A control circuit for a time delay relay

Abstract

This utility model discloses a control circuit for a time-delay relay, comprising a main control circuit, a communication circuit, an input detection circuit, a relay output circuit, an output control circuit, and a power supply circuit. The output terminal of the main control circuit is connected to the communication circuit and the relay output circuit, respectively. The input terminal of the main control circuit is connected to the communication circuit, the input detection circuit, and the output control circuit, respectively. The relay output circuit is connected to the communication circuit, the input detection circuit, the relay output circuit, the output control circuit, and the power supply circuit, respectively. This utility model uses a DC-DC converter to output the required voltage. External signals are acquired using opto-isolation. The main control chip receives data and sends control commands and display data, enabling simultaneous display of multiple digital tubes. External loads are controlled by relay contact switching. An RS485 / TTL communication circuit is used to implement the circuit communication protocol.

Description

Technical Field

[0001] This utility model relates to the field of relay control circuit technology, and in particular to a control circuit for a time delay relay. Background Technology

[0002] Relay modules, as a basic electronic control switching device, are widely used in industrial automation, power systems, building control and other fields to realize functions such as low-voltage control of high-voltage, signal isolation and conversion, and time-delay operation.

[0003] In existing technologies, traditional time-delay relay modules typically have the following limitations and drawbacks:

[0004] Most existing modules focus on single-function delay control or relay driving, lacking flexible communication capabilities with other systems. Furthermore, their communication interfaces are limited, typically supporting only one communication protocol (such as RS485 or TTL), making them difficult to adapt to complex industrial networks with different communication standards, thus restricting their application scope.

[0005] In industrial environments, complex electromagnetic interference (EMI) and ground potential differences exist. Many existing modules' input detection circuits lack effective electrical isolation measures or have insufficient isolation levels, allowing external interference signals to easily enter the main control system, causing malfunctions or even damaging the core controller. Simultaneously, the back electromotive force generated by the relays on the output side when disconnecting inductive loads can easily damage the driver transistors if a fast and effective discharge circuit (such as a freewheeling diode) is lacking, affecting system reliability. Utility Model Content

[0006] The purpose of this invention is to provide a control circuit for a time-delay relay, providing the voltage power required by the output circuit. External signals are acquired using opto-isolation, the main control chip receives data and sends control commands and display data, enabling simultaneous display of multiple digital tubes. External loads are controlled by relay contact switching, and an RS485 / TTL communication circuit is used to implement the circuit communication protocol, thus solving the aforementioned problems.

[0007] To achieve the above objectives, this utility model provides the following technical solution: a control circuit for a time-delay relay, comprising a main control circuit, a communication circuit, an input detection circuit, a relay output circuit, an output control circuit, and a power supply circuit. The output terminal of the main control circuit is connected to the communication circuit and the relay output circuit, respectively. The input terminal of the main control circuit is connected to the communication circuit, the input detection circuit, and the output control circuit, respectively. The relay output circuit is connected to the communication circuit, the input detection circuit, the relay output circuit, the output control circuit, and the power supply circuit, respectively.

[0008] Preferably, the pins PA0, PA1, PA2 and PA15 of the main control chip U5 in the main control circuit are connected to buttons KEY2, KEY3, KEY4 and KEY1 respectively, and buttons KEY2, KEY3, KEY4 and KEY1 are used to input control signals.

[0009] The USART1_RX and USART1_TX pins of the main control chip U5 enable USART communication;

[0010] The SWCLK and SWDIO pins of the main control chip U5 are connected to the SWD1 interface.

[0011] Preferably, the communication circuit includes an RS485 communication sub-circuit and a TTL communication sub-circuit. The RS485 communication sub-circuit uses chip U11 as an RS485 transceiver. The 485_TX pin of chip U11 is connected to the 485 isolation circuit and the 485 non-isolation circuit. The transmission and reception switching is controlled by the 485_TX level. The isolation power supply U15 of the 485 isolation circuit supplies power to the isolation side circuit.

[0012] Preferably, the input detection circuit uses optocouplers U101-U102, model EL354C, which internally contain light-emitting diodes and phototransistors to achieve electrical isolation of the input signal.

[0013] Preferably, the relay output circuit includes a 10A relay sub-circuit and a 30A relay sub-circuit. The 10A relay sub-circuit uses relay JK1 to drive transistor Q201; the 30A relay sub-circuit uses relay JK101 to drive transistor Q1201.

[0014] The relay output circuit also includes freewheeling diodes D201 and D1201 to protect the relay coil.

[0015] Preferably, the output control circuit includes chip U3, where GRID0-GRID12 and SEG1-SEG8 pins correspond to the rows and columns of LEDs, respectively, and are used to turn different LEDs on and off. Chip U3 also controls the display of digital tubes DS8*4-4 and DS8*2-4.

[0016] Preferably, the power supply circuit includes a DC-DC converter chip U4 and a linear regulator U2, which output 5V and 3.3V voltages respectively.

[0017] The technical effects and advantages of this utility model are as follows:

[0018] This invention utilizes a DC-DC converter to supply the required voltage to the output circuit. External signals are acquired using opto-isolation, and the main control chip receives data, sends control commands and displays data, enabling simultaneous display of multiple digits on a digital tube. External loads are controlled via relay contacts, and an RS485 / TTL communication circuit is used to implement the circuit communication protocol. A reset button ensures system recovery in case of malfunctions, and the SWD1 interface supports program download and online debugging, accelerating development and troubleshooting. Attached Figure Description

[0019] Figure 1 This is a module diagram of the present utility model;

[0020] Figure 2 This is the schematic diagram of the main control circuit of this utility model;

[0021] Figure 3 This is a schematic diagram of the communication circuit of this utility model;

[0022] Figure 4 This is a schematic diagram of the input detection circuit of this utility model;

[0023] Figure 5 This is a schematic diagram of the relay output circuit of this utility model;

[0024] Figure 6 This is a schematic diagram of the output control circuit of this utility model;

[0025] Figure 7 This is the schematic diagram of the power supply circuit of this utility model.

[0026] In the picture:

[0027] 1. Main control circuit; 2. Communication circuit; 3. Input detection circuit; 4. Relay output circuit; 5. Output control circuit; 6. Power supply circuit. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0029] Please see Figure 1A control circuit for a time-delay relay includes a main control circuit 1, a communication circuit 2, an input detection circuit 3, a relay output circuit 4, an output control circuit 5, and a power supply circuit 6. The output terminal of the main control circuit 1 is connected to the communication circuit 2 and the relay output circuit 4, respectively. The input terminal of the main control circuit 1 is connected to the communication circuit 2, the input detection circuit 3, and the output control circuit 5, respectively. The relay output circuit 4 is connected to the communication circuit 2, the input detection circuit 3, the relay output circuit 4, the output control circuit 5, and the power supply circuit 6, respectively.

[0030] The circuit receives input signals from the input detection circuit 3 and external information transmitted through the communication circuit 2 via the main control circuit 1. After analysis and processing, it sends corresponding control commands to the relay output circuit 4 and the digital tube display circuit 4 to coordinate the operation of each part of the circuit.

[0031] Communication circuit 2 is responsible for data communication with the outside world. It can receive external data and transmit it to the main control circuit 1, and can also transmit the information sent by the main control circuit 1 to external devices, thus acting as a bridge connecting the system and the outside world.

[0032] The main function of the input detection circuit 3 is to detect certain parameters of the external environment or the internal system, convert the detected signals into electrical signals and transmit them unidirectionally to the main control circuit 1, so as to provide a basis for the system's decision-making.

[0033] The relay output circuit 4 controls the external actuators according to the control commands issued by the main control circuit, so as to realize various output actions of the system.

[0034] The output control circuit 5 is used to display numbers or indicate the device status.

[0035] Please see Figure 2 The main power input VCC of the main control chip U5 in the main control circuit 1 is 5V, which provides a power circuit for the microcontroller. The pins PA0, PA1, PA2 and PA15 of the main control chip U5 are connected to the buttons KEY2, KEY3, KEY4 and KEY1 respectively. Buttons KEY2, KEY3, KEY4 and KEY1 are used to input control signals.

[0036] The USART1_RX and USART1_TX pins of the main control chip U5 enable USART communication, allowing for the reception and transmission of serial communication, as well as serial data transmission with other devices (such as computers and sensors).

[0037] The SWCLK and SWDIO pins of the main control chip U5 are connected to the SWD1 interface. SWDIO and SWCLK are serial debugging interfaces, which, together with the SWD1 interface below, are used for microcontroller program download and online debugging.

[0038] Filter circuits C13 and C14 are connected in parallel between 5V and GND to suppress high-frequency noise in the power supply and ensure the stability of the microcontroller's power supply.

[0039] PA12 and PA11 of the main control chip U5 can be used for serial peripheral interfaces (such as driving LED dot matrix, sensors, etc.).

[0040] Please see Figure 3 Communication circuit 2 is a collection of multi-protocol communication interface circuits. The circuit covers RS485 (isolated / non-isolated) and TTL common industrial communication interfaces, which are used to realize data transmission and reception and signal isolation protection between devices. Communication circuit 2 includes RS485 communication sub-circuit and TTL communication sub-circuit.

[0041] The RS485 communication sub-circuit uses chip U11 as an RS485 transceiver to achieve level conversion. The DE / RE pins of chip U11 are connected to transistor Q2, and the transmit / receive switching is controlled by the 485_TX level, with high level for transmission and low level for reception. Bus protection resistors R12 and R13 ensure that the bus is at the default level when idle.

[0042] The isolation power supply U15 supplies power to the isolated side circuit, achieving power isolation. Chip U14 enables electrical isolation transmission of TTL signals and ensures that there is no direct electrical connection between USART1_TX / RX (non-isolated side) and 485_TX / RX (isolated side).

[0043] The TTL communication sub-circuit converts bus signals to TTL levels and directly interfaces with the serial port of the main control chip U5. Resistors R98 / R99 are used to connect or disconnect signals during circuit debugging or mass production.

[0044] Please see Figure 4 The input detection circuit 3 ensures the safe and stable transmission of external digital input signals to the internal circuit through protective components and optocoupler isolation. The core component is an EL354C optocoupler, used to achieve isolated transmission of electrical signals, enhance the circuit's anti-interference capability, and simultaneously achieve electrical isolation between the input and output sides, ensuring system safety. The input detection circuit 3 uses optocouplers U101-U102, model EL354C, which internally contain a light-emitting diode (LED) and a phototransistor. When there is current on the input side, the LED emits light, and the phototransistor conducts upon receiving light, thereby transmitting the electrical signal from the input side to the output side via an optical signal, achieving "electrical-optical-electrical" signal conversion and isolation.

[0045] The workflow is as follows: When an external valid input signal is received, current flows through the current-limiting resistor and through the LED, illuminating the LED. Simultaneously, the internal light-emitting part of the optocoupler conducts and emits light. The light-receiving part of the optocoupler conducts under the excitation of light, causing a change in the output level on the light-receiving side. This changed level signal is transmitted to the main control circuit 1, informing it that there is an external input signal on this channel.

[0046] When the external input signal disappears (e.g., the switch is turned off), the light-emitting diode goes out, the light-receiving part of the optocoupler is cut off, the output level of the light-receiving side returns to the initial stable state, and the main control circuit 1 recognizes that the signal has disappeared.

[0047] Please see Figure 5 The relay output circuit 4 includes a 10A relay sub-circuit and a 30A relay sub-circuit. The 10A relay sub-circuit is based on the 10A relay JK1 and achieves circuit control through contact switching. When the OUT1_C input is high, current flows through R401 into the base of transistor Q201, transistor Q201 conducts, the coil of relay JK1 is energized, the internal electromagnet is attracted, and the contacts switch: NO1 (normally open) closes, and NC1 (normally closed) opens.

[0048] When the OUT1_C input is low, there is insufficient current at the base of transistor Q201, and transistor Q201 is cut off. The relay JK1 coil is de-energized, and the contacts reset: NO1 opens and NC1 closes.

[0049] The 30A relay sub-circuit is based on the 30A relay JK101 and controls an external high-voltage / high-current load through contact switching. When the OUT1_C input is high, current flows through R1401 into the base of transistor Q1201, turning on transistor Q1201. The relay JK101 coil is energized, the internal electromagnet is attracted, and the contacts switch: NO1 (normally open) closes, and NC1 (normally closed) opens.

[0050] When the OUT1_C input is low, there is insufficient current to the base of transistor Q1201, and transistor Q1201 is cut off. The coil of relay JK101 is de-energized, and the contacts reset: NO1 opens and NC1 closes.

[0051] R401 is a current-limiting resistor, protecting the transistor while controlling the base current. R101 is a pull-down resistor, ensuring that transistor Q201 is reliably cut off when there is no input. The freewheeling diode D201 is used to protect the coil of relay JK1 (when relay JK1 is de-energized, the reverse electromotive force generated by the coil is freewheeled by the diode, preventing the transistor from being damaged).

[0052] Please see Figure 6The output control circuit 5 includes chip U3, which is a dedicated LED digital tube driver control chip. It supports serial data input via the DIN pin and clock synchronization via the SCLK pin, facilitating communication with microcontrollers and other main control devices. The pins GRID0-GRID12 and SEG1-SEG8 correspond to the gate and segment of the LED, respectively. By controlling these pins, different LEDs can be turned on and off, thus displaying specific patterns or characters.

[0053] External capacitors C1402-C1602 are used for power supply filtering to stabilize the chip's operating voltage; pins such as SCLK (serial clock) and DIN (serial data) are used for serial communication with external controllers (such as microcontrollers) to transmit display data.

[0054] The digital tube includes DS8*4-4 (0.4-inch 8-segment 4-digit digital tube) and DS8*2-4 (0.36-inch 8-segment 4-digit digital tube) for displaying numbers or characters. Each digital tube has 8 segments (SEG1-SEG8) and multiple digits (GRID1-GRID8) for displaying numbers or characters. The segments and digits of the digital tube are controlled by the driver chip U3 (TM1640B).

[0055] Please see Figure 7 The power supply circuit includes a DC-DC converter chip U4 and a linear regulator U2, which output 5V and 3.3V voltages respectively. The main function of the power supply circuit is to regulate and filter the input voltage and then output a stable voltage. The combination of multiple capacitors and inductors ensures the purity and stability of the output voltage.

[0056] The power input is connected to the circuit via a 2A 30V fuse (F1). A transient voltage suppressor diode (TVS0) protects the circuit from transient voltages. Diode M7 is used for circuit protection and rectification. A large-capacity electrolytic capacitor C1 is used for filtering to ensure stable input voltage, and a ceramic capacitor C3 is used for further filtering. Inductor L1 and electrolytic capacitor C6 are used for final filtering and energy storage. The DC-DC converter chip U4 has pin 1 connected to the input power supply and outputs a converted 5V voltage through pin 2. The converted 5V voltage is then converted to 3.3V by the voltage regulator chip U2.

[0057] Finally, it should be noted that the above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A control circuit for a time-delay relay, characterized in that, It includes a main control circuit (1), a communication circuit (2), an input detection circuit (3), a relay output circuit (4), an output control circuit (5), and a power supply circuit (6). The output terminal of the main control circuit (1) is connected to the communication circuit (2) and the relay output circuit (4) respectively. The input terminal of the main control circuit (1) is connected to the communication circuit (2), the input detection circuit (3), and the output control circuit (5) respectively. The relay output circuit (4) is connected to the communication circuit (2), the input detection circuit (3), the relay output circuit (4), the output control circuit (5), and the power supply circuit (6) respectively.

2. The control circuit for a time-delay relay according to claim 1, characterized in that, The main control chip U5 of the main control circuit (1) has pins PA0, PA1, PA2 and PA15 connected to buttons KEY2, KEY3, KEY4 and KEY1 respectively. Buttons KEY2, KEY3, KEY4 and KEY1 are used to input control signals. The USART1_RX and USART1_TX pins of the main control chip U5 enable USART communication. The SWCLK and SWDIO pins of the main control chip U5 are connected to the SWD1 interface.

3. The control circuit for a time-delay relay according to claim 1, characterized in that, The communication circuit (2) includes an RS485 communication sub-circuit and a TTL communication sub-circuit. The RS485 communication sub-circuit uses chip U11 as an RS485 transceiver. The pin 485_TX of chip U11 is connected to the 485 isolation circuit and the 485 non-isolation circuit. The transmission and reception switching is controlled by the 485_TX level. The isolation power supply U15 of the 485 isolation circuit supplies power to the isolation side circuit.

4. The control circuit for a time-delay relay according to claim 1, characterized in that, The input detection circuit (3) uses optocouplers U101-U102, model EL354C, which contain light-emitting diodes and phototransistors to achieve electrical isolation of the input signal.

5. The control circuit for a time-delay relay according to claim 1, characterized in that, The relay output circuit (4) includes a 10A relay sub-circuit and a 30A relay sub-circuit. The 10A relay sub-circuit uses relay JK1 to drive transistor Q201; the 30A relay sub-circuit uses relay JK101 to drive transistor Q1201. The relay output circuit (4) also includes freewheeling diodes D201 and D1201 for protecting the relay coil.

6. The control circuit for a time-delay relay according to claim 1, characterized in that, The output control circuit (5) includes a chip U3. The GRID0-GRID12 and SEG1-SEG8 pins of the chip U3 correspond to the rows and columns of LEDs, respectively, and are used to turn different LEDs on and off. The chip U3 also controls the display of the digital tubes DS8*4-4 and DS8*2-4.

7. The control circuit for a time-delay relay according to claim 1, characterized in that, The power supply circuit includes a DC-DC converter chip U4 and a linear regulator U2, which output 5V and 3.3V voltages respectively.

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