描述

共享型以太網或半雙工以太網的媒體訪問是由載波偵聽多路訪問/碰撞檢測（CSMA/CD）確定的。在半雙工的通訊方式下，發(fā)送和接收不能同時進行，否則數(shù)據會發(fā)生碰撞。站點發(fā)送前，首先要看是否有空閑的信道。發(fā)送時，站點還會在一段時間內收聽，確保在這一時間內沒有其它站點在進行同步傳送，最終本站發(fā)送成功。反之，發(fā)生碰撞，源站點發(fā)送阻塞信號加強碰撞。競爭站點延遲后（延遲時間由算法確定，是隨機的）重試。在這種機制下，所有站點和所有集線器都必須在同一碰撞域內。對工業(yè)以太網來說，10Mbps和100Mbps是最常用的。在10Mbps，全部采用雙絞線的以太網網絡中，與距離有關的概念有兩個，即網段（Segment）和網絡范圍(Network Diameter)。前者指連接兩個設備（集線器、交換機或主機）的距離，后者指網絡中兩個最遠端設備之間的距離。不管是10Mbps或100Mbps的網絡，網段的最遠距離不能超過100米?？紤]網絡延伸，最有用的規(guī)則就是5-4-3規(guī)則（僅僅針對10Mbps中繼器）。規(guī)則的內容如下：一個網絡最多有五個網段，四個中繼器，不多于三個的混合網段?；旌暇W段指的是同軸總線網段（已淘汰）。由于雙絞線網段的最遠距離是100米，最大網絡（網絡范圍）就是500米。

主營：世界知名品牌的PLC、DCS系統(tǒng)備件模塊

①Allen-Bradley(美國AB)系列產品》

②Schneider(施耐德電氣)系列產品》

③General electric(通用電氣)系列產品》

④Westinghouse（美國西屋）系列產品》

⑤SIEMENS(西門子系列產品)》

⑥銷售ABB Robots.FANUC Robots、YASKAWA Robots、KUKA Robots、Mitsubishi Robots、OTC Robots、PanasonicRobots、MOTOMAN Robots。

⑦estinghouse（西屋）：OVATION系統(tǒng)、WDPF系統(tǒng)、MAX1000系統(tǒng)備件。

⑧Invensys Foxboro（福克斯波羅）：I/A Series系統(tǒng)，F(xiàn)BM（現(xiàn)場輸入/輸出模塊）

順序控制、梯形邏輯控制、事故追憶處理、數(shù)模轉換、輸入/輸出信號處理、數(shù)

據通信及處理等。Invensys Triconex:冗余容錯控制系統(tǒng)、基于三重模件冗余（TMR）

結構的zui現(xiàn)代化的容錯控制器。

⑨Siemens(西門子)：Siemens MOORE，Siemens Simatic C1，Siemens數(shù)控系統(tǒng)等。

⑩Bosch Rexroth（博世力士樂）：Indramat，I/O模塊,PLC控制器,驅動模塊等。

◆Motorola（摩托羅拉）：MVME 162、MVME 167、MVME1772、MVME177等系列。

STAINLESS STEEL HOPPER 60 GALLON HEAT EXCHANGER&PUMP

CONDENSER,MICRO BREWERY,BIODIESEL,AIR DRYER,

EMERSON MOTOR CONTROL T-60 OPERATOR INTERFACE TERMINAL

CAMCO 601RDM4H24-330 ROTARY RDM INDEXER BALDOR 90V DC

FANUC A06B-0143-B075 AC SERVO MOTOR MODEL a12/3000

FANUC A06B-0127-B675 MODEL a6/2000 SERVO MOTOR#7000RS

ABB SIEMENS 1FK6083-6AZ21-9?ZZ9-Z SERVO MOTOR 150 KG

OMRON ZFV-CA45 COLOR SENSOR W/SFV-SC150 SENSEHEAD

THERMAL DYNAMICS PAK MASTER 50 PLASMA CUTTING SYSTEM

YOKOGAWA DD SERVO ACTUATOR DR1300A60 MOTOR#94RA0551C

MATTHEWS PRO-POINT P31 TOUCH SCREEN INTERFACE

MMC-SD-1.0-230 GIDDINGS&LEWIS CONTROL MODULE

SP1204 CONTROL TECHNIQUES UNIDRIVE

YOKOGAWA DD SERVO ACTUATOR DR1030B60 MOTOR#94RB39830

KENSOL MARKING EQUIPMENT HEAT FOIL PRESS HEAT STAMP

FANUC A06B-0127-B677 MODEL a6/2000 SERVO MOTOR#7000

FANUC A06B-0127-B575#7000 SERVO MOTOR a6/2000

FANUC A06B-0127-B577#7008 SERVO MOTOR a6/2000 REFUR.

BANNER A-GAGE EZ-ARRAY MEASURING SENSORS W/SOFTWARE

YT213001-BC/2 FANUC AXIS DRIVE UNIT NEW

FANUC A06B-0127-B675 MODEL a6/2000 SERVO MOTOR#7000

GRACO FIRE BALL SERIES B09D GREASE PUMP FOR 20 GAL DRUM

FLUID AUTOMATION INC.PNEUMATIC GREASE COMPRESSOR

GIDDINGS&LEWIS MMC 2-AXIS ANALOG UNIT W/MMC ETHERNET

OMRON GPC03 GRAPHIC PROGRAMMING CONSOLE,W/ACCESSORIES

HOFFMAN 2 DOOR ENCLOSURE W/ALLEN BRADLEY 60 AMP SWITCH

11800-PR01D STAR AUTOMATION SEQUENCE BOARD NEW

UNITED SILICONE UNI-PRINTER UP 300 PAD PRINTER W/TOOLS

YOKOGAWA PARKER COMPUMOTOR DYNASERV SR1030B62 DD SERVO

YOKOGAWA DD SERVO ACTUATOR DR1300A60 MOTOR#94RA0551C

FANUC A16B-2200-0842 MAIN CPU PCB BOARD

1551471 MTI-1 BRIDGEPORT INTERFACE CARD NEW

3169-108 EATON/LEBOW LOAD CELL NEW

A16B-1210-0970/?04B FANUC AXIS CONTROL BOARD NEW

10MAIO-16 DAYTRONIC BOARD LOGIC I/O BOARD NEW

LG10A65PIQ BANNER PHOTOELECTRIC LASER W/CABLE MQDC-830

STANLEY VIDMAR 4 DRAWER TOOL CABINET BALL BEARING SLIDE

GE FANUC AFE TECHNOLOGIES CONTROL PANEL IC752DFT000A

YOKOGAWA COMPUMOTOR 500 INDEXER W/CABLES&MANUALS

YOKOGAWA DARWIN DATA ACQUISITION UNIT DA100-D1-1M,S10

WEIGH-TRONIX 3275 CHECKWEIGHER DIGITAL SCALE 6 LB

FANUC VELOCITY CONTROL UNIT A06B-6050-H304

RCC48 GE CONTROLLER CARD

TAMAGAWA FA-CODER ENCODER TS5850 N60,5K-1X-3-8-108

GE FANUC 90-30 CPU PROCESSOR MODULE PN#IC693CPU331-CD

SIEMENS MICROMASTER 440 VFD 1.50 KW 6SE6440-2UD21-5?AA1

YOKOGAWA PARKER COMPUMOTOR DYNASERV SR1015B62 DD SERVO

A20B-1000-0560/?02B FANUC BOARD NEW

YOKOGAWA DARWIN DCV/TC/RTD INPUT MODULE DU100-11 S1

060-1430-06 HONEYWELL LOAD CELL SENSOR NEW IN BOX

9504-50 ALLEGRO VENTILATION BLOWER

REXROTH INDRAMAT COMMUNICATIONS MODULE RMK12.2-IBS-BKL

LSS-120/208-3Y LEA INTERNATIONAL SURGE SUPPRESSION NEW

ALLEN BRADLEY 1756-IF8/A ANALOG INPUT CONTROL LOGIX

MOTOMAN YASKAWA MRC JANCD-MSL02 MRC CARD NEW

ITW VORTEC CABINET COOLER MODEL 721 VENTURI COOLER NEW

A16B-1210-0940 FANUC SUB MEMORY BOARD NEW

C500-CT001 OMRON COUNTER CONTROLLER NEW

C500-CT001 OMRON COUNTER CONTROLLER NEW

TOKIMEC ELECTRONIC CONTROLLER MODEL EC-Y-S-1A-25 NEW

STNM-DR-040B(U)SANYO NUTRUNNER SERVO DRIVER

437D493 GE AUXILLARY MOTHER BOARD LIGHTING CONTROL

6454-5MO MEDAR FIRING BOARD NEW

75B49 STRUTHERS-DUNN OUTPUT MODULE NEW IN BOX

EATON LEBOW LOAD CELL 3397-200 W/OVERLOAD PROTECTOR NEW

QEL CTS-M5 TOXIC GAS TRANSMITTER/SENSOR MONITOR NEW

SENSOTEC IN-LINE AMPLIFIER PART#060-6827-02

BANNER MINI-SCREEN MSCA-1 LIGHT CURTAIN CONTROLLER

JANCD-MRY01 YASKAWA MOTOMAN PCB MOTION CONTROL BOARD

JANCD-MCP02-1 REV C YASKAWA CNC MOVEMENT CONTROL BOARD

JANCD-MIF05 YASKAWA YASNAC PC BOARD REV.B USED

JANCD-MEW02 REV B YASKAWA PC BOARD USED 1 AVAILABLE

JANCD-MCP01 YASKAWA PC BOARD USED

437D491 GE MOTHER BOARD LIGHTING CONTROL

TAMAGAWA SEIKI TS5858 N 5/5K-1X-ET5-3-9.5?2-0 FA-CODER

503-17132-00 GIDDINGS&LEWIS PIC TURBO PROCESSOR

UM840 NACHI BOARD NEW

MKS 0248A-01000SV GENERAL PURPOSE FLOW CONTROL VALVE

57701-481 DURANT DIGITAL BIDIRECTIONAL COUNTER NEW