描述

屏蔽:一般采用金屬外殼屏蔽，將PLC系統(tǒng)內(nèi)置于金屬柜之內(nèi)。金屬柜外殼可靠接地，能起到良好的靜電、磁場(chǎng)屏蔽作用，防止空間輻射干擾。

布線(xiàn):強(qiáng)電動(dòng)力線(xiàn)路、弱電信號(hào)線(xiàn)分開(kāi)走線(xiàn)，并且要有一定的間隔;模擬信號(hào)傳輸線(xiàn)采用雙絞線(xiàn)屏蔽電纜。

3.2PLC控制系統(tǒng)的軟件設(shè)計(jì)

在進(jìn)行硬件設(shè)計(jì)的同時(shí)可以著手軟件的設(shè)計(jì)工作。軟件設(shè)計(jì)的主要任務(wù)是根據(jù)控制要求將工藝流程圖轉(zhuǎn)換為梯形圖，這是PLC應(yīng)用的最關(guān)鍵的問(wèn)題，程序的編寫(xiě)是軟件設(shè)計(jì)的具體表現(xiàn)。在控制工程的應(yīng)用中，良好的軟件設(shè)計(jì)思想是關(guān)鍵，優(yōu)秀的軟件設(shè)計(jì)便于工程技術(shù)人員理解掌握、調(diào)試系統(tǒng)與日常系統(tǒng)維護(hù)。

（1）PLC控制系統(tǒng)的程序設(shè)計(jì)思想。由于生產(chǎn)過(guò)程控制要求的復(fù)雜程度不同，可將程序按結(jié)構(gòu)形式分為基本程序和模塊化程序。

基本程序:既可以作為獨(dú)立程序控制簡(jiǎn)單的生產(chǎn)工藝過(guò)程，也可以作為組合模塊結(jié)構(gòu)中的單元程序;依據(jù)計(jì)算機(jī)程序的設(shè)計(jì)思想，基本程序的結(jié)構(gòu)方式只有三種:順序結(jié)構(gòu)、條件分支結(jié)構(gòu)和循環(huán)結(jié)構(gòu)。

模塊化程序:把一個(gè)總的控制目標(biāo)程序分成多個(gè)具有明確子任務(wù)的程序模塊，分別編寫(xiě)和調(diào)試，最后組合成一個(gè)完成總?cè)蝿?wù)的完整程序。這種方法叫做模塊化程序設(shè)計(jì)。我們建議經(jīng)常采用這種程序設(shè)計(jì)思想，因?yàn)楦髂K具有相對(duì)獨(dú)立性，相互連接關(guān)系簡(jiǎn)單，程序易于調(diào)試修改。特別是用于復(fù)雜控制要求的生產(chǎn)過(guò)程。

（2）PLC控制系統(tǒng)的程序設(shè)計(jì)要點(diǎn)。PLC控制系統(tǒng)I/O分配，依據(jù)生產(chǎn)流水線(xiàn)從前至后，I/O點(diǎn)數(shù)由小到大;盡可能把一個(gè)系統(tǒng)、設(shè)備或部件的I/O信號(hào)集中編址，以利于維護(hù)。定時(shí)器、計(jì)數(shù)器要統(tǒng)一編號(hào)，不可重復(fù)使用同一編號(hào)，以確保PLC工作運(yùn)行的可靠性。

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(chǎng)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)》
?
5,《智能型消防供水控制系統(tǒng)》

6,《化工廠(chǎng)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(xiàn),變電站綜合自動(dòng)化控制系列

本特利，英維思，伍德沃德，?？怂共_、西屋、瑞恩、施耐德莫迪康、ABB、AB、西門(mén)子、摩托羅拉、GE發(fā)那科、安川、博世力士樂(lè)，ACSO，力士樂(lè)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。

NEW GILBARCO PARTS K93682 FIRMWARES/SWITCH MEMBRANES++

SIEMENS 3-POLE 3RV 30A CIRCUIT BREAKER 3RV1742-5ED10

NEW 3300’SPOOL HERAEUS HIGH TEMP.NICKEL SENSOR CABLE

NEW 1000’SPOOL BELDEN 82262 877 RG62/U 93ΩCOAX CABLE

48 NEW HAMILTON SCHOOLMATE HA7 STEREO/MONO HEADPHONES

QTY 200 CHROME SIDE TANK MOUNT TOILET FLUSH HANDLES

25 RFS CELLFLEX SCF12-011 HARDLINE CONNECTORS COAX 1/2

QTY 593 NEW EVIDENCE GRADE CD-R CDR DISKS 80MIN 700MB

500’SPOOL 15 CONDUCTOR 24 GAUGE COMPUTER CABLE C0746A

NEW BALLUFF MICROPULSE TRANSDUCER BTL5-M1-M0305-R?-S32

NERA 5GHz HIGH POWER TRANSCEIVER FOR EVOLUTION ODU?

NEW AMAT APPLIED MATERIALS GAS DISTRIBUTION PLATE,133

SPEAKMEN SEF-1800 COMBINATION FAUCET/EYEWASH STATION

WirelessLogix OPTis Autonomous EVDO OPTisRD HSP01 GPS

INTRUDALERT 5500 SECURITY CENTRAL CONTROL SYSTEM UNIT

LUCENT STINGER STGRRTI-LIM-T1-?8 CARD/BOARD/MODULE

NICE NORTEL MERIDIAN 2.5GB TAPE DRIVE UNIT NT6D45CA

GOOD NERA 23GHz FU23AAA0A-11UA EVOLUTION SERIES ODU

NICE LOT NORTEL MERIDIAN SYSTEM BOARDS/CARDS NT0966AA++

ROLL DPOINT POLYMER MEMBRAGE W/COATING SOLUTION HVAC

GENTEQ MOT09192 CONDENSER FAN MOTOR FOR TRANE HVAC

NICE NORTEL NT3921GE 824-849MHZ 800 BAND FULL DUPLEXER

NEW MATRIX ACD3X TX5 TREADMILL MOTOR CONTROL 110V

QTY 20 NEW TYCO ACC338UMM20 MAGNETIC CONTACTORS 30A 3P

BELL&GOSSETT 650PF 208V DUAL 115V PUMP CONTROLLER

NEW AMAT APPLIED MATERIALS VALVE GATE SEAL 35 x 336mm

CASE LUBRIPLATE FMO-85 FOOD GRADE EQUIPMENT LUBRICANT

SPELLMAN CA354-01202 HVSC CA356-00115 X-RAY COMPONENT?

NEW ADC ANALOG DEVICE CONTROLLER ZITON MADULA ZM2 ZM8

80 HP UNIVERSAL MONOCHROME LY CHIP/SMARTCHIP XHU1324LY

AMAT APPLIED MATERIALS CHAMBER EXHAUST POCKET SHIELD

QTY 10 NEW ABB B6 MINI CONTACTORS B6-22-00-80 240V

40 NEW TRENDNET TEW-L202 LMR200 WIRELESS ANTENNA CABLES

1000’18/4 18 GAUGE 4C CL3P/CMP COMMUNICATIONS CABLE

HUBBELL OPTICHANNEL FCR350SP54R RACK MOUNT ENCLOSURE

ACCQCOMM TELEDYNE ADFM DIGITAL INTERFACE MONITOR MODULE

ALCATEL-LUCENT/ANDREW UMTS BTS 1120 BASE STATION

NEW UNDERMOUNT BATHROOM SINK W/CHROME WIDESPREAD FAUCET

QTY 5 NEW HUBBELL 17kV MCOV ELBOW ARRESTERS 225ELA21

NEW STERLING THREAD ROLLING DIE SET 1/2-20 UNR X8

ASTEC 73-553-0005 380V IN/600W 5V POWER MODULE

1500 SENSORMATIC MICROGATOR HARD SECURITY TAGS

GAMEWELL DACT-E3 DIGITAL ALARM COMMUNICATOR TRANSMITTER

ANDREW RF TOWER MOUNTED AMPLIFIER E15Z01P05 TMA 1900

HARLEY OEM MOUSE TRAP CLUTCH COVER CHROME 1952 KNUCKLEH

KYOCERA 2FA93021 FUSER/FIXING ASSY FOR KM-7530 COPIER

NEW MARATHON ELECTRIC BK3074 3-PHASE 1/2-3/4HP MOTOR

AT&T/LUCENT/PAR?TNET 539A9 R4.1 PROCESSOR W/103E9/206EC

NEW HONEYWELL TDC3000 MP-ZLCNIO LCN I/O CARD UPGRADE

48x PRIORI 043J-WH1 Junction Box 4/Under Cabinet Lights

48x PRIORI 043J-BR1 Junction Box 4/Under Cabinet Lights

4 ERTELALSOP DISC-PAK LIQUID FILTERS CARTRIDGES 11-1/4

SPOOL SLATE 100’ALPHA 3247 3C 600V 16AWG CABLE/WIRE

SPOOL SLATE 100’ALPHA 3248 4C 600V 16AWG CABLE/WIRE

40 NEW VIASYSTEMS KALEX BLANK PRINTED CIRCUIT BOARDS

NEW Transition Networks CFETF1014-105 Converter Module

COOPER WHEELOCK SAFEPATH 4 REMOTE MICROPHONE STATION

15 NEW KIDDE 60-9196984-000 Co2 SYSTEM BRASS VENT PLUGS

NICE MOTOROLA X502 INTEGRATED SITE CONTROLLER CLN1441B

1000’SPOOL ALPHA 1292C COMMUNICATIONS CABLE 2C/22AWG

NEW LS PHOTO STUDIO PRO 2 LIGHT&3 MUSLIN BACKDROP KIT

JUKI MC-9 SEWING MACHINE VACUUM/FILTER ATTACHMENT KIT

NEW AMETEC 24319810 CONTROL PANEL BOARD TNCTM100KIAL

QTY 72 NEW PHILIPS 4-WAY GOLD COAXIAL CABLE SPLITTERS

NORTEL PERIPHONICS TPPB-1000 NTV15631E5 DTC MODULE

VINTAGE SKELLY SUPREME MOTOR OIL STICK MATCHES W/BOX

Enlarge

NEW FUSION UV SYSTEMS PWB/POWER SUPPLY BOARD 558591-A

QTY 12 NEW BURNDY HYDROREDUCER IN-LINE REDUCER SPLICERS

NEW 1000’SPOOL ESSEX 18AWG SERIES 6 HDTV COAX CABLE

NORTEL NORSTAR/LUCENT NTAX88CA PCB BOARD/CARD NTAX88

6 NEW GE CMH70/U/830/MED 70W CERAMIC METAL HALIDE BULBS

NEW 500’PULL BOX PROCONNECT RG6/U HD COAX CABLE 3GHZ

40 ROLLS AIRTECH VACUUM BAGGING SEALING TAPE 1/2 x 25′

GALLON CHESTERTON 690 FG FOOD GRADE EQUIPMENT LUBRICANT

10 NEW DINEX DX1S03D SOLAR SERVER CAFETERIA TRAYS IVORY