Self-adaptive multi-channel temperature acquisition system and method

Abstract

The invention discloses a self-adaptive multi-channel temperature acquisition system and method, the system comprises a microprocessor and a plurality of signal acquisition circuits which are connected with the microprocessor and have the same structure, and each signal acquisition circuit comprises a self-adaptive circuit, a conditioning circuit and an ADC chip which are connected in sequence. Each module can complete corresponding signal conditioning, acquisition and processing, so that the maintenance cost is reduced, and the maintainability and supportability of the system are improved; the design complexity of the engine signal acquisition system is reduced, and the reliability is improved; and the identification of the platinum resistor and the thermocouple is judged according to the acquisition result when the excitation current is switched on and switched off. The identification of different platinum resistor types is determined through an acquisition result when excitation current is output, the identified temperature sensor type result is set in an internal register, different temperature sensor types are represented through different bits, and multiple paths of temperature sensors can be determined at the same time.

Description

Technical Field

[0001] The invention belongs to the technical field of temperature acquisition control, and in particular relates to an adaptive multi-channel temperature acquisition system and method. Background Art

[0002] The aircraft engine system has a large number of temperature sensors such as temperature and pressure. The engine integrated controller collects corresponding signals to continuously monitor and control the normal operation of the engine. The engine integrated control system adopts closed-loop control technology. It collects information from various temperature sensors on the working environment and working status of the engine, processes the information, and completes the control of various working states of the engine according to various control laws of the engine. At the same time, it monitors the status of the engine in real time to protect the safety of the engine.

[0003] The existing engine integrated control field usually uses different platinum resistance (PT46, PT100, PT500, PT800 and PT1000) and thermocouple type (TC-E and TC-K) temperature sensors. Each temperature sensor signal needs to use a dedicated interface signal processing circuit, which is relatively poor in versatility and scalability. With the miniaturization of the system, the system platform has increasingly stringent requirements on the performance, volume, weight and power consumption of the engine; at the same time, the system development cycle is getting shorter and shorter, and the development schedule is getting tighter and tighter. In this case, it is very important to use a universal temperature signal acquisition circuit for design. At present, there is no module for adaptive temperature sensor signal acquisition. Summary of the invention

[0004] The object of the present invention is to provide an adaptive multi-channel temperature acquisition system and method to overcome the problems of poor versatility and miniaturization of existing engine temperature acquisition controllers.

[0005] In order to solve the above problems, the present invention adopts the following technical solutions: An adaptive multi-channel temperature acquisition system comprises a microprocessor, wherein the microprocessor is connected to a plurality of signal acquisition circuits, and each signal acquisition circuit has the same structure; The signal acquisition circuit includes an adaptive circuit, a conditioning circuit and an ADC chip connected in sequence, and the ADC chip is connected to a microprocessor; The microprocessor and the multiple ADC chips are all connected to a power supply.

[0006] Furthermore, the adaptive circuit includes an excitation current acquisition circuit, and the output end of the excitation current acquisition circuit is connected to the positive connection end of the adaptive circuit; The input end of the excitation current acquisition circuit is connected to a voltage signal end and an excitation signal end; A gain amplification control circuit is provided between the positive connection terminal and the negative connection terminal of the adaptive circuit; The negative connection end of the adaptive circuit is connected to a return end and a ground end.

[0007] Furthermore, the input end of the excitation current acquisition circuit and the input end of the gain amplification control circuit are respectively connected to control signal ends.

[0008] Furthermore, a protection circuit is provided between the negative connection terminal and the ground terminal of the adaptive circuit, and a DC-DC module is installed on the circuit between the microprocessor and the power supply.

[0009] Furthermore, a reference voltage module is installed on the circuit between the ADC chip and the power supply.

[0010] In a second aspect, an adaptive multi-channel temperature acquisition method is provided, comprising the following steps: The adaptive circuit collects and processes the voltage signal of the temperature sensor; The obtained voltage signal is filtered through a conditioning circuit, and the voltage is amplified or reduced before being input into the ADC chip; The microprocessor receives input signals from various ADC chips and identifies the type of temperature sensor; After the temperature sensor type is determined, the registers in the microprocessor are set.

[0011] Furthermore, the voltage signal of the temperature sensor acquired by the adaptive circuit includes the voltage signal acquisition across the platinum resistor and the voltage signal acquisition across the thermocouple.

[0012] Furthermore, the step of collecting the voltage signal across the platinum resistor is as follows: The excitation current is turned on, and the voltage signal of the excitation current on the platinum resistor is amplified to a signal range suitable for acquisition by the ADC chip through the gain amplification control circuit; The ADC chip inputs the collected signal into the microprocessor.

[0013] Furthermore, the step of collecting the voltage signal at both ends of the thermocouple is: Disconnect the excitation current; The thermocouple signal is amplified to a signal range suitable for acquisition by the ADC chip through a gain amplification control circuit; The ADC chip inputs the collected signal into the microprocessor.

[0014] Furthermore, the microprocessor receives input signals from various ADC chips and distinguishes the type of temperature sensor in the following process: when the voltage collected when the excitation current is turned on is greater than 0v and the voltage collected when the excitation current is turned off is equal to 0v, it is judged to be a platinum resistance; otherwise, it is a thermocouple.

[0015] Compared with the prior art, the present invention has the following beneficial technical effects: The present invention provides an adaptive multi-channel temperature acquisition system, comprising a multi-channel signal acquisition circuit and a microprocessor connected to the multi-channel signal acquisition circuit, wherein each signal acquisition circuit comprises an adaptive circuit, a conditioning circuit and an ADC chip connected in sequence, wherein the signal acquisition circuit is used to acquire the voltage of an external temperature sensor, and the microprocessor is used to distinguish the acquired temperature sensor. Compared with a traditional engine sensor signal acquisition circuit, an adaptive temperature sensor design is adopted, and each module can complete corresponding signal conditioning, acquisition and processing, thereby reducing maintenance costs and improving the maintainability and security of the system; reducing the design complexity of the engine signal acquisition system and improving reliability; being compact and light, with an area of ​​about 40% of that of a traditional circuit, and having obvious advantages in applications where equipment size, weight and power consumption are limited.

[0016] Preferably, the adaptive acquisition circuit includes an excitation current control circuit, which can output the acquired temperature to the temperature sensor.

[0017] Preferably, the adaptive acquisition circuit includes a gain amplification control circuit, which can amplify or reduce the collected voltage signal to make it conform to the acquisition range of the ADC chip.

[0018] Preferably, the adaptive acquisition circuit includes a conditioning circuit, and the conditioning circuit can filter the voltage signal of the temperature sensor to ensure signal stability.

[0019] Preferably, a protection circuit is provided at the negative connection end of the adaptive circuit, and the protection circuit is used for protecting the input interface.

[0020] The present invention provides an adaptive multi-channel temperature acquisition method, which controls the on and off of the excitation current, uses an adaptive circuit to acquire and process the voltage signal of the temperature sensor, and inputs it into a microprocessor for discrimination through the processing of a conditioning circuit and an ADC chip. After the discrimination is completed, the register in the microprocessor is set, and the identification of platinum resistance and thermocouple is determined by the acquisition results when the excitation current is turned on and off. The identification of different types of platinum resistance is determined by the acquisition results when the excitation current is output, and the identified temperature sensor type result is set in an internal register, and different bits are used to represent different temperature sensor types, so that multiple temperature sensors can be discriminated at the same time, the logic is simple, and there is no need to repeatedly discriminate the same temperature sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a structural diagram of an adaptive multi-channel temperature acquisition system in an embodiment of the present invention; Figure 2 is a structural diagram of an adaptive circuit in an embodiment of the present invention; Figure 3 This is a flow chart of an adaptive multi-channel temperature acquisition method in an embodiment of the present invention; Figure 4 This is a flow chart of temperature sensor type identification in an embodiment of the present invention; Figure 5 It is the principle block diagram of the signal converter; Figure 6 This is a schematic diagram of the signal collector structure. DETAILED DESCRIPTION

[0022] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail in the following specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0023] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0024] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0026] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] An adaptive multi-channel temperature acquisition system, such as Figure 1As shown, it includes a microprocessor and a signal acquisition circuit with the same multi-channel structure connected to the microprocessor. The signal acquisition circuit includes an adaptive circuit for connecting to an external temperature sensor. The output end of the adaptive circuit is bidirectionally connected to the input end of a conditioning power supply. The output end of the conditioning power supply is bidirectionally connected to the input end of an ADC chip. The ADC chip is bidirectionally connected to the microprocessor via SPI. The adaptive acquisition circuit is used to collect the voltage across the temperature sensor. The conditioning circuit is used to amplify / reduce the temperature sensor signal to adapt to the range of the ADC chip, and filtering is provided to ensure signal stability. The ADC chip is used to collect the voltage signal output by the ADC chip and transmit it to the microprocessor after processing. The microprocessor is used to distinguish and save the type and category of the temperature sensor. The microprocessor and multiple ADC chips are all connected to a power supply.

[0028] In this embodiment, a DC-DC module is installed on the circuit between the power supply and the microprocessor, and a reference voltage module Vref is installed on the circuit between the power supply and the plurality of ADC chips; In an optional implementation manner, Figure 2 As shown, the adaptive circuit includes an excitation current acquisition circuit, the input end of the excitation current acquisition circuit is connected to the control port CTRL, the excitation current signal port EXC and the voltage signal Vref, the output end of the excitation current acquisition circuit is connected to the positive connection terminal IN+ of the adaptive circuit, a gain amplification control circuit is arranged between the positive connection terminal IN+ of the adaptive circuit and the negative connection terminal IN- of the adaptive circuit, the positive connection terminal IN+ of the adaptive circuit and the negative connection terminal IN- of the adaptive circuit are used to connect with the identified temperature sensor, the temperature sensor includes a thermocouple and a platinum resistance, the input end of the gain amplification control circuit is connected to the control port CTRL, the negative connection terminal IN- of the adaptive circuit is connected to the reflux port EXCCM and the ground port GND, a protection circuit is arranged between the ground port GND and the negative connection terminal IN- of the adaptive circuit, and the protection circuit is used to complete the protection of the input interface.

[0029] In this embodiment, for the platinum resistance, thermocouple and other temperature sensor signals, a universal multi-channel platinum resistance and thermocouple signal acquisition circuit is implemented inside the signal converter, which belongs to the field of aircraft engine control system and is suitable for various aircraft engine control systems that are sensitive to equipment size, weight, power consumption, performance and cost. This circuit module has a total of 24 groups of temperature acquisition input channels, which can be adaptively configured into different types of thermocouples and platinum resistance types through software. It can adapt to a variety of working environments and has the characteristics of small package, low power consumption, low cost, and rich peripherals.

[0030] The acquisition circuit module measures all channel data with a maximum update interval of 50Hz and a measurement resolution of ±0.1℃. The internal temperature signal acquisition circuit diagram of the module is as follows: Figure 1 As shown, there are 24 groups of temperature input channels, which can be configured into different types of thermocouples and platinum resistance types through software adaptive configuration to adapt to various working environments. The acquisition circuit module is mainly composed of internal DC / DC power supply, voltage reference, 3-way AD converter, adaptive circuit, conditioning circuit and microprocessor.

[0031] The principle of its internal adaptive circuit is as follows: The adaptive configuration of thermocouples and platinum resistors is achieved through a combination of internal adaptive circuits and related software. Users can use two-wire or four-wire systems to connect platinum resistors. The gain is automatically configured within the module circuit according to the temperature sensor type of the channel. For users, they only need to connect platinum resistors or thermocouples externally.

[0032] The identification of platinum resistance and thermocouple is determined by the acquisition results when the excitation current is turned on and off. The identification of different types of platinum resistance is determined by the acquisition results when the excitation current is output.

[0033] The identified temperature sensor type result is set in the internal register, and different bits are used to represent different temperature sensor types, as shown in Table 1. The upper 4 bits represent different platinum resistance types, and the lower 4 bits represent different thermocouple types.

[0034] Table 1 Temperature sensor types

[0035] The present invention implements a universal multi-channel platinum resistance and thermocouple signal acquisition circuit for two types of temperature sensor signals, namely, platinum resistance and thermocouple. On the premise of meeting the basic function of engine sensor signal acquisition, the present invention realizes the requirements of the system platform on the performance, volume, weight and power consumption of the engine integrated controller, and has great advantages in versatility and scalability.

[0036] The present invention also provides an adaptive multi-channel temperature acquisition method, such as Figure 3 As shown, the following steps are included: The adaptive circuit collects and processes the voltage signal of the temperature sensor; The obtained voltage signal is filtered through a conditioning circuit, and the voltage is amplified or reduced before being input into the ADC chip; The microprocessor receives input signals from various ADC chips and identifies the type of temperature sensor; After the temperature sensor type is determined, the registers in the microprocessor are set.

[0037] Detailed, the temperature sensor identification process is as follows Figure 4 As shown, the specific steps are: The on-excitation current of the adaptive circuit is set, and the current is input into the microprocessor through the processing of the conditioning circuit and the collection of the ADC chip, that is, the collection is started to obtain the collected voltage value V1; The excitation current of the adaptive circuit is set to be disconnected, and the voltage value V2 is obtained by inputting it into the microprocessor through the processing of the conditioning circuit and the collection of the ADC chip, that is, the collection is started; The microprocessor determines whether V1 is greater than 0v and V2 is equal to 0v. If so, it determines that the collected temperature sensor is a platinum resistance. If not, it determines that the collected temperature sensor is a thermocouple. After the temperature sensor type is identified, it is saved in the corresponding position of the register in the microprocessor to avoid repeated acquisition and identification of the temperature sensor.

[0038] The voltage signal of the temperature sensor obtained by the adaptive circuit acquisition and processing includes the voltage signal acquisition of the two ends of the platinum resistor and the voltage signal acquisition of the two ends of the thermocouple; The steps for collecting the voltage signal at both ends of the platinum resistor are as follows: The excitation current is turned on, and the voltage signal of the excitation current on the platinum resistor is amplified to a signal range suitable for acquisition by the ADC chip through the gain amplification control circuit; The ADC chip inputs the collected signal into the microprocessor.

[0039] Specifically, the excitation current is disconnected, and the gain amplification control circuit amplification factor is set according to the type of thermocouple, the thermocouple signal is amplified to a signal range suitable for AD acquisition, the thermocouple signal is acquired, the thermoelectric potential is obtained, and the conversion of the thermoelectric potential to temperature is realized through software.

[0040] The steps for collecting the voltage signal at both ends of the thermocouple are: Disconnect the excitation current; The thermocouple signal is amplified to a signal range suitable for acquisition by the ADC chip through a gain amplification control circuit; The ADC chip inputs the collected signal into the microprocessor.

[0041] Specifically, the excitation current is turned on, and the gain amplification control circuit amplification factor is set according to the type of platinum resistor. The voltage signal of the excitation current on the platinum resistor is amplified to a signal range suitable for AD acquisition, and the voltage signal at both ends of the platinum resistor is collected. The resistance value is calculated based on the current, and the conversion from resistance to temperature is realized through software.

[0042] According to the different voltages in the microprocessor, the specific model of the platinum resistance or thermocouple can be determined.

[0043] In one embodiment provided by the present invention, a signal converter product based on a multi-channel universal platinum resistance and thermocouple temperature acquisition circuit is developed according to the design concept of the present invention. Figure 5 The block diagram is shown below. Figure 6 The figure is a structural diagram. The signal converter consists of two printed parts, of which: the power board is mainly used to realize the external power signal conversion, and complete the power supply to the main control board and the pressure sensor. The main control board is mainly used to complete the temperature signal conditioning and acquisition and the communication with the host computer, and connects the two bottom boards through two flexible printed circuit boards to realize the product external interface connection.

[0044] The signal converter housing adopts a sealed structure, and connectors are installed on the front and rear panels. The installation form and installation size meet the structural requirements of the task book. It can meet the requirements of the aircraft engine system platform for miniaturization, standardization, and low-cost control of sensor signal acquisition products. It can maximize the optimization of system performance, avoid repeated packaging, shorten product development cycle and reduce costs.

[0045] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. An adaptive multi-channel temperature acquisition system, characterized in that: It includes a microprocessor, wherein the microprocessor is connected to multiple signal acquisition circuits, and each signal acquisition circuit has the same structure; The signal acquisition circuit includes an adaptive circuit, a conditioning circuit and an ADC chip connected in sequence, and the ADC chip is connected to a microprocessor; The microprocessor and the multiple ADC chips are all connected to a power supply.

2. The adaptive multi-channel temperature acquisition system according to claim 1, characterized in that: It also includes a detection circuit, the adaptive circuit includes an excitation current collection circuit, and the output end of the excitation current collection circuit is connected to the positive connection end of the adaptive circuit; The input end of the excitation current acquisition circuit is connected to a voltage signal end and an excitation signal end; A gain amplification control circuit is provided between the positive connection terminal and the negative connection terminal of the adaptive circuit; The negative connection end of the adaptive circuit is connected to a return end and a ground end.

3. The adaptive multi-channel temperature acquisition system according to claim 2, characterized in that: The input end of the excitation current acquisition circuit and the input end of the gain amplification control circuit are respectively connected to the control signal end.

4. The adaptive multi-channel temperature acquisition system according to claim 2, characterized in that: A protection circuit is arranged between the negative connection terminal and the ground terminal of the adaptive circuit, and a DC-DC module is installed on the circuit between the microprocessor and the power supply.

5. The adaptive multi-channel temperature acquisition system according to claim 1, characterized in that: A reference voltage module is installed on the circuit between the ADC chip and the power supply.

6. An adaptive multi-channel temperature acquisition method, characterized in that: The adaptive multi-channel temperature acquisition system according to claim 1 comprises the following steps: The adaptive circuit collects and processes the voltage signal of the temperature sensor; The obtained voltage signal is filtered through a conditioning circuit, and the voltage is amplified or reduced before being input into the ADC chip; The microprocessor receives input signals from various ADC chips and identifies the type of temperature sensor; After the temperature sensor type is determined, the registers in the microprocessor are set.

7. The adaptive multi-channel temperature acquisition method according to claim 6, characterized in that: The voltage signal of the temperature sensor acquired by the adaptive circuit includes the voltage signal acquisition at both ends of the platinum resistor and the voltage signal acquisition at both ends of the thermocouple.

8. The adaptive multi-channel temperature acquisition method according to claim 7, characterized in that: The steps of collecting the voltage signal at both ends of the platinum resistor are as follows: The excitation current is turned on, and the voltage signal of the excitation current on the platinum resistor is amplified to a signal range suitable for acquisition by the ADC chip through the gain amplification control circuit; The ADC chip inputs the collected signal into the microprocessor.

9. The adaptive multi-channel temperature acquisition method according to claim 7, characterized in that: The steps of collecting the voltage signal at both ends of the thermocouple are as follows: Disconnect the excitation current; The thermocouple signal is amplified to a signal range suitable for acquisition by the ADC chip through a gain amplification control circuit; The ADC chip inputs the collected signal into the microprocessor.

10. The method for adaptive multi-channel temperature acquisition according to claim 6, characterized in that: The microprocessor receives input signals from various ADC chips and determines the type of the temperature sensor in the following process: when the voltage collected when the excitation current is turned on is greater than 0V and when the voltage collected when the excitation current is turned off is equal to 0V, it is judged to be a platinum resistance; otherwise, it is a thermocouple.

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