Reliability of distributed controller in safety I&C system

The control logics of digital safety I&C system TXS are downloaded to different controllers for distributed control, which are classified according to functions into four kinds: signal acquisition, data logic processing, data logic voting, and signal monitoring & service. RS (Risk Spectrum) program is applied to automatically build the fault tree model for quantitative analysis. In order to improve the modeling efficiency, ActiveX and Visio are applied in graphical configuration and analysis of topological structure for the hardware components of TXS. With the function module BA11 of HP-injection system as an example, two control distribution strategies are proposed and compared with the original method. Results show that, within the safety range, the response time of HP-injection system can be improved by the proposed strategy No.1 with its unavailability increased by 0.87%, which can be reduced by 3.6%, adopting the proposed strategy No.2.