CN218037791U

CN218037791U - Control circuit of pod temperature control device

Info

Publication number: CN218037791U
Application number: CN202222488136.4U
Authority: CN
Inventors: 陈亮; 朱云飞; 贾晋生; 栗晨
Original assignee: Xi'an Taishide Aviation Electrical Appliance Co ltd
Current assignee: Xi'an Taishide Aviation Electrical Appliance Co ltd
Priority date: 2022-09-20
Filing date: 2022-09-20
Publication date: 2022-12-13
Anticipated expiration: 2032-09-20

Abstract

The utility model discloses a control circuit of a pod temperature control device, which comprises a collecting circuit connected with a temperature sensor circuit, wherein a sampling resistor R1 is connected in series on the collecting circuit, and both ends of the sampling resistor R1 are connected with a RC filter circuit; the output end of the RC filter circuit is connected with a buffer circuit, the output end of the buffer circuit is connected to an AD conversion chip, and the AD conversion chip is also connected with a main control chip; the RC filter circuit is used for collecting the voltage of the sampling resistor R1, the buffer circuit is used for realizing impedance matching of the circuit, and the AD conversion chip is used for converting an analog signal into a digital signal and transmitting the digital signal to the main control chip; the utility model discloses an insert filter circuit and buffer circuit on nacelle temperature sensor gathers the circuit, can reduce the noise through filter circuit and promote stability, can realize impedance matching through buffer circuit, improved acquisition circuit's input impedance, match temperature sensor better, further improve precision and stability.

Description

Control circuit of pod temperature control device

Technical Field

The utility model belongs to the technical field of the temperature control circuit, especially, relate to a nacelle temperature control device's control circuit.

Background

The pod is typically a separate bin on the aircraft for storing weapons or equipment, and the temperature parameters within the pod need to be controlled to within limits due to the requirements of the weapons or equipment stored therein.

The general method is that a plurality of temperature sensors are installed in the nacelle, information collected by all the temperature sensors is transmitted to an airborne control device in a cable mode, and the control device performs unified regulation and control according to a preset control rule.

A common current acquisition circuit is provided with a sampling resistor, samples the resistor and then transmits the sampled resistor to an AD conversion module, however, for an aircraft pod, the acquisition precision requirement is high, and noise exists in the conventional acquisition circuit, so that the acquisition precision cannot meet the requirement.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a nacelle temperature control device's control circuit increases filter circuit and buffer circuit on existing temperature sensor circuit to reduce the noise, promote the collection precision.

The utility model adopts the following technical scheme: a control circuit of a pod temperature control device comprises an acquisition circuit connected with a temperature sensor circuit, wherein a sampling resistor R1 is connected in series on the acquisition circuit, and two ends of the sampling resistor R1 are connected with an RC filter circuit;

the output end of the RC filter circuit is connected with a buffer circuit, the output end of the buffer circuit is connected to an AD conversion chip, and the AD conversion chip is also connected with a main control chip;

the RC filter circuit is used for collecting the voltage of the sampling resistor R1, the buffer circuit is used for realizing impedance matching of the circuit, and the AD conversion chip is used for converting analog signals into digital signals and transmitting the digital signals to the main control chip.

Furthermore, the RC filter circuit comprises a resistor R2 connected with one end of the sampling resistor R1, the other end of the R2 is connected with a resistor R4 in series, and the other end of the resistor R4 is connected with a high-voltage input end of the buffer circuit;

the other end of the sampling resistor R1 is connected with a resistor R3, the other end of the R3 is connected with a resistor R5 in series, and the other end of the resistor R5 is connected with the low-voltage input end of the buffer circuit;

the connecting ends of the resistor R2 and the resistor R4 are connected to one ends of the capacitor C1 and the capacitor C2, and the other end of the resistor R4 is also connected to one end of the capacitor C3;

the connecting ends of the resistor R3 and the resistor R5 are connected to the other ends of the capacitor C1 and the capacitor C2, and the other end of the resistor R5 is also connected with the other end of the capacitor C3.

Further, the buffer circuit includes a chip ADA4666-2;

the 3 rd pin of the chip ADA4666-2 is connected with the high-voltage end of the RC filter circuit, and the 2 nd pin is connected with the low-voltage end of the RC filter circuit;

the 2 nd pin of the chip ADA4666-2 is connected in series with the resistor R24 and then connected with the 1 st pin of the chip ADA 4666-2.

Furthermore, the main control chip is also connected with a resistance acquisition circuit for measuring an external resistance, the resistance acquisition circuit comprises a chip U3, a pin 1 of the U3 is connected with a resistor RU1, a pin 2 of the U3 is connected with the other end of the resistor RU1 after passing through a resistor RU2 and is connected with a measured resistor in series;

one path of a 3 rd pin of the U3 is connected with +3.3V, and the other path of the pin is connected with a capacitor CD1 in series and then is grounded;

the high-voltage end of the tested resistor is connected with a resistor RU3 in series and then connected with a pin 3 of a chip U6A, and a pin 2 of the chip U6A is connected with a pin 1;

the low-voltage end of the tested resistor is connected with a 5 th pin of a chip U6B in series with a resistor RU4, and a 6 th pin and a 7 th pin of the chip U6B are connected;

the 1 st pin of the chip U6A and the 7 th pin of the chip U6B are connected to the same AD conversion chip.

Furthermore, the main control chip is also connected with a pressure sensor circuit and a humidity sensor circuit through an acquisition circuit.

The utility model has the advantages that: the utility model discloses an insert filter circuit and buffer circuit on the nacelle temperature sensor collection circuit, can reduce the noise through filter circuit and promote stability, can realize impedance matching through buffer circuit, improved acquisition circuit's input impedance, match temperature sensor better, further improve precision and stability.

Drawings

Fig. 1 is a schematic block diagram of a pod temperature control device according to an embodiment of the present invention;

fig. 2 is a functional block diagram of a control circuit according to an embodiment of the present invention;

fig. 3 is a schematic circuit diagram of an RC filter circuit in an embodiment of the present invention;

fig. 4 is a schematic circuit diagram of a snubber circuit in an embodiment of the present invention;

fig. 5 is a schematic circuit diagram of a resistance measurement circuit according to an embodiment of the present invention;

fig. 6 is a schematic diagram of PT100 three-wire measurement in an embodiment of the present invention;

fig. 7 is a schematic diagram of an AD conversion chip connected to a buffer circuit and its peripheral circuit according to an embodiment of the present invention.

Detailed Description

The present invention will be described in detail with reference to the accompanying drawings and specific embodiments.

In the embodiment of the present invention, as shown in fig. 1, the pod temperature control device is powered by a 28V dc power supply, an integrated system power indicator, a self-checking fault indicator, and a memory pre-warning indicator. The pod temperature control device collects 5 paths of temperature sensors in a temperature field, outputs a DO signal according to internal temperature control logic, controls the on-off of the contactor and realizes the start-stop of the heating device; and controlling the 1-path fan to start and stop according to the instruction of the task machine. Meanwhile, the self-checking module is designed in the interior, can carry out self-checking on the sensor, the heating device and the storage capacity, and displays a self-checking result and a temperature sensor signal on a liquid crystal display or a ground data processing computer. The ground data processing computer can perform program programming, debugging and data management through an Ethernet interface.

The power supply module in the equipment has the functions of undervoltage, overvoltage and overcurrent protection; the equipment has 8 paths of PT100 temperature analog quantity and 8 paths of 4-20 mA analog quantity acquisition functions; the device is provided with 8 discrete quantity output channels, can be configured to be 28V/on or ground/on, and has a driving current which is not less than 1A; the device is provided with 8 discrete quantity input channels which can be configured to be 28V/on or ground/on; controlling the starting and stopping of the fan control of the heating contactor; the device has a data recording and storing function, and meets the functional requirements of sensor data, operation records, data power failure protection and the like in the operation process. When the storage capacity reaches the early warning value, data unloading or storage zero clearing is carried out through a storage capacity early warning lamp and a self-checking function prompt; the equipment has BIT self-checking capability. The self-checking content includes but is not limited to the self-checking of a PT100 sensor of the equipment, the measurement of the working current of the 3-way three-phase alternating-current heating device, the self-checking of a communication link, the early warning of storage capacity and the like. The fault information is checked through a ground computer query interface or through a query button on a temperature display unit; the device is provided with an internal calendar clock, which adds time stamps to the data collected and stored. Time alignment can be performed by a ground data processing computer; the device has 1-path Ethernet bus interface, supports UDP multicast function, and can perform program programming, debugging and data management functions through a ground data processing computer; the device is provided with 1 path of RS422 bus interface and is used for sending 5 paths of temperature sensor signals to external devices; the device is provided with a hardware fault protection circuit such as a hardware watchdog; the device provides configuration management software and data offload management software. The device reserves a 1-way ARINC429 bus interface.

More specifically, the sampling frequency of the analog quantity of the equipment is not lower than 32Hz; the temperature measurement precision is +/-0.5 ℃; the humidity measurement precision is +/-1 percent, and the range is 0-100 percent; the switching value driving capability is 28V/1A; the storage capacity is not less than 8GB; height used: 13000m; the overload range is used: can bear the overload of-1 g to 3g in the longitudinal direction. The display screen can clearly indicate in sunlight; the external dimension is as follows: no more than 185mm x 177mm x 70mm (including aviation plug); weight: not more than 5kg. Power consumption: not more than DC28V/5A; a power input interface 28VDC; temperature signal transmission: a 1-way 422 interface; interface with a ground data processing computer: an Ethernet interface; reserving 1 path of ARINC429 bus interface; memory: 1G; and (3) storing: 8G; the system comprises the following steps: vxworks 6.9; LCD screen: 4.3 inches liquid crystal screen, resolution 480 is multiplied by 272; reliability, maintainability, and testability design. Mature software and hardware design and device model selection are adopted to meet relevant requirements: MTBF is not less than 100h, MTTR is not more than 1.5h; working temperature: -40 ℃ to +55 ℃; storage temperature: -55 ℃ to +70 ℃; working pressure: 16.4Kpa.

The embodiment discloses a control circuit of a pod temperature control device, which comprises an acquisition circuit connected with a temperature sensor circuit, wherein a sampling resistor R1 is connected in series on the acquisition circuit, and two ends of the sampling resistor R1 are connected with an RC filter circuit; the output end of the RC filter circuit is connected with a buffer circuit, the output end of the buffer circuit is connected to an AD conversion chip, and the AD conversion chip is also connected with a main control chip; the RC filter circuit is used for collecting the voltage of the sampling resistor R1, the buffer circuit is used for realizing impedance matching of the circuit, and the AD conversion chip is used for converting analog signals into digital signals and transmitting the digital signals to the main control chip.

The utility model discloses an insert filter circuit and buffer circuit on nacelle temperature sensor gathers the circuit, can reduce the noise through filter circuit and promote stability, can realize impedance matching through buffer circuit, improved acquisition circuit's input impedance, match temperature sensor better, further improve precision and stability.

Specifically, as shown in fig. 3, the RC filter circuit includes a resistor R2 connected to one end of the sampling resistor R1, the other end of the R2 is connected in series with a resistor R4, and the other end of the resistor R4 is connected to the high voltage input end of the buffer circuit; the other end of the sampling resistor R1 is connected with a resistor R3, the other end of the R3 is connected with a resistor R5 in series, and the other end of the resistor R5 is connected with the low-voltage input end of the buffer circuit; the connecting ends of the resistor R2 and the resistor R4 are connected to one ends of the capacitor C1 and the capacitor C2, and the other end of the resistor R4 is also connected to one end of the capacitor C3; the connecting ends of the resistor R3 and the resistor R5 are connected to the other ends of the capacitor C1 and the capacitor C2, and the other end of the resistor R5 is also connected with the other end of the capacitor C3.

In one embodiment, as shown in FIG. 4, the buffer circuit includes a chip ADA4666-2; the 3 rd pin of the chip ADA4666-2 is connected with the high-voltage end of the RC filter circuit, and the 2 nd pin is connected with the low-voltage end of the RC filter circuit; the 2 nd pin of the chip ADA4666-2 is connected in series with the resistor R24 and then connected with the 1 st pin of the chip ADA 4666-2.

As described above, the current collection line in the present embodiment is a4 to 20mA current collection line, which is used for collecting the pressure sensor, the humidity sensor, the heating contactor, and the like. In the embodiment, the 8-path 4-20 mA current signal measuring circuit adopts a high-precision low-temperature drift sampling resistor, is processed by an RC filter circuit, is acquired by using an 18-bit high-precision synchronous sampling analog-to-digital converter, and is subjected to data transmission by an SPI (serial peripheral interface). The input impedance is 1M omega and the sampling rate is 200kSPS. The AD conversion chip connected to the acquisition line is an AD7608 chip as shown in fig. 7.

In addition, the main control chip is further connected with a resistance acquisition circuit for measuring an external resistance, as shown in fig. 5, the resistance acquisition circuit includes a chip U3 (in this embodiment, an LT3092EST chip is specifically selected, a 1 st pin of the U3 is connected with a resistor RU1, a 2 nd pin of the U3 is connected with the other end of the resistor RU1 through a resistor RU2 and is connected in series with a measured resistor, one path of the 3 rd pin of the U3 is connected with +3.3V, the other path of the U3 is connected in series with a capacitor CD1 and then grounded, a high voltage end of the measured resistor is connected in series with the resistor RU3 and then connected with a 3 rd pin of a chip U6A (in this embodiment, an ADA4666-2 chip is specifically selected), a 2 nd pin of the chip U6A is connected with a 1 st pin of the chip U6A, a low voltage end of the measured resistor is connected in series with a RU4 and then connected with a 5 th pin of a chip U6B, a 6 th pin of the chip U6B (in this embodiment, an ADA4666-2 chip is connected with a 7 th pin of the chip), and a 1 st pin of the chip U6A chip is connected to a same conversion chip AD.

The resistance measuring circuit adopts the design of an I/V conversion idea, the current source outputs 1 path of 10mA constant current, a loop is formed by the measured resistance, the voltage difference of the high end and the low end of the resistance is collected, and the single-gain operational amplifier is used for driving. In order to meet the test requirement of the 3-path resistor, a relay is used for switching, and time-sharing measurement is realized. And the differential voltage driven by the operational amplifier is acquired by using a high-speed 24-bit sigma-delta analog-to-digital converter, and data transmission is carried out by adopting an SPI (serial peripheral interface). To improve the sampling accuracy of the AD, an external reference chip is used.

As a specific implementation form, as shown in fig. 2, the main control chip is further connected with a pressure sensor line and a humidity sensor line through an acquisition line. The mainboard (i.e. the main control chip) adopts a ZYNQ7020 as a core design, and an external system configuration circuit, a storage circuit, a man-machine interaction circuit and a functional interface circuit. The ZYNQ7020 is composed of a dual-core ARM Cortex-A9 processor and a Xilinx 7 series FPGA, and can run an operating system and realize each interface. In this example a vxworks6.9 system is used.

The system configuration circuit consists of a POWER part, a RST part, a CLOCK part and a JTAG part and is a basic function circuit of ZYNQ. The POWER part realizes POWER conversion, and converts an input +5V POWER supply into 1.0V, 1.5V and 3.3V working POWER supplies required by ZYNQ. The RST circuit is used for a reset CLOCK circuit of the CPU to realize a PL CLOCK and a PS CLOCK required by ZYNQ work, and the JTAG circuit is used for loading and debugging ZYNQ.

The storage circuit consists of DDR3, QSPI Flash and eMMC and is used for storing ZYNQ data, and the system can identify the power failure state and complete the function of power failure protection of the data. DDR3 and ZYNQ directly exchange data and are used for storing temporary data of CPU work. QSPI Flash is used for ZYNQ to start the storage of configuration data. The eMMC is used to store systems, application software, and test data.

The human-computer interaction circuit comprises an LED control interface, a SCREEN driving interface and a KEY interface and is used for realizing human-computer interaction. The LED interface is used for controlling the self-checking fault lamp and the storage capacity early warning lamp. The SCREEN driving interface is used for driving the liquid crystal display to display. The KEY interface is used for panel KEY connection and reading KEY states.

The function interface circuit consists of a discrete magnitude input interface, a discrete magnitude output interface, a PT100 acquisition interface, a 4-20 mA current acquisition interface, a resistance measurement interface, an RS422 interface, an ARINC429 interface and an Ethernet interface and is used for realizing each function required by equipment.

8 way discrete magnitude input circuit designs adopt the design thinking of light isolation, guarantee that input and treater end are kept apart, and input end circuit can not cause the damage of treater end circuit unusually, has improved discrete magnitude input circuit's security. The discrete quantity input can select the setting 28V or GND.8 the design of the volume output circuit that disperses adopts physics optoisolation's design, guarantee that output relay's solenoid control circuit keeps apart with the circuit preceding stage, and protection preceding stage circuit does not receive the influence of back stage circuit, has improved the reliability of volume output circuit that disperses. The discrete magnitude output can be selectively set to be 28V/suspended or GND/suspended, the rated output current is 1A, and the overcurrent protection self-recovery function is achieved.

In addition, the embodiment of the utility model provides an 8 way PT100 temperature measurement circuits are designed, as shown in fig. 6, all adopt the three-wire type, use 2 completely matched current sources to carry out lead resistance error compensation, current source 1 connects the PT100 high-end, current source 2 connects the PT100 low-end, share the same return wire again; the voltage difference between two ends of the PT100 is acquired by using a high-resolution sigma-delta analog-to-digital converter, and the mode converter uses a differential reference voltage to ensure that a sampling value and temperature change form a proportional relation, so that the measurement accuracy of the PT100 is improved. Wherein AIN1 (+) and AIN1 (-) are acquisition voltages, and REFIN (+) and REFIN (-) are acquisition voltages.

In addition, the RS422 bus is adopted in the embodiment to communicate with a task machine (control computer) so as to finish temperature data uploading and fan control. ARINC429 reserves communication interfaces for the devices. The Ethernet is used for programming and data downloading, so that data unloading of the ground equipment is completed, and data analysis can be conveniently carried out at the later stage. Temperature control unit end connectors are of type JY27473T20B35SN and JY27473T08B35SN. According to the signal characteristics, the special PT100 cable is used for 8 paths of sensor signals, 3 paths of current measuring signals and 8 paths of PT100 temperature signals, the wire resistance is equal, the equipment is well grounded, and the electromagnetic shielding effect of the cable is improved. The actual environment condition of equipment use is considered, and the cable conductor all uses high temperature resistant, low impedance cable.

Claims

1. The control circuit of the nacelle temperature control device is characterized by comprising an acquisition line connected with a temperature sensor line, wherein a sampling resistor R1 is connected in series on the acquisition line, and two ends of the sampling resistor R1 are connected with an RC filter circuit;

the RC filter circuit is used for collecting the voltage of the sampling resistor R1, the buffer circuit is used for realizing impedance matching of the circuit, and the AD conversion chip is used for converting an analog signal into a digital signal and transmitting the digital signal to the main control chip.

2. The control circuit of a nacelle temperature control device according to claim 1, wherein the RC filter circuit includes a resistor R2 connected to one end of the sampling resistor R1, the other end of the R2 is connected in series with a resistor R4, and the other end of the resistor R4 is connected to the high voltage input terminal of the snubber circuit;

3. The control circuit of a pod temperature control device of claim 2, wherein the snubber circuit comprises a chip ADA4666-2;

4. The control circuit of the pod temperature control device according to claim 2 or 3, wherein the main control chip is further connected with a resistance acquisition circuit for measuring an external resistance, the resistance acquisition circuit comprises a chip U3, a 1 st pin of the U3 is connected with a resistance RU1, a 2 nd pin of the U3 passes through a resistance RU2 and then is connected with the other end of the resistance RU1, and the resistance RU2 is connected with a measured resistance in series;

one path of the 3 rd pin of the U3 is connected with +3.3V, and the other path of the pin is connected with a capacitor CD1 in series and then is grounded;

5. The control circuit of a nacelle temperature control device as claimed in claim 4, wherein the main control chip is further connected with a pressure sensor line and a humidity sensor line through the acquisition line.