毕业设计英语翻译

毕业设计英语翻译

【篇一：毕业设计中英文翻译】

英文资料翻译

题目基于网络信息的自动化控制

系别专业班级学生姓名学号指导教师

2012年4月

con trol based on n etwork and

in formatio n

a automation networking application areas networking is used in all areas of automation. in factory automation, process automati on and buildi ng automati on n etworks perform diverse tasks. likewise, there are dist inct differe nces betwee n tasks performed for applicati ons in differe nt in dustry sectors that all have unique characteristics and con seque ntly vary ing requireme nts. the way devices are conn ected, con figured, and excha nge data also differ.

there is no on e-size-fits-all for in dustrial n etworks; rather, buses are optimized foter differe nt characteristics. for example, factory automati on and process automati on are ofte n used in harsh and hazardous en viro nments where a producti on in terrupti on is costly. these requireme nts con trast sig nifica ntly with build ing automati on, for example, where keep ing costs low is a main driving force.

factory automatio n

factories with assembly-l ine manu facturi ng, as in the automotive, bottli ng, and mach inery in dustries, are predo minan tly con trolled using discrete logic and sen sors that sense whether or not, for example, a process mach ine has a box standing in front of it. the network types ideal for simple discrete i/o focus on low overhead and small data packets, but they are un suitable for larger, messages like con figurati on download and the like. examples of this network type are seriplex, i nterbus-s, and as-i (as-in terface), which are sometimes called sen sor buses or bit level buses. other more adva need protocols orie nted toward discrete logic in clude device net, con troln et, and profibus (dp and fms applicati on profiles). these buses are sometimes referred to as device

buses or byte-level buses. factory automati on in volves fast-moving mach inery and therefore requires quicker resp onse than slower processes. traditi on ally, these tasks have bee n han dled by plcs.

process automati on

process plants in industry segments like refining, pulp paper, power, and chemicals are dominated by continuous regulatory con trol. measureme nt is an alog (here meaning scalar values tran smitted digitally), and actuatio n is modulat ing. of course, process industries also use some discrete control and the predo minan tly discrete manu facturi ng in dustries use some modulating. fieldbus on/off valves are already available in the market, as are small remotely moun ted i/o modules for discrete sen sors .in the past, a dcs or sin gle-loop con troller did this.

process-related n etwork in clude foun dati on fieldbus, profibus (pa application profile), and hart. all these buses as a category are now typically referred to as fieldbus (without the capital f), though some would argue that one or the other does not bel ong. these three protocols were specifically desig ned for bus-powered field in strume nts with predefi ned parameters and comma nds for asset man ageme nt in formatio n like iden tificati on, diag no stics, materials of con structi on, and fun cti ons for calibratio n and commissi onin g. i n term of size, the n etworks used in in dustrial automati on are con sidered to con stitute local area n etworks (la n) spa nning areas no greater tha n a kilometer or two in diameter and typically confined to a sin gle build ing or a group of build in gs. n etworks that exte nd only a few meters are in sufficie nt, and n etworks that spa n cities or eve n the globe are overkill.

field and host tier networks

even within control systems for the process sector there is a n eed for differe nt n etwork characteristics at each tier of the control system hierarchy. at the field and there are instruments such as tran smitters and valve positti oners that have their specific needs, and valve positioners that have their specific n eeds (fig.5-1a-1). whe n fieldbus bega n to evolve, the process in dustry put a large nu mber of requireme nts on the field-level n etwork that were not met by other types of n etworks. many new desig n con sideratio ns n eeded to be take n into acco unt.