Transmission algorithm of digital communicating data for digital NDIS

Taking the advantages of good stability and high reliability, digital communication are becoming a more critical component of instrument and control (I and C) systems in nuclear plant power (NPP), especially for the next generation. With China's rapid development of NPP I and C of third generation AP1000 technology, most of Nuclear Detecting Instrument System (NDIS) are supplied by foreign manufacturer and digital NDIS is unavailable in China. In the digital control system design customized for field nuclear instrument, all parts need to be taken into account for signal acquisition, processing, threshold comparison and control. Fast and intelligent communication data processing is often of concern and needs research. Transmission algorithm of digital communicating data for NDIS is designed to solve the real-time-control problems in the amount of time and equipment limitation which caused by physical characteristics of RS485 high-speed data bus. The algorithms include data link establishment and link management, data subcontracting computing, and data test. In the case of limited system scan cycle time and multi-exchanged data of digital NDIS, it can guarantee the normal transmission of sufficient data for information of all devices. (authors)