Multifunctional transmitting circuit compatible with temperature acquisition and signal output

Abstract

The utility model provides a multifunctional transmitting circuit compatible with temperature acquisition and signal output, which solves the problems of independent design, poor compatibility, high cost and the like of the traditional PT100 signal circuit and 4-20mA signal circuit, and adopts the scheme that the multifunctional transmitting circuit comprises an analog signal sampling circuit for outputting voltage through an independent power supply module DC1 and providing reference voltage through a reference source chip, a 3 * NP terminal is adopted; the lightning protection circuit comprises a bidirectional TVS (Transient Voltage Suppressor) diode, a piezoresistor and a gas discharge tube so as to perform static electricity prevention, surge prevention and high-frequency filtering; the voltage division circuit is used for converting a direct-current signal of an external temperature acquisition port into a voltage signal, synchronously filtering the voltage signal and then electrically connecting the voltage signal with a rear-end MCU or ADC, the acquisition switching circuit is used for performing mode switching through four groups of jumper caps, and the switching modes comprise a PT100 two-wire system, a PT100 three-wire system and a 4-20mA sampling channel.

Description

Technical Field

[0001] This utility model relates to the field of signal acquisition circuits, and in particular to a multifunctional transmitter circuit that is compatible with temperature acquisition and signal output. Background Technology

[0002] PT100 platinum resistance temperature signal acquisition and 4-20mA current acquisition are widely applicable to industrial environmental control, environmental monitoring and other scenarios. PT100 platinum resistance is widely used in temperature measurement due to its high precision and stability; while 4-20mA current signal is the standard signal transmission method in industrial fields due to its strong anti-interference ability and long transmission distance.

[0003] In existing technologies, the PT100 signal circuit and the 4-20mA signal circuit are usually designed independently. The PT100 requires a dedicated conditioning circuit, and the 4-20mA requires an additional transmission module, resulting in high system complexity. Multi-chip solutions lead to large board area and high cost, and cannot be flexibly configured for different application scenarios. To address these issues, we propose a multi-functional transmission circuit that integrates temperature acquisition and signal output. Utility Model Content

[0004] The technical problem to be solved by this utility model is to overcome the defects of the existing technology. This utility model proposes a multi-functional transmitter circuit that is compatible with temperature acquisition and signal output. The circuit design is compatible with RTD and DC signal acquisition, and the acquisition signal switching function is realized synchronously through the jump cap.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is: a multi-functional transmitter circuit that is compatible with temperature acquisition and signal output, comprising:

[0006] An analog signal sampling circuit includes an independent power supply module (DCI), a reference source chip, and a port. The independent power supply module (DCI) is used to output voltage and provide a reference voltage after passing through the reference source chip. The port is electrically connected to the reference source chip and includes at least 3 NP terminals for connecting to an external temperature acquisition port, a signal output port for communication, and grounding.

[0007] The surge protection circuit is located at the port inlet and is powered by the independent power module DCI. It includes a bidirectional TVS diode, a varistor, and a gas discharge tube. Multiple bidirectional TVS diodes are connected in parallel and in series with the varistor. One end of the gas discharge tube is connected in series with the varistor, and the other end is grounded.

[0008] A voltage divider circuit, connected to the analog signal sampling circuit, converts the DC signal from the external temperature acquisition port into a voltage signal, which is then simultaneously filtered and electrically connected to the back-end MCU or ADC.

[0009] The acquisition switching circuit uses four sets of jumpers to switch modes, including PT100 two-wire system, PT100 three-wire system, and 4-20mA sampling channel.

[0010] Furthermore, in the analog signal sampling circuit, the independent power supply module DCI model is B0505XT, and the reference source chip model is REF3030.

[0011] Furthermore, in the lightning protection circuit, the bidirectional TVS diode is model SMBJ15CA, the varistor is model MZ11-10A300-600RM, and the gas discharge tube is model SE90-230X.

[0012] Furthermore, the bidirectional TVS diodes include at least three.

[0013] Furthermore, the voltage divider circuit converts the input 4-20mA DC signal into a voltage signal through a 39-ohm resistor, and then filters it through 10nF and 100nF capacitors.

[0014] Furthermore, in the acquisition switching circuit, the four jumper caps are JT4B, JT4A, JT3B, and JT3C, with three configurations: JT4B is used to switch the PT100 wire system, and floating defaults to three-wire system or 4-20mA acquisition; JT4A and JT3C are bound together to switch to the 4-20mA sampling channel; and JT3B is used to switch to the PT100 sampling channel.

[0015] Compared with the prior art, the beneficial effects of this utility model include: the independent power supply module DCI in the reference source circuit supplies power to the entire circuit, the output voltage is synchronously provided as a reference voltage after passing through the reference source chip, and the lightning protection circuit at the port input provides electrostatic discharge protection, surge protection and high frequency filtering for the entire circuit. The signal acquisition process can be switched by the acquisition switching circuit to cope with different working conditions. The circuit ports are reused, and there are fewer redundant circuits. Due to the cost-compatibility design, compared with the original design of a dedicated conditioning circuit for PT100 and an additional transmitter module for 4-20mA, the cost is lower and the system is simpler. Attached Figure Description

[0016] 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:

[0017] Figure 1 The schematic diagram shows a reference source circuit structure according to one embodiment of the present invention;

[0018] Figure 2The schematic diagram shows a schematic diagram of the port portion circuit structure according to one embodiment of the present invention;

[0019] Figure 3 The schematic diagram shows a lightning protection circuit structure according to one embodiment of the present invention.

[0020] Figure 4 The schematic diagram shows a voltage divider circuit structure according to one embodiment of the present invention;

[0021] Figure 5 The schematic diagram shows a data acquisition switching circuit structure according to one embodiment of the present invention. Detailed Implementation

[0022] 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.

[0023] According to one embodiment of the present invention, in conjunction with Figures 1-5 As shown.

[0024] Regarding the overall circuit structure, in this embodiment, a multifunctional transmitter circuit that integrates temperature acquisition and signal output includes:

[0025] An analog signal sampling circuit (combining a reference source circuit and a port section circuit) includes an independent power supply module DCI, a reference source chip, and a port. The independent power supply module DCI is used to output voltage and provide a reference voltage after passing through the reference source chip. The port is electrically connected to the reference source chip and includes at least 3*NP terminals for connecting to an external temperature acquisition port, a signal output port for communication, and grounding.

[0026] The surge protection circuit is located at the port inlet and is powered by the independent power module DCI. It includes a bidirectional TVS diode, a varistor, and a gas discharge tube. Multiple bidirectional TVS diodes are connected in parallel and in series with the varistor. One end of the gas discharge tube is connected in series with the varistor, and the other end is grounded.

[0027] A voltage divider circuit, connected to the analog signal sampling circuit, converts the DC signal from the external temperature acquisition port into a voltage signal, which is then simultaneously filtered and electrically connected to the back-end MCU or ADC.

[0028] The acquisition switching circuit uses four sets of jumpers to switch modes, including PT100 two-wire system, PT100 three-wire system, and 4-20mA sampling channel.

[0029] As can be seen, in order to achieve compatibility between the PT100 signal circuit and the 4-20mA signal circuit, the entire circuit is first powered by the independent power supply module DCI in the reference source circuit. The output voltage is synchronously provided as a reference voltage after passing through the reference source chip. Then, the surge protection circuit at the port input provides electrostatic discharge protection, surge protection, and high-frequency filtering for the entire circuit. The signal acquisition process can be switched by the acquisition switching circuit to cope with different operating conditions. The circuit ports are reused, and there are fewer redundant circuits. Due to the cost-effective design for compatibility, compared with the original design of a dedicated conditioning circuit for PT100 and an additional transmitter module for 4-20mA, the cost is lower and the system is simpler.

[0030] The following combination Figures 1-5 Further explanation of the electronic components in each circuit structure:

[0031] For the analog signal sampling circuit, the reference source outputs 5V through the B0505XT independent power supply module DC1, and provides a 3V reference voltage via the REF3030 reference source chip U4. Each 3P port can be designed for one sampling channel; if the AD / MCU ​​sampling channel supports N channels, 3*NP terminals can be used.

[0032] The surge protection circuit is located at the port inlet and uses an SMBJ15CA bidirectional TVS diode, an MZ11 varistor, and an SE90 gas discharge tube for electrostatic discharge protection, surge protection, and high-frequency filtering, improving circuit reliability and sampling accuracy. The voltage divider circuit converts the 4-20mA DC signal from the input line into a voltage signal using a 39-ohm resistor. After filtering, the clean sampling signal is transmitted to the backend MCU / ADC.

[0033] The acquisition switching circuit uses four sets of jumpers for mode switching: PT100 two-wire, PT100 three-wire, and 4-20mA. The four jumpers have three configurations: JT4B is used to switch to the PT100 wire configuration, while leaving it floating defaults to three-wire or 4-20mA acquisition. JT4A and JT3C are paired to switch to the 4-20mA sampling channel. JT3B is used to switch to the PT100 sampling channel.

[0034] 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. A multi-functional transmitting circuit compatible with temperature acquisition and signal output, characterized in that, The application relates to a temperature acquisition device, which comprises the following parts: an analog signal sampling circuit, which comprises an independent power module DCI, a reference source chip and a port, the independent power module DCI is used to output a voltage and provide a reference voltage via the reference source chip, the port is electrically connected with the reference source chip and at least comprises 3*NP terminals to connect an external temperature acquisition port, a signal output port communication and a ground; a lightning protection circuit, which is located at an incoming line of the port and is powered by the independent power module DCI, and comprises bidirectional TVS diodes, a pressure-sensitive resistor and a gas discharge tube, the bidirectional TVS diodes are connected in parallel and are connected in series with the pressure-sensitive resistor, and the gas discharge tube is connected in series with the pressure-sensitive resistor at one end and is grounded at the other end; a voltage dividing circuit, which is connected with the analog signal sampling circuit to convert a direct current signal of the external temperature acquisition port into a voltage signal, and is electrically connected with a rear-end MCU or an ADC after synchronous filtering, a collection switching circuit, which switches modes through four groups of jumpers, and the switching modes include PT100 two-wire system, PT100 three-wire system and 4-20mA sampling channel.

2. The multi-functional transmitting circuit compatible with temperature acquisition and signal output according to claim 1, characterized in that: In the analog signal sampling circuit, the independent power module DCI is of B0505XT type, and the reference source chip is of REF3030 type.

3. The multi-functional transmitting circuit compatible with temperature acquisition and signal output according to claim 1, characterized in that: In the lightning protection circuit, the bidirectional TVS diodes are of SMBJ15CA type, the pressure-sensitive resistor is of MZ11-10A300-600RM type, and the gas discharge tube is of SE90-230X type.

4. The multi-functional transmitting circuit compatible with temperature acquisition and signal output according to claim 1, characterized in that: The bidirectional TVS diodes at least comprise three.

5. The multi-functional transmitting circuit compatible with temperature acquisition and signal output according to claim 1, characterized in that: The voltage dividing circuit converts the incoming 4-20mA direct current signal into a voltage signal through a 39-ohm resistor, and then filters through 10nF and 100nF capacitors.

6. The multi-functional transmitting circuit compatible with temperature acquisition and signal output according to claim 1, characterized in that: In the collection switching circuit, the four groups of jumpers are JT4B, JT4A, JT3B and JT3C, and three configurations are included, which are respectively JT4B used for switching the PT100 system, the three-wire system or the 4-20mA collection in a suspended state by default, JT4A and JT3C are bound to switch to the 4-20mA sampling channel, and JT3B is used for switching to the PT100 sampling channel.

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