Based on MSP430F149 single chip microcomputer, a timing detection system for launch control is designed. Using digital signal processing technology and computer automatic control technology, the system collects the control signal at the ignition contact and butt plug, analyzes the voltage amplitude, current, signal noise, rising and falling edge width of the signal, displays the deviation between the detection signal and the standard value, and gives the evaluation value; At the same time, the reliability of docking is detected, the same pipe is docked three times, and the signal difference is analyzed to evaluate the reliability of docking; Record the test data of each time in detail, compare and analyze with the historical data during each test, and obtain the change law of the data of the same pipe and the consistency with the data of all other pipes, so as to determine the potential fault of the generation and control system and give maintenance guidance. The detection system not only makes the detection data accurate and the process simplified, but also saves time, and can effectively improve the operational efficiency of the rocket.
Minimum system design based on MSP430F149
MSP430F149 single chip microcomputer is suitable for many complex control applications. Selecting this chip to build the minimum system can fully meet the requirements of normal operation of the system. The minimum system designed based on MSP430F149 is the core control part of the hardware. In addition to the power supply circuit and reset circuit necessary for the normal operation of the single chip microcomputer, the system also includes multi-core switching circuit, keyboard and liquid crystal display circuit, communication interface circuit, data storage circuit and sound alarm circuit.
Power circuit design
In the application of single chip microcomputer, reset signal must be provided to ensure that the single chip microcomputer can be reset correctly and enter the correct working state. In addition, MCU also needs stable voltage signal, so it must provide power circuit. The power supply circuit and reset circuit are shown in Figure 2. In the figure, the input voltage is converted into 3.3V voltage by tps70633 chip to meet the working voltage requirements of single chip microcomputer. The reset signal is generated by max809str and sent to the single chip microcomputer. In order to reduce interference, a 0.1 is added to the power end of each chip μ Filter the capacitance of F.
Fig. 2 power supply circuit and reset circuit diagram
Design of multi-core automatic switching circuit
In the automatic test system, it is often necessary to collect multi-channel data, and sometimes obtain data signals of different channels in different test processes. In the past, people often solved this problem by increasing the number of analog switches at the front end of a / D sampling. However, if the detection system contains the switching of high-voltage circuit, the analog switch is no longer suitable. The relay has obvious advantages in this regard. It has the ability to switch large current and voltage, and can completely isolate the drive control circuit from the controlled contact circuit, High safety factor.
When selecting the relay, considering the actual technical requirements, functional characteristics and environmental adaptability, and referring to the performance parameters, volume, installation mode and load characteristics of the relay, the tx2-5v relay produced by Panasonic company is selected as the switching device for measuring circuit switching. The relay has the advantages of fast response time, high withstand voltage value, small volume and low power consumption. It can meet the requirements of long-time continuous scanning and working under high voltage.
Fig. 3 Schematic diagram of multi-core automatic switching circuit
The measurement of terminal voltage and loop resistance of the ignition device of 32 core cable is relative to the rocket system. The detection system also needs to adjust the analog signal, analog-to-digital conversion and single chip microcomputer to process the data. Therefore, the multi-core automatic switching circuit should not only realize the automatic switching of constant voltage and constant current, but also realize the switching between multi-channel signals. In the circuit design, each core adopts a two-way relay to realize switching, which can not only realize the loading of constant voltage and constant current of the core cable, but also realize the measurement and switching of multi-channel signals. The principle of automatic switching circuit is shown in Figure 3. In the figure, in1 ~ in30 are omitted before in31, and the line connection of in1 ~ in30 is the same as that of in31; Pin 1 of J32 is connected with pin 6 of J1.