描述
FCS系統(tǒng)的基礎(chǔ)是數(shù)字智能現(xiàn)場裝置
數(shù)字智能現(xiàn)場裝置是FCS系統(tǒng)的硬件支撐,是基礎(chǔ),道理很簡單,F(xiàn)CS系統(tǒng)執(zhí)行的是自動控制裝置與現(xiàn)場裝置之間的雙向數(shù)字通信現(xiàn)場總線信號制。如果現(xiàn)場裝置不遵循統(tǒng)一的總線協(xié)議,即相關(guān)的通訊規(guī)約,不具備數(shù)字通信功能,那么所謂雙向數(shù)字通信只是一句空話,也不能稱之為現(xiàn)場總線控制系統(tǒng)。再一點(diǎn),現(xiàn)場總線的一大特點(diǎn)就是要增加現(xiàn)場一級控制功能。如果現(xiàn)場裝置不是多功能智能化的產(chǎn)品,那么現(xiàn)場總線控制系統(tǒng)的特點(diǎn)也就不存在了,所謂簡化系統(tǒng)、方便設(shè)計(jì)、利于維護(hù)等優(yōu)越性也是虛的。
(3) FCS系統(tǒng)的本質(zhì)是信息處理現(xiàn)場化
對于一個(gè)控制系統(tǒng),無論是采用DCS還是采用現(xiàn)場總線,系統(tǒng)需要處理的信息量至少是一樣多的。實(shí)際上,采用現(xiàn)場總線后,可以從現(xiàn)場得到更多的信息。現(xiàn)場總線系統(tǒng)的信息量沒有減少,甚至增加了,而傳輸信息的線纜卻大大減少了。這就要求一方面要大大提高線纜傳輸信息的能力,另一方面要讓大量信息在現(xiàn)場就地完成處理,減少現(xiàn)場與控制機(jī)房之間的信息往返??梢哉f現(xiàn)場總線的本質(zhì)就是信息處理的現(xiàn)場化。
減少信息往返是網(wǎng)絡(luò)設(shè)計(jì)和系統(tǒng)組態(tài)的一條重要原則。減少信息往返常常可帶來改善系統(tǒng)響應(yīng)時(shí)間的好處。因此,網(wǎng)絡(luò)設(shè)計(jì)時(shí)應(yīng)優(yōu)先將相互間信息交換量大的節(jié)點(diǎn),放在同一條支路里。
減少信息往返與減少系統(tǒng)的線纜有時(shí)會相互矛盾。這時(shí)仍應(yīng)以節(jié)省投資為原則來做選擇。如果所選擇系統(tǒng)的響應(yīng)時(shí)間允許的話,應(yīng)選節(jié)省線纜的方案。如所選系統(tǒng)的響應(yīng)時(shí)間比較緊張,稍微減少一點(diǎn)信息的傳輸就夠用了,那就應(yīng)選減少信息傳輸?shù)姆桨浮?br />
現(xiàn)在一些帶現(xiàn)場總線的現(xiàn)場儀表本身裝了許多功能塊,雖然不同產(chǎn)品同種功能塊在性能上會稍有差別,但一個(gè)網(wǎng)絡(luò)支路上有許多功能雷同功能塊的情況是客觀存在的。選用哪一個(gè)現(xiàn)場儀表上的功能塊,是系統(tǒng)組態(tài)要解決的問題。
考慮這個(gè)問題的原則是:盡量減少總線上的信息往返。一般可以選擇與該功能有關(guān)的信息輸出最多的那臺儀表上的功能塊。
產(chǎn)品承諾:
保?證?全新原裝進(jìn)口,
保?證?安全準(zhǔn)時(shí)發(fā)貨,
保?證售后服務(wù)質(zhì)量,
優(yōu)勢價(jià)格,大量現(xiàn)貨。
主營DCS系統(tǒng)配件
機(jī)器人系統(tǒng)配件
大型伺服系統(tǒng)配件
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YORK ROTARY SCREW COMPRESSOR W/YORK ISN CODEPAK
DYNATEC 510-6-P12-24 GLUE MACHINE USED*
GIANT LOT OF FUSES,GOULD SHAWMUT ,FUSETRON,BUSS,?
GOULDS ITT 1X1 1/4-6 COMMERCIAL WATER PUMP 1/2 HP, NEW
RELIANCE ELECTRIC 3RA2004 SERVO DRIVE USED
RELIANCE ELECTRIC BRUSHLESS AC SERVO CONTROLLER, USED
GRACO 205395, 50:1 FIREBALL BARRELL 425 AIR PUMP, USED
MAGNETEK L717 GP+ 10 HP E PLUS ADJUSTABLE SPEED
RELIANCE ELECTRIC 3RA2002 SERVO DRIVE USED
TEST GUAGE CART – 3 GAUGES, 3 DRAWERS, USED
RELIANCE ELECTRIC 3RA2001 SERVO DRIVE USED
RELIANCE ELECTRIC 3RA2008U SERVO CONTROLLER USED
WESTINGHOUSE LD3600WK 600A CIRCUIT BREAKER USED
LIGHTNIN ND-4A MIXER, USED
AIR DRAULICS 10002510 CYCLINDER ,USED
VALMET PIC-200/100-170?-31488 SS PNEUMATIC CYLINDER, NEW
WESTINGHOUSE HKD3400F CIRCUIT BREAKER USED
VIKING HL4125 HYDRAULIC PUMP, 1 5/8x 11/16 SHAFT, USED
VON RUDEN 90-464 RATIO 1:1:1 GEAR BOX, USED
ROSEMOUNT ANALYTICAL pH MODEL 1003 UNILOC DIVISION,NEW
GENERAL ELECTRIC E10F2 1HP ELECTRIC MOTOR NEW
EFDYN MASA 2 X 6 PS HV 4598 SHOCK ABSORBER NEW
GENERAL ELECTRIC 5KC49PN0446X 1 HP ELECTRIC MOTOR, NEW
ELECTROMOTIVE SBPN-6-WH SWITCH NEW
RELIANCE ELECTRIC 3RA2004 SERVO DRIVE USED
ALLEN-BRADLEY 2192F-BJC-24J MOTOR CONTROL CTR UNIT USED
ALLEN-BRADLEY 2192F-BJC-24-11?0 MOTOR CTR UNIT USED
ALLEN-BRADLEY 2154B-AAB-38 MOTOR CTRL CTR USED
ALLEN-BRADLEY 2112B-BDBD-24J-?98-106-107 MOTOR CTRL CTR
ALLEN-BRADLEY 2112B-BDBD-1-4G?-24J-98-106-107 MOTOR CTR
WESTINGHOUSE JDB3225W 225A CIRCUIT BREAKER/JDB 25K USED
BOSTON GEAR 88KRF724-408-87?-J MOTOR USED
GENERAL ELECTRIC DS3827BS6 THYRISTOR, NEW
HYTROL 4AC 20-1 RH GEAR REDUCER NEW
KLOCKNER-MOELLE?R N 11-400-CNA CIRCUIT BREAKER USED
NIBCO WD-3110-0 VALVE NEW
FIFE CSP-01-06 ESU01 SENSOR USED
TOP TECH TT-E75-3SP2 3/4 HP ELECTRIC MOTOR , NEW
IDT PERIPHERAL CONTROL UNIT POWER SUPPLY USED
ALLEN-BRADLEY 2192F-D23444O/3?-2E MOTOR CTRL CTR USED
LOT OF 6 OMRON G3PA-210B SOLID STATE RELAYS, USED
ALLEN-BRADLEY 1771-AB CHASSIS/WITH MODULES USED
FASCO E2204 1/3 HP ELECTRIC MOTOR , NEW
GENERAL ELECTRIC L737BS 1/4 HP ELECTRIC MOTOR, NEW
RELIANCE/TIGEAR 7916130DB 1.39HP GEARMOTOR USED
GENERAL ELECTRIC L736CS 1/4HP MOTOR NEW
DODGE TIGEAR MR34619 1HP GEAR BOX, USED
NIHON SEIKI BN-6041-63-30L PNEUMATIC CYLINDER, NEW
EATON IDT 92-00314-09 UNIVERSAL PCU, USED
ALLEN-BRADLEY 2192F-U4-26J MOTOR CONTROL CTR UNIT USED
E G D MFG SS20 2×2 INDL SHOCK ABSORBER CYLINDER, NEW
ALLEN-BRADLEY 160-BA01NSF1P1 STARTER USED
ALLEN-BRADLEY 1771-ARC REMOTE I/O ADAPTER MODULE
LOT OF 4/ OMRON D4A-2501N LIMIT SWITCH USED
INDUSTRIAL CONTROL CFM61 SWITCH NEW
HBM PLC-XX200 LOAD CELL, NEW*
GE DS3820HSM HEAT SINK, NEW
WESTINGHOUSE JDB3225W CIRCUIT BREAKER USED
ACOPIAN A24MT350 DC POWER SUPPLY USED
RELIANCE ELECTRIC 3RA2002 SERVO DRIVE USED
RELIANCE ELECTRIC 3RA2002 SERVO DRIVE USED
HIMMELSTEIN 6-201 TRANSDUCER USED
ALLEN-BRADLEY 1771-P2 POWER SUPPLY USED
TELEMECANIQUE LB1 LB03P MOTOR STARTER USED
LOT OF 2/ ALLEN-BRADLEY 509-B0D STARTER USED
KLOCKNER MOELLER DIL1M STARTER USED
ALLEN-BRADLEY 700-RTA10L100A1 RELAY USED
ALLEN-BRADLEY 1771-P2 POWER SUPPLY, USED
LOT OF 2/ LEVITON 2336 FLANGED OUTLET NEW
WESTINGHOUSE FD-K 100A CIRCUIT BREAKER USED
SHARK/RELIANCE ELECTRIC 45C922 SLOT RACK USED
WARNER ELECTRIC MC4 PRECISION TORK, USED
SMC NAQ5000 VALVE USED
SMC NAR825-N12 VALVE USED
SMC VP7-8-FG-S VALVE USED
3 ALLEN-BRADLEY 1794-ASB FLEX I/O POWER SUPPLY, USED
SIEMENS 1P GES7 221-1EF00-0XA0 MODULE USED
SIEMENS 1P GES7 222-1EF00-0XA0 MODULE USED
SMC RSH50-30BL CYLINDER NEW
VERSA VIS-2302 PNEUMATIC VALVE, NEW
SMC NVFS2200-1F PNEUMATIC VALVE, NEW
SMC NVFS2100-5FZ PNEUMATIC VALVE, NEW
SMC NVS4114-0009D PNEUMATIC VALVE, new
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NORGREN S-A03205C CYCLINDER USED
PIAB XLC60 3301044 VACUUM PUMP,USED
SMC XTO-1239 VALVE NEW
ABB GCB0432 R2 DRIVE USED
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