西门子6ES7518-4AP00-0AB0

6ES7518-4AP00-0AB0

我们已经知道有的FCS是由PLC发展而来，而有的FCS是由DCS发展而来，那么，今天FCS已走向实用化，PLC与DCS前景又将如何？

　　PLC于60年代末期在美国首先出现，目的是用来取代继电器，执行逻辑、计时、计数等顺序控制功能，建立柔性程序控制系统。1976年正式命名，并给予定义：PLC是一种数字控制电子计算机，它使用了可编程序存储器储存指令，执行诸如逻辑、顺序、计时、计数与演算等功能，并通过模拟和数字输入、输出等组件，控制各种机械或工作程序。经过30多年的发展，PLC已十分成熟与完善，并开发了模拟量闭环控制功能。

　　PLC在FCS系统中的地位似乎已被确定并无多少争论。PLC作为一个站挂在高速总线上。充分发挥PLC在处理开关量方面的优势。另外，火力发电厂辅助车间，例如补给水处理车间、循环水车间、除灰除渣车间、输煤车间等，在这些车间的工艺过程多以顺序控制为主。PLC对于顺序控制有其的优势。编者以为，辅助车间的控制系统应以遵循现场总线通讯协议的PLC或能与FCS进行通讯交换信息的PLC为优选对象。

Nortel 380-24F AL4512A01 4 x AA1419013 16 x AA1419014

BayStack Switch with 24 x 1000Base-SX Gbic's

Nortel NTPM17AB module for Optera Metro 5000 - 

NORTEL NTCA04FK OPTERA OC-192 WDM REGENR TRMTR SNT4ME1

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NORTEL NTCA04FP OPTERA OPTA-LH 10G RGRCVR UN WMR3F50

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Nortel AL4500E12-e6 POE routing switch 4550T 48 port

Nortel Meridian Mail

Nortel Baystack BS5520-24T-PWR 5520 AL1001A06 216814

Nortel Baystack BS5520-24T-PWR 5520 AL1001A06-E5 (EUED)

20 Nortel I2004 NTDU82BA NTDU82 Icon Keys w PC PORT PS

NORTEL PASSPORT 8692SF ROUTING MODULE DS1404065

Agilestar - AA1419026-E5-AS - For Nortel -  in Box

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MCK Citel E-GWY2T-SUM 24 Pt Nortel Avaya PBXGateway II

* WE SPEAK MCK * 2 PORT T1 * OVERNIGHT OPTION *

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Agilestar - AA1419025-E5-AS - For Nortel -  in Box

IBM 32R1868 4 port Nortel Layer 2-7 Gigabit Module

Nortel/Avaya OPT11C Release 4.0t Succession NAPNS

Nortel/Avaya OPT11C Release 4.0t Succession NACCS 

72 Digital sets, 192 Analog sets

Avaya / Nortel BCM400 NT7B10AAFH - N0015222 3.7 (2 NTBB

IBM NORTEL 6-PORT 10GB ETHERNET SWITCH MODULE 39Y9265

 Nortel Ethernet Routing Switch 4550t Phone System

Nortel BCM200 4.0 Base System - Standard - NT7B10AAFU

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NORTEL 4p GE SFP Module NTNA50AA NTNA5002 

Nortel Meridian NT5C07AC 50 amp Rectifier

Nortel Package #4 8 Lines, 24 Ext,4 Phones,Voicemail

NORTEL ETHERNET ROUTING SWITCH 4550T WITH AL4500E02E6

1 Nortel BCM400 3.7 BCM 400 R3.7 64vm

NORTEL CORE CIRCUIT NTLX03AB OC-3 RTF NTLX08AB NTLX05AB

1 Nortel BCM50 r5 8x28 BCM 50 5.0 r5.0 4x12 + 4x16 16vm

with updated patches loaded

Nortel CallPilot 150 96 Mailboxes Call Pilot Voicemail 

Call Center Application Enabled

6100 M3 MCU 8-port Nortel Meridian 1 and Universal Digi

IBM 39Y9267 Nortel 10 Gb Ethernet Switch Module for IBM

 in box Nortel DS1402001 8010 Passport 8600

1 Nortel BCM50 r3 4x4x8 BCM 50 3.0 r3.0 2vpgwy MCDN ICC

with updated patches

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Nortel Shasta 5000 BSN NTJT29CB 02 - SSC-II Subscriber 

Nortel Networks DS1404093 Passport 8348GTX Module

48 Port Ethernet Module 8348GTX - Mint Condition

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40  Nortel I2004 IP Phone NTEX00BB NTEX00 FirmwareUp

Northern Telecom NTRB33AA Fiber Junctor Nortel NTRB33AA

Nortel Option 11 PBX Phone System with 56 phones

32R1783-Nortel 10 Gb Uplink Ethernet Switch Mod 32R1785

for IBM BladeCenter 8852,8677,8720,8730,FRU PN 32R1785

Nortel Contivity 2700 - DM1401104 Extranet VPN Router

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Agilestar - AA1419051-E6 - For Nortel -  in Box

SR2104010E5 Nortel NM-1DS3 Module 3120 Clear Chan T3

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Tasman 1450 2- 10/100 8- E1/T1 1- HSSI Nortel Router

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 Surplus Nortel 8608GBE DS1404038 1000BaseX GBIC MOD

Nortel 5520-48T-PWR Ethernet Routing Switch ~STSI

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Nortel Norstar Meridian BCM 50 NTBU0972 VOIP T7316e

23 YEARS THE PHONE CONNECTION HIGHEST FEEDBACK RESELLER