CN112600549B

CN112600549B - Universal interface circuit suitable for testing various types of transmission signals of recovery and landing system

Info

Publication number: CN112600549B
Application number: CN202011463421.XA
Authority: CN
Inventors: 杜以强; 乔茂永; 吕智慧; 张莹; 裴晓燕; 闫云龙; 王立武; 黎光宇; 张显; 夏彩云
Original assignee: Beijing Institute of Space Research Mechanical and Electricity
Current assignee: Beijing Institute of Space Research Mechanical and Electricity
Priority date: 2020-12-11
Filing date: 2020-12-11
Publication date: 2023-02-28
Anticipated expiration: 2040-12-11
Also published as: CN112600549A

Abstract

A universal interface circuit suitable for testing multiple types of transmission signals of a recovery and landing system. The circuit comprises a signal conditioning and isolating circuit and a comparison level setting and comparing circuit. The signal conditioning circuit uniformly conditions different active, passive and grounding signals output by the recovery and landing system into detectable levels. The comparison level setting circuit sets a threshold value of a signal to be detected under the control of a computer; the comparison circuit outputs the comparison result between the signal to be detected and the threshold value to a back-end computer system. The invention adopts isolated signal conditioning and dynamic setting of comparison threshold, thereby improving the universality and safety of the test circuit.

Description

Universal interface circuit suitable for testing various types of transmission signals of recovery and landing system

Technical Field

This patent belongs to electronic measurement interface technical field, relates to a general test interface circuit that is fit for multiple type input, and the test of all kinds of state signals of in particular to return and landing system.

Background

With the development of recovery and landing technologies, particularly in the control of a space-to-ground shuttle vehicle represented by a new generation of manned spacecraft, a large number of active and passive state signals are introduced into a return system for system state identification, different interface circuits are required to be customized to meet the test requirements to measure the signals, and further the problems of test resource waste, poor equipment universality and the like are caused, and equipment cannot be multiplexed among different test tasks.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the circuit adopts specific methods of independent power supply, operational amplifier isolation, fixed gain, comparison threshold control and the like to realize product design and support state tests of passive switch signals, switch grounding signals, high and low voltage signals and the like. The problem that output signals in different states are tested by using the same circuit is solved, the equipment reusability is improved, and meanwhile, signals with different amplitudes are identified by using the settable threshold.

The technical scheme of the invention is as follows: a universal interface circuit suitable for various types of signal transmission tests of a recovery and landing system comprises a signal conditioning and isolating circuit and a comparison level setting and comparing circuit; the signal conditioning and isolating circuit comprises an interface power supply, an isolating power supply, a voltage division circuit and an isolating amplifier;

the passive input signal is supplied by the interface power supply and then is sent to the voltage division circuit, and the signal is sent to the output end after being reduced to the level available for the isolation amplifier; the active signal is directly sent to a voltage division circuit and is sent to an output end after being reduced to the level available for the isolation amplifier; the comparison level setting and comparing circuit comprises a gain adjustment circuit, a comparator circuit, a voltage reference circuit, a D/A converter and a logic output circuit; the comparison level is generated by a voltage reference and a D/A converter, the output value of the comparison level is set by a computer system according to a test task and a signal to be tested, and after the signal to be tested is changed, the gain adjustment is input to a comparator to be compared with the comparison level to generate logic output.

VP, VN and VG are used as signal input ports, and two ports with different combinations are selected to access a tested signal into a test interface circuit during measurement; the passive signal is connected between the VP and VN points, an interface power supply provides bias level for the passive signal, the passive signal is input into an isolation amplifier after voltage division, and the isolation amplifier is powered by an isolation power supply which is in common with the interface power supply; an active signal is accessed between the VN point and the VG point and is input into the isolation amplifier after being subjected to voltage division; each measuring channel forms signal isolation between different measuring channels according to the use of an independent interface power supply and an independent isolation power supply; an input signal is input to a back-end circuit by using an isolation amplifier, and the front end and the back end are electrically isolated; the comparison level can be set according to the test task, and various test comparison levels are provided.

Compared with the prior art, the invention has the advantages that:

1) The invention is suitable for testing various input status signals of the return and landing system, and the same interface unit is used for various signals, thereby effectively reducing the configuration requirement of testing hardware;

2) The channels, the front end and the back end are tested and electrically isolated, so that the test process is safer, and potential danger to the tested equipment is avoided;

3) The comparison level can be set, so that the identification of the input signal level can be realized under the control of a computer, and the test of the multi-state level is solved.

Drawings

Fig. 1 is a schematic diagram of the circuit of the present invention.

Detailed Description

The structure and the working principle of the invention are further explained in the following with the attached drawings.

A schematic diagram of a generic test interface circuit for multiple types of inputs is shown in fig. 1. The circuit comprises an interface power supply 1, an isolation power supply 2, a voltage division circuit 3, an isolation amplifier 4, a gain adjustment 5, a comparator 6, a voltage reference 7, a D/A converter 8 and a logic value output 9.

The working principle is as follows: an external input switch signal and a grounding signal are input between two points VP and VN, the voltage provided by the interface power supply 1 is loaded to the high end of the voltage division circuit 3, is adjusted to be within the input range of the isolation operational amplifier 4 through voltage division, and the isolation of the front end and the rear end of the signal is completed on the input signal through the isolation operational amplifier 4. The voltage signal input from outside is input between VN and VG, and is input into the isolation operational amplifier 4 for output after being adjusted by the voltage division circuit 3. The output signal of the isolation operational amplifier 4 is input to the input end of the gain adjustment 5, the signal after the gain adjustment is input to the input end of the comparator 6, and is compared with the comparison level output by the D/A converter 8, and then the signal is output to the logic processing circuit through the logic value output 9, and the state is post-processed.

After the divider resistance 3 reduces the input 0V-40V level signal to the transmission voltage suitable for the isolation amplifier 4, the level signal is isolated from the back end circuit of the test equipment through the AMC1311B low offset error and temperature drift isolation amplifier, thereby improving the safety of the tested product. Secondly, each circuit input end uses independent power supply, and the channels are completely isolated, so that the condition that different tested products and signals using different reference standards are simultaneously accessed into the same test equipment can be met.

The level signal output by the isolation amplifier 4 is adjusted into a single-ended signal by the gain adjustment operational amplifier 5, and is sent to the comparator 6 for identification. The gain of the gain adjusting operational amplifier 5 is digitally controlled, and the amplification factor can be selected in 1, 2, 4, 16 and other gears. The comparison level of the comparator 6 is generated by D/A, and the comparison level can be preset, and can also quickly identify the step value of the level under the control of a logic circuit after the input level is changed, so that the problem of multi-level state telemetering identification is solved.

The passive signals are input from VP and VN ends, are supplied with power by an independent interface power supply 1, are adjusted into voltage signals and are sent to a back-end circuit for processing. Because the interface power supply 1 and the isolation power supply 2 only supply power to the front end of the current channel, the grounding and other conditions of passive signals at the outside do not need to be considered. Meanwhile, as the circuit bandwidth is high (the bandwidth is controlled to be effectively recognized to be not more than 1 MHz), the mechanical shaking condition of the contact can be recognized, and the mechanical shaking condition of the contact can be recognized in an environmental test.

The invention is not described in detail and is within the knowledge of a person skilled in the art.

Claims

1. A universal interface circuit suitable for testing various types of input signals of a recovery and landing system is characterized in that: the circuit comprises a signal conditioning and isolating circuit and a comparison level setting and comparing circuit; the signal conditioning and isolating circuit comprises an interface power supply (1), an isolating power supply (2), a voltage division circuit (3) and an isolating amplifier (4);

a passive input signal is supplied with power by the interface power supply (1) and then is sent to the voltage division circuit (3), and the signal is sent to an output end after being reduced to the level available for the isolation amplifier (4); the active signal is directly sent to the voltage division circuit (3) and is sent to the output end after being reduced to the level available for the isolation amplifier (4); the comparison level setting and comparing circuit comprises a gain adjustment (5), a comparator (6), a voltage reference (7), a D/A converter (8) and a logic output (9); the comparison level is generated by a voltage reference (7) and a D/A converter (8), the output value of the comparison level is set by a computer system according to a test task and a signal to be tested, and when the signal to be tested changes, the gain adjustment (5) inputs the signal to a comparator (6) to be compared with the comparison level to generate a logic output (9);

VP, VN and VG are used as signal input ports, and two ports with different combinations are selected to access a tested signal into a test interface circuit during measurement; the passive signal is connected between the VP and VN points, an interface power supply (1) provides bias level for the passive signal, the passive signal is input into an isolation amplifier (4) after voltage division, and the isolation amplifier is powered by an isolation power supply (2) which is in common with the interface power supply (1); the active signal is accessed between two points VN and VG and is input into an isolation amplifier (4) after being subjected to voltage division; each measuring channel forms signal isolation between different measuring channels by using an independent interface power supply (1) and an isolation power supply (2); an input signal is input to a back-end circuit by using an isolation amplifier, and the front end and the back end are electrically isolated; the comparison level can be set according to the test task, and various test comparison levels are provided.