For Nuclear Main Pump Of High Reliability DCS I / O Board Design And Control Methods

With the rapid development of society and the advanced technology, computerequipment is more and more used in industrial process control. And the distributedcontrol systems (Distribution Control System) which based on computer and networkcommunication come into being. With the expansion of industrial production, singledistributed control systems can’t satisfy the requirements of people to production safetyand reliability. The researchers study a dual redundant DCS and triple redundant DCS.Normally，the dual redundant can basically meet the needs of production safety andreliability, most production process control apply dual redundant DCS. Only theindustry which requires high security and reliability must applies triple redundant DCS.The passage designs triple redundant DCS for the security and reliability of nuclearmain pump in the nuclear power facilities, and the DCS can be used effectively in thenuclear power.Based on studying dual redundant and triple redundant DCS abroad, This passagedesign the overall structure to triple redundant DCS firstly. The structure of tripleredundant DCS use the same three equipments in parallel and the same threeequipments run at the same time. The same three equipments transfer the output resultto the voting system and the voting system will determine the final output. The DCS useModbus communication protocol and use RS-485twisted pair cable for transferringsignal. Secondly, this passage has a detailed design on the I/O card of triple redundantDCS and it gives the figure of structure and hardware circuit diagram of each unit. TheDCS achieves triple redundancy of I/O card. Thirdly, we test the I/O card and the resultstell us the I/O card can achieve the desires results and we verified triple redundancy issuperior to dual redundancy in reliability. Finally, this passage describes in detail how toachieve the triple redundant control and it describes how to achieve triple redundancy by hardware. Then it introduces the thought of triple redundancy in software anddescribes how to achieve the whole triple redundant DCS system overall. And itintroduces the method that how the voting system determines the final output result.