An inspection system internet of things terminal controller

Abstract

The utility model provides a kind of receiving and inspecting goods system internet of things terminal controller, including control unit, signal acquisition unit, execution drive unit, communication expansion unit and power management unit, control unit includes microprocessor and the EEPROM circuit of two-way communication with it;Execution drive unit includes multiple groups of relay circuit;Communication expansion unit includes isolated network circuit and UART RS232 circuit;Power management unit includes external 12V power interface circuit, protection circuit and internal voltage stabilizing power supply circuit.The utility model realizes the electrical isolation and level matching of high and low voltage signals in industrial field, with strong anti-interference ability, rich interface, safe and reliable characteristics, suitable for the field control of internet of things receiving and inspecting goods system.

Description

Technical Field

[0001] This utility model relates to the field of Internet of Things (IoT) terminal equipment technology, specifically to an IoT terminal controller for a goods receiving and inspection system. Background Technology

[0002] With the rapid development of IoT technology, industrial automation control systems are increasingly being used in receiving and inspection scenarios. As a key component connecting industrial field equipment with upper-level management systems, the IoT terminal controller of the receiving and inspection system needs to possess multiple functions such as signal acquisition, execution control, and communication expansion, while also meeting the reliability requirements of the industrial environment.

[0003] Currently, digital input / output modules commonly used in industrial automation control typically employ opto-isolation technology to achieve signal isolation. For example, CN210626921U discloses a relay output isolated digital input module based on RS-485 communication. This module includes an isolated digital input circuit, a relay output circuit, a microcontroller, an electrical isolator, an RS-485 transceiver, and a power supply circuit. The isolated digital input circuit has five isolated digital input channels, and the relay output circuit has five relay output channels. While this design achieves signal acquisition and control functions for low-power electrical equipment in industrial settings to a certain extent, it still has the following shortcomings:

[0004] 1. Currently, there are signal compatibility and isolation defects between industrial field equipment and main control unit. Although the digital input module proposed in patent document CN210626921U adopts opto-isolation technology, the protection measures are not perfect under high voltage surge or ground loop interference, which can easily lead to damage to the core circuit of microprocessor. In particular, there is a lack of systematic solutions for electrical isolation and level matching between 12V high voltage digital signal and low voltage logic circuit of microprocessor.

[0005] 2. Existing controllers have insufficient reliability in harsh industrial environments, especially in dusty or drastically temperature-changing scenarios. The induced electromotive force generated when the relay is turned off may break down the drive transistor, causing system failure. The patent document lacks strict control over the reverse recovery time of the freewheeling diode in the relay drive circuit, which increases the risk of single-point failure and is not conducive to building an efficient and reliable IoT system architecture.

[0006] Therefore, there is an urgent need to develop an IoT terminal controller for receiving and inspecting systems that features high integration, robust signal isolation and protection, strong communication capabilities, and high reliability, in order to solve the aforementioned technical problems and meet the needs of modern industrial IoT applications. Utility Model Content

[0007] In view of the shortcomings of the existing technology, the purpose of this utility model is to provide an Internet of Things (IoT) terminal controller for a goods receiving and inspection system to solve the problems mentioned in the background technology.

[0008] To achieve the above objectives, this utility model provides the following technical solution: an IoT terminal controller for a receiving and inspection system, comprising a control unit including a microprocessor and an EEPROM circuit for bidirectional communication; a signal acquisition unit including a 12V digital input interface circuit directly connected to the input terminal of a digital conditioning circuit, the output terminal of which is connected to the GPIO input port of the microprocessor; an execution drive unit including multiple sets of relay circuits, the control terminal of each set of relay circuits being independently connected to the GPIO output port of the microprocessor; a communication expansion unit including an isolated network circuit bidirectionally connected to the ETH interface of the microprocessor, and a UART-to-RS232 circuit bidirectionally connected to the UART interface of the microprocessor; and a power management unit including an external 12V power interface circuit, a protection circuit, and an internal voltage regulator circuit connected in sequence; wherein the internal voltage regulator circuit outputs a 3.3V system voltage, which, after being filtered by a ferrite bead, forms a tree-like power supply network, which supplies power in parallel to the microprocessor, EEPROM circuit, digital conditioning circuit, isolated network circuit, and UART-to-RS232 circuit.

[0009] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0010] 1. By using optocoupler isolation and TVS protection design in the digital signal conditioning circuit, electrical isolation between 12V industrial signals and 3.3V logic circuits is achieved, which can suppress ±30kV surge interference. Unlike existing technologies, this effectively protects the core circuit of the microprocessor from high voltage damage, while ensuring stable and reliable signal transmission. At the same time, this utility model adopts a highly integrated design to replace the traditional "industrial control computer + serial port card + external PLC" architecture, simplifying system deployment, reducing wiring complexity, reducing system failure points, and improving overall reliability.

[0011] 2. The design of real-time indicator lights for input / output / communication status enables full-link status visualization, facilitating engineers to quickly locate fault points and reducing maintenance time and costs. At the same time, the relay circuit is designed with ≤100ns ultra-fast recovery diodes to suppress turn-off overvoltage, prevent breakdown of the drive transistor, improve the reliability of the execution unit, and extend the service life of the equipment. Attached Figure Description

[0012] The disclosure of this utility model is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of this utility model. In the drawings, the same reference numerals are used to refer to the same parts. Wherein:

[0013] Figure 1 This is a schematic diagram of the overall circuit principle structure of the IoT terminal controller of the receiving and inspection system proposed in one embodiment of the present utility model;

[0014] Figure 2 This is a schematic diagram of the principle structure of the digital signal conditioning circuit proposed in one embodiment of the present invention;

[0015] Figure 3 This is a schematic diagram of the principle structure of a single relay circuit proposed in one embodiment of the present invention;

[0016] Figure 4 This is a schematic diagram of the protection circuit principle structure proposed in one embodiment of the present utility model;

[0017] Figure 5 This is a schematic diagram of the internal voltage regulator circuit principle structure proposed in one embodiment of the present invention;

[0018] Figure 6 This is a schematic diagram of the circuit principle structure of the digital input indicator light group proposed in one embodiment of the present invention;

[0019] Figure 7 This is a schematic diagram of the circuit principle structure of the system status indicator light group proposed in one embodiment of this utility model;

[0020] Figure 8 This is a schematic diagram of the UART to RS232 circuit principle structure proposed in one embodiment of this utility model. Detailed Implementation

[0021] It is readily understood that, based on the technical solution of this utility model, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of this utility model. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative descriptions of the technical solution of this utility model and should not be considered as the entirety of this utility model or as limitations or restrictions on the technical solution of this utility model.

[0022] As an embodiment of this utility model, the present utility model provides a technical solution: an Internet of Things terminal controller for a receiving and inspection system. It can be understood that the controller consists of multiple functional units, including a control unit, a signal acquisition unit, an execution drive unit, a communication expansion unit, a power management unit, and a status indication unit.

[0023] In one embodiment of this utility model, such as Figure 1 As shown, the control unit is the core of the entire terminal controller, containing a microprocessor and an EEPROM circuit that communicates bidirectionally with it.

[0024] It should be noted that the microprocessor is responsible for processing the input signals from the signal acquisition unit and executing the actions of the drive unit according to preset logic control. In addition, the microprocessor also exchanges data with external devices through the communication expansion unit. The EEPROM circuit is used to store the system's configuration parameters and operating data, ensuring that the data is not lost in the event of a power outage, thereby achieving persistent storage of system parameters.

[0025] In one embodiment of this utility model, such as Figure 2 As shown, the signal acquisition unit includes a 12V digital input interface circuit and a digital conditioning circuit. It can be understood that the 12V digital input interface circuit is directly connected to the input terminal of the digital conditioning circuit, while the output terminal of the digital conditioning circuit is connected to the GPIO input port of the microprocessor.

[0026] Unlike existing designs, the digital signal conditioning circuit proposed in this invention uses opto-isolation conversion to adjust the output signal to 3.3V to adapt to the GPIO port of the microprocessor. This design achieves electrical isolation and level matching between the 12V high-voltage digital signal and the low-voltage logic circuit of the microprocessor in industrial environments, protecting the microprocessor from high voltage damage and ensuring the stability and reliability of signal transmission.

[0027] In specific implementation, the digital signal conditioning circuit includes a bidirectional TVS diode D15, an optocoupler U8, and a Schottky diode D21. The bidirectional TVS diode D15 (SMAJ30CA) is connected in parallel between the positive and negative terminals INPUT_01+ and INPUT_01- of the digital signal conditioning circuit input to suppress ±30V surge interference. The positive terminal INPUT_01+ is connected to the anode of the LED in the optocoupler U8 (EL357N) via a current-limiting resistor R16 (preferably 2KΩ±5%, 1 / 2W). The negative terminal INPUT_01- is connected to the cathode of the LED in the optocoupler U8 via a Schottky diode D21 (B5819WT), forming a reverse connection protection path. The collector of the phototransistor in optocoupler U8 is connected to the system power supply VCC_3V3, and the emitter is directly connected to signal ground GND through a pull-up resistor R27 (3.3KΩ±5%, 1 / 10W). The other end is led out through the output terminal IOINPUT_01 of the digital conditioning circuit, transmitting the conditioned signal to the GPIO port of the microprocessor. It should be noted that this design ensures that the external 12V digital signal can be safely converted to a 3.3V logic level acceptable to the microprocessor, while achieving electrical isolation through opto-isolation, effectively preventing damage to the microprocessor from electrical interference and surges in the industrial environment.

[0028] In one embodiment of this utility model, such as Figure 3As shown, the execution drive unit consists of multiple relay circuits, with the control terminal of each relay circuit independently connected to the GPIO output port of the microprocessor. It should be noted that in practical applications, to significantly reduce MCU pin usage while simultaneously achieving centralized management of relay status, synchronous control, and real-time fault feedback (such as overcurrent / overheat coding), and significantly improving system scalability and anti-interference capabilities, the drive signals can be integrated via a serial bus protocol. That is, (originally requiring 12 GPIOs, now only 3-4 SPI lines are needed), changing the relay control terminal from direct GPIO connection to SPI bus connection.

[0029] In practical implementation, the relay circuit includes an optocoupler U10 (EL357N), an NPN transistor Q1, a relay E1, and a freewheeling diode D13 (1N5819). Pin 1 of the optocoupler U10 (anode of the LED) is connected to the power supply VCC_3V3 via resistor R25; pin 2 (cathode of the LED) is directly connected to logic ground GND_IN; pin 4 is connected to the power supply VCC_12V; pin 3 is connected in two ways: one to the base of the transistor Q1 via resistor R33, and the other directly to logic ground GND_IN via resistor R35. The emitter of the transistor Q1 is directly connected to GND_IN, and its collector is connected to the anode of the freewheeling diode D13 and terminal 2 of the relay E1 coil. The cathode of the freewheeling diode D13 is connected to VCC_12V, and terminal 1 of the relay E1 coil is connected to the power supply VCC_12V.

[0030] It should be noted that, in order for the microprocessor to control the switching of the relay through optocoupler isolation and thus control external devices, and to protect the circuit from damage caused by the back electromotive force generated when the relay coil is disconnected through the freewheeling diode, this invention proposes that the reverse recovery time of the freewheeling diode D13 be ≤100ns, satisfying the formula: Where t rr V is the diode reverse recovery time, representing the time it takes for the diode to turn off from the current state. L is the relay coil inductance, and V is the current. peak This is the voltage limit value at the moment of shutdown. The peak current of the freewheeling diode D13 is greater than the coil operating current to ensure that the induced voltage at the moment of turn-off is ≤35V.

[0031] The principle is as follows: At the instant the relay is turned off, when the microprocessor cuts off the base current of transistor Q1 through optocoupler U10, Q1 abruptly changes from conducting to cutoff. The relay coil (inductor L) generates a reverse induced electromotive force e due to this sudden current change. The polarity of this electromotive force makes coil terminal 2 positive and terminal 1 negative. At this time, this electromotive force, superimposed with the power supply voltage VCC_12V, forms a high-voltage pulse. If not suppressed, it will break down Q1 (typical withstand voltage 40-60V). During this critical stage, D13 is momentarily forward-conducting because the anode (connected to terminal 2) potential is higher than the cathode (connected to VCC_12V), constructing a discharge circuit of "coil terminal 2 → D13 → VCC_12V → coil terminal 1," allowing the magnetic field energy to be slowly released in the form of current. The reverse recovery time t of D13 is limited. rr ≤100ns (e.g., t of 1N5819) rr =30ns) to ensure it can respond and conduct within a ns time, clamping the potential of coil terminal 2 to VCC_12V+0.7V≈12.7V, thereby suppressing the turn-off spike voltage within a safe range (≤35V). If t rr If the time is too long (e.g., 30μs for a common diode), the delayed establishment of the discharge path will cause a huge / drastic increase in current (di / dt), resulting in a high voltage of hundreds of volts (e.g., the theoretical peak reaches 96kV when L=120mH). However, the ultrafast recovery characteristic completely eliminates the risk of breakdown and reduces electromagnetic interference by instantaneously establishing a low impedance path.

[0032] In one embodiment of this utility model, such as Figure 8 As shown, the communication expansion unit includes an isolated network circuit with a bidirectional ETH interface connected to the microprocessor, and a UART-to-RS232 circuit with a bidirectional UART interface connected to the microprocessor. It can be understood that the isolated network circuit achieves secure communication between the microprocessor and external network devices through electrical isolation, preventing network surges from damaging the system. The UART-to-RS232 circuit converts the microprocessor's UART signals to RS232 standard signals, expanding the controller's communication capabilities and enabling it to exchange data with various industrial devices.

[0033] In one embodiment of this utility model, such as Figure 1 As shown, the power management unit includes an external 12V power interface circuit, a protection circuit, and an internal voltage regulator circuit connected in sequence. Among them, as... Figure 4 As shown, the protection circuit includes diode D2 (1N5819), diode D3 (1N5819), and Zener diode D17.

[0034] In practical implementation, the anode of diode D2 is connected to the power input terminal VCC_12V, and the cathode of D2 is connected to the anode of diode D3, forming a series reverse connection protection channel; the cathode of diode D3 is directly connected to the power output terminal VCC_12V, the anode of Zener diode D17 is connected to VCC_12V, and the cathode is connected to the ground terminal GND_IN, forming reverse breakdown protection and clamping overvoltage energy. It can be understood that this design effectively prevents external power reverse connection and overvoltage from damaging the system.

[0035] like Figure 5 As shown, the internal voltage regulator circuit includes a voltage regulator chip U3, filter capacitors C3, C4, and C46, ​​an energy storage capacitor C45, and an inductor L1. The voltage regulator chip U3 has its VIN pin connected to the input power supply VCC_5R0V. Its BOOT pin is connected sequentially to the filter capacitor C3 and the inductor L1, with one path connected to ground via the energy storage capacitor C45. This path is used to boost the internal MOS drive voltage through the capacitor bootstrap effect, ensuring deep saturation of the power transistor. The other path is connected to the output node VCC_3R3V. Its SW pin is connected to one end of the inductor L1 and one end of the capacitor C4. Its FB pin is connected to one end of the resistor R20, its EN pin is connected to one end of the resistor R15, and its GND pin is connected to the ground of all grounded capacitors / resistors. The other end of the filter capacitor C4 is grounded, and the filter capacitor C46 is connected in parallel between the output node VCC_3R3V and ground, forming a low-impedance filter. The internal regulated power supply circuit outputs a 3.3V system voltage, which, after being filtered by a ferrite bead, forms a tree-like power supply network that supplies power in parallel to the microprocessor, EEPROM circuit, digital signal conditioning circuit, isolated network circuit, and UART to RS232 converter circuit. This design ensures that all parts of the system receive a stable and clean power supply, improving the overall system reliability and anti-interference capability.

[0036] In one embodiment of this utility model, such as Figure 6 - Figure 7 As shown, the status indicator unit includes a power indicator light group circuit, a digital input indicator light group circuit, a relay status indicator light group circuit, and a system status indicator light group circuit.

[0037] In practical implementation, the power indicator light group circuit is directly connected to the 3.3V output terminal of the internal regulated power supply circuit to indicate the power activation status. The digital input indicator light group circuit and the relay status indicator light group circuit are connected in parallel to the GPIO output port of the microprocessor. Furthermore, the digital input indicator light group circuit and the relay status indicator light group circuit are connected point-to-point in parallel to the corresponding relay circuit control terminal and digital input channel to synchronously feedback the relay operation status. The system status indicator light group circuit is directly connected to the GPIO port of the microprocessor to monitor equipment operation and communication anomalies. Through these indicator lights, operators can intuitively understand the working status of each part of the controller, facilitating fault diagnosis and system maintenance.

[0038] Therefore, it can be understood that the IoT terminal controller of this receiving and inspection system integrates a control unit, signal acquisition unit, execution drive unit, communication expansion unit, power management unit, and status indication unit to realize the functions of signal acquisition, processing, and control in the industrial field. It features multiple protection measures, including electrical isolation, surge protection, and reverse connection protection, ensuring reliable operation of the system in complex industrial environments. Simultaneously, the rich communication interfaces and status indication functions provided enable the controller to seamlessly interface with upper-level systems and facilitate status monitoring and fault diagnosis by maintenance personnel, meeting the high reliability, high integration, and ease of maintenance requirements of modern receiving and inspection systems for IoT terminal control devices.

[0039] The technical scope of this utility model is not limited to the content described above. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this utility model, and all such modifications and variations should fall within the protection scope of this utility model.

Claims

1. An Internet of Things (IoT) terminal controller for a goods receiving and inspection system, characterized in that: include: Control unit: includes a microprocessor and an EEPROM circuit for bidirectional communication with it; Signal acquisition unit: includes a 12V digital input interface circuit, which is directly connected to the input terminal of the digital conditioning circuit, and the output terminal of the conditioning circuit is connected to the GPIO input port of the microprocessor; Execution drive unit: includes multiple sets of relay circuits, and the control terminal of each set of relay circuits is independently connected to the GPIO output port of the microprocessor; Communication expansion unit: includes a network circuit bidirectionally connected to the ETH interface of the microprocessor, and a UART to RS232 circuit bidirectionally connected to the UART interface of the microprocessor; Power management unit: includes an external 12V power interface circuit, a protection circuit, and an internal voltage regulator circuit connected in sequence; The internal voltage regulator circuit outputs a 3.3V system voltage, which is filtered by a ferrite bead to form a tree-like power supply network, which supplies power to the microprocessor, EEPROM circuit, digital signal conditioning circuit, network circuit, and UART to RS232 circuit in parallel.

2. The IoT terminal controller for a goods receiving and inspection system according to claim 1, characterized in that: It also includes a status indication unit: This includes a power indicator light group circuit, a digital input indicator light group circuit, a relay status indicator light group circuit, and a system status indicator light group circuit, wherein: The power indicator light group circuit is directly connected to the 3.3V output terminal of the internal regulated power supply circuit to indicate the power activation status. The digital input indicator light group circuit and the relay status indicator light group circuit are respectively connected in parallel to the GPIO output port of the microprocessor. The digital input indicator light group circuit and the relay status indicator light group circuit are respectively connected in parallel to the corresponding relay circuit control terminal and digital input channel to synchronously feedback the relay operation status. The system status indicator light group circuit is directly connected to the GPIO port of the microprocessor to monitor equipment operation and communication abnormalities.

3. The IoT terminal controller for a goods receiving and inspection system according to claim 1, characterized in that: The digital signal conditioning circuit outputs a 3.3V signal to the GPIO port of the microprocessor through opto-isolation conversion, so as to achieve electrical isolation and level matching between the 12V high-voltage digital signal and the low-voltage logic circuit of the microprocessor in the industrial field, and ensure the stability and reliability of signal transmission while protecting the microprocessor from high voltage damage.

4. An IoT terminal controller for a goods receiving and inspection system according to claim 1 or 3, characterized in that: The digital conditioning circuit includes a bidirectional TVS diode D15, an optocoupler U8, and a Schottky diode D21, wherein: The bidirectional TVS diode D15 is connected in parallel between the positive terminal INPUT_01+ and the negative terminal INPUT_01- at the input of the digital conditioning circuit to suppress ±30V surge interference. The positive terminal INPUT_01+ is connected to the anode of the LED of the optocoupler U8 via a series current-limiting resistor R16; the negative terminal INPUT_01- is connected to the cathode of the LED of the optocoupler U8 via the Schottky diode D21, forming a reverse connection protection path. The phototransistor collector of the optocoupler U8 is connected to the system power supply VCC_3V3 on one side, and the emitter is directly connected to the signal ground GND via the pull-up resistor R27. The other side is led out through the output terminal IIOINPUT_01 of the digital conditioning circuit to transmit the conditioned signal to the GPIO port of the microprocessor.

5. An IoT terminal controller for a goods receiving and inspection system according to claim 1 or 2, characterized in that: The relay circuit includes an optocoupler U10, an NPN transistor Q1, a relay E1, and a freewheeling diode D13, wherein: Pin 1 of the optocoupler U10 is connected to power supply VCC_3V3 via resistor R25, pin 2 is directly connected to logic ground GND_IN, pin 4 is connected to power supply VCC_12V, and pin 3 is connected to the base of transistor Q1 via resistor R33, and directly connected to logic ground GND_IN via resistor R35. The emitter of transistor Q1 is directly connected to GND_IN, and the collector is connected to the anode of freewheeling diode D13 and terminal 2 of relay E1 coil. The cathode of freewheeling diode D13 is connected to VCC_12V, and terminal 1 of relay E1 coil is connected to power supply VCC_12V.

6. The IoT terminal controller for a goods receiving and inspection system according to claim 1, characterized in that: The protection circuit includes diodes D2 and D3, and a Zener diode D17. The anode of diode D2 is connected to the power input terminal VCC_12V, and the cathode of D2 is connected to the anode of diode D3, forming a series reverse connection protection channel. The cathode of diode D3 is directly connected to the power output terminal VCC_12V. The anode of Zener diode D17 is connected to VCC_12V, and the cathode is connected to the ground terminal GND_IN, forming reverse breakdown protection and clamping overvoltage energy.

7. The IoT terminal controller for a goods receiving and inspection system according to claim 1, characterized in that: The internal voltage regulator circuit includes a voltage regulator chip U3, filter capacitors C3, C4, and C46, ​​an energy storage capacitor C45, and an inductor L1. The voltage regulator chip U3 pin VIN is connected to the input power supply VCC_5R0V. The BOOT pin is connected in sequence to the filter capacitor C3 and the inductor L1. One path is grounded through the energy storage capacitor C45, which is used to improve the internal MOS drive voltage through the capacitor bootstrap effect to ensure deep saturation of the power transistor. The other path is connected to the output node VCC_3R3V. The SW pin is connected to one end of the inductor L1 and one end of the capacitor C4. The FB pin is connected to one end of the resistor R20. The EN pin is connected to one end of the resistor R15. The GND pin is connected to the ground of all grounded capacitors / resistors. The other end of the filter capacitor C4 is grounded, and the filter capacitor C46 is connected in parallel between the output node VCC_3R3V and ground to form a low-impedance filter.

8. The IoT terminal controller for a goods receiving and inspection system according to claim 5, characterized in that: The reverse recovery time of the freewheeling diode D13 is ≤100ns, satisfying the formula: In the formula, L is the diode reverse recovery time, representing the time it takes for the diode to turn off from the current state. This is the voltage limit value at the moment of shutdown. The peak current of the freewheeling diode D13 is greater than the coil operating current to ensure that the induced voltage at the moment of turn-off is ≤35V.

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