【正文】 ading channel output waveform of output waveform B 90 176。1 The properties and application of photoelectric encoder The working principle, photoelectric encoder Photoelectric encoder, is a kind of photoelectric transformation through the machine will output shaft geometric displacement convert pulse or digital sensors. This is the most sensor, photoelectric encoder and grating is by photoelectric detection device. Grating is in certain parts of the diameter of the circular plate to open several rectangle hole. Caused by the code, motor and motor coaxial rotates grating and motor rotate speed, with the light emitting diode and other electronic ponents testing unit output pulse signal with several, its principle diagram is shown in figure 1, Through the calculation of the output pulse of photoelectric encoder per number can reflect the current motor speed. In addition, the direction of rotation, the code for the judge may also provide phase difference dish of 90 186。 two pulses. According to the measuring principle, encoder can be divided into optical and magic type, inductive and capacitor. According to the calibration method and the signal output form, can be divided into incremental, absolutely and hybrid three. Incremental encoder Incremental encoder is directly for the use of photoelectric pulse output three square principle of A and B and Z, A and B group phase, pulse 90 186。, D flipflop output waveform W1) for Q (high level, Q (W2) for lowlevel waveform crosscoupled nand gates, open, counting pulse waveform W3) by (bidirectional, send to the 74LS193 counter CU input pulses, add count, At this time, below, its output crosscoupled nand gates close for high level (waveform W4). When the photoelectric encoder counterclockwise, channel A output waveform of output waveform delay than channel B 90 176。 the signal, So, when the steering wheel clockwise, count the output circuit for 2048 ~ 2948, when steering counterclockwise, 4 count the output circuit for 2048804, D0 output data counts circuit D11 ~ to data processing circuit. In practice, the steering wheel frequently made clockwise and counterclockwise rotation, because existence, work longer quantization error after a period of time, the steering wheel when the output of a circuit to count, but may not 2048 several words deviation, To solve this problem, we added a steering wheel to detect circuits, systems, data processing circuit after work on the operation state in the simulator, system test in the back, if detection circuit in the back wheel, and counts circuit in the data output, but not to count 2048 reset circuit, and the initial reset. Photoelectric encoder gravity measurement instrument in the application The rotary photoelectric encoder, the shaft and gravity measuring instrument for knob shaft. Gravity measurement of the angular displacement volume knob pensation for a signal is transformed, Rotary photoelectric encoder and absolute encoder two points and incremental encoder. Incremental encoder is the output pulse form, its code plate sensor than absolute encoder code easier to disk and higher resolution. Generally need only three barcode, here39。s code of WaiDao and middle way has the same number of uniform distribution of not pervious to light and sector (raster), but is two sector mutual stagger half area. When the code salver, turning the output signal is A difference for 90 176。and39。 39。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 fo