【正文】 r 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 photoelectric detection device, the output signal transmission medium by twistedpair cable instead of ordinary shield cable. Twistedpair cable has two important characteristics of cable, one is by electromagic interference with strong protection ability, because the space of electromagic interference current online can cancel each other out. Twistedpair cable is another technical characteristics of two mutually twisted line spacing is small, after two lines of interference lines distance equal to two lines, basic capacitance of shielding work basic and same, it is to restrain monmode interference effect more apparent. Using PLC software to monitor or interference. In the continuous process photoelectric detection device has the timing signal, at the same time, the whole process of signal and corresponding different stages. As shown in figure 5. 圖 5 送引錠過程和光電信號關系 1 send before starting the process, photoelectric signal 1 1. 2 after the start sending process, in A stage, roller, start sending bar. When the lever block photoelectric device emit light, the photoelectric signal for 0, When light guide bar through central 2 small round hole, photoelectric device sends a signal to 2 and 3, 1. 3 sent in B stage, the process of photoelectric signal for 0, roller suspension bar, stop sending, fanshaped 10 section pressure straightening machine, pull. and 1 , synchronous bar to give. 4 sent in C stage, process, and no longer bar ceiling light, photoelectric signal four blocks for 1, 2, stop synchronous synchronous 1, lead bar to give. This work is over optoelectronic device. 9 According to the light of electrical device testing work process, as long as the scene of sending each photoelectric signal process, based on the time process and photoelectric signal relationship, using PLC application of relevant data, prepare to meet the requirements of PLC program, PLC program o