【正文】 ulse signal can be obtained by counting were measured after the digital signal. Therefore, we in the car driving simulators, steering wheel rotation Angle measurement chooses EPC 755A photoelectric encoder, the output circuit as sensors, choose open collector output resolution selection 360 pulse/circle, considering the steering wheel rotation is a twoway street, clockwise and counterclockwise, can also needs to the output signal phase coder to count. Figure 2 shows the actual use of photoelectric encoder and discrimination, phase twoway counts circuit with a D flipflop circuit and two crosscoupled nand gates, with 74LS193 3 counts circuit. 3 圖 2 光電編碼器鑒相計(jì)數(shù)電路 When the photoelectric encoder clockwise, channel, A leading channel output waveform of output waveform B 90 176。low , will change between reciprocating alternate positive and backward pulse, the two counter on the number and replace them when they can eliminate the shadow ring (below instrument readings will involve this). Thus, the clock generator frequency of vibration frequency may be greater than the maximum. Can see from figure 4, a pulse signal of the cycle, four counts pulse. For example, the number of every lap pulse coder for 1000 produce four times the number of pulse frequency, and its resolution is 4000 for degree. Actually, this kind of sensor products will enlarge the output signal of photosensitive 7 ponents such as plastic circuit and sensor encapsulation testing ponents together, so just add subdivision and counts circuit can form a angular measurement system (74159 is 416 decoder). Application problem analysis and improvement measures Application problem analysis Photoelectric detection devices transmit and receive devices are installed in the production and use of exposed many defects, its internal factors have external factors, which is mainly embodied in the following aspects: Devices or accept device for mechanical vibration, caused by the shift or offset, receiving devices not reliable to receive light signals, but cannot produce signals. For example, Photoelectric encoder used in steel rolling speed regulation systems, because of photoelectric encoder is bolted directly in motor shell, photoelectric encoder shaft through hard shrapnal and motor rotor connections, because motor with load is a load of impact, while rolling steel rotor motor will have caused the shell and vibration. According to the mensuration, After steel time electricity encoder vibration velocity for mm/s, this can damage the vibration velocity of photoelectric encoder internal functions. A pulse, thereby causing instability in control system, or misoperation cause accidents. Because of photoelectric detection device installed in production, production environment factors in photoelectric detection devices not reliable work. Such as the installation position of high temperature, humidity, photoelectric detection device to internal electronic ponents characteristics change or damage. For example in continuous caster send tracking system, because of photoelectric detection equipment installation location near the slab, high temperature environment caused by photoelectric detection device signal or damage caused by accidents or production. Production site for all kinds of electromagic interference source photoelectric detection device, of interference, photoelectric detection device of output waveform distortion distortion occurs, the system maloperation accident or production. For example, Photoelectric detection device installed in the production equipment of the signal, the body to the control system of the cable transmission distances in 20100 meters, cable, although usually choose multiple shielded cable conductor, but due to cable capacitance between lines of resistance and impact plus and other cable laying together, vulnerable to all sorts of electromagic interference effect, thus causing waveform distortion, thus to drive system feedback signal and practical value deviation, and cause the system precision. Measures for improvement 8 Change of photoelectric encoder installation. Photoelectric encoder is not installed in motor shell, but in the motor based on a fixed bracket to independent installation photoelectric encoder, photoelectric encoder axis and motor shaft center must at the same level, two axis adopt soft rubber or nylon hose connection, to reduce the impact of photoelectric encoder motor load of mechanical shock. By this way after vibration testing, the vibration velocity to mm/s. Reasonable choice of ph