我们新研制出一种用于纸浆白度测定的智能白度仪，该仪表采用西门子公司生产的S7-224 CPU结合软件功能进行数据处理，具有较好的可靠性、重复性、精确度和稳定性。为了使其能与其它智能设备之间实现通信，我们将通过现场总线技术把它连接到网络中，使它成为造纸厂现场总线控制系统的一部分。

2.现场总线的选择

  2.1现场总线技术的选择

  现场总线集控制技术、计算机技术、通信技术于一体，是当今自动化领域技术发展的热点之一。这项技术可将多个智能控制仪表连接成网络系统，实现分布式计算机控制，提高检测和控制精度，改善系统的动态响应速度，提高系统安全性，从而得到了广泛的应用。

  近年来，几种有影响的现场总线技术已在一些特定的应用领域里显示出各自的优势。在此，我们选定了现为德国和欧洲标准的PROFIBUS（Process Fieldbus）现场总线。一方面由于它是目前数据传输率快的一种现场总线，传输率高可达12Mbps，另一方面它能够很好的与西门子的传动设备相配合，并与西门子PLC（Programmable Logic Controller）结合紧密且组态简便。

  2.2 PROFIBUS现场总线简介

  参照ISO/OSI参考模型,PROFIBUS现场总线只包含物理层、数据链路层和应用层。由PROFIBUS-DP，PROFIBUS-FMS， PROFIBUS-PA组成PROFIBUS系列。

  PROFIBUS-DP：经过优化的高速、廉价的通信连接，专为自动控制系统和设备级分散I/O之间通信设计，使用PROFIBUS-DP模块可取代价格昂贵的24V或0～20mA并行信号线。用于分布式控制系统的高速数据传输。

  PROFIBUS-FMS ：解决车间级通用性通信任务，提供大量的通信服务，完成中等传输速度的循环和非循环通信任务，用于纺织工业、楼宇自动化、电气传动、传感器和执行器、可编程序控制器、低压开关设备等一般自动化控制。

  PROFIBUS-PA专为过程自动化设计，标准的本质安全的传输技术，实现了IEC1158-2中规定的通信规程，用于对安全性要求高的场合及由总线供电的站点。

  本设计中采用的是PROFIBUS-DP标准，PROFIBUS-DP（或DP标准）是由欧洲标准EN50170定义的一种远程I/O通信协议。DP表示分布式外围设备，亦即远程I/O。PROFIBUS-DP还用到了应用层接口（ALI），ALI将过程对象转换为通信对象。

TOTAL CONTROL COMMUNICATION MODULE FOR 5& 6" DEVICENET,FANUC QPJ-DVN-202 CO
        MAZAK & FANUC LOG-IN L-BTR REV A CNC PCB BOARD
        MAZAK & FANUC CNC CONTROL PANEL 21146004831
        MAZAK & FANUC CNC CONTROL PANEL 21146003973
        IC660TBD023K FANUC GE FOR IC660EBD021E CC
        IC660TBD023B FANUC GE BLOCK 24VDC SINK I/O 16 CIRC W/2/3 SENSOR COMPATB BI
        IC660BBD023 GE FANUC IC660TBD023B IC660TBD023K FOR IC660EBD021E BJ
        IC660BBD023 GE FANUC BLOCK 24VDC SINK I/O 16 CIRCUITS, 2/3 WIRE SENSOR C BI
        IC610MDL179A FANUC GE E-20T-1, 890711 OUTPUT,115/230VAC TERM BLK 8 PT BI
        HE610TTL100 GE FANUC 7830432-1 5VDC CC
        GE FANUC SERIES O-TT A61L-0001-0093 OPERATOR INTERFACE PANEL (L7)
        GE FANUC SERIES 90-30 POWER IC693PWR321S, IC693MDL655H, IC693MDL655J DI
        GE FANUC SERIES 15-TT MONITOR A02B-0094-C050 & FUJITSU N860-3157-T001 (4D)
        GE Fanuc QuickPanel Display QPICGAE0000-A 10.4 TFT, Ethernet Warranty
        GE Fanuc PCB PC Board 193X526AA G01 193X526AAGO1 I93X526AAG0I
        GE FANUC OPERATOR PANEL 44C741024-G01R07 WITH A860-0202-T001 PULSE GEN (T1
        GE FANUC IC697MDL750 D4C7A2 VA-5 44A729644-G01 PLC OUTPUT MODULE DK
        GE FANUC IC697MDL340 VA-5 D5B7A 44A720846-001R03/3 PLC OUTPUT MODULE DK
        GE FANUC IC697MDL340 D5B7A 44A720846-001R03/3 PLC OUTPUT MODULE DI
        GE FANUC IC697CHS790D EXPANSION RACK, A20B-1002-0680 POWER UNIT DD
        GE FANUC IC6967MDL250 PLC bbbbb MODULE I5C7A2 44A721695-001 44A729662G01 DI
        GE FANUC IC693UAA003BP1 PROGRAMMABLE CONTROLLER SERIES 90 MICRO ,EC
        GE Fanuc IC693CPU341V Series 90-30 CPU Module
        GE Fanuc IC693CMM321-EF Ethernet Controller Module
        GE Fanuc IC693CMM321-EF Ethernet Controller Module
        GE Fanuc IC660BBA020 Genius Analog bbbbb / Output Module
        GE FANUC IC610ABM100D ASCII BASIC MODULE CC
        GE FANUC IC600DM736A MEMORY MODULE 128K,44A297025-G01,44B712805-002/3 , CN
        GE Fanuc ethernet controller IC693CMM321-EE -60 day warranty
        GE FANUC CIRCUIT BOARD MARK CENTURY 1050,814006-211 5-64991-001 FI
        GE FANUC BOARD IC481, 44B294157-001, 44A294502-G01, 44B294245-002/2 FE
        GE FANUC BOARD ASM 44A294534-G02, FAB 44A296364-001, 44B296461-002/3 FE
        GE FANUC BOARD 44A294511-G01, BD 44B294177-001, 44B294269-002/4 FE
        GE Fanuc AC Servo Motor A06B-0113-B075#7008 0.2 kW, 49 V, 200 Hz, 2.8 A
        GE Fanuc A20B-1001-0731/02A Expansion Module PC Board
        GE Fanuc A20B-0008-0540/01A Control Module I/O Module Board
        GE Fanuc A20B-0008-0430 CRTC Puncher Board
        GE Fanuc A20B-0007-0090/07D PC Board
        GE Fanuc A16B-2200-0220/04A PC Board
        GE Fanuc A16B-1100-0330/02A Control Card Digital Servo 3-Axis
        GE Fanuc A14B-0061-B001 Power Unit
        GE Fanuc A13B-0070-B001 Tape Reader Without Reel
        GE Fanuc A06B-6047-H003 Servo DC Velocity Control Unit
        GE Fanuc A06B-6047-H002 Velocity Control Unit
        GE Fanuc A06B-0522-B543#7008 Model 1-0 AC Servo Motor
        GE Fanuc A06B-0346-B255 Model 5F/3000 AC Servo Motor
        GE Fanuc A06B-0313-B672#7076 Model 0S AC Servo Motor
        FUJITSU FANUC A860-0055-T062 CNC TAPE READER UNIT FANUC A860-0050-T062 BK
        FUJITSU FANUC A02B-0047-C011 ,A61L-0001-0072,A20B00070440 NEEDS 2 COVER BN
        FANUC/HITACHI BMU A87L-0001-0105 07C CNC MEMORY BOARD,812262681, FE
        FANUC SERVO AMPLIFIER BOARD A16B-2202-0661/03A, MES-1A,A16B-2202-0661 BM
        FANUC PULSE CODER A860-0316-T101 , A860-0356-X006 BV
        FANUC POWER SUPPLY A16B-2202-0181/01A
        FANUC OPT 1 A16B-2200-0912 BOARD WITH DAUGHTER BOARDS
        FANUC OPERATOR PANEL A04B-0231-C212 WITH I/O BOARD A16B-2300-0110
        Fanuc LCD Screen PCB LM622HW 97-2420-0 DEC-32V0
        Fanuc IC660ELB922J Dual Channel PCIM Card 44A736290-002R09
        Fanuc IC660ELB922J Dual Channel PCIM Card 44A736290-002R09
        fanuc FUJITSU A14B-0061-B103, A20B-0007-0340/04A bbbbb MODULE DC
        Fanuc EE-4583-005 Battery Pack / Fuse Unit
        FANUC AC SERVO MOTOR A06B-0313-B175 (MISSING PARTS)
        Fanuc AC Servo Drive Amplifier C Series A06B-6066-H008 D
        Fanuc AC Servo Drive Amplifier A06B-6066-H008 D22
        Fanuc A860-0360-T201 Alpha A64 Pulse Coder
        Fanuc A860-0360-T061 Alpha A64 Pulse Coder
        Fanuc A860-0346-T061 Serial Pulse Coder A A06B-0346-B356
        FANUC A20B-9000-0180 /03B SIGNAL CONVERTER PC BOARD AO
        Fanuc A20B-8100-0760/03A Auxiliary Axis Control Board
        Fanuc A20B-8001-0830/03C Wide Mini Motherboard
        Fanuc A20B-8001-0700/02B Interface Card
        Fanuc A20B-8001-0121/04B Remote I/O Board A20B-1006-0220/01A RJ2
        Fanuc A20B-8001-0121/03A RJ2 Remote I/O Board A20B-1006-0220/01A
        Fanuc A20B-8001-0121/02A RJ2 Remote I/O Board A20B-1006-0220/01A
        FANUC A20B-1007-0850 /03B ROBOTIC/PLC SWITCH LED CONTROL BOARD BH
        FANUC A20B-1007-0850 /03B ROBOTIC/PLC SWITCH LED CONTROL BOARD BH
        Fanuc A20B-1007-0800/02B Power Relay Board
        Fanuc A20B-1007-0490/03A Redundant Emergency Stop Board RJ3
        FANUC A20B-1003-0230/12C PC MOTHERBOARD A20B-1003-023 DC
        Fanuc A20B-1002-0430/01A Video Digitizer Board
        Fanuc A20B-0008-0540/01A Control Module I/O Interface
        Fanuc A20B-0008-0461/04A PC Board Resolver Inductosyn Board
        Fanuc A20B-0008-0440-03A PCB Board
        Fanuc A16B-3200-0070/03A Main CPU Board
        Fanuc A16B-3200-0040/06D Main CPU Board
        Fanuc A16B-2203-0370/13E Power Supply Module RJ3
        Fanuc A16B-2203-0291/02A Ethernet Remote PCB ER1T RJ2
        Fanuc A16B-2202-0010/03A PowerMate Servo Amplifier Control Board
        Fanuc A16B-2201-0891/03A Remote Ethernet PCB Board RJ2
        Fanuc A16B-2201-0890/04A Remote Ethernet Board 44A731604-G01
        Fanuc A16B-2201-0880/04B PowerMate Servo Amplifier Base Board
        Fanuc A16B-2201-0854/03B OPT3 Option Module
        FANUC A16B-2201-0640/02A PC CONTROL CARD, PCB, CIRCUIT BOARD Z100
        FANUC A16B-2201-0630 MASTER BOARD, A320-2201-T636/04,A350-1004-T962/03 CM
        Fanuc A16B-2201-0580/03C Main CPU Board
        Fanuc A16B-2201-0580/ 03C Main CPU Board
        Fanuc A16B-2201-0371/06B PMC Control Board
        FANUC A16B-2201-0071 /04B I/O PC CONTROL BOARD BE
        Fanuc A16B-2200-0941/05A Option Board
        Fanuc A16B-2200-0853/05B Axis Control Board
        Fanuc A16B-2200-0853/03B Axis Control Board
        Fanuc A16B-2200-0853 Axis Control Board
        Fanuc A16B-2200-0852/03B Axis Control Board
        Fanuc A16B-2200-0843/04C CPU Processor Board
        Fanuc A16B-2200-0843/03B CPU Processor Board
        Fanuc A16B-2200-0842/08F Main CPU Board
        Fanuc A16B-2200-0842/07F Main CPU Board
        Fanuc A16B-2200-0842/05D Main CPU Board
        Fanuc A16B-2200-0842/05D Main CPU Board
        Fanuc A16B-2200-0841/07E Main CPU Processor Board
        Fanuc A16B-2200-0841/07E Main CPU Board
        Fanuc A16B-2200-0841/06E Main CPU Processor Board
        Fanuc A16B-2200-0841/05D Main CPU Processor Board
        Fanuc A16B-2200-0841/04C Main CPU Processor Board
        Fanuc A16B-2200-0841/03B Main CPU Processor Board
        Fanuc A16B-2200-0841 Main CPU Processor Board
        Fanuc A16B-2200-0840/08F Main CPU Board
        FANUC A16B-2200-0524 .12A BASE 0 PC BOARD DC
        FANUC A16B-2200-0470/11B BASE-1 PCB BOARD A16B-2200-047, CI
        Fanuc A16B-2200-0431/03A Remote I/O Board with 96635301 Interface
        Fanuc A16B-2200-0431/01A Remote I/O Board with 96635301 Interface
        Fanuc A16B-2200-0431/01A Remote I/O