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3BDS009029R5001 B

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Section 2  Transmission Technology

PROFIBUS is an industrial communication system that uses a range of media such 
as copper cable, fibre optics or wireless, with bit-serial transmission for coupling 
smart field devices to a control system.

This chapter describes the transmission technologies mostly used in connection with 
the AC 800M Controller. PROFIBUS provides different transmission technologies, 
based on international standards such as IEC 61158 and IEC 61784, which 
describes the digital data communications for measurement and control in fieldbus 
networks.

RS485 Transmission Technology

RS485 is the most commonly used transmission technology for PROFIBUS DP. It 
uses a shielded twisted pair copper cable and enables transmission rates up to 12 
Mbit/s. Because of its simply installation it is cost-effective and requires no expert 
knowledge.

The bus structure allows adding or removing of field devices as well as step by step 
commissioning without influencing the system. Later extensions have no impact on 
devices that are already working on the bus. RS485 is scalable in its transmission 
rate from 9,6 kbit/s up to 12 Mbit/s, which is set in the PROFIBUS master.

AC 800M and CI854(A)

In connection with the AC 800M Controller, the Communication Interface 
CI854(A) interacts as PROFIBUS master and builds up a PROFIBUS network with 
RS 485 technology. Up to 12 CI854(A) modules can be placed at one AC 800M 
Controller and each interface works as a single PROFIBUS master, which can be 
configured with its own transmission rate. Supported transmission rates are 9.6; 
19.2; 93.75; 187.5; 500; 1500; 3000; 6000 and 12000 kbit/s. Not support are the 

Summary of Contents for AC 800M

Page 1: ...Power and productivity for a better worldTM AC 800M PROFIBUS DP Installation System Version 5 0 5 1...

Page 2: ......

Page 3: ...AC 800M PROFIBUS DP Installation System Version 5 0 5 1...

Page 4: ...assumes no responsibility for any errors that may appear in this document In no event shall ABB be liable for direct indirect special incidental or consequential damages of any nature or kind arising...

Page 5: ...Protocols 18 PROFIBUS Technology Terms 20 Transmission Technology Overview 22 FISCO Fieldbus Intrinsically Safe Concept 23 Section 2 Transmission Technology RS485 Transmission Technology 25 AC 800M an...

Page 6: ...Calculation of transmission delay time TTD 54 Section 3 Fieldbus Topologies Overview 57 Point to Point Topology 59 Line Topology 60 Line Topology with spurs 60 Tree Topology 62 Star Topology 63 Ring T...

Page 7: ...93 Installation hints for electrical data cables 93 Installation hints for optical fibre cables 95 Special conditions regarding the installation of PROFIBUS DP 96 Installation hints for CI854 A 98 In...

Page 8: ...Table of Contents 8 3BDS009029R5001 B...

Page 9: ...ions Commissioning and testing of PROFIBUS equipment For a list of documentation related to ABB PROFIBUS products please see the Released User Manuals and Release Notes on page 14 Any security measure...

Page 10: ...S networks in connection with the AC 800M controller and the PROFIBUS master interface CI854 A Also the readers get recommendations and important hints for installation work Section 4 Commissioning of...

Page 11: ...sting includes terms and definitions that apply to the 800xA System where the usage is different from commonly accepted industry standard definitions and definitions given in standard Electrical warni...

Page 12: ...romagnetic environment and to accept or emit RF disturbances within defined limits FDE Fault Disconnection Electronic The FDE in field devices ensures that the communication of the bus segment does no...

Page 13: ...PA PROFIBUS FMS Fieldbus Message Specification Is designed for communication at the cell level where programmable controllers such as PLCs and PCs primarily communicate with each other It was the for...

Page 14: ...een any of the release cycles listed in the first bullet RLM 01 Redundancy Link Module for PROFIBUS DP The RLM 01 connects a non redundant PROFIBUS slave to the line redundant PROFIBUS RS485 A communi...

Page 15: ...out This User Manual Released User Manuals and Release Notes 3BDS009029R5001 B 15 For standards and commercially available PROFIBUS documentation please visit the PROFIBUS Web Site http www profibus c...

Page 16: ...Released User Manuals and Release Notes About This User Manual 16 3BDS009029R5001 B...

Page 17: ...r smart devices to PLCs and controller like AC 800M This user manual provides a brief overview of the PROFIBUS technology to help you by planning commissioning and testing It does not release you from...

Page 18: ...distinguishes between master and slave The masters determine the data communication on the bus A master can send messages without an external request if it has access rights to the bus token The slave...

Page 19: ...ation system and the decentralized periphery in the field also intrinsic safety RS485 IS via DP Ex barriers into hazardous area One feature of PROFIBUS DP is its scalable high speed of transmission up...

Page 20: ...ystem and device behavior Level 1 defines the physical aspect of transmission physical layer This includes for example the method of transmission the transmission medium and lengths of lines while lev...

Page 21: ...es master and slaves can be addressed Each address can only be used once in a single PROFIBUS network Communication Protocols At the protocol level PROFIBUS offers a broad spectrum of options which en...

Page 22: ...ed twisted pair copper Multimode glass fibre single mode glass fibre PCF plastic Remote feeding Available over additional wire Available over additional wire Optional available over signal wire Availa...

Page 23: ...segment in this case the Linking Device All other components work as passive current sinks The basic current consumption of a bus station is at least 10 mA It must be ensured for each bus station tha...

Page 24: ...st conform to the following limits 90 Ohm R 100 Ohm 0 F C 2 2 F On condition that the points are all satisfied the proof of intrinsic safety has been provided by means of the FISCO model Devices that...

Page 25: ...le and enables transmission rates up to 12 Mbit s Because of its simply installation it is cost effective and requires no expert knowledge The bus structure allows adding or removing of field devices...

Page 26: ...le type and speed The maximum permissible bus length depends on the transmission rate and the bus cable type Different cable types designation A to D for different applications are available for conne...

Page 27: ...because of the typically 10 mm diameter of the coating They can therefore only be connected to screw terminals of PROFIBUS devices Depending on the ambient EMC conditions EN 50170 also allows for lay...

Page 28: ...onsidered as another bus node since the integrated bus drivers are an additional load on the bus It is recommended to use not more than three series connected repeaters on a line However the number of...

Page 29: ...Section 2 Transmission Technology RS485 network limits 3BDS009029R5001 B 29 Figure 2 RS485 network limits...

Page 30: ...to ensure good conductivity Furthermore the data lines should be laid separately and away from all power cables Never use spur lines for transmission rates 1 5 Mbit s see also Line Topology with spurs...

Page 31: ...ation of a bus network PROFIBUS DP only requires approx 1 ms at 12 Mbit s for the transmission of 512 bits of output data distributed over 32 stations The following figure shows different bus cycle ti...

Page 32: ...curely screwed onto the RS485 interfaces Attaching or removing the bus connector plugs inadequately attached bus connector plugs or loose bus wires within the plug can lead to malfunctions in the netw...

Page 33: ...ly developed for interconnection of intrinsically safe field devices considerably simplifies planning and installation MBP cable type and speed MBP is synchronous transmission with a fixed transmissio...

Page 34: ...stor direct current 44 Ohm km Wave resistance at 31 25 kHz 100 Ohm 20 Wave attenuation at 39 kHz 3 dB km Capacitive asymmetry 2 nF km Group runtime distortion 7 9 39 kHz 1 7 s Covering level of the sh...

Page 35: ...is summarized from the power consumption of all connected field devices plus a reserve of 9 mA per segment for the operating current of the FDE Fault Disconnection Electronics The FDE prevents faulty...

Page 36: ...g of 44 Ohm km A requirement for a PROFIBUS PA slave to be able to function properly is that the input voltage on the bus line must be at least 9 V The following therefore applies to the maximum volta...

Page 37: ...through which its power supply current flows For the first station this would be URL1 i1 RL1 or URL1 i1 l1 r where r the resistance coating of the line For the second station this appears as follows...

Page 38: ...signal in correct polarity If a field device is connected backwards it will see an inverted version of the alternating voltage and won t be able to communicate However there are non polarized field d...

Page 39: ...le time calculation The PROFIBUS PA data telegrams of the MBP transmission is very similar to asynchronous RS 485 transmission While the bytes are transmitted asynchronously in the form of UART charac...

Page 40: ...t was assumed that only one cyclic value 5 bytes user data must be transmitted per device With each additional value the minimum cycle time increases by 5 x 8 bits 31 25 kbit s 1 3 ms For a first esti...

Page 41: ...Fully transparent in the PROFIBUS line No configuration and commissioning Direct access from PROFIBUS DP master to PROFIBUS PA slaves Support of all cyclic and acyclic PROFIBUS protocol services DP V1...

Page 42: ...on between the two media is provided by an optical link module which convert the RS485 to fibre optic transmission technology In the communication between the stations on the bus there is no differenc...

Page 43: ...receiver port when detecting an error at the transmit port and vice versa Also hybrid cable copper cables and fiber optic cables contained in one cable are available This means that by using hybrid ca...

Page 44: ...connected Fibre cable types and its maximum distance are already described in Table 6 PROFIBUS DP slaves are always connected to the RS485 network Fibre optic transmission technology has to be conver...

Page 45: ...tted send time forwarding of the received signals is blocked until frames can be received again correctly or if no signal is received for one second Line monitoring with echoes The optical link module...

Page 46: ...d cut off This segmentation causes the module at the other end of the optical fiber to be segmented as well Both modules connected to the segmented field bus partial network send test frames to the se...

Page 47: ...s are necessary If single point to point connections are to be built up this can be achieved using two modules each with one optical port This operating mode should preferably be used if an interrupte...

Page 48: ...ink monitoring If both operating modes are used within an optical fiber line the operating mode Line topology without fiber link monitoring determines the availability of this fiber line It is recomme...

Page 49: ...sible in the event of a malfunction Line topology without optical fiber link monitoring Use this operating mode if you connect an optical link module with another optical fiber network component which...

Page 50: ...star coupler Further optical link modules are connected to this by dual fiber optical fiber lines transmit receive fibres The modules of the star coupler are connected to one another via the electric...

Page 51: ...al star segment wherever possible Modules with one or two optical ports can be used to create an active PROFIBUS star coupler Modules with one optical port are sufficient for connecting a terminal or...

Page 52: ...optical ports of the same type Monitoring mechanisms to be set on the optical link modules Send echo yes Monitor echo yes Suppress echo yes Segmentation yes An interruption of one or both optical fibe...

Page 53: ...ting Retry on the PROFIBUS master shall be set to at least 3 After the error has been corrected no frames should be present in the network when the optical line is transformed back into an optical rin...

Page 54: ...If the planning software being used to configure the PROFIBUS network does not support the PROFIBUS parameter TTD then the two times min TSDR and max TSDR are to be extended instead by 2 x TTD reactio...

Page 55: ...erall processing delay results from the number of modules passed between telegram transmitter and receiver multiplied by 1 5 tbit Delay time of other active PROFIBUS network components The delay time...

Page 56: ...Calculation of transmission delay time TTD Section 2 Transmission Technology 56 3BDS009029R5001 B...

Page 57: ...s intelligent Remote I Os are also used as interface systems for conventional 4 20 mA or HART field devices to record process data on the field level All relevant signals such as input and output data...

Page 58: ...ew Section 3 Fieldbus Topologies 58 3BDS009029R5001 B of each Not every topology is applicable for each transmission technology like RS485 or fibre optics Figure 13 Possible topologies for fieldbus ne...

Page 59: ...topology is mostly used in sub segments for example to connect HART devices to Remote I O For the HART device the remote I O operates as a master however the remote I O is part of the PROFIBUS network...

Page 60: ...ogy should use connectors or wiring practices such that disconnection of a single device is possible without disrupting the continuity of the whole segment Line Topology with spurs With this topology...

Page 61: ...than 6 6 m When using spurs with low transmission rates 93 75 kbit s the ratio between spur cable length and next bus termination should be at least 1 20 There is always a cable of several centimeters...

Page 62: ...l as in between It is practical if devices on the same segment are well separated but in the general area of the same junction box When using this topology the maximum spur length must be taken into c...

Page 63: ...combined to form an active PROFIBUS star coupler The modules of the star coupler are connected to one another via RS485 PROFIBUS DP In opposite to the tree topology the star topology contains more mai...

Page 64: ...degree of network operating safety is achieved by closing the line A redundant ring can be also realized to increase the high availability This structure is commonly used in connection with fibre opti...

Page 65: ...e can be adjusted in steps from 9 6 kbit s to 1 5 Mbit s For extremely time critical PROFIBUS DP applications additional transmission rates of 3 6 and 12 Mbit s are possible The maximum segment length...

Page 66: ...of the line structure According to the rules of certification each PROFIBUS DP device needs a minimum voltage of 5 V If it is not sure from the very beginning that for a planned installation the requ...

Page 67: ...nd 6 of the connector respectively The 5 V supply for the terminating resistors VP should have a minimum current rating of 10 mA the current load can increase to 12 mA if a NULL signal is sent through...

Page 68: ...qually well at the beginning end or middle of a PROFIBUS segment The terminating resistor must be turned on in the connector for the first last device on the bus segment It must be turned off for the...

Page 69: ...ive surface When laying the bus cables particular care should be taken to ensure that the cable shield is connected to the shield grounding clamp over a large area The two PROFIBUS data lines are desi...

Page 70: ...ible cable length and the maximum number of fieldbus devices Repeaters increase the signal propagation times This should be taken into account during planning Table 8 General Data PROFIBUS DP Maximum...

Page 71: ...Section 3 Fieldbus Topologies RS485 limits and network design 3BDS009029R5001 B 71 Figure 24 RS485 network design with bus termination and repeater...

Page 72: ...line structure stations are connected to the trunk cable using T junctions The tree topology is comparable to the classic field installation method The multi core cable is replaced by the two wire bu...

Page 73: ...exceeded The optimum design of a fieldbus segment requires detailed calculation of the partial voltage drops By selecting a cable with a larger diameter it will be compensated to a certain extent see...

Page 74: ...ubscribers The time required for a complete cycle of data exchange depends essentially on the transmission rate the number of subscribers and the size of the measurement Value and status values to be...

Page 75: ...reas in no time at all Requirements are Devices certified acc to FISCO EC type attestation of conformity U I and P acc to EN 50 020 Cable parameters observed R L C Bus termination existing and correct...

Page 76: ...ends of the line According to the FISCO model the termination must conform to the following limits 90 Ohm R 100 Ohm 0 F C 2 2 F Figure 26 Bus termination according to FISCO A fieldbus terminator is i...

Page 77: ...ctly via the EMC cable gland The following points shall be taken into account when selecting a junction or connector Non interrupted bus operation when exchanging or extending a PA transmitter Externa...

Page 78: ...optimization of the fieldbus length and the adaption to existing system structures It must be taken into account that the limitation of the spur length for intrinsically safe installations according...

Page 79: ...Field devices shall be able to function with the mid point of one terminator or one inductive coupler directly to ground Neither of the two conductors of the twisted pair may be grounded at any point...

Page 80: ...ngs as well as the connections between the shields of the different cable segments have to be low impedance for high frequencies As far as unshielded devices are connected to a shield cable further me...

Page 81: ...a In the safe area the shield shall be connected to earth through a capacitor The impedance of the connection should be minimized for high frequencies However the need for an electric envelope as comp...

Page 82: ...Linking Device or the power link module and on all field devices For intrinsically safe applications a potential compensation between the safe and hazardous areas is required If there is no potential...

Page 83: ...fied for spur length using the MBP transmission technology with 31 25 kbit s transmission rate Table 9 Recommended length of the spurs Number of spur cables Length of one spur cable intrinsically safe...

Page 84: ...ected to a PROFIBUS network The optical transmission method offers the following advantages Plastic PCF or glass fiber optic cables are insensitive to electromagnetic radiation and make the EMC measur...

Page 85: ...800M in a star topology The following diagram shows PROFIBUS DP with a fiber optical link for bridging long distances for electrical isolation of parts of the system or as a measure for protecting ag...

Page 86: ...Optical link modules and AC 800M in a star topology Section 3 Fieldbus Topologies 86 3BDS009029R5001 B Figure 31 Fiber optical link for bridging long distances...

Page 87: ...tical ring The line redundant interfaces of CI854A RLM01 etc can be connected to the ring by connecting each line to a separate optical link module It is also possible to configure the master and slav...

Page 88: ...Optical link modules and AC 800M in a ring topology Section 3 Fieldbus Topologies 88 3BDS009029R5001 B Figure 32 Redundant optical ring...

Page 89: ...kes it possible to considerably increase the availability and thus the reliability in comparison with a single system One particular advantage is scalable redundancy that begins with a redundant PROFI...

Page 90: ...Redundancy concepts Section 3 Fieldbus Topologies 90 3BDS009029R5001 B Figure 34 Master Line and Slave Redundancy...

Page 91: ...cuit and error adaptation in respect of cables connectors repeaters media converters and links If the PROFIBUS slave has not been implemented a redundant PROFIBUS interface and if however an analysis...

Page 92: ...Conversion of a non red PROFIBUS line into two redundant lines and vice versa Automatic line selection Transmission rate 9 6 kbit s 12 Mbit s Monitoring of the communication Repeater functionality Red...

Page 93: ...you to avoid damage when installing data cables Protect data cables during storage and transportation shrink cap Observe minimum and maximum ambient conditions Install data cables separately separate...

Page 94: ...the normal cases wire A pin 8 has green color and wire B pin 3 has red color Make sure that the braid shield and if applicable the tape shield underneath it is in good contact with the appropriate co...

Page 95: ...ks between buildings Fiber optic cables provide for protective voltage separation and ensure lightning protection without requiring additional measures Use multi wire cable to reduce cable laying cost...

Page 96: ...rough the cable shield or data lines A more flexible solution is provided by fiber optic cables Additionally another screen grounding is required at each cubicle entry in non intrinsically safe and in...

Page 97: ...distance of 30 cm is provided The lines provided for the energy line e g for converter actuators are screened with a copper braiding PROFIBUS International PI stipulates that the bus cable has additi...

Page 98: ...the data cable wire B red to the terminal PIN3 RxD TxD P 2 Connect the cable shield for both lines to functional ground e g by using a grounding clamp 3 Connect the PROFIBUS DP cable to one of the co...

Page 99: ...be provided It is preferable to use PROFIBUS terminals with an integrated resistor combination that can be turned on and off A short circuit proof power supply to supply the resistors located in the c...

Page 100: ...e that the distance between the PROFIBUS DP socket of the head station and an intrinsically safe PROFIBUS PA connection of the Power Link Module PL 890 must be at least 50 mm measured straight 2 If a...

Page 101: ...used independently of whether or not it is a manufacturer specific or profile GSD always use the DP GSD Some PROFIBUS PA field device manufacturers do not offer any PROFIBUS DP GSDs In this case the e...

Page 102: ...ieves the bus subscriber from supplying the resistor network Now the redundant master or the last subscriber on this transmission line can be switched idle without loss of communication Depending on t...

Page 103: ...d by a PROFIBUS network to 10 km two wire cable and 93 75 kBit s and the number of stations to 127 with a maximum of 32 bus connections per segment Please find detailed information in the manufacturer...

Page 104: ...to a cabinet from the outside must be clamped at the point of entry inside the cabinet and connected to the cabinet ground with a large contact surface area When removing the cable jackets it is impor...

Page 105: ...open or short circuits of data cables or shield and incorrectly connected terminating resistors The measurements should be carried out for each bus segment after installing the PROFIBUS cables and att...

Page 106: ...on around 195 ohms between pin 3 and 6 one bus termination switched on around 220 ohms between pin 3 and 8 both bus terminations switched on around 110 ohms between pin 3 and 8 one bus termination swi...

Page 107: ...following pictures shows the correct installation as well as the common installation errors Use an oscilloscope to check the voltage signals on the bus segment 1 A correct PROFIBUS installation The m...

Page 108: ...missioning of PROFIBUS 108 3BDS009029R5001 B 2 One bus termination is not powered 5 V or two 390 Ohm resistors are missing The measured voltage between the both transmission lines is 0 62 V Figure 42...

Page 109: ...ed 5 V or two 390 Ohm resistors are missing and one additional bus termination 220 Ohm placed between the transmission lines The measured voltage between the both transmission lines is 0 43 V 4 One ad...

Page 110: ...In contrast to PROFIBUS PA you must ensure the correct polarity for PROFIBUS DP When using a 9 pin D SUB connector the connector assignment is Pin No 3 RxD TxD P Receive Transmit data Plus and Pin No...

Page 111: ...ed to verify the quality of potential or operating fieldbus segments A list of supplier is available on the PROFIBUS International web page www profibus com Can I add new wire and mix it with installe...

Page 112: ...rminator has the same characteristic impedance as the bus and is required to preserve the integrity of the signal It is especially important on long segments and placement is critical one should be co...

Page 113: ...91 D Data security 22 Data transmission 22 Delay times 74 DGND 67 DP V0 21 DP V1 21 DP Cable type A 26 D Sub 67 Dual fiber optical 47 E EMC 69 Energy lines 97 F FDE 35 73 Fibre Optic 42 Fibre optics 8...

Page 114: ...84 Point to Point 59 Polarity 38 104 PROFIBUS 17 DP 19 DP PA Linking Device 40 PA 19 Protocols 18 Protection type 22 PTB 23 R Redundancy 89 Redundancy Link Module 92 Remote feeding 22 Repeater 102 RLM...

Page 115: ...de in this User Manual for 800xA 5 1 Rev A The revision index of this User Manual is not related to the 800xA 5 1 System Revision Revision Index Description Date First version published for 800xA 5 0...

Page 116: ...Updates in Revision Index B 116 3BDS009029R5001 B...

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Page 118: ...6778 0222 E Mail processautomation sg abb com www abb com controlsystems ABB Automation GmbH Control Systems Mannheim Germany Phone 49 1805 26 67 76 Fax 49 1805 77 63 29 E Mail marketing control prod...

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