核电厂安全级DCS模拟量调理电路硬件诊断研究

Study on Hardware Diagnosis of Analog Quantity Conditioning Circuit of Nuclear Power Plant Safety Level DCS

为满足不断发展的大规模、高复杂性分布式控制系统(DCS)对系统可靠性和安全性的要求,设计了一种应用于安全级DCS 4~20 mA模拟量调理电路的硬件诊断方案.由高精度基准源、高精密低温漂电阻、比较器等组成诊断电路,PhotoMOS开关、定时器等组成时序控制电路.整个方案以纯硬件的方式,实现了对通道的高精度诊断,并将诊断结果通过干触点进行上报,保证模拟量采集数据的有效性.理论分析表明隔离分配通道的转换精度优于最大量程的±0.2%(0~55℃),通道的诊断精度优于±0.08%,通道的响应时间优于4 ms.该诊断电路利用纯硬件的方式为模拟量调理通道提供快速有效的诊断,为有效提高核电厂安全级DCS的可靠性和安全性提供了技术前瞻,具有很高的应用价值.

To meet the requirements of the reliability and security of the developing large scale and highly complex distributed control system(DCS).A hardware-diagnosing method applied to the safety level DCS with 4~20 mA analog quantity conditioning circuit is proposed.The diagnosis circuits involves the high precision reference source,the high precision low temperature-drift resistance and the comparator.The time control circuit contains the PhotoMOS switch and the timer.The whole scheme realizes the high-precision diagnosis of the channel in the way of pure hardware,and reports the diagnosis results through the dry contact to ensure the validity of the analog data collection.Theory analysis shows that conversion accuracy of the isolated distribution channels is less than±0.2%full scale(0~55℃),the diagnostic accuracy of channel is within±0.08%,and the response time is shorter than 4 ms.This design which has high application value provides rapid and effective diagnosis for the analog quantity conditioning channel by using hardware itself,and provides a technology prospect for effectively improving the reliability and safety of the nuclear power plant safety level DCS.