Temperature acquisition board and temperature control system

Abstract

The utility model relates to the technical field of temperature acquisition, and particularly discloses a temperature acquisition board and a temperature control system, the temperature acquisition board comprises a PCB circuit board, and the PCB circuit board is provided with at least one wiring port module and at least one PT100 thermal resistor; the wiring port module is provided with four wiring terminals, the four wiring terminals form a single acquisition channel, and the four wiring terminals are electrically connected with the PT100 thermal resistor in a four-wire system wiring mode. According to the temperature acquisition board, the PT100 thermal resistor is connected to the temperature acquisition board in a four-wire system wiring mode, so that temperature data of an applied environment can be accurately acquired.

Description

Technical Field

[0001] This utility model relates to the field of temperature acquisition technology, and in particular to a temperature acquisition board and a temperature control system having the temperature acquisition board. Background Technology

[0002] The PT100 temperature sensor is widely used in meteorology, agriculture and forestry, chemical fiber, food, automotive, home appliances, industrial automation measurement, and various experimental instruments due to its high accuracy, stability, reliability, and long lifespan. The PT100 temperature sensor can be wired in two-wire, three-wire, and four-wire configurations. The four-wire configuration is suitable for long-distance transmission and industrial applications, especially in situations requiring extremely high measurement accuracy. Therefore, this invention urgently needs to provide a solution that allows the PT100 temperature sensor to be connected to a temperature acquisition board via a four-wire connection for accurate acquisition of ambient temperature. Utility Model Content

[0003] The present invention aims to provide a temperature acquisition board capable of accurately acquiring ambient temperature, and a temperature control system having the temperature acquisition board.

[0004] To solve the above-mentioned technical problems, this utility model provides the following technical solution:

[0005] The present invention discloses a temperature acquisition board, comprising a PCB circuit board, on which at least one wiring port module and at least one PT100 thermal resistor are provided; the wiring port module has four wiring terminals, the four wiring terminals form a single acquisition channel, and the four wiring terminals are electrically connected to the PT100 thermal resistor using a four-wire wiring method.

[0006] The temperature acquisition board described in this utility model can accurately acquire temperature data of the applied environment because the PT100 thermal resistor is connected to the temperature acquisition board using a four-wire wiring method.

[0007] Furthermore, the temperature acquisition board also includes a multi-channel analog switch, which is electrically connected to the wiring port module; the multi-channel analog switch is used to collect temperature data from the PT100 RTD connected to the wiring port module.

[0008] Furthermore, the multi-channel analog switch is also electrically connected to an analog-to-digital converter; the multi-channel analog switch sends the received temperature data to the control module via the analog-to-digital converter.

[0009] Furthermore, the temperature acquisition board also includes an RS485 communication module; the RS485 communication module includes an optocoupler U1, a transceiver U3, and an isolated transceiver U2; the input terminal of the optocoupler U1 receives the RS485 RTS signal, which is driven by a 3.3V power supply and a resistor R4, and the output terminal of the optocoupler U1 generates an RTS1 signal, which is connected to the receive enable pin RE and the transmit enable pin DE of the isolated transceiver U2. The optocoupler U1 is powered by a 5V power supply connected in series with a resistor R3, and the ground terminal of the optocoupler U1 is grounded; the transceiver U3 receives the RS485 TX1 signal from the control module, which is input to the transceiver U3 through the TX1 pin, and the transceiver U3 outputs the RS485 signal through the RX1 pin. The RX1 signal is transmitted back to the control module; the A and B pins of the isolated transceiver U2 are pulled up or pulled down to the 5V power supply through resistors R11 and R21, and then connected to RS485 terminal B1 and RS485 terminal A1 through resistors R14 and R19 to realize the input or output of the isolated RS485 signal.

[0010] Furthermore, the temperature acquisition board also includes a first isolation circuit, which is electrically connected to the 24V power module. The first isolation circuit includes an input filter circuit, a power conversion circuit, and an isolated output circuit. The input filter circuit includes an inductor L1 electrically connected to the 24V power module, and the inductor L1 is connected in series with a diode D5. The input filter circuit also includes a filter network formed by capacitors C3, C4, C5, C6, C7, and C8 connected in parallel. This filter network, along with the inductor L1 and diode D5, forms the input filter circuit, which is electrically connected to the power conversion circuit. The power conversion circuit includes a buck converter U5, which is electrically connected to the input filter circuit. The power conversion circuit also includes... Resistors R29 and R30, and capacitor C14 are connected in parallel to the buck converter U5. The output of the buck converter U5 is connected to inductor L2. Inductor L2 is connected to a parallel circuit formed by capacitors C13, C9, C10, and C11 to achieve secondary filtering and output a stable 5V power supply. The isolation output circuit is electrically connected to the power conversion circuit. The isolation output circuit includes an isolation chip M1, which is electrically connected to the power conversion circuit and connected to the 5V power output of the power conversion circuit. The output of the isolation chip M1 is connected to a parallel circuit formed by capacitors C17, C18, and C19 to output an isolated 5V power supply. The isolation output circuit is electrically connected to the control module.

[0011] Furthermore, the temperature acquisition board also includes a DIP switch, which is electrically connected to the control module;

[0012] And / or, the temperature acquisition board further includes an LED status indicator, which is electrically connected to the control module.

[0013] Furthermore, the temperature acquisition board also includes a debugging interface, which is electrically connected to the control module;

[0014] And / or, the temperature acquisition board further includes a memory, which is electrically connected to the control module.

[0015] Furthermore, the wiring port module has sixteen ports.

[0016] Furthermore, the control module is an MCU.

[0017] The temperature control system of this utility model includes a controller and at least one temperature acquisition board, wherein the temperature acquisition board is electrically connected to the controller via an RS485 line.

[0018] The temperature control system described in this utility model, having the aforementioned temperature acquisition board, can accurately acquire ambient temperature data through a four-wire wiring method, which is beneficial for the controller to adjust and control the monitored ambient temperature. Attached Figure Description

[0019] The above and other objects, features, and advantages of this invention will become clearer through a more detailed description of the preferred embodiments shown in the accompanying drawings. The same reference numerals indicate the same parts throughout the drawings, and the drawings are not intentionally drawn to scale with actual dimensions; the focus is on illustrating the gist of this invention.

[0020] Figure 1 This is a schematic diagram of the temperature acquisition board of this utility model.

[0021] Figure 2 This is a schematic diagram of the connection of the temperature control system of this utility model.

[0022] Figure 3 This is the circuit schematic of an RS485 communication module.

[0023] Figure 4 This is the circuit schematic of the first isolation circuit.

[0024] Figure 5 This is the schematic diagram of an MCU circuit. Detailed Implementation

[0025] To facilitate understanding of this utility model, a more comprehensive description will be given below with reference to the accompanying drawings.

[0026] It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to and integrated with the other component, or there may be an intervening component present. The terms "mounted," "one end," "the other end," and similar expressions used in this document are for illustrative purposes only.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0028] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0029] In the description of this specification, the references to terms such as "preferred embodiment," "another embodiment," "other embodiment," or "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0030] This utility model specifically provides an embodiment of a temperature acquisition board, see [link to embodiment]. Figure 1The system includes a PCB circuit board, on which at least one wiring port module and at least one PT100 RTD are installed. The wiring port module has four terminals, which form a single acquisition channel. The four terminals are electrically connected to the PT100 RTD using a four-wire connection method. In other words, each acquisition channel has four terminals, and the PT100 RTD is electrically connected to each of the four terminals one-to-one via four wires. Specifically, two wires are used to connect to the circuit and obtain power, while the remaining two wires are connected to the circuit and used to acquire the voltage signal of the corresponding PT100 RTD. The number of PT100 RTDs can be the same as or less than the number of wiring port modules; this is not limited here. In addition, the temperature acquisition board also includes a control module, a 24V power supply module, and an RS485 communication module mounted on the PCB circuit board. The control module can be an MCU. The wiring port module and the RS485 communication module are electrically connected to the control module, and the RS485 communication module is also electrically connected to the controller via an RS485 line. The control module is used to identify the number of acquisition channels and poll the temperature data of the PT100 RTDs connected to all acquisition channels. The acquired temperature data is then sent to the controller via the RS485 communication module. This polling acquisition enables real-time monitoring and acquisition of data, ensuring the timeliness and accuracy of the data, and is automated. Rotational data acquisition reduces reliance on manual operation and lowers the possibility of human error. The method used by the control module to identify the number of acquisition channels and to rotate the temperature data across all channels is existing technology. The 24V power module provides power to the temperature acquisition board. This power module can be battery-powered or connected to an external power source via wires. When connected to an external power source, since it uses AC or industrial power, the 24V power module needs to convert the high-voltage electricity to 24V for the temperature acquisition board. However, the circuit structure for this high-voltage to low-voltage conversion is existing technology and not the focus of this invention. Furthermore, in this embodiment, the wiring port module has sixteen ports, allowing simultaneous connection of sixteen PT100 RTDs, resulting in more acquisition points and more accurate temperature data. In this embodiment, the PT100 RTDs are connected to the temperature acquisition board using a four-wire connection, enabling accurate acquisition of temperature data from the applicable environment.

[0031] In a preferred embodiment, the temperature acquisition board further includes a multi-channel analog switch, which is electrically connected to the control module and also electrically connected to the wiring port module. The multi-channel analog switch acquires temperature data of the PT100 RTDs connected to the wiring port module specified by the control module according to the instructions of the control module, and transmits the temperature data to the control module. The instructions issued by the control module can be either polling all PT100 RTDs connected to the wiring port group or specifying the acquisition of temperature data from one or more PT100 RTDs connected to the wiring port group. By setting a multi-channel analog switch between the wiring port module and the control module, the selection and switching of acquisition channels can be realized, facilitating centralized management of multiple PT100 RTDs. Specifically, the multi-channel analog switch is existing technology; the appropriate number of channels of the multi-channel analog switch is selected according to the number of PT100 RTDs to be managed. For example, when eight PT100 RTDs need to be managed, an eight-channel analog switch is used.

[0032] In a preferred embodiment, an analog-to-digital converter is electrically connected between the multi-channel analog switch and the control module; the multi-channel analog switch sends the received temperature data to the control module via the analog-to-digital converter, the analog-to-digital converter and the control module are connected via an SPI port, and the analog-to-digital converter is existing technology.

[0033] In a preferred embodiment, the temperature acquisition board further includes an RS485 communication module; see [link to previous embodiment]. Figure 3 and 5The RS485 communication module includes an optocoupler U1, a transceiver U3, and an isolated transceiver U2. The input of optocoupler U1 receives the RS485 RTS signal, which is driven by a 3.3V power supply and resistor R4. The output of optocoupler U1 generates the RTS1 signal, which is connected to the receive enable pin RE and the transmit enable pin DE of the isolated transceiver U2 to control its transmit and receive states. Optocoupler U1 is powered by a 5V power supply connected in series with resistor R3. The ground terminal of optocoupler U1 is grounded to achieve signal isolation. Transceiver U3 receives the RS485 TX1 signal from the control module, which is input to transceiver U3 through the TX1 pin. Transceiver U3 outputs the RS485 signal through the RX1 pin. The RX1 signal is transmitted back to the control module. Pins A and B of the isolated transceiver U2 are pulled up or pulled down to a 5V power supply via resistors R11 and R21, and then connected to RS485 ports B1 and A1 via resistors R14 and R19, respectively, to achieve isolated RS485 signal input or output. Additionally, TVS diodes D1 and D2 are connected in parallel at pins A and B of the isolated transceiver U2 for surge protection. Furthermore, resistor R16 is connected between resistors R11 and R21 to optimize signal transmission quality and reduce reflection interference. This circuit structure effectively isolates the data signal, ensuring interference resistance during signal transmission. Both transceiver U3 and the isolated transceiver U2 are existing technologies.

[0034] In a preferred embodiment, the temperature acquisition board further includes a first isolation circuit structure, which is described in detail below. Figure 4 and 5The first isolation circuit is electrically connected to the 24V power module. The first isolation circuit includes an input filter circuit, a power conversion circuit, and an isolated output circuit. The input filter circuit includes an inductor L1 electrically connected to the 24V power module. Inductor L1 is also connected in series with diode D5. The input filter circuit also includes a filter network formed by capacitors C3, C4, C5, C6, C7, and C8 connected in parallel to filter out high-frequency noise in the input power supply. The filter network, in series with inductor L1 and diode D5, forms the input filter circuit, which is electrically connected to the power conversion circuit. The power conversion circuit includes a buck converter U5, which is electrically connected to the input filter circuit. The power conversion circuit also includes resistors R29 and R30, and capacitor C14. Resistor R29... Resistor R30 and capacitor C14 are connected in parallel to the buck converter U5. Resistor R29, R30, and capacitor C14 form a feedback loop to precisely regulate the output voltage. The output of buck converter U5 is connected to inductor L2. Inductor L2, capacitors C13, C9, C10, and C11 form a parallel circuit to achieve secondary filtering and output a stable 5V power supply. The isolation output circuit is electrically connected to the power conversion circuit. The isolation output circuit includes isolation chip M1, which is electrically connected to the power conversion circuit and connected to the 5V power output from the power conversion circuit. The output of isolation chip M1 is connected to a parallel circuit formed by capacitors C17, C18, and C19 to output an isolated 5V power supply. The isolation output circuit is also electrically connected to the control module. The first isolation circuit is used for power conversion and isolation, enabling the control module to obtain electrically isolated power, improving system stability and anti-interference capability, and ensuring reliable operation of the control module.

[0035] In a preferred embodiment, the temperature acquisition board further includes a DIP switch, which is electrically connected to the control module. The communication address is set via the DIP switch, facilitating data transmission and reception based on address information.

[0036] In a preferred embodiment, the temperature acquisition board further includes an LED status indicator light, which is electrically connected to the control module. The LED status indicator light receives status commands sent by the control module and operates based on these commands to display the working status of the control module. The LED status indicator light can be a light-emitting diode (LED), and there can be only one or multiple LEDs. The working status of the control module is displayed by showing different colors or different frequencies of illumination. The working status of the control module includes normal operation, standby, fault, or stopped operation. Specifically, the control module sends different status commands to the LED status indicator light in different operating states to control the LED status indicator light to operate based on the status commands and display the working status of the control module. For example, when pausing operation, a command to display a red light is sent to the LED status indicator light, controlling the LED status indicator light to display red, informing technicians that the control module has stopped operating.

[0037] In a preferred embodiment, the temperature acquisition board also includes a debugging interface, which is electrically connected to the control module. By setting the debugging interface, the program can be upgraded or downloaded, thereby adjusting the operating logic of the control module, etc.

[0038] In a preferred embodiment, the temperature acquisition board further includes a memory, which is electrically connected to the control module. Storing data in the memory ensures that the data can be quickly accessed when needed.

[0039] This utility model also provides a specific embodiment of a temperature control system, see [link to embodiment]. Figure 1 and Figure 2 The system includes a controller, which can be a PLC, and at least one of the aforementioned temperature acquisition boards. The number of temperature acquisition boards depends on the number of temperature acquisition points in the actual monitored environment. The RS485 communication module in the temperature acquisition board is electrically connected to the controller via an RS485 line. When there are multiple temperature acquisition boards, they are connected in parallel and all are electrically connected to the controller via RS485 lines. Because the temperature control system in this embodiment has the aforementioned temperature acquisition boards, it can accurately acquire environmental temperature data using a four-wire wiring method, which is beneficial for the controller to adjust and control the monitored environmental temperature. For example, when monitoring the internal temperature of an oven, the temperature acquisition board needs to be placed inside the oven. To stabilize the temperature acquisition board, a clamp is also needed to hold it in place, ensuring that the temperature acquisition board is stably positioned in the monitored environment.

[0040] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A temperature acquisition board, comprising a PCB circuit board, wherein at least one wiring port module and at least one PT100 thermal resistor are disposed on the PCB circuit board; characterized in that: The wiring port module has four wiring terminals, which form a single acquisition channel. The four wiring terminals are electrically connected to the PT100 thermal resistor using a four-wire wiring method.

2. The temperature acquisition board according to claim 1, characterized in that: The temperature acquisition board also includes a multi-channel analog switch, which is electrically connected to the wiring port module; the multi-channel analog switch is used to obtain temperature data from the PT100 RTD connected to the wiring port module.

3. The temperature acquisition board according to claim 2, characterized in that: The multi-channel analog switch is also electrically connected to an analog-to-digital converter; the multi-channel analog switch sends the received temperature data to the control module via the analog-to-digital converter.

4. The temperature acquisition board according to claim 1, characterized in that: The temperature acquisition board also includes an RS485 communication module; the RS485 communication module includes an optocoupler U1, a transceiver U3, and an isolated transceiver U2; the input of the optocoupler U1 receives the RS485 RTS signal, which is driven by a 3.3V power supply and a resistor R4; the output of the optocoupler U1 generates an RTS1 signal, which is connected to the receive enable pin RE and the transmit enable pin DE of the isolated transceiver U2. The optocoupler U1 is powered by a 5V power supply connected in series with a resistor R3, and the ground terminal of the optocoupler U1 is grounded; the transceiver U3 receives the RS485 TX1 signal from the control module, which is input to the transceiver U3 through the TX1 pin; the transceiver U3 outputs the RS485 signal through the RX1 pin. The RX1 signal is transmitted back to the control module; the A and B pins of the isolated transceiver U2 are pulled up or pulled down to the 5V power supply through resistors R11 and R21, and then connected to RS485 terminal B1 and RS485 terminal A1 through resistors R14 and R19 to realize the input or output of the isolated RS485 signal.

5. The temperature acquisition board according to claim 1, characterized in that: The temperature acquisition board also includes a first isolation circuit, which is electrically connected to the 24V power supply module. The first isolation circuit includes an input filter circuit, a power conversion circuit, and an isolated output circuit. The input filter circuit includes an inductor L1 electrically connected to the 24V power supply module, and the inductor L1 is connected in series with a diode D5. The input filter circuit also includes a filter network formed by capacitors C3, C4, C5, C6, C7, and C8 connected in parallel. This filter network, along with the inductor L1 and diode D5, forms the input filter circuit, which is electrically connected to the power conversion circuit. The power conversion circuit includes a buck converter U5, which is electrically connected to the input filter circuit. The power conversion circuit also includes a resistor. Resistors R29, R30, and capacitor C14 are connected in parallel to the buck converter U5. The output of the buck converter U5 is connected to inductor L2. Inductor L2 is connected to a parallel circuit formed by capacitors C13, C9, C10, and C11 to achieve secondary filtering and output a stable 5V power supply. The isolation output circuit is electrically connected to the power conversion circuit. The isolation output circuit includes an isolation chip M1, which is electrically connected to the power conversion circuit and connected to the 5V power output from the power conversion circuit. The output of the isolation chip M1 is connected to a parallel circuit formed by capacitors C17, C18, and C19 to output an isolated 5V power supply. The isolation output circuit is electrically connected to the control module.

6. The temperature acquisition board according to claim 1, characterized in that: The temperature acquisition board also includes a DIP switch, which is electrically connected to the control module. And / or, the temperature acquisition board further includes an LED status indicator, which is electrically connected to the control module.

7. The temperature acquisition board according to claim 1, characterized in that: The temperature acquisition board also includes a debugging interface, which is electrically connected to the control module. And / or, the temperature acquisition board further includes a memory, which is electrically connected to the control module.

8. The temperature acquisition board according to claim 1, characterized in that: The wiring port module has sixteen ports.

9. The temperature acquisition board according to any one of claims 3-7, characterized in that: The control module is an MCU.

10. A temperature control system, comprising a controller, characterized in that: It also includes at least one temperature acquisition board as described in any one of claims 1-9, the temperature acquisition board being electrically connected to the controller via an RS485 line.

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