Lifting Machinery Condition Monitoring Anti-interference Study

It is considered that noise jams normal signal in signal processing. therefore, we always hope to acquire data without noise. But it is actually impossible. Because of this , there appear a series of signal processing arithmetics and theoretics.By analyzing port crane monitoring & assessment system's performance and its surrounding, it is found that it is sense organ and its jam sources are high-power equipments, its radiate manner is that transducers' and electromotor's wires couple test system. It is severity point where signal transfer from sensor to electric ark. In order to reduce channel noise, we should enhance circuit's precision and anti-jams competence. We advance basic standard which is used to test circuit hardware, high common-mode rejection ratio, good stability of sensor, low noise, low drifting.Design as follow basing on the standard above.Design pretreatment circuit, use two levels magnified circuit and instrumentation amplifier INA115 and INA128, improve common-mode rejection ratio and reduce drifting, select power supply designed by frequency spectrum equilibrium, reduce effect of outer test circuit. Select signal wire with good shield, reduce jam from outer radiate. Because range of oscillation frequency of port crane is from 0.1 Hz to 1000Hz, use eight ranks lowpass MAX295 wiping out over 1000Hz signal in order to prevent signal aliasing. Signal is transmitted from sensor to data collection box, high-power equipment radiate signal, we use a self adaptive filter which has two channels, one is private input, the other one is noise, we can use later one canceling former one' noise. Its program is compiled by matlab. Self adaptive filter is simulated by a sine signal and a random signal. it effectively controls the channel noise and is validated by the project application. We use 7892-1 dual 12-bit serial input analog-to-digital converter and TMS320LF2812A microprocessor produced by Tl company, we design peripheral device of TMS320LF2812A and complete data acquisition, signal processing, saving data and signal communication. The whole system bring into play self signal processing advantage, increase its performance and operation speed. In addition, while basic functions are completed, its anti-jams is considered filly. We apply anti-jams measures in hardware and achieve good effect.