| It is widely recognized now that digital control system is an important facility nec-essary to industrial process for guaranteeing safe and reliable operation. Based on the socalled client/server structure and multi-level network architecture, the sophisticated mid-ware and data link are widely used in the existing distributed control system (DCS), whichmay degrade the reliability and safety of the system. In this decade, the design philoso-phy, such as object oriented and server embedded, pops up and makes the functionalityof DCS upgrade. With such philosophy, the infrastructure of DCS is getting more ?at,and its functionality more distributed. Specially, the peer to peer (P2P) network supportssuch kind of design methodology. This work focuses the techniques coming out of theDCS based on P2P networks. Especially, the implementation technique, failure modesand their effects on safety and reliability of the system are considered. The newly de-veloped DCS based on the techniques proposed well demonstrates the design matchingthe goal. Needless to say, successfully development of the control facility will improvethe applicability of the native DCS products to the safety important industrial processes,nuclear power plant, large scale petrochemical industry, for examples. The contributionsof the work are listed as following.1. It is known that the traditional control systems based on client/server (C/S) archi-tecture are getting to face some bottlenecks for improving their real-time, reliabilityand safety. This work proposes a new methodology based on the so called peer-to-peer (P2P) to construct the digital control system, which makes the structure of thesystem more ?at and distributed. In this work, the principle and communicationmechanism of the control system based on P2P are explored. Especially, compar-ing with the traditional control systems based on C/S structure, the proposed onedemonstrates high qualities on reliability, link load and delay, maintainability andcost-efficiency.2. Considering the issues mentioned above, network resource management strategyfor the control system developed is set up. In this work, the searching mechanismbased on the name service and two-level Harsh searching algorithm is proposed.Site applications well illustrated the efficiency, realness and safety of the controlproposed.3. The despatching mechanism for tag-list resource on the network is set up to enableresource sharing in the control system. Especially, the block sharing algorithm of resource library (TDBS) is proposed to improve the safety and maintainability ofthe system.4. Based on exploring the failure mode of the control system developed, based on thefuzzy colored Petri net, a method for verifying fail-safe of the peer-to-peer controlsystem is proposed. Through analyzing the failure mode and intelligent reasoning,some critical routing of the failure propagation in the control systems is detectedcorrectly and effectively. Therefore, the weakness of the control systems could befound out and the innovative approach could be adopted correspondingly.5. A new type control system based on peer-to-peer architecture, named as SUPMAX,is developed and tested. It is well proven that this new type control system based onthe P2P architecture has some nice features over the ones based on C/S architecture,including real-time performance, operating safety, maintenance convenience andetc..The site application of the SUPMAX control system well demonstrated the feasibil-ity of the methodology based on P2P network to upgrade the control systems for safetyimportant industrial.
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