国产精品久久久久久久久,四季AV一区二区夜夜嗨,日韩精品无码中文字幕电影,www.五月婷婷.com

我們新研制出一種用于紙漿白度測(cè)定的智能白度儀，該儀表采用西門(mén)子公司生產(chǎn)的S7-224 CPU結(jié)合軟件功能進(jìn)行數(shù)據(jù)處理，具有較好的可靠性、重復(fù)性、精確度和穩(wěn)定性。為了使其能與其它智能設(shè)備之間實(shí)現(xiàn)通信，我們將通過(guò)現(xiàn)場(chǎng)總線技術(shù)把它連接到網(wǎng)絡(luò)中，使它成為造紙廠現(xiàn)場(chǎng)總線控制系統(tǒng)的一部分。

2.現(xiàn)場(chǎng)總線的選擇

  2.1現(xiàn)場(chǎng)總線技術(shù)的選擇

  現(xiàn)場(chǎng)總線集控制技術(shù)、計(jì)算機(jī)技術(shù)、通信技術(shù)于一體，是當(dāng)今自動(dòng)化領(lǐng)域技術(shù)發(fā)展的熱點(diǎn)之一。這項(xiàng)技術(shù)可將多個(gè)智能控制儀表連接成網(wǎng)絡(luò)系統(tǒng)，實(shí)現(xiàn)分布式計(jì)算機(jī)控制，提高檢測(cè)和控制精度，改善系統(tǒng)的動(dòng)態(tài)響應(yīng)速度，提高系統(tǒng)安全性，從而得到了廣泛的應(yīng)用。

  近年來(lái)，幾種有影響的現(xiàn)場(chǎng)總線技術(shù)已在一些特定的應(yīng)用領(lǐng)域里顯示出各自的優(yōu)勢(shì)。在此，我們選定了現(xiàn)為德國(guó)和歐洲標(biāo)準(zhǔn)的PROFIBUS（Process Fieldbus）現(xiàn)場(chǎng)總線。一方面由于它是目前數(shù)據(jù)傳輸率快的一種現(xiàn)場(chǎng)總線，傳輸率高可達(dá)12Mbps，另一方面它能夠很好的與西門(mén)子的傳動(dòng)設(shè)備相配合，并與西門(mén)子PLC（Programmable Logic Controller）結(jié)合緊密且組態(tài)簡(jiǎn)便。

  2.2 PROFIBUS現(xiàn)場(chǎng)總線簡(jiǎn)介

  參照ISO/OSI參考模型,PROFIBUS現(xiàn)場(chǎng)總線只包含物理層、數(shù)據(jù)鏈路層和應(yīng)用層。由PROFIBUS-DP，PROFIBUS-FMS， PROFIBUS-PA組成PROFIBUS系列。

  PROFIBUS-DP：經(jīng)過(guò)優(yōu)化的高速、廉價(jià)的通信連接，專為自動(dòng)控制系統(tǒng)和設(shè)備級(jí)分散I/O之間通信設(shè)計(jì)，使用PROFIBUS-DP模塊可取代價(jià)格昂貴的24V或0～20mA并行信號(hào)線。用于分布式控制系統(tǒng)的高速數(shù)據(jù)傳輸。

  PROFIBUS-FMS ：解決車(chē)間級(jí)通用性通信任務(wù)，提供大量的通信服務(wù)，完成中等傳輸速度的循環(huán)和非循環(huán)通信任務(wù)，用于紡織工業(yè)、樓宇自動(dòng)化、電氣傳動(dòng)、傳感器和執(zhí)行器、可編程序控制器、低壓開(kāi)關(guān)設(shè)備等一般自動(dòng)化控制。

  PROFIBUS-PA專為過(guò)程自動(dòng)化設(shè)計(jì)，標(biāo)準(zhǔn)的本質(zhì)安全的傳輸技術(shù)，實(shí)現(xiàn)了IEC1158-2中規(guī)定的通信規(guī)程，用于對(duì)安全性要求高的場(chǎng)合及由總線供電的站點(diǎn)。

  本設(shè)計(jì)中采用的是PROFIBUS-DP標(biāo)準(zhǔn)，PROFIBUS-DP（或DP標(biāo)準(zhǔn)）是由歐洲標(biāo)準(zhǔn)EN50170定義的一種遠(yuǎn)程I/O通信協(xié)議。DP表示分布式外圍設(shè)備，亦即遠(yuǎn)程I/O。PROFIBUS-DP還用到了應(yīng)用層接口（ALI），ALI將過(guò)程對(duì)象轉(zhuǎn)換為通信對(duì)象。

ZIMMER Rush Bone Pin Driver Bender Extractor 3.2mm 4.8mm 805-02
Zimmer Mcnutt Bone Pin Driver, Bender, Extractor 13"        
Zimmer Lot Of 5 Wrench, Pin Driver Bender, Rod Drivers V. Mueller Bone Tap
ZIMMER Driver Bender Extractor 805-03 Great Condition
Zimmer 805-03 Bone Pin Driver-Bender-Extractor
Zimmer 1292-99 Spinal Rod Bender
Yellow Jacket Bender 60378 for 5/8 od
Yellow Jacket 60390 3 In 1 Tubing bender 1/4", 5/16" & 3/8" Free Shipping
Yellow Jacket 60390 1/4"-5/16"-3/8" 3-In-1 Tube Bender (Bending Radius: 15/16")
Yellow Jacket 60380 7/8" Tube Bender (Bending Radius: 3")
Yellow Jacket 60379 3/4" Tube Bender (Bending Radius: 3")
Yellow Jacket 60375 3/8" Tube Bender (Bending Radius: 15/16")
Yellow Jacket 60374 5/16" Tube Bender (Bending Radius: 11/16")
Yellow Jacket 60373 1/4" Tube Bender (Bending Radius: 9/16")
Yellow Jacket 60361 Spring Tube Bender 7/8" -        !
Yellow Jacket 60342 Reverse bend adapter for 60331 hand bender
Yellow Jacket 60331 Complete Ratchet Hand Bender Kit
Yato professional mini pipe tube bender 6, 8 & 10mm plumbing fuel brake YT-21840
Woodward-Fab Pipe/Tube Bender Kit SPBENDKIT
Woodward-Fab Manual Pipe/Tube Bender WFB2
WNS Universal Bar Bender / Metal Former Bends Flat Square Round & Angle Steel
WNS Tube Bender/ Pipe Bender c/w 4 Die Sets - Roll Cages Motorcycle Frame (TB3)
WNS Tube Bender/ Pipe Bender c/w 3 Die Sets - Roll Cages Motorcycle Frame (TB3T)
WNS Metal Pipe / Tube Roller Roll Bender Square Tube, Round, Square & Flat Bar
WNS Metal Pipe / Tube Roller Bender Round Tube / Pipe, Round, Square & Flat Bar
WNS Hand Sheet Metal Straight Folder Bender 1060mm x 1.2mm Capacity Lightweight
WNS Hand Sheet Metal Box & Pan Folder Bender 910mm x 1.5mm Capacity (BPF910)
WNS Hand Sheet Metal Box & Pan Folder Bender 600mm x 1.0mm Capacity (BPF600)
WNS Hand Sheet Metal Bender Box & Pan Folder 2000mm Length x 1.2mm Cap (BPF2000)
WNS Hand Sheet Metal Bender Box & Pan Folder 1320mm Length x 1.5mm Cap (BPF1320)
WNS Hand Sheet Metal Bender Box & Pan Folder 1260mm Length x 1.2mm Cap (BPF1260)
Wire Stripper, 30 - 10 Awg, 6-1/4" Oal GB-Gardner Bender GS-361 032076068837
Wire Stripper, 20 - 10 Awg, 6-1/4" Oal GB-Gardner Bender GS-355 032076068790
Wire Stripper With Lock, 20 - 10 Awg, 6" Oal GB-Gardner Bender GS-360
Wire Disconnect, 22 - 16 AWG, 600 V, Red, 100 Pieces GB-Gardner Bender 10-141F
Wire Connector Tan 100 Pack Gardner Bender Wirenuts and Connectors 10-1H1
Winggard Twist-On Wire Connector Blue 50 Pack Gardner Bender 10-089 076335047515
Winggard Twist-On Wire Connector Blue 100 Pack Gardner Bender 13-089
Wing Gard Blue Twist-On Connectors, 2-Pack Gardner Bender TV Wire and Cable
Wing Connector Yellow 100 Box Gardner Bender Wirenuts and Connectors 10-084
WILMAR LARGE TUBING BENDER W703
WICKMANN FUSEHOLDER 853000010C TYPE 853 (LOT OF 25) ***NIB***
Whitney Jensen 247 portable power press brake sheet bl bender
White 1" X 10' Silicone Self-Sealing Tape Gardner Bender Electrical Tape
Wheeler Rex Ratchet Manual Pipe Cutter
Wet and Forget 128oz Mld&mldw Cleaner 802128
WESTWOOD T100-230 TB-60, ELECTRODE TIP BENDERS , 5" LONG SET OF 2 BENDERS
Westward Tubing Bender, 5/16" OD
Westward Tubing Bender, 1/4" OD 3CYU6
Westward 3CYV2 Tubing Bender 1/4", 5/16", & 3/8" OD
WESTFALIA BENDER PIPELINE WASHER MANUALS COMPLETE SET
WARSAW ORTHOPEDIC Stainless Steel Bender Driver Extractor 13" Good Condition
Warsaw Orthopedic Driver Bender Extractor Bone Pin MC Nut 13" Long - BRAND        !
Waring 028538 MX1000XT MX1200XTP Xtreme Series Bender Drive Coupling
Wallace Model 462 Heavy Pipe Bender with Dies to 4"
Wagner No. 955 Conduit Hand Bender 1-1/4" EMT w/Bubble levels
WACKER REBAR BENDER 2008 MODEL STEEL BENDER 110 VOLT WITH CARRY BOX SITE WORK
W.A. Whitney Buss Bar Bender & Hydraulic Fabricator Catalog
Vtg Star Gages 1/2' EMP Shrink Back Pipe Bender 22 Degree To 60 Degree 37" Long
Vtg General S106 6-Piece Tubing Bender Set 1/4" 5/16" 3/8" 7/16" 1/2"5/8" W/Box
VTG BENFIELD INCH MARKER PIPE BENDER 3/4'' EMT 1/2'' RIGID USA & HANDLE
VTBEND1 Lead Benders for 1/4W-3W Resistors, also Diodes and Capacitors
Volt-Doctor Voltage Continuity Tester Gardner Bender Electrical Tools GVC-300
Voltage & Continuity Tester Garner Bender Volt-Doctor GVC 300 6-600 V AC/DC Test
VISION PLATE BENDER WITH 4 PUNCHES MODEL VIPB II GR-010
Virax® Motorised 3/8in.-2in Gas Hydraulic Bender 230v AC Sliding Cheek 240843