CN111413557B - A portable ID module reading and testing device for auxiliary power units - Google Patents

Abstract

The invention discloses a portable reading and testing device for an ID module of an auxiliary power device, which comprises an electrical socket matched with an electrical plug of the ID module, a switch chip, an analog-to-digital conversion chip, a relay, a singlechip, a display module and a resistance grading circuit formed by connecting resistors of different orders of magnitude in series. The invention has the advantages that the serial number of the APU is read by additionally arranging the reading test device which has simple structure, small volume and convenient carrying, and the device does not occupy the airborne equipment and the test bed equipment of the airplane, so that the reading efficiency of the ID module can be effectively improved; in addition, the reading and testing device can automatically identify and select the proper grading resistor as the voltage dividing resistor, so that the measurement result of the resistance value of the resistor to be tested is more accurate, and the identification result is more accurate.

Description

A portable ID module reading and testing device for auxiliary power unit

Technical Field

The invention belongs to the technical field of aircraft maintenance, and in particular relates to an auxiliary power unit ID module reading and testing device.

Background Art

The ID module of the aircraft auxiliary power unit, or APU, is an electrical component installed on the A320 series aircraft, an auxiliary power unit model APS3200. Its main function is to permanently record the serial number of a certain APU once and for all through destructive engraving, making it easier for line maintenance personnel and workshop maintenance personnel to identify the identity of the APU.

The structure of the ID module is shown in Figure 1. It is cylindrical in shape as a whole, with a circular four-pin electrical plug a at the front end. The outer surface of the electrical plug has threads for connecting the ID module to the socket of the APU wiring harness. The rear end is a resistor integrated circuit with a detachable housing, as shown in the enlarged area indicated by the arrow. The integrated circuit changes the total resistance value of each path by cutting off the connecting wires between different terminals, as shown in the area indicated by CUT ZONE, to complete the recording of different APU serial numbers.

For line maintenance, the reading of the ID module requires maintenance personnel to enter the cockpit of the aircraft and use the onboard system. For workshop maintenance, the reading of the ID module requires connecting it to the test bench and confirming the identity of the APU before proceeding to the next step. The reading principle of the ID module is as follows: There are four pins in the ID module, namely P10, P9, P14 and P5, among which P9 is a common pin, and the others are independent output pins of each resistor. The resistance between P9-P10, P9-P14, and P9-P5 is read respectively, and then the ID module serial number is calculated according to the manual.

The ID module is installed on the APU. As a mechanical device with high vibration and high temperature, the APU is prone to damage to the ID module. When the damage exceeds the standard, the ID module needs to be replaced. The maintenance personnel calculate the resistance of the ID module according to the reference formula given in the manual, and cut the wire of the ID module according to the calculation result. After cutting, the ID module needs to be read again to confirm that the output serial number is the calculated serial number. Once the worker makes a calculation error or an error occurs when cutting the wire, the ID module will be scrapped, and a new one needs to be used and the above process repeated. In the prior art, reading and replacing the ID module is not only time-consuming, but also occupies the aircraft's onboard equipment and test bench equipment. If a calculation error or a cutting error occurs, the ID module will be scrapped (the price of an ID module is more than 1,700 US dollars), resulting in an increase in maintenance costs, which seriously affects the work efficiency and maintenance costs of the line maintenance and maintenance workshop.

Summary of the invention

The purpose of the present invention is to provide a portable reading and testing device for an auxiliary power unit ID module, which is used to assist relevant staff in reading the serial number of the ID module and making an ID module with a corresponding serial number.

The invention object of the present invention is achieved by the following technical solutions: A portable reading and testing device for an auxiliary power unit ID module, comprising an electrical socket matched with an electrical plug of the ID module, a switch chip, an analog-to-digital conversion chip, a relay, a single-chip microcomputer, a display module and a resistance grading circuit formed by connecting resistors of different orders of magnitude in series;

The switch chip is a single-ended multi-channel switch, and the resistance grading circuit is composed of 5 grading resistors of 200, 2K, 20K, 200K, and 2M in Ω connected in series, and one end of the low-level resistor is connected to the power supply;

After the electrical socket is connected to the electrical plug, the common pin on the electrical plug of the ID module is grounded through the electrical socket, and the independent output pins of the resistors on the electrical plug of the ID module are connected to different relays through the electrical socket respectively. After being output through the relay, they are connected to the common input end of the switch chip. The first, second, third, fourth and fifth output ends of the switch chip are sequentially connected to the low potential ends of the grading resistors of the resistance grading circuit starting from the power supply. The data acquisition end of the analog-to-digital conversion chip collects the voltage on the working circuit of the resistor to be measured connected by the switch chip and the relay, and outputs it to the single-chip microcomputer after conversion. The single-chip microcomputer controls the switch chip to connect the appropriate switch channel according to the signal to accurately measure the resistance value of the resistor to be measured. After completing the measurement of all the resistors to be measured, the serial number of the ID module is calculated and output through the display module.

As an improvement of the present invention:

An analog circuit is added, wherein the analog circuit is composed of a plurality of resistance circuits with a common end, each resistance circuit is composed of a plurality of resistances connected in series with a resistance value set by a corresponding ID module, and each resistor on each resistance circuit is respectively connected in parallel with a control switch;

A single-pole double-throw switch is connected in series between the electrical socket and each of the relays, and the relay is selected to connect to the electrical socket or the corresponding resistance circuit of the analog circuit through the single-pole double-throw switch, and the other end of these resistance circuits, i.e., the common end, is grounded;

The single chip microcomputer calculates the number of wires to be cut according to the input ID module serial number and displays it through the display module. After the user cuts it, the single chip microcomputer automatically verifies it and displays the verified ID module serial number on the display module.

Corresponding to different positions of the single-pole double-throw switch, the single-chip microcomputer is provided with an ID module reading mode and an ID module testing mode.

As a preferred solution, the other data acquisition end of the analog-to-digital conversion chip is connected to one end of the high-level resistor of the resistance grading circuit, and the acquired value is converted and output to the single-chip microcomputer. When the single-chip microcomputer senses that the values of the two acquisition ends are equal, it outputs a prompt message through the display module to remind the worker that the ID module or the analog circuit is not connected or is broken.

Beneficial effects:

1) The device of the present invention has a simple structure, a small size, is easy to carry, is simple to operate, and has a wide range of application environments. It can be used to read the serial number of an APU on an airline or in a workshop, and can effectively improve the reading efficiency of the ID module while avoiding occupying aircraft-borne equipment and test bench equipment;

2) Accurate identification: The present invention can automatically identify and select appropriate graded resistors as voltage divider resistors for situations where the serial numbers are different in size, that is, the resistance ranges are different, so that the measurement results are accurate and the identification results are more accurate;

3) The present invention is provided with an analog circuit. Before operating the ID module to cut off, it can be simulated and checked once through the analog circuit. Moreover, during the simulation, only the serial number needs to be input, and the device automatically calculates the cutting position. It has high accuracy and is very convenient to use. It can greatly avoid the scrapping of the ID module caused by calculation errors or cutting errors, which is conducive to reducing maintenance costs.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the structure of an ID module;

FIG2 is a circuit diagram of a reading test device according to a specific embodiment of the present invention;

FIG. 3 is a flow chart of selecting a suitable voltage-dividing resistor by a single-chip microcomputer of a reading test device according to a specific embodiment of the present invention.

DETAILED DESCRIPTION

The following takes the ID module reading test device adapted to the ID module of the APS3200 model APU on the Airbus A320 series aircraft as an example to introduce the solution of the present invention in detail.

The circuit schematic diagram of the portable reading test device for the auxiliary power unit ID module of this embodiment is shown in FIG2, which includes an electrical socket for matching with the electrical plug of the ID module to be tested (as shown in FIG1). After they are connected, the three-way circuit resistors of the ID module to be tested, namely P9-P10, P9-P14, and P9-P5, are connected to the circuit of FIG2 through the electrical socket, specifically as shown in the figure, and are connected to the corresponding ports P10, P14, P5, and P9 in the figure respectively. The lower right corner of the figure is a simulation circuit, which also has three groups of resistance circuits, namely T1-G, T2-G, and T3-G, which are respectively used to simulate the three groups of resistance circuits P9-P10, P9-P14, and P9-P5 of the ID module, and the resistance values correspond to the resistance values of the resistors on the simulated resistance circuit, and each resistor is connected in parallel with a control switch to simulate the wire cutting operation.

SW1, SW2, and SW3 are single-pole double-throw switches. By changing their positions, the ID module or the analog circuit can be connected, that is, the resistance to be measured can be selected.

RL1, RL2, and RL3 are three relays, which are controlled by the single-chip computer U1. U1 outputs high-level signals in turn, turning on transistors Q1, Q2, and Q3 in sequence, and connecting the three groups of resistor circuits of the ID module or analog circuit to the switch chip U3 in sequence. U3 is a single-ended 8-channel multi-way switch.

Corresponding to different positions of the single-pole double-throw switches SW1, SW2, and SW3, the microcontroller U1 is provided with two modes: an ID module reading mode and an ID module testing mode.

In the ID module reading mode, the microcontroller U1 executes the following ID module serial number reading process.

After the resistance circuit of the ID module to be tested is connected to U3 through the relay, the single-chip computer U1 selects the appropriate graded resistor as the voltage divider resistor according to the process of Figure 3. U1 can also adopt the solution of directly selecting the appropriate channel after measuring the resistance once to avoid multiple judgments. The analog-to-digital conversion chip U2 collects the voltage across the graded resistor through its data acquisition terminal CHO and outputs it to the single-chip computer U1 as the basis for U1's judgment. U1 selects U3 by outputting control signals to the channel selection input terminals C, B, and A of U3. After U1 completes the resistance measurement of the three-way resistance circuit of the ID module, it calculates the serial number of the ID module and outputs it through the display module.

X0, X1, X2, X3, and X4 are the output terminals of the switch chip U3, which are connected in sequence to the low potential terminals of each grading resistor of the resistance grading circuit from the power supply, as shown in Figure 2. The data acquisition terminal CH1 of the digital-to-analog conversion module U2 is connected to one end of the high-level resistor of the resistance grading circuit, i.e., the 2M resistor, and converts its acquisition value and outputs it to the single-chip microcomputer U1. When the single-chip microcomputer U1 senses that the acquisition values of the two acquisition terminals are equal, the resistance value of the resistance circuit to be measured is output as ∞ through the display module LCD1 to remind the worker that the ID module is not connected or the circuit is broken.

The resistance grading circuit is composed of five grading resistors, 200, 2K, 20K, 200K, and 2M, connected in series. The use of the resistance grading circuit is beneficial to improving the accuracy of the resistance measurement result of the present invention.

In the ID module test mode, the microcontroller U1 executes the following ID module test process.

Displaying prompt information for inputting the serial number of the ID module to be simulated through the display module;

Calculate the number of wires that need to be cut according to the input ID module serial number;

After the user operation is cut off, a review is performed, and the reviewed ID module serial number is displayed through the display module. The review is to measure the resistance of the analog circuit and calculate the ID module serial number based on the resistance.

ID module reading example

After measuring the resistance of the three-way resistor circuit of the ID module, the process of calculating the serial number of the ID module is as follows:

Taking the ID module with serial number 1512 as an example, the process of obtaining its serial number by measuring its resistance is as follows:

1) Read the test device. First, measure the resistance between the ID module pins P10-P9. The resistance value is: 10Ω (without cutting).

2) Read the test device and then measure the resistance between the ID module pins P14-P9. The resistance value is: 10ΩΩ (without cutting)

3) Read the test device and finally measure the resistance between P5-P9. The resistance value is: 405Ω

4) The reading test device performs matching according to the measured resistance value and the data in Table 1, and finally obtains the ID module serial number, that is, the APU serial number.

Table 1 The corresponding resistance range and value when different wire numbers or combinations are cut

The reading test device outputs through its display module, and the APU serial number is 1512 (indicating that the cut wire number is W10).

The resistance value between P5 and P9 is 405Ω, which is exactly in the interval 394-500Ω corresponding to W10. The value corresponding to W10 is 512. The APU serial number = the sum of the values in the table + 1000. Therefore, the above APU serial number = 0 + 0 + W10 value + 1000, which is equal to 512 + 1000 = 1512. It can be seen that the present invention can accurately read the ID module serial number.

Main procedures

The microcontroller calculates the ID module serial number through the above program.

The purpose of range matching is to make slight changes in resistance visible, that is, to improve resolution. For example, for a 100.5 ohm resistor, a change of 0.5 ohm can be monitored in the 0-200 ohm range, but in the 0-1M ohm range, the microcontroller will automatically ignore the change of 0.5 ohm.

ID module test example

Enter 1512 on the display module screen, and the system will display that the wire number to be cut is W10. Refer to the ID module reading example and you will see that the display is correct.

According to the prompt on the display, press the ID module wire number W10 that is to be cut off in the previous step in the analog circuit area;

The reading test device reads the APU serial number corresponding to the ID module analog circuit (the process is the same as the ID module reading process) and outputs it through the display screen. The output result is 1512.

Through the above two examples, it can be seen that the reading and testing device of the present invention can correctly read the ID module serial number, input the APU serial number to be simulated, and the reading and testing device of the present invention can also correctly give the wire number to be cut.

The reading and testing device of this embodiment can complete the ID module reading and disconnection test of the APS3200 model APU without relying on the aircraft onboard system and the test bench device, thereby improving maintenance efficiency.

Claims (4)

1. The portable reading and testing device for the ID module of the auxiliary power device is characterized by comprising an electrical socket matched with an electrical plug of the ID module, a switch chip, an analog-to-digital conversion chip, a relay, a singlechip, a display module and a resistance grading circuit formed by connecting resistors of different orders of magnitude in series;

the switch chip is a single-ended multichannel switch, the resistance grading circuit is formed by connecting 5 grading resistors with the unit of omega in series with 200, 2K, 20K, 200K and 2M, and one end of the low-grade resistor is connected with a power supply;

after the electric socket is connected with the electric plug, a public pin on the electric plug of the ID module is grounded through the electric socket, each independent output pin of each resistor on the electric plug of the ID module is connected with different relays through the electric socket respectively, after the independent output pins are output through the relays, the public input end of the switch chip is connected, the first, second, third, fourth and fifth output ends of the switch chip are sequentially connected with the low potential ends of each grading resistor of the resistor grading circuit from a power supply, a data acquisition end of the analog-to-digital conversion chip acquires the voltage on a working circuit of the resistor to be tested, which is connected through the switch chip and the relays, the voltage is converted and then is output to the single chip microcomputer, the single chip microcomputer controls the switch chip to be connected with a proper switch channel according to the converted voltage signal so as to accurately measure the resistance value of the resistor to be tested, and after measurement of all the resistors to be tested is completed, the serial number of the ID module is calculated and is output through the display module.

2. The portable reading and testing device for the auxiliary power device ID module according to claim 1, wherein an analog circuit is additionally arranged, the analog circuit is composed of a plurality of resistor circuits with common ends, each resistor circuit is formed by connecting a plurality of resistors with resistance values set by referring to the corresponding ID module in series, and each resistor on each resistor circuit is respectively connected with a control switch in parallel;

a single-pole double-throw switch is respectively connected in series between the electric socket and each relay, the relay is selected to be communicated with the electric socket or the corresponding resistance circuit of the analog circuit through the single-pole double-throw switch, and the other ends of the resistance circuits are grounded in common;

the singlechip calculates the wire number to be cut off according to the input ID module serial number, and displays the wire number through the display module, and after the user operates to cut off, the singlechip automatically rechecks and displays the rechecked ID module serial number on the display module.

3. The portable reading and testing device for an ID module of an auxiliary power unit according to claim 2, wherein the single-chip microcomputer is provided with an ID module reading mode and an ID module testing mode corresponding to different positions of the single-pole double-throw switch.

4. The portable reading and testing device for the auxiliary power device ID module according to claim 3, wherein the other data acquisition end of the analog-to-digital conversion chip is connected with one end of the advanced resistor of the resistor grading circuit, the acquired value is converted and then is output to the singlechip, and when the singlechip senses that the values of the two acquisition ends are equal, the display module outputs prompt information to remind a worker that the ID module or the analog circuit is not connected or disconnected.