基于PLC的空气干燥器性能自动检测系统研究

Automatic testing system of air dryer performance based on PLC

针对现有车用空气干燥器性能检测系统存在的自动化程度低、操作复杂、检测结果可靠性低等问题,对干燥器性能检测工艺原理进行了分析总结,对空气干燥器密封性,开启特性,流量特性等方面的检测方法进行了研究,提出了一种基于可编程逻辑控制技术(PLC)与人机界面技术(HMI)的自动化检测系统。创新设计了系统的电气方案、检测流程及人机界面,提出了采用电气比例减压阀以实现检测基准压力的自动调节;采用高精度压力传感器和流量传感器,实现了卸荷阀气路状态的实时监测;采用PLC实现了检测数据的自动存储与运算。实际的产品检测结果表明,所设计系统可有效改进现有的空气干燥器性能检测工艺,气密性等关键性能的检测精度可提高40倍,检测时间可缩短为1/6,检测出错率降低为1/8,工人工作量降低为1/10。

Aiming at the issues of test bed for the air dryer, such as poor automation, complex operation and low reliability, the testing process principle was analysed and summarized. The testing method of sealing characteristic, opening characteristic and discharge characteristic was researched. A novel automatic testing system was designed based on programmable logic controller （PLC） and human machine interface（HMI） technology. A novel electric control project, testing scheme and HMI were applied in the testing system. The air pressure of the system was automatically adjusted by the electric proportional valve. The state of the unloading valve was online monitored by comparing the air pressure difference. The detecting data was stored and computed automatically with the PLC. The testing results indicate that the de- signed system can greatly improve current testing process. The testing accuracy of key performance such as air tightness can be improved on 40 times. The testing time can be shortened as 1/6. The false testing rate can be decreased to 1/8. The workload of the testing personnel can be decreased to 1/10.