1、外文翻译 Digital Meter for Measuring Rotational Speed Abstract A digital meter for measuring the rotational speed is introduced in this paper. It is controlled by an MCS-51 series single-chip microcomputer 8032. It contains the following features: rational design, high accuracy, wide measurability range
2、 and powerful function and dependability. Moreover, it is very nimble and convenient to use. The work principle is presented in detail in the paper and the block diagram and program flowchart are given as well. Key works: digital measuring apparatus； rotation speed； single-chip micro-computer The ro
3、tor speed control system of industry is one of the important parameters. Mechanical tachometer measuring speed, the rotor contact with the measured object must be to get the synchronous speed, through the internal gear shift instruction after the pointer speed with the size of the header. Use of mec
4、hanical tachometer measured object can interfere with movement, especially when measured rotor mass is very small, speed tables on the rotor pressure is not a small additional load, which affects the measurement accuracy. This paper describes a 8032 single-chip microcomputer as the core to the non-c
5、ontact Digital Tachometer. 1 speed measuring principle The gun speed-sensitive devices with infrared sensors, launched by the specialized infrared detection devices, while receiving reflected back from the measured object infrared, photoelectric conversion into electrical pulses through the signal,
6、does not affect the rotation of the object. Tubes and pipes are fixed in the detection of acceptable shelf, through the lens focus, semi-transparent film not only to the reflected infrared light fired rotating objects, they can rotate the object by the reflected infrared light through the translucen
7、t membrane back fired for management. Along the circumference of a rotating body even paste some reflection paper, it directed reflection infrared to receive the reflected acceptance of the infrared control. Photovoltaic conversion shown in Figure In the optical triode 3DU5C adding an appropriate bi
8、as, when 3DU5C by infrared irradiation, at the conduction state, A point for the low level, 3DG6 end, B point is high； when no infrared radiation, the photoelectric transistor closed A high point presentation, so 3DG6 low collector point B, B point of the pulse signal through the inverter 1,2 plasti
9、c, and then the door 3 RP, frequency and speed will be proportional to the size of the corresponding changes The speed pulse signal. Speed pulse signal into the 8032 microcontroller timer / counter, through the microcontroller to calculate speed software processing. Figure 1 Schematic photoelectric
10、conversion When the machine used in the measurement speed M / T method and timing method were used. M/T M / T method is the detection time Tc, the time according to speed pulse m1 and m2 to calculate the speed pulse. If a fixed period Tc, the total time taken and pulse rotation pulse fp fcs Pulse on
11、 m1 and m2, timing pulse frequency f, rotor output pulses per revolution for the p, the speed n = 60fm1 / pm2 (r / min). Such as the speed measured over 1 s pulses for the m1, rotor output pulse number per revolution, that great number of p, the speed n = 60m1 / p (r / min). 2 hardware speed measure
12、ment instrument Figure 2 constitute the grounds of speed 8032 MCU measuring circuit. 8032 is MCS-51 series single chip, compared with the common 8031 chip, a feature more than 8032 strong T2 timer / counters and 128 bytes of internal RAM, which T2 counter with 16-bit auto-reload and capture, can for
13、 timer / counter with, but also used as a baud rate generator. The system used for time T2, which take into account regular pulse, regular pulse signal directly from the 8032 chip address latch signal ALE client leads, and through the 74LS74 dual D flip-flop frequency, was two points. When using 6 M
14、Hz crystal oscillator, the time pulse frequency fc is 0.5 MHz. T0 accrual speed pulse counter fp, T1 time pulse counter for taking into account fc, trigger DFF1, DFF2 and 1,2,3,4 component count and gate control circuit, can also start and stop counters T0 and T1. P0 port to allow control through th
15、e end of 8D with latch 74LS377 extends an 8-bit output, as a five segment LED digital display of the data line selection code. P3.0, P3.1 access switches S1 and S4, S1 for the very few P set selector switch, S4 input pulse for the very few keys. P3.2 and P3.3 are connected S2 and S3 switch, S2 switc
16、h method for the speed selection key； select the use of M / T method speed, or velocity measurement with time. S3 for the speed frequency select switch, to select the measuring speed or frequency measurements. When using regular method to measure the speed, the system can be easily measured by measu
17、ring the frequency. 3 software design and anti-interference measures System programming includes the main program, interrupt procedures, code conversion routines, display routines, etc. The hardware structure of two measurement methods are identical, but different software process, to set the speed
18、through the P3.2 port approach. The following two measurement methods were discussed works. M / T method, first of all by the end of 8032 the P1.1 output start pulse signal, the start pulse cleared DFF1 and DFF2 two triggers, so that Q1 ended output low, blocking the door 2,3,4, Q- 1 side open the d
19、oor for the high one, and trigger DFF2 the Q-2-ended output is high, ready for the start of work. When the speed pulse signal fp receives the rising edge, the flip-flop DFF1 turn, Q-1 is low, blocking the door 1, Q1 is high, open the door 2,3,4, so that start time T2, m1, m2 and started counting. In
20、 the interrupt program, the P1.2 8032 ended output pulse signal to stop, set bit trigger DFF2, Q-2 low-side outputs, blocking the door 2,3,4, T0, T1 and stop counting. Interrupt the program while reading speed signal pulses and timing signal pulses m1 m2, in the main program, in accordance with m1, m2, P and f calculated speed n = 60fm1/pm2, and converted to BCD code sent to the digital look-up table display, complete a data collection and display. In the regular method, due to the timing signal generated 1 s, while the maximum
