描述

在工業(yè)控制中，某些輸入量(如壓力、溫度、流量、轉(zhuǎn)速等)是連續(xù)變化的模擬量，某些執(zhí)行機(jī)構(gòu)(如伺服電動(dòng)機(jī)、調(diào)節(jié)閥、記錄儀等)要求PLC輸出模擬信號，而PLC的CPU只能處理數(shù)字量。模擬量首先被傳感器和變送器轉(zhuǎn)換為標(biāo)準(zhǔn)的電流或電壓，如4～20mA，1~5V，0~10V，PLC用A/D轉(zhuǎn)換器將它們轉(zhuǎn)換成數(shù)字量。這些數(shù)字量可能是二進(jìn)制的，也可能是十進(jìn)制的，帶正負(fù)號的電流或電壓在A/D轉(zhuǎn)換后一般用二進(jìn)制補(bǔ)碼表示。

D/A轉(zhuǎn)換器將PLC的數(shù)字輸出量轉(zhuǎn)換為模擬電壓或電流，再去控制執(zhí)行機(jī)構(gòu)。模擬量I/O模塊的主要任務(wù)就是完成A/D轉(zhuǎn)換(模擬量輸入)和D/A轉(zhuǎn)換(模擬量輸出)。

例如在爐溫控制系統(tǒng)中，爐溫用熱電偶檢測，溫度變送器將熱電偶提供的幾十毫伏的電壓信號轉(zhuǎn)換為標(biāo)準(zhǔn)電流(如4～20mA)或標(biāo)準(zhǔn)電壓(如l～5V)信號后送給模擬量輸入模塊，經(jīng)A/D轉(zhuǎn)換后得到與溫度成比例的數(shù)字量，CPU將它與溫度設(shè)定值比較，并按某種控制規(guī)律(如PID)對二者的差值進(jìn)行運(yùn)算，將運(yùn)算結(jié)果(數(shù)字量)送給模擬量輸出模塊，經(jīng)D/A轉(zhuǎn)換后變?yōu)殡娏餍盘柣螂妷盒盘枺脕碚{(diào)節(jié)控制天然氣的電動(dòng)調(diào)節(jié)閥的開度，實(shí)現(xiàn)對溫度的閉環(huán)控制。

歐美品牌停產(chǎn)的，常用的“PLC”備品備件

我司產(chǎn)品應(yīng)用于以下領(lǐng)域：

1,《發(fā)電廠DCS監(jiān)控系統(tǒng)》

2,《智能平鋼化爐系統(tǒng)制造》

3,《PLC可編程輸送控制系統(tǒng)》

4,《DCS集散控制系統(tǒng)》
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5,《智能型消防供水控制系統(tǒng)》

6,《化工廠藥液恒流量計(jì)算機(jī)控制系統(tǒng)》

7,《電氣控制系統(tǒng)》造紙,印染生產(chǎn)線,變電站綜合自動(dòng)化控制系列

本特利，英維思，伍德沃德，福克斯波羅、西屋、瑞恩、施耐德莫迪康、ABB、AB、西門子、摩托羅拉、GE發(fā)那科、安川、博世力士樂，ACSO，力士樂等各大品牌的DCS系統(tǒng)配件，機(jī)器人系統(tǒng)配件，大型伺服系統(tǒng)備件。

C52781 Sloan Dektak V300-Si 12″Wafer Surface Profiler

C73574 MRSI 505 Assembly Work Cell Pick&Place System

K69474 Logitech LP50 Precision Lapping&Polish.System

C71289 Micrion 9100 Focused Ion Beam FIB Milling System

C73914 Varian Unity Inova 500 NMR Spectrometer System

C54479 Jeol JSM-IC848 Scanning Electron Microscope

C75409 Zeiss EM902A Transmission Electron Microscope

C69679 K&S 4524AD Digital Manual Ball Wire Bonder

C72437 Finnigan MAT 8230 Mass Spectrometer

A74871 Mydax 2VLH60W Water-Cooled Chiller/Heater

C68069 HP 83000 Digital Test System Model F660

G52281 Nanometrics Nanospec 9000 Film Analysis System

G40450 ADE Technologies Polar Kerr System

A69510 Logitech 1WBT2 Wafer Substrate Bonder,3 Station

G69555 Logitech 1WBS2 Wafer Substrate Bonder

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G54625 Asymtek A-612C Dispensing System

G50677 FK Delvotec 6320 Bonder System

C59111 Electroglas 2001CXE 6”Wafer Prober 2001CX 2001X

C69224 K&S 4522 Multi-Process Gold Wire Ball Bonder

A73230 Beckman P/ACE MDQ Capillary Electrophoresis Sys

C55921 YES Yield Engineering Sys YES5 Vapor Prime Oven

A73251 Kodak Image Station 4000MM Pro Imaging System

G70686 Multiline Technology Optiline Post X-Ray Machine

C59242 Electroglas 3001X 8″Wafer Prober Probe Station

C74218 PE Sciex API QStar Pulsar 1 Mass Spectrometer

A51532 Asymtek Millennium Series Dispensing System,600

C56237 Zevatech CT-3000 Pick and Place Machine

G54212 Asymtek A-618C Millennium Dispensing System

G66395 Hitachi S-2300 Scanning Electron Microscope

G54295 Asymtek Dispensing System

G75521 TA Inst.TGA2050 Thermogravimetr?ic Analyzer

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A70055 Thermo Nicolet Nexus 470 FT-IR,Centaurus Scope

A69734 LC Packings Famos,Switchos,Ultimate HPLC Sys

AE43005 Synax SX-141 Pick and Place Wafer Handler

AN43004 Alessi 6″Prober XYZ w/Microscope,Extras

A58421 Wentworth Labs 8″Prober MM2004(0-043-0001)

C69531 Rudolph AutoEL III 2B 4A Automatic Ellipsometer

C69866 K&S 4129 Vertical Feed Wedge Bonder w/Heated Tip

A73561 Cincinnati Test Systems Sentinel M24 Leak Test

C57559 Tokyo Seimitsu TSK A-WD-4000A Wafer Dicing Saw

A74058 Yamato Ohkawara DL-41 Spray Dryer

L66981 Disco Corp Automatic Dicing Saw DAD-3D/8

C71085 Gaertner Scientific Corp.L115 S Ellipsometer

C70347 Solid State Measurements CV Test Analysis System

C69865 K&S 4124 Gold Ball Wire Bonder w/LWD Microscope

C69864 K&S 4124 Gold Ball Wire Bonder w/Negative E.F.O.

C69692 K&S 4124 Thermosonic Gold Ball Wire Bonder

C28990 Orthodyne 20R Wire Bonder w/Nikon SMZ-1 Scope