Siemens SIMATIC NET PROFIBUS guide

PROFIBUS Optical Bus Terminal (OBT) C79000-G8976-C122-02

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Siemens SIMATIC NET PROFIBUS manual Profibus Optical Bus Terminal OBT C79000-G8976-C122-02

Contents

Simatic NET Profibus Networks Manual 05/2000 6GK1970-5CA20-0AA1 Release Safety Guidelines Qualified PersonnelCorrect Usage Trademarks Symbols Symbols Contents Passive Components for RS-485 Networks Active Components for RS-485 Networks Active Components for Wireless Networks Testing ProfibusPassive Components for Electrical Networks Passive Components for PROFIBUS-PA Dimension Drawings Installing LAN CablesInstalling Network Components in Cubicles Glossary-1 Index Index-1Page Profibus Networks Communication Systems Distributed Systems Overview of the Simatic NET System Simatic NET Industrial Ethernet/Fast Ethernet AS-Interface Basics of the Profibus Network Attachable Systems Transmission Media Standards Access Techniques Token BUS/Master-Slave Method Transmission Techniques Active and Passive Nodes Advantages Transmission Techniques According to EIA Standard RS-485EIA Standard RS-485 Restrictions Properties of the RS-485 Transmission Technique Integrated Optical Interfaces, OBT, OLM Transmission Techniques for Optical ComponentsProfibus User Organization Guideline Characteristics of the Optical Transmission Technique OBT Transmission Technique for Wireless Infrared Technology IEC 61158-2 Standard Characteristics of the IEC 61158-2 Transmission TechniqueTransmission Technique for PROFIBUS-PA Page Topologies of Simatic NET Profibus Networks Topologies of RS-485 Networks Transmission RateLAN Cable Node Attachment Connecting Segments Using RS-485 Repeaters Components for Transmission Rates up to 1.5 Mbps Components for Transmission Rates up to 12 Mbps Topologies of Optical Networks Interfacing Electrical and Optical Networks/Components Topology with Integrated Optical Interfaces OLMs Topologies with OLMsProfibus Optical Bus Terminal OBT Bus Topologies Example of a Bus Topology with OLMs Star Topologies with OLMs Optical Channels Mixed Structure Redundant Optical Rings using OLMsMonitoring FO Links Topologies of Simatic NET Profibus Networks Alternative Cabling Strategy Combination of Integrated Optical Interfaces and OLMs Topologies of Wireless Networks Maximum Length of a LinkPoint-to-Point Link Infrared Link Module ILM Point-to-Multipoint Link Point-to-Point Link with Two Profibus ILMs ILM Profibus Field Device Power Supply via PROFIBUS-PA Topologies with PROFIBUS-PABus and Star Topology SpliTConnect System Tap Line ExpansionTotal Cable Tap Line Lengths for DP/PA Couplers Connectivity Devices 1 DP/DP Coupler Uses How the DP/DP Coupler Works Parameter Assignment Connecting to PROFIBUS-PA DP/PA Bus Coupling 3 DP/PA Coupler Uses of the DP/PA Coupler Properties of the DP/PA Coupler Ex Configuring the DP/PA CouplerProperties of the DP/PA Coupler General DP/PA Link 4 DP/PA LinkDefinition Properties How the DP/PA Link WorksDP/PA Link PA master Rules Connecting PROFIBUS-DP to RS-232C 18 DP/RS-232C Link for PROFIBUS-DP How the DP/RS-232C Link Works Device Connecting with the DP/AS-Interface Link 20 DP/AS-Interface Link DP/AS-Interface Link How the DP/AS-Interface Link 65 Works 22 DP/AS-Interface Link 23 Example of a Configuration with DP/AS-Interface Link How the DP/AS Interface Link 20 Works Connecting PROFIBUS-DP to instabus EIB 24 DP/EIB Link Building Automation Industrial Automation How the DP/EIB Link Works S7-300 ET 200M Configuring Instabus EIBPage Configuring Networks Parameters Configuring Electrical NetworksProfibus Networks Segments for Transmission Rates up to a Maximum of 500 Kbps Transmission Rates up to a Maximum of 500 Kbps Segments for a Transmission Rate of 1.5 Mbps Length of the Tap LinesTransmission Rate 1.5 Mbps Node Attachments at 1.5 Mbps Value Factors Rules Between two DTEs 10 m Segments for Transmission Rates up to a Maximum of 12 Mbps Transmission Rate up to a Maximum of 12 Mbps Configuring Electrical Networks with RS-485 Repeaters RS-485 Repeater Configuring Configuring Optical Networks Configuration Parameters for Optical Networks How a Fiber-Optic Cable Transmission System Works IntroductionTransmission Path Transmitter Receiver Attenuation Optical Power Budget of a Fiber-Optic Transmission System Optical Power Budget Power Budget Plastic and PCF FO CablesGlass FO Cables Splices Link Power Margin Work Sheet Cable Lengths for Plastic and PCF FO Paths Fiber-optic cableFor 1 Network = Lengths between two Nodes in m Mixing Plastic Fiber-Optic and PCF Fiber-Optic Calculation Examples Link power margin Attenuation of the transmission pathAFOC = Number * aSpl 10.0 dB 12 dB Blank form for a power budget using OLMs Transmission Delay Time Configuring Optical Buses and Star Topologies with OLMs Creating a System Overview Setting the Profibus Properties Properties Profibus Dialog Entering the Cabling Configuration Options Cables Tab Checking the Bus Parameters Bus Parameters Adapted to the System Raising the Retry Value to at Least the Value Configuring Redundant Optical Rings with OLMsConfiguration of a Non-existent Node Checking and Adapting the Slot Time Transmission Rate Transmission rate Minimum slot Time Example of Configuring the Bus Parameters in StepStructure of the Network Example Calculation of the Slot Time Entering the Bus Parameters Bus Parameters/User-Defined Dialog Passive Components for RS-485 Networks Overview Simatic NET Profibus CablesProfibus Cables LAN Cables for Profibus UV resistance Sienopyr FR Passive Components for RS-485 Networks FC Standard Cable FC Standard Cable 6XV1 830-0EH10 FC-FRNC Cable LAN cable with halogen-free outer sheath LAN Cable with Halogen-free Outer Sheath 6XV1 830-0LH10 FC Food Cable FC Food Cable 6XV1 830-0GH10 FC Robust Cable FC Robust Cable 6XV1 830-0JH10 Profibus Flexible Cable Profibus flexible cable 6XV1 830-0FH10 Properties Filler FC Underground CableFC Underground Cable 6GK1 830-3FH10 FC Trailing Cable Trailing Cable 6XV1 830-3EH10 Properties Example of Using the Profibus Trailing Cable in a Drag Chain Segment Lengths Passive Components for RS-485 Networks Profibus Festoon Cable Festoon Cable 6XV1 830-3GH10 10 Installation of the Profibus Festoon Cable Schematic Passive Components for RS-485 Networks Installation Guidelines 11 Use of the Profibus Cable for Festoons Inner sheath SIENOPYR-FR Marine CableSIENOPYR-FR Marine Cable 6XV1830-0MH10 Uses FastConnect Bus Connector FastConnect System Functions Designed for Industry OLM Technical Specifications Order numbers 6ES7 0BA50-0XA0 0BB50-0XA0 6GK1 0FC00 Disconnecting a Station Bus Connector with PG SocketPinout of the Sub-D Male Connector Pin Signal Meaning Name Passive Components for RS-485 Networks Using the FastConnect Stripping Tool for Preparing FC Cables OFF Bus Connectors Appearance FMS/DP Order 6ES7 972-0BA11-0XA0 6ES7 972-0BA40-0XA0 6GK1 Numbers 6ES7 972-0BB40-0XA0 0BA30-0XA0 500-0EA02 PG socket Disconnecting a Station Appearance 6ES7 972-0B.11 Siemens Connecting Up the LAN Cable First and last station on Further stations on the bus Passive Components for RS-485 Networks 18 Bus Connector order number 6ES7 972-0BA30-0XA0 Appearance 6ES7 972-0BA30-0XA0 Cable guides Insulation displacement terminals Connecting the LAN Cable to Bus Connector 6ES7 972-0B.40 Appearance 6ES7 972-0B.40 23 Connecting the LAN Cable to Bus Connector 6ES7 972-0B.40 Installing the Bus Connector with Axial Cable Outlet Appearance 6GK1500-0EA02 Fitting the Bus Connector Plugging the Bus Connector into the Module Removing the Bus Connector Possible disturbance of data traffic on the bus Bus Terminals for RS-485 Networks Versions Bus terminal RS-485 Bus terminal 12 M Design and Functions of the RS-485 Bus Terminal Bus Terminal RS-485 RXD/TXD-P Additional PG Interface 28 RS-485 Bus Terminal with Additional PG Interface Design and Functions of the 12M Bus Terminal 29 12M Bus Terminal BT12M Bus terminal 12 M 30 Operator Controls Restriction when using the 12M bus terminal at 500 Kbps Termination 31 Drilling Diagram for the Bus Terminal Mounting/Attaching the LAN Cables Passive Components for RS-485 Networks Passive Components for RS-485 Networks 33 Ways of Installing and Grounding the Bus Terminal Grounding Wall Mounting Technical Data of the RS-485 Bus Terminal Technical Data of the RS-485 Bus Terminal Technical Data of the 12M Bus Terminal Technical Data of the 12M Bus TerminalElectromagnetic Compatibility Climatic Conditions Test Marks Mechanical ConditionsConstruction Cable Connections Cable Connections to Network Components Cable Connection without Bus Connection ElementsAll-round shielding of the LAN cable must be retained Avoid accidental shield contact with the environment Keep to the permitted ambient conditions Preassembled Connecting Cables 1 830-1T Connecting Cable Function Simatic NET 830-1T connecting cable 2 830-2 Connecting Cable 35 830-2 Connecting Cable Simatic NET 830-2 connecting cable Active Components for RS-485 Networks What is an RS-485 Repeater? Using the RS-485 Repeater 6ES7 972-0AA01-0XA0RS-485 Repeater Design of the RS-485 Repeater Layout of the Repeater Function Layout Pin no Signal name Meaning Pinout of the Sub D Connector PG/OP ConnectorTechnical Specifications Block Diagram Block Diagram of the RS-485 Repeater Off Possible Configurations with the RS-485 RepeaterTerminating Resistor On/Off Segments 1 and 2 Terminated Segment 1 Terminated, Segment 2 Connected ThroughSegment Terminating resistor Segments 1 and 2 Connected Through Terminating resistor Bus segment 2 off Installing and Uninstalling the RS-485 Repeater Installation on an S7-300 Rail Installing the RS-485 Repeater on an S7-300 Rail Removing the RS-485 from the Standard Rail Installation on a Standard RailRemoving the Repeater from an S7-300 Rail Ungrounded Operation of the RS-485 Repeater Ungrounded Operation Cable Type Connecting the Power SupplyConnecting the Power Supply Connecting the LAN Cable Connecting the Profibus Cable What is a Profibus Terminator? Profibus TerminatorOrder number Design of the Profibus Terminator Lists the technical data of the Profibus terminator Standard cable 6XV1 830-0EH10 Page Passive Components for PROFIBUS-PA FC Process Cable PVC outer sheath SpliTConnect Tap How the SpliTConnect Tap Works Simatic NET Produktinformation Personnel qualification requirements Insert the strand holder 6 onto the not stripped off strands Grounding Hinweis SpliTConnect Coupler SpliTConnect Terminator Technische Daten /Technical Data Passive Components for Electrical Networks Fiber-Optic Cables Fiber-Optic Cable FO Properties of Fiber-Optic Cables Plastic Fiber-Optic CablesPlastic Fiber-Optic Cables Properties of Fiber-Optic Cables Core Cladding Jacket buffer Plastic Fiber Optic, Duplex CordPlastic FO Cable, Duplex Cord 6XV1821-2AN50 Fiber-Optic Cables Simatic NET Profibus Plastic Fiber Optic, Duplex Cord Plastic Fiber-Optic, Standard Cables Plastic FO Cable, Standard Cable 6XV1821-0A Simatic NET Profibus plastic fiber-optic, standard cable Standard lengths PVC outer jacket Kevlar strain relief PCF fibers PCF Fiber-Optic CablesPCF FO Cable, Standard Cable 6XV1821-1B Simatic NET Profibus PCF fiber-optic cable Passive Components for Electrical Networks Simple Configuration Glass Fiber-Optic CablesSimatic NET Standard Fibers Guidelines for Laying Cables Cable Type Fiber-Optic Standard Cable Indoor Fiber-Optic TB3 Frnc or Trailing Cable Duplex Fiber-Optic Marine Cable Cable Type Fiber-Optic Indoor Fiber-Optic Standard CableCable Type Flexible Fiber-Optic 13.3 ± Fiber-Optic Standard Cable Fiber-Optic Standard Cable Indoor Fiber-Optic Cable Indoor Fiber-Optic Cable Flexible Fiber-Optic Trailing Cable Flexible Fiber-Optic Trailing Cable Uses Passive Components for Electrical Networks Sienopyr Duplex Fiber-Optic Marine Cable Sienopyr Duplex Fiber-Optic Marine Cable 6XV1 830-0NH10 Ordering Special Cables Special CablesFiber Types Cable Structures Ordering Requirements Fiber-Optic ConnectorsConnectors for Plastic Fiber-Optic Cables Accessories Order Numbers Cable Lengths Installing Plastic Fiber-Optic Cables Instructions for Assembling Plastic Fiber-Optic Cables Bfoc Connectors for Glass Fiber-Optic Cables Bfoc Connectors for OLMsConnectors for Glass Fiber Cables Fitting Connectors On-Site Preassembled CablesPage Active Components for Optical Networks Optical Bus Terminal OBT Optical Bus Terminal Operating Instructions 6GK1 500-3AA00 Optical Link Module OLM Design Functions Profibus OLM/P11 Page Active Components for Wireless Networks Infrared Link Module ILM Ordering Data Profibus ILMPage Testing Profibus Logging Functions Hardware Test Device BT200 for PROFIBUS-DP Possible UsesArea of Application Design Figure A-1 Hardware Test Device BT200 for Profibus DP Checking the Accessibility of Nodes FunctionsChecking the Profibus Cable Checking the RS-485 Interface of a Slave How the Unit Functions Ordering Data Test Methods Testing FO Transmission Paths Necessity of a Final TestOptical Power Source and Meter Arrangement for Measuring Attenuation Evaluating the Results of the Attenuation Measurements Optical Time Domain Reflectometer Otdr Figure A-3 Optical Time Domain Reflectometer Otdr How an Otdr Functions Figure A-4 How an Otdr Functions Otdr Evaluation Otdr provides the measurement results graphically Checking the Optical Signal Quality with Profibus OLM OLM/G12 Page Page Why Protect Your Automation System From Overvoltage? Protecting LAN Cables from LightningFurther Literature Bus Cables within Buildings LAN Cables between Buildings Coarse Protection PLC PLC Instructions for Installing Coarse Protection Instructions for Installing Fine Protection Page Page Installing LAN Cables LAN Cables in Automation Systems LAN Cables as Important Plant ConnectionsKeep the Overall System Concept in Mind Networking Simatic with Simatic NET Electrical Safety Power Supply VoltageDC Power Supply Protection from External Electrical Influences Mechanical Protection Mechanical Protection of LAN CablesProtection of Electrical and Optical LAN Cables Redundant LAN Cables Do not kink or crimp the trailing and festoon cables Install LAN cables separately Electromagnetic Compatibility EMC Electromagnetic Compatibility of LAN CablesMeasures to Counter Interference Voltages Installation and Grounding of Inactive Metal Parts Using the Shields of Electrical LAN CablesGrounding Cable Shields Handling the Shield When do potential differences occur? Equipotential Bonding Rules for Equipotential Bonding When and why is equipotential bonding necessary?How do you avoid potential differences? Installing LAN Cables Routing Electrical LAN Cables Cable Categories and Clearances Clearance Table How to Read the TableConditions Outside closets Cables for LayWithin closets Cabling within Closets Cabling within Buildings EMC Rules for Electrical LAN Cables Cabling outside BuildingsFiber-optic cables should be given preference Connecting Switched Inductances to Suppressors Power Supply for Programming DevicesSpecial Noise Suppression Measures Underground Cabling Cabinet Lighting Electromagnetic Compatibility of Fiber-Optic Cables Temperatures Pull Cables Using Cable Grips and Protect ConnectorsGeneral Storage and Transportation Fitting Strain Relief PressureTorsion Do not twist trailing cables and festooned cables Attachments to Profibus Cables Installing other CablesAvoid Loops Additional Instructions on Installing Fiber-Optic Cables Attaching Profibus Fiber-Optic Cables Page Page Installation Instructions for Simatic NET Simatic NET Personnel qualification requirements Copyright Siemens AG All Rights ReservedPage Page Setting the Cutting Depth of the Cable Knife Page Separating the Simatic NET Plastic Fiber Optic Duplex Cord Removing the Buffer Fitting Simplex Connectors Connector must be towards the center Simatic NET Profibus Plastic Fiber Optic Stripping Tool Set Simatic NET Profibus Plastic Fiber Optic, standard cableSimatic NET Profibus Plastic Fiber Optic, duplex cord Other commercially available accessories Plug adapter Simatic NET Personnel qualification requirements Page Setting the Cutting Depth of the Cable Knife Foil working from the end of the cable Separating the Simatic NET Plastic Fiber Optic Duplex Cord Removing the Buffer Crimping the Bfoc Connector Grinding and Polishing Bfoc Connectors Page Simatic NET Profibus Plastic Fiber Optic Standard cable Simatic NET Profibus Plastic Fiber Optic Duplex cordSimatic NET Profibus Plastic Fiber Optic Bfoc crimping tool Simatic NET Profibus Plastic Fiber Optic Bfoc polishing set Other commercially available accessories Simatic NET Profibus PCF Fiber Optic Standard Cable Personnel qualification requirements Simatic NET Profibus PCF Fiber Optic Standard Cable Using the Pulling Loop Marking Simatic NET Profibus PCF Fiber Optic Standard Cable Assembled with 2 x 2 Bfoc connectors For connecting OLM/PSimatic NET Profibus PCF Fiber Optic, standard cable Simatic NET Profibus PCF Fiber Optic cable IEC 60529, EN Installing Network Components CubiclesIP Degrees of Protection Degree of Protection Code Contact and Solid Body Water Protection Number Outdoor Installation Simatic NET ComponentsVentilation Openings Heat Dissipation Standards Dimension Drawings Dimension Drawings of the Bus Connectors Figure F-2 Bus Connector to IP 20 6ES7 972-0BA30-0XA0 On OFF Siemens Figure F-6 FastConnect Bus Connector 6GK1 500-0FC00 Dimension Drawings of the RS-485 Repeater Figure F-7 RS-485 Repeater on Standard Rail 125 Dimension Drawing of the Profibus Terminator Figure F-9 Profibus Terminator 40.3 44.5 Dimension Drawings of the RS-485 Bus Terminal Figure F-10 RS-485 Bus Terminal on 15 mm high Standard Rail Dimension Drawings of the BT12M Bus Terminal Figure F-11 BT12M Bus Terminal on 15 mm high Standard Rail Dimension Drawings of the Optical Bus Terminal OBT Simatic NET Dimension Drawings Infrared Link Module ILM Sieme N S Dimension Drawings Optical Link Module OLM Dimension Drawings Page Operating Instructions ILM / OLM / OBT Operating Instructions ILM / OLM / OBT Simatic NET Attenzione Simatic NET Profibus ILM General Personnel qualification requirements Modes and Settings Installation and StartupInstalling the Profibus ILM Signaling Contact Displays Help With Problems During Operation Product Symbols Introduction Description of the Device Siemens Profibus ILM Transmission Rate Topologies Point-to-Point-Link Point-to-Point Link with Two Profibus ILMs Slave Infrared Link Modul ILM 6ZB530-3AC30-0BA1 Slave Page ILM Point-to-Multipoint Link Infrared transmission link 2 0.5 to 15 m Constant Light Monitoring Signal RegenerationMonitoring the Received Optical Level Monitoring the Optical Link with an Acknowledgment Pulse Monitoring the Optical LinkMonitoring the Optical Receive Activity Infrared Link Modul ILM 6ZB530-3AC30-0BA1 Modes and Settings Setting the Terminating Resistor Setting the Transmission Rate 3 4 5 6 7 8 Setting Operation With Acknowledgment Pulse Operation with Signaling Contact 3 4 5 6 7 Installation and Startup General Notes on Installation and Startup 6ZB5530-3AC30-0BA1 Infrared Link Modul ILM Installing the Profibus ILM 6ZB5530-3AC30-0BA1 Infrared Link Modul ILM Thickness of sheet Approx mm depending on Siemens ILM Screw M6 x By turning Connecting the Electrical RS 485 Bus Cables 6ZB5530-3AC30-0BA1 Infrared Link Modul ILM Connecting the Power Supply and the Signaling Contact 20 to 30 Max Max mA Max a NEC Class Displays LED Display Possible Causes Signaling Contact Status Displays for Incorrect Operation LOW LED 6ZB5530-3AC30-0BA1 Infrared Link Modul ILM Errors Due to Incorrect Network Configuration Transmission Delay Time TTD Delay Time of the Profibus ILMDelay Time of Further Active Profibus Network Components Technical Specifications 6ZB5530-3AC30-0BA1 Infrared Link Modul ILM Infrared Link Modul ILM 6ZB530-3AC30-0BA1 Illumination Range LOW LED displays critical receive levels Appendix References Installation Guidelines Product nameEMC 89/336/EEC Area of application Copyright  by Siemens OLM/P11 Safety Instructions Qualified personnelCertified usage Trademarks Contents Order Numbers Introduction OLM Non operating mode related functions Operating mode related functions General Functions Operating mode related functions Line monitoring with echoesSend echo Monitor echo Line topology Please note Monitoring mechanisms Line topology without optical fiber link monitoring Star topology Network structure in an optic star topology Redundant optical ring Network structure in a redundant optical ring topology Monitoring mechanisms OLM/G12-1300 Safety noticeOLM/G11-1300 General information about setting up Setting the compatibility DIL switch S7 compatibility in Position Setting the operating mode Operating mode Electrical Port without segment monitoringSetting the operating mode of the optical ports CH2, CH3 Operating mode Line without optical fiber link monitoring Operating mode Redundant optical ring Installation Connecting the optical lines Mounting on a mounting plate Mounting the modulesMounting on a hat rail Connecting the electric RS 485 bus lines Observe the following safety notice Connecting the power supply Connecting the signaling contact lines Defining the receiving level of the optical ports Measuring sockets LED Indicators and Troubleshooting LED Indicators What the LED indicators and signaling contacts mean Troubleshooting Fault indicated on the system LEDFault indicated on CH1 Fault indicated on CH2 / CH3 Version 1.0 8/00 Configuration of optical line and star topologies Configuration of redundant optical rings Constants for calculating the slot time at DP standard Voltage/power supply Signal transmissionRetimer Safety Mechanical ambient conditions Electromagnetic compatibility EMCClimatic ambient conditions CE Designation Literature notes List of abbreviations Function not guaranteed Measuring sockets Simatic NET Support and Training Simatic Training CentersSimatic Customer Support Hotline Nuremberg Nürnberg Johnson City Singapore Singapur Further support Simatic Customer Support On-line ServicesSource for special cables Page Profibus Optical Bus Terminal OBT Manual Copyright Siemens AG 1998 All rights reserved Network Topology Installation and Startup10-1 Profibus Optical Bus Terminal OBT C79000-G8976-C122-02 Introduction OBT Power Supply Operating ModeConnections Sensitivity Not supplied Simatic NET Profibus OBT ProductSupplied Profibus Optical Bus Terminal OBT C79000-G8976-C122-02 Interfaces Optoelectric Signal Conversion and Signal RegenerationFunctional Description Displays Automatic Transmission Rate DetectionSupported FO Fiber Types + 24V green CH1, CH2 , CH3 channel 1 to 3, yellow Operator Controls Network Topology Optical Bus Using Long Fiber Optic Sections OLM/G11 OBT Attaching RS-485 Segments Example of Attaching RS-485 Segments Profibus Optical Bus Terminal OBT C79000-G8976-C122-02 Installation and Startup Precedure for Installation Installation and Startup Installation Installing the Profibus OBT Installation on a Mounting Plate Installing a Module on a Mounting Plate PE M L+ NEC CLASS2 Connecting the Optical Cables C D Connecting the Electrical RS-485 Cable Profibus Optical Bus Terminal OBT C79000-G8976-C122-02 Troubleshooting LED Display Possible Cause of Problem Profibus Optical Bus Terminal OBT C79000-G8976-C122-02 Technical Specifications Technical Specifications Technical Specifications Technical Specifications Profibus Optical Bus Terminal OBT C79000-G8976-C122-02 Installation Instructions Product NameEU Directive EMC 89/336/EEC Information for Manufacturers of Machines Profibus Optical Bus Terminal OBT References Siemens AG Profibus Optical Bus Terminal OBT C79000-G8976-C122-02 Abbreviations ISO/OSI Profibus Optical Bus Terminal OBT C79000-G8976-C122-02 Simatic NET A&D PT2 Profibus Optical Bus Terminal OBT C79000-G8976-C122-02 General Information Abbreviations/Acronyms General Information Standards, Manuals and Further Information References Further Information Order NumbersPage Simatic NET Support and Training Simatic Training CenterSimatic Customer Support Hotline Nuremberg Johnson City Singapore Simatic Basic Hotline Simatic Customer Support Online Services Ordering Special Cables, Accessories, and ToolsFurther Support Simatic Premium Hotline Glossary GAP factor Ground Lightning arresters Lightning protection equipotential bondingMaster Master-slave technique Optical power budget FO Optical power loss FOMaxTSDR MinTSDR Signal propagation time Reaction timeRedundancy Reference potential Simatic NET PC modules SlaveSoftnet for Profibus Standard rail Token ring Token rotation timePage Index Index