基于锁定放大技术的真空度检测系统OA北大核心CSTPCD

In allusion to the low accuracy of vacuum degree measurement in medium and low vacuum environment,an AC fixed temperature locking amplification vacuum degree measurement method is proposed based on the fixed temperature bridge rebalancing method.The offset voltage signal of the fixed temperature bridge enters the phase sensitive detection after pre-amplification and bandpass filtering,and the collected offset voltage signal is processed by means of the locking amplification technology.This method can improve the signal-to-noise ratio of the detection system and enhance the measurement accuracy of the offset voltage.The constant temperature control of the bridge is implemented in the XC866 microcontroller,and the relay feedback critical proportionality method is used to realize the self-tuning of control parameters.An experimental platform for AC temperature locking amplification vacuum degree testing is constructed,and the obtained vacuum detection data is processed and calibrated.The experimental results show that the AC temperature locking amplification vacuum detection system can realize a vacuum measurement error within 15%in the range from 10-1 Pa to 103 Pa,which verifies the effectiveness and feasibility of the designed scheme.