The digital measurement of the circular motion [1] The circumference of the circumference C = 2πr, where r is the radius of the circumference. If the circumference of the circumference C is equally divided at the edge, the arc length corresponding to each adjacent two equal points is L=α×r, which is proportional to r. The larger the radius r is, the larger the distance between adjacent bisectors is, and it is easier to measure the bisector by the method of light interruption by the switch. However, the larger the radius r is, the larger the entire grating disk is. Therefore, the system that requires the volume and the measurement range cannot take the radius of the grating disk arbitrarily.
Ordinary photoelectric switches cannot judge the forward and reverse rotation of the grating disk, and it is impossible to measure the increase or decrease of the measurement data. The ST256C is a dual light speed direct-shooting photoelectric sensor. The utility model is composed of a high-transmittance infrared photodiode and a high-sensitivity phototransistor, and has high resolution and non-contact detection, and can discriminate the moving direction of the object to be measured and the forward and reverse rotational speed measurement. The internal circuit is shown as follows: ST256C internal circuit diagram ST256C wiring diagram knows that when an object passes through the ST256C photosensitive gap from top to bottom, there are four cases: A) Q1 and Q2 are not blocked, Q1, Q2 Turn on, 3 feet and 5 feet output high level; B) When Q1 is blocked, Q2 is not blocked, Q1 is cut off, Q2 is turned on, 3 feet output low level, 5 feet output high level; C) When Q1 and Q2 are completely blocked, Q1 and Q2 are cut off, and the output of pin 3 and pin 5 is low level; D) when the object continues to move down, Q1 is not blocked, Q2 is blocked, and Q1 is turned on. Q2 cutoff, 3 feet output high level.
y test technology volume theory and research foot output low level. To sum up, the object moves from top to bottom. The output of the 3 feet and 5 feet is: 11, 01, 00, 10. In the same way, when the object passes through the photosensitive gap of the ST256C from bottom to top, the 3 feet and 5 feet are sequentially output as: 11 , 10, 00, 01. If the output direction of the 3 pin 5 pin is changed from 11 to 01, the moving direction of the object is the positive direction, and the movement of the object when the output level of the 3 pin 5 pin is changed from 11 to 10 is defined. The direction is the reverse direction, thereby achieving the forward and reverse measurement of the measured object. The ST256C has a photosensitive gap of 1.3mm and a beam spacing of 0.7mm. Therefore, the gap between the teeth on the grating disk should be 1.3mm or more. Because the object passes through the ST256C photosensitive gap from bottom to top, there are four variations, that is, the number of meters is 4. Therefore, the number of teeth of the grating disk can be determined based on the detected range. For example, the maximum value of the measurement is 300, the number of teeth of the grating disk is 300/4=75, and the diameter of the grating disk is: 1.3×150/π=62 mm.
System design [2] [3] This system uses HT48R10A-1 single-chip microcomputer as the processing unit, the display uses seven-digit pen-type digital tube, the single-chip microcomputer directly drives. HT48R10A-1 Introduction HT48R10A-1 is an 8-bit high performance, high efficiency RISC architecture microcontroller, 1K x 14 bit OTP/MASKROM, 64 x 8 SRAM, 63 instructions. Internal special features such as suspend, wake-up, oscillator selection, and buzzer drive increase the flexibility of the microcontroller while reducing cost.
The two output terminals of the software programming ST256C are respectively connected to the PC.1 and PC.2 ports of the MCU. PC.1/TMR is a multiplexed port. Through the mask option, PC.1 is selected as a general-purpose input and output port. By detecting the high and low level changes on the PC.1 and PC.2 ports, it is judged whether the ST256C is counting forward or backward. After the MCU detects the detected data and displays it through the LED, the digitization of the spring measurement is realized.
Conclusion The system is designed to be inexpensive and easy to program. In practical applications, many peripheral circuits have been added. For example, a voltage stabilizing circuit, a starting circuit, an automatic power-off circuit, an undervoltage detecting circuit, a unit switching circuit, and the like. The solution is stable and reliable, and has been successfully applied to MJ-EBS-001A, B, C and other electronic human scales of a certain company, and has achieved good economic benefits.
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