在40年代，過程控制是基于3～15PSI的氣動標(biāo)準(zhǔn)信號。其后，由于4～20mA模擬信號的使用，使得模擬控制器得到了廣泛應(yīng)用，但是并不是所有的傳感儀表和驅(qū)動裝置都使用統(tǒng)一的4～20mA信號。70年代，由于在檢測、模擬控制和邏輯控制領(lǐng)域率先使用了計算機，從而產(chǎn)生了集中控制。進入80年代，由于微處理器的出現(xiàn)，促使工業(yè)儀表進入了數(shù)字化和智能化的時代，4～20mA模擬信號傳輸逐步被數(shù)字化通信代替，加之分布式控制以及網(wǎng)絡(luò)技術(shù)的迅速發(fā)展，促進了控制、調(diào)度、優(yōu)化、決策等功能一體化的發(fā)展。然而由于檢測、變送、執(zhí)行等機構(gòu)大都采用模擬信號連接，其傳送方式是一對一結(jié)構(gòu)，這使得接線復(fù)雜，工程費用高，維護困難，而信號傳輸精度底，易受干擾，儀表互換性差，這都阻礙了上層系統(tǒng)的功能發(fā)揮。另一方面，由于智能儀表的功能遠(yuǎn)遠(yuǎn)超過了現(xiàn)場模擬儀表，如對量程和零點進行遠(yuǎn)方設(shè)定，儀表工作狀態(tài)實現(xiàn)自診斷，能進行多參數(shù)測量和對環(huán)境影響的補償?shù)?。由此可見，智能儀表和控制系統(tǒng)的發(fā)展，都要求上層系統(tǒng)和現(xiàn)場儀表實現(xiàn)數(shù)字通信。

Susol Cerus TS800HU 500 Amp 3p 65k 480v Breaker With 220 ~ 240v Shunt

Susol Cerus TS800HU 500 Amp 3p 65k 480v Circuit Breaker With 120v Shunt

Susol Cerus TS800HU 500 Amp 3p 65k 480v Circuit Breaker With 480v Shunt

Susol Cerus TS800HU 600 Amp 3p 65k 480v Breaker With 220 ~ 240v Shunt

Susol Cerus TS800HU 600 Amp 3p 65k 480v Circuit Breaker With 120v Shunt

Susol Cerus TS800HU 600 Amp 3p 65k 480v Circuit Breaker With 480v Shunt

Susol Cerus TS800HU 800 Amp 3p 65k 480v Breaker With 220 ~ 240v Shunt

Susol Cerus TS800HU 800 Amp 3p 65k 480v Breaker With 220 ~ 240v UVR

Susol Cerus TS800HU 800 Amp 3p 65k 480v Breaker With 380 ~ 440v UVR

Susol Cerus TS800HU 800 Amp 3p 65k 480v Breaker With 440 ~ 480v UVR

Susol Cerus TS800HU 800 Amp 3p 65k 480v Circuit Breaker With 120v Shunt

Susol Cerus TS800HU 800 Amp 3p 65k 480v Circuit Breaker With 480v Shunt

Susol Cerus TS800HU ATU 500 Amp 3p 65k 480v Circuit Breaker With 12v Shunt

Susol Cerus TS800HU ATU 500 Amp 3p 65k 480v Circuit Breaker With 24v Shunt

Susol Cerus TS800HU ATU 500 Amp 3p 65k 480v Circuit Breaker With 48v Shunt

Susol Cerus TS800HU ATU 500 Amp 3p 65k 480v Circuit Breaker With Auxiliary

Susol Cerus TS800HU ATU 600 Amp 3p 65k 480v Circuit Breaker With 12v Shunt

Susol Cerus TS800HU ATU 600 Amp 3p 65k 480v Circuit Breaker With 24v Shunt

Susol Cerus TS800HU ATU 800 Amp 3p 65k 480v Circuit Breaker

Susol Cerus TS800HU ATU 800 Amp 3p 65k 480v Circuit Breaker With 120v UVR

Susol Cerus TS800HU ATU 800 Amp 3p 65k 480v Circuit Breaker With 12v Shunt

Susol Cerus TS800HU ATU 800 Amp 3p 65k 480v Circuit Breaker With 24v Shunt

Susol Cerus TS800HU ATU 800 Amp 3p 65k 480v Circuit Breaker With 24v UVR

Susol Cerus TS800HU ATU 800 Amp 3p 65k 480v Circuit Breaker With 48v Shunt

Susol Cerus TS800HU ATU 800 Amp 3p 65k 480v Circuit Breaker With 48v UVR

Susol Cerus TS800HU ATU 800 Amp 3p 65k 480v Circuit Breaker With Auxiliary

Suss Microtec Standard Vespel Wedge Cam 200AA160-21

SUTHERLAND INK RUB TESTER

Suzuki Supermini 105cc dirtbike 2006 2500

SVG / COATER Model SVG-8126PC/ 8136 HPO PROGRAM OPERATION CONTROL

SVG 851-9558-006 Reticle Handler Assembly Long Stroke

SVG 90S Shuttle Tranfer Arm 99-43012-01

SVG 99-80266 Station CPU resist coater ASML litho

SVG 99-80266 Station CPU resist coater ASML litho, sealed bag

SVG Danaher Linear Air Bearing Stage 851-0448-001A

SVG/ASML 859-0541-008 A Motor Drive Assy.

SVII BOARD TYPE A E4809-770-065-A/ DRIVE BLII-D50-30A TOP BOARD

SVX020A14A1B1 VARIABLE FREQUENCY DRIVE VFD EATON CUTLER HAMMER 20HP DRIVE (f)

SVX025A1 4A1B1 Cutler Hammer Adjustable Frequency Drive

SVX075A1-4A1N1 Cutler Hammer VFD SVX9000 Motor Frequency Drive SVX075A14A1N1

SW-475TR M/A-Com SPDT High Isolation Switch, 0.5-3.0Ghz

SWAGELOK TI-UT24GA24GA24-360-0223 Coreflex U Series PFA Hose w/Titanium end

Swanson-Erie Agile Slim Assembly Systems, Racetrack Indexer, Rotary Table

SWECO 2-1/2 HP MOTION GENERATOR PLUS 460 VAC 1160 RPM 21 FRAME 3 PHASE

SWEED CA7000 INDUSTRIAL GRADE SCRAP RECYCLE MOBILE CABLE CUTTER HYDRAULIC SHEAR

SWEO ENGINEERING 614-510-170 NSPP

SWIFT VISION ENGINEERING VISION SYSTEM

Swires TVA2000

SWITCH PRESSURE HYDRA-ELECTRIC PN 1036-2 Equivalent to: 136740-2-1 Honeywell

SWITCH, ETHERNET, 7 PORTS, 24V, 2832603 2295677

SWITCH, ETHERNET, 8 PORTS, 24V, 2832577 2295675

SWITCH; SAFETY 600AMP 3POLE 600VAC NEMA-1; NON-FUSE - THN3366

Switchback 6600 Power Supply P/N 11147-B-E50JJ

switchgear section 1 of 2

Switchgear Section 2 of 2

SWT508-PX Compter Wire Cable Stripping Cutting Peeling Sub-line Machine

SX-16 Matrix Mu