF).

[0396] This circuit provides a precise system clock for the MCU; the traces for crystals and capacitors on the PCB should be as short as possible and grounded nearby to reduce parasitics.

[0397] 3) SWD debugging interface

[0398] The simplest 4-wire SWD: V3.3 (target voltage reference), SWCLK (clock), SWDIO (bidirectional data), GND (ground).

[0399] Used for firmware download and online debugging; the host computer / emulator uses V3.3 as the I / O level reference.

[0400] like Figure 9 As shown:

[0401] A set of optocoupler-isolated MCU and external interface circuits. It electrically isolates the microcontroller (5V logic domain) from external field signals / power supplies (EXT_VCC / EXT_GND), improving interference immunity and safety. The circuit includes:

[0402] 4 control outputs (HEATER, AIR1, AIR2, STANDBY_OUT);

[0403] 12 external digital inputs (G_INPUT1…G_INPUT12);

[0404] Four MCU-to-external open-collector outputs (MCU_OUTPUT1…MCU_OUTPUT4).

[0405] The two sides are isolated from each other by multiple four-channel optocouplers (U6, U7, U8, U9, U10, package / pins similar to PC847 / LTV-847 series).

[0406] II. Main Electronic Components

[0407] Optical couplers: U6, U7, U8, U9, U10 (4 channels each).

[0408] Resistors (typical): 510Ω (current limiting for the optocoupler LED on the MCU side); 2.2kΩ (current limiting / voltage divider on the external input side); 1kΩ (pull-down to GND on the MCU input side; pull-down to EXT_GND1 / EXT_GND2 on IN11 / IN12 respectively); 10kΩ (pull-up to EXT_VCC on the external output side).

[0409] Capacitors: 0.1µF (debouncing / filtering for most inputs); 1nF (filtering for G_INPUT9–12).

[0410] Power supply: +5V (MCU side); EXT_VCC / EXT_GND (external side, also EXT_VCC1 / 2, EXT_GND1 / 2).

[0411] III. Connection Relationships (by Module)

[0412] 1) U6: MCU control → isolation → internal module

[0413] Left side (LED): HEATER_O / AIR1_O / AIR2_O / STANDBY_O are each connected in series with the optocoupler LED via a 510Ω ohmmeter, and then back to GND.

[0414] Right side (transistor): Even-numbered pins are connected to +5V; odd-numbered pins are output to HEATER, AIR1, AIR2, and STANDBY_OUT respectively.

[0415] Function: When the MCU sends a 1, the LED lights up, causing the output to be "transmitted" to a high level (≈+5V, default effective high).

[0416] 2) U7 / U8: External input (G_INPUT1–8) → MCU_IN1–8

[0417] External side: EXT_VCC is connected to the positive terminal of the LED through approximately 2.2kΩ; each G_INPUTx is connected to the negative terminal of the LED through its own 2.2kΩ, and 0.1µF (debouncing / filtering) is connected in parallel to EXT_GND.

[0418] MCU side: Even-numbered pins are connected to +5V; odd-numbered pins are connected to MCU_IN1…8, and each has a 1kΩ pull-down to GND.

[0419] Logic: G_INPUTx is externally shorted to EXT_GND → LED turns on → optocoupler turns on → MCU_INx goes high; when released, it is pulled low by 1kΩ.

[0420] 3) U9: External Input (G_INPUT9–12) → MCU_IN9–12

[0421] External side: Similar to the above, but the filter capacitor is 1nF, and there is also current limiting such as R54 / R56≈2.2kΩ.

[0422] MCU side: IN9 / IN10: Even-numbered pins are connected to +5V, and odd-numbered pins are connected to MCU_IN9 / 10, each with a 1kΩ pull-down to GND.

[0423] IN11 / IN12: Even-numbered pins are connected to EXT_VCC1 and EXT_VCC2 respectively; odd-numbered pins are connected to MCU_IN11 / 12 and pulled down to EXT_GND1 and EXT_GND2 respectively with 1kΩ, used to detect the presence / status of external power supply 1 / 2.

[0424] 4) U10: MCU → External open collector output (MCU_OUTPUT1–4)

[0425] Left side (LED): MCU_OUT1…4 each drive the LED through a 510Ω resistor, returning to GND.

[0426] Right side (transistor): emitter connected to EXT_GND; collectors are MCU_OUTPUT1…4, each pulled up to EXT_VCC by 10kΩ.

[0427] Logic: MCU_OUTx=1 → LED lights up → transistor turns on → output is pulled low to EXT_GND (effective low); MCU_OUTx=0 → LED turns off → output is pulled high by 10kΩ (EXT_VCC).

[0428] IV. Working Principle

[0429] Opto-isolation: Blocks ground loops and surge interference, protecting the MCU; it can also perform level / power domain conversion.

[0430] Input detection: adopts the "external point to ground effective" method; after RC debouncing, the external action is converted into 0 / 1 of MCU by optocoupler.

[0431] Output drive: It has both internal 5V logic effective high control (U6) and external open collector interface (U10) for easy driving of PLC / relay, etc.

[0432] External power supply monitoring: IN11 / IN12 uses an external power supply as a pull-up, which can directly detect whether EXT_VCC1 / 2 exists or whether its status is normal.

[0433] V. Quick Overview of Logical Relationships

[0434] Shorting G_INPUTx and EXT_GND together → MCU_INx = 1; Disconnecting G_INPUTx → MCU_INx = 0.

[0435] MCU_OUTx=1→MCU_OUTPUTx=0 (pulled to EXT_GND); MCU_OUTx=0→MCU_OUTPUTx is pulled up from 10kΩ to EXT_VCC.

[0436] U6 channels: *_O=1 → corresponding output terminal ≈ +5V (effective high); *_O=0 → output high impedance / default level determined by the subsequent stage.

[0437] VI. Power Supply and Interface Considerations

[0438] The MCU operates at +5V; external power is supplied by EXT_VCC / EXT_GND (or EXT_VCC1 / 2, EXT_GND1 / 2).

[0439] For external inputs, it is recommended to use dry contacts or NPN open collector to ground; if it is a voltage input, a current-limiting resistor should be selected appropriately to ensure that the LED current is within specifications.

[0440] The pull-up voltage of the open collector output is determined by EXT_VCC and must be compatible with the logic / voltage withstand capability of the driven device.

[0441] The RC filter value is related to the input debouncing time. If there are special timing requirements, it needs to be adjusted according to the system cycle.

[0442] like Figure 10 As shown:

[0443] This is a pin definition diagram for interfaces / ports, not a complete schematic diagram. The board provides temperature acquisition (PT100 three-wire), multiple general-purpose inputs, MCU digital outputs, paired Delay± signals for peripherals (labeled "AIR / Standby"), and SPI (LED_CS / CLK / MOSI) interfaces for display. It also exposes external power supplies EXT_VCC / EXT_GND and two sets of peripheral power distribution ports.

[0444] II. Main Interfaces and Signal Definitions

[0445]

[0446] III. Connectivity (Network Level)

[0447] Power / Ground: P4 provides V5 and GND (for LED / display); P8 brings out EXT_VCC / EXT_GND; P10 provides two sets of peripheral power supplies (EXT_VCC1 / 2 and EXT_GND1 / 2).

[0448] Display and HMI: The SPI three-wire LED_CS / CLK / MOSI (P4) connects to the external LED module; Key1~Key4 are four button inputs fed back to the MCU.

[0449] Temperature acquisition: PT100A / B / C (P5) is connected to the temperature measurement front end on the board (constant current source + ADC, not shown in the figure); TDelay± is brought out in pairs with temperature-related channels.

[0450] General input: G_INPUTx on P7 / P8 is a multiplexer / status input with a common ground reference.

[0451] Execution control: MCU_OUT1~4 (P8) is used to drive peripherals; AIR1 / 2Delay± of P9 and Standby_Delay± of P11 are paired lines oriented towards peripherals / modes.

[0452] IV. Possible Working Principles (Functional Level)

[0453] 1. Sensing and data acquisition: The PT100 uses a three-wire method to compensate for the resistance of the wires, and a constant current source on the board is used for excitation, and the instrumentation amplifier / ADC is used for sampling and conversion of temperature; G_INPUT and Key1~Key4 are used as digital inputs.

[0454] 2. Calculation and Control: The MCU reads the temperature and input, generates control quantities based on logic, and interacts with peripherals via MCU_OUTx and various Delay± channels.

[0455] 3. Human-machine interface and instructions: Display data is sent to the LED module via SPI (LED_CS / CLK / MOSI).

[0456] 4. Power supply and distribution: V5 supplies power to the display; EXT_VCC / EXT_GND and P10 are the two power ports for peripherals.

[0457] The above description is only a preferred embodiment of the present utility model and does not limit the patent scope of the present utility model. All equivalent structural transformations made under the inventive concept of the present utility model using the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the protection scope of the present utility model.

Claims

1. A temperature controller for a gas conveying device, characterized in that, It comprises: a microcontroller (MCU) and its electrically connected temperature detection module, human-computer interaction module, output driving module, power management module and external interface module; The temperature detection module is connected with an analog-to-digital converter (ADC) through a resistance temperature detection element (RTD), the analog-to-digital converter (ADC) provides an excitation current to the resistance temperature detection element (RTD) and carries out differential sampling, and the analog-to-digital converter (ADC) is electrically connected with the microcontroller (MCU) through a serial peripheral interface (SPI); The human-computer interaction module comprises a display unit and function keys electrically connected with the microcontroller (MCU); The output driving module comprises a driving channel for a heater and a plurality of driving channels for air path actuators; The power management module provides working voltage for the microcontroller (MCU), the analog-to-digital converter (ADC) and the display unit, and carries out surge / voltage protection on the external input power supply; The external interface module is used to connect the resistance temperature detection element (RTD), the heater, the air path actuators and general input / output (I / O) with the temperature controller; The microcontroller (MCU) is configured to carry out closed-loop temperature control according to the collected temperature signal, and carry out timing and delay control on the heater and the air path actuators.

2. The temperature controller according to claim 1, wherein The resistance temperature detection element (RTD) is a three-wire PT100 temperature sensor, the analog-to-digital converter (ADC) has a double constant current source (IDAC) and is connected to two leads of the PT100 temperature sensor to realize lead resistance compensation; the two ends of the PT100 temperature sensor are respectively connected with the differential input ends (AIN0, AIN1) of the ADC, and the reference end (REFP, REFN) of the analog-to-digital converter (ADC) is connected with a reference voltage source; an RC anti-noise filter network is arranged at the input side of the PT100 temperature sensor.

3. The temperature controller according to claim 1 or 2, wherein The analog-to-digital converter (ADC) communicates with the serial peripheral interface (SPI) of the microcontroller (MCU) through chip select (CS), clock (CLK), master out slave in (MOSI) and master in slave out (MISO), and provides a sampling ready interrupt signal to the microcontroller (MCU) through a data ready (DRDY) pin.

4. The temperature controller according to claim 1, wherein The power management module comprises a surge / transient suppression diode for external DC input, and a cascaded voltage stabilizing circuit to obtain 5V and 3.3V power supply, and decoupling and energy storage capacitors are arranged at each voltage stabilizing stage and key device power supply pin.

5. The temperature controller according to claim 1, wherein The output drive module includes several switch drive units composed of NPN transistors, each drive unit containing a base current limiting resistor and a pull-up / pull-down resistor, and being connected in parallel with a freewheeling diode of an inductive load to protect the inductive load; the drive units are respectively used for on-off control of a heater, a first gas path actuator and a second gas path actuator, and are provided with a delay / edge shaping network composed of a resistor, a capacitor and a diode to realize time sequence linkage of the heater and the gas path actuators.

6. The temperature controller according to claim 1, wherein, The external interface module is provided with a plurality of general input conditioning channels, each channel including a voltage dividing / current limiting resistor and an RC filter, and then being connected to a digital input pin of a microcontroller (MCU) to realize anti-interference collection of external switch quantities or state quantities.

7. The temperature controller according to claim 1, wherein, The human-computer interaction module includes a display unit driven in series and at least four function keys, the display unit being connected to a microcontroller (MCU) through a chip selection, a clock and a serial data line, and the keys being connected to the microcontroller (MCU) through an interface circuit to realize setting of temperature, working mode and calibration operation.

8. The temperature controller according to claim 1, wherein, The external interface module is provided with an independent port (T-Port) for a resistance temperature detection element (RTD), a port (AIR-Port) for connecting a gas path actuator and a main port (Main Port) for external connection of the system, so as to quickly connect with a heating assembly and a gas path assembly of a gas delivery device.

9. The temperature controller according to claim 1, wherein, The temperature controller is further provided with an independent standby control output channel, which is used for automatically switching to a standby / cooling mode when the system is abnormal or the temperature reaches an upper limit, so as to reduce heating power and maintain safety of gas delivery.

10. The temperature controller according to claim 1, wherein, The microcontroller (MCU) is further configured to perform open circuit and short circuit diagnosis of a resistance temperature detection element (RTD) and over-temperature protection; when over-temperature, resistance temperature detection element (RTD) disconnection or external abnormal input is detected, the heater drive channel is closed in time and the gas path actuator is opened according to a preset delay to assist cooling, and alarm information is prompted on the display unit.

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