02 Transmission Media Profibus
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Automation and Drives
Transmission media for PROFIBUS Interface for the first station
Interface for the last station Bus termination
+5V
Bus termination
VP (6)
(6) VP + 5 V
390 >
390 >
Data line B
RxD/TxD-P (3)
220 >
(3) RxD/TxD-P
220 >
Data line A
RxD/TxD-N (8)
(8) RxD/TxD-N
390 >
390 > (5) DGND
DGND (5)
A
B
A
B
Station 1 .............. Station 32 SITRAIN IK-PBSYS / Transmission Media
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Contents
07/2007 © Siemens AG 2007 - All reights reserved
Page
Electrical network, introduction ......................................................................................................... Cables for the electrical PROFIBUS network .................................................................................... Structure of a segment in the electrical network ................................................................................ Use of “FastConnect - Technology“ ......................................................................................... Principal outlay for the interfaces used with RS 485 ......................................................................... Terminating resistor for the electrical PROFIBUS DP ....................................................................... Resistor for terminating PROFIBUS ................................................................................................. Topology of an electrical PROFIBUS system with repeaters ............................................................. Configuration options with repeaters ................................................................................................. DP/DP coupler ................................................................................................................................. Diagnostic repeater .......................................................................................................................... BT200 test unit for bus cables to RS485 ........................................................................................... Components of an optical bus system .............................................................................................. Advantages of the optical bus system ............................................................................................... Glass FOC: Fiber-optic cable ........................................................................................................... Glass FOCs: Various types .............................................................................................................. Optical Link Modul (OLM/ S4) .......................................................................................................... Line topology .................................................................................................................................... Star topology .................................................................................................................................... Bus cable and connections for PROFIBUS PA ................................................................................. Basic PROFIBUS-PA components: Coupler and Link .......................................................................
SITRAIN Training for Automation and Industrial Solutions
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2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
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Automation and Drives
Electrical network, introduction
Explosion proof area
Drive
PROFIBUS cable Connecting cable SITRAIN IK-PBSYS / Transmission Media
Electrical network
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07/2007 © Siemens AG 2007 - All reights reserved
The electrical network uses a shielded twisted-pair cable. The RS 485 interface uses voltage differences. It is therefore more insensitive to disturbances than a voltage or current interface. In PROFIBUS, the nodes are connected to the bus with a bus terminal or bus connector (up to 32 nodes per segment). The individual segments are connected through repeaters. The transmission rate can be adjusted in steps from 9.6 kbit/s to 1.5 Mbit/s. For extremely time-critical PROFIBUS DP applications, the transmission rates 3 and 6 as well as 12 Mbit/s to IEC 61158/ EN 50170 can also be used. The maximum segment length depends of the transmission rate. The electrical network can be configured as a line ( bus) or tree topology (see diagram above). For failsafe applications using PROFIBUS PA transmission technology to IEC 61158-2 is used. In this case, the transmission rate is 31.25 kbit/s.
Features
• High-quality bus cable • Transmission method to RS 485 (in acc. with EIA) • Bus topology with bus terminals and bus connector for connecting PROFIBUS nodes • Transmission procedure to IEC 61158/EN 50170 for universal automation (PROFIBUS FMS/DP) as well as IEC 61158-2 for intrinsically safe applications (PROFIBUS PA) • The network components (DP/PA coupler or DP/PA link) convert the DP transmission technique from RS 485 (bit coding by means of voltage difference signals) to IEC 61158-2 (bit coding by means of current signals) • Simple, system-wide installation and grounding concept • Easy installation.
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Cables for the electrical PROFIBUS network Data cable A: Green core Data cable B: Red core Structure
Shielded twisted-pair cable
Loop resistance
135 ... 165 ohms
Wave impedance
110 ohm / km
Core diameter
0.64 mm
Core cross-section
> 0.34 mm²
Capacitance per unit length
< 30 pF / m
SITRAIN IK-PBSYS / Transmission Media
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07/2007 © Siemens AG 2007 - All reights reserved
FC standard cable 6XV1 830-0EH10 The 6XV1 830 0EH10 bus cable is the standard FastConnect bus cable for PROFIBUS networks. It complies with the requirements of EN 50170, cable type A, with solid copper cores (AWG 22). The combination of twisted cores, foil shield and braided shield makes it especially suitable for installation in industrial environments subjected to electromagnetic interference. The design also guarantees additional stability of the electrical and mechanical data in the installed state. The cable design permits the use of the FastConnect (FC) stripping tool for fast connection of the cable. With the help of the FastConnect stripping tool it is possible to strip the outer shield and cable shield of the new FastConnect bus cables to the correct length in a single step. In this way, the new bus connectors ( except 6ES7 972-0BA30-0XA0) can be connected easily and quickly to the bus cable. Features
The shield material contains special substances which makes the bus cable: • • • •
Application
Non-flammable Self-extinguishing in the event of a fire Resistant to mineral oils and grease Made of non-halogen-free shield material.
The bus cable has been designed for permanent installation in buildings (in-house wiring).
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Structure of a segment in the electrical network Segment range 9.6-19.2-93.75 187.5 500 1500 12000
kbit/s kbit/s kbit/s kbit/s kbit/s
1200m 1000m 400m 200m 100m
without repeater : max. 1000 m on 9.6 kbit/s max. 32 nodes with repeaeter : max. 1000 m on 9.6 kbit/s max. 31 nodes per segment max. 9 repeater in line, max. 127 nodes
twisted, shielded pair
Busconnector SITRAIN IK-PBSYS / Transmission Media
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07/2007 © Siemens AG 2007 - All reights reserved
Twisted-pair cable
The electrical PROFIBUS network uses a shielded twisted-pair cable. The RS 485 interface uses voltage difference signals.
Noise immunity
This interface is especially insensitive to disturbances.
Connection method In PROFIBUS, the nodes are connected to the bus with a bus connector or bus terminal. 32 nodes
Up to 32 interfaces can be connected per bus segment.
Segment length
The maximum segment length depends on the transmission rate.
Transmission rate
The transmission rate can be adjusted in steps from 9.6 kbit/s to 1.5 Mbit/s. For extremely time-critical DP applications and short distances, the additional transmission rates of 3.6 and 12 Mbit/s can be used.
Repeaters
Individual segments are connected via repeaters. The 12 Mbit repeater permits cascading of 10 segments.
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Use of “FastConnect - Technology“ 1. Measure
2. Strip
3. Remove
4. Insert cores into the colored sockets of the connector
6. Tighten cable strain relief
5. Push sockets down
A: Green core B: Red core
SITRAIN IK-PBSYS / Transmission Media
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07/2007 © Siemens AG 2007 - All reights reserved
Preventing errors through FastConnect Correct physical installation of the bus system is a prerequisite for smooth operation of the system. Since badly assembled connectors often result in downtimes, it is important to take great care during installation. The FastConnect connection method for PROFIBUS supports and speeds up this work significantly. Easy-to-use tools, bus cables and connectors permit correct assembly within minutes: • FastConnect stripping tool (6GK1 905-6AA..) • FastConnect standard bus cable (6XV1 830-0E...) • FastConnect bus connector with insulation displacement (6ES7 972-0B .50) Procedure
1.Measure the cable length by comparing the cable with the measuring template. 2.Insert the measured cable end into the stripping tool. Use the index finger of the left hand to determine how deep to insert the cable. Insert the cable in the stripping tool as far as the stop. Turn the stripping tool four times in the clockwise direction to strip the cable. 3.Pull the stripping tool from the end of the cable while closed. Bits of the cable will remain in the tool. When the tool is opened, the bits can be removed. If the white filling was not removed during stripping, remove it with your hand. Pierce the protective foil between the cores with a screwdriver to remove it more easily. Remove the protective foil of the cores.
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Principal outlay for the interfaces used with RS 485 Interface for the first station
Interface for the last station Bus termination
+5V
Bus termination
VP (6)
(6) VP + 5 V
390 >
390 >
Data line B
RxD/TxD-P (3)
220 >
(3) RxD/TxD-P
220 >
Data line A
RxD/TxD-N (8)
(8) RxD/TxD-N
390 >
390 > (5) DGND
DGND (5)
A
B
A
B
Station 1 .............. Station 32
SITRAIN IK-PBSYS / Transmission Media
Bus termination
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07/2007 © Siemens AG 2007 - All reights reserved
This slide shows the wiring and bus termination for a PROFIBUS system with cable type A. This is the preferred installation and termination method for all PROFIBUS networks. The termination for the network is usually located at the beginning and end of the segment. It must be ensured that the terminating resistors are always supplied with power. It is recommended to connect one bus termination to the master and the other one to the last slave of the segment.
Note:
When using repeaters it is meaningful to install one bus termination at the output and the other one at the last station of the bus segment or at the input of the next repeater.
Note:
The stations to which the terminating resistor is connected must always be supplied with power since the bus connector draws power from the station to which it is connected.
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Terminating resistor for the electrical PROFIBUS DP CPU with PROFIBUS DP interface Terminating resistor required
N
N
N
N
N= PROFIBUS DP nodes
CPU with PROFIBUS DP interface Terminating resistor required
Terminating resistor required
N
N
SITRAIN IK-PBSYS / Transmission Media
N
N
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N
N= PROFIBUS DP nodes
07/2007 © Siemens AG 2007 - All reights reserved
Terminating resistor Switch on the terminating resistor of the first and last station of a segment. For bus connectors of the older type, this is done by opening the cover of the bus connector and setting the switch to ON (see diagram). For newer bus connectors, set the red toggle which is located outside the connector to the ON position. Termination principle PROFIBUS is only terminated correctly if the power supply of the node into which the terminating resistor has been inserted has been switched on. If this is not convenient, PROFIBUS can also be connected over an active RS485 terminating resistor (6ES7972-0DA00-0AA0). In this case, the terminating resistor is supplied permanently with a separate voltage from the other I/O components or a voltage that is connected up-circuit from the I/O. Termination of the bus system allows the nodes (e.g. ET 200L) to be connected or disconnected freely without causing errors.
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Resistor for terminating PROFIBUS
PROFIBUS connection
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Cable termination with/without PROFIBUS terminator All segments must be terminated at their ends regardless of the transmission rate. For this purpose, the existing cable termination consisting of a resistor combination must be switched on in the corresponding connection elements. Additional cable segments are not permitted following an activated resistor combination. A cable termination is only active if it is connected to a supply voltage. For this purpose, the corresponding data terminal or RS485 repeater must be supplied with power. Alternatively, the PROFIBUS terminator can be used as a permanent cable termination. PROFIBUS terminator The PROFIBUS terminator is an active bus termination. The main advantage is that nodes on the bus can be switched off, removed or replaced without negatively affecting the data communication. This applies especially to the nodes at the two ends of the bus cable where up to now the terminating resistors had to be connected and supplied. The PROFIBUS terminator can be mounted onto a standard mounting rail.
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Topology of an electrical PROFIBUS system with repeaters OP270
PG attached via tap line for maintenance purposes OP270
OP270
Terminating resistor activated
SITRAIN IK-PBSYS / Transmission Media
RS 485 repeater
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You will require an RS 485 repeater if: • More than 32 stations (including the repeater) are connected to the bus • Bus segments on the bus are to be operated ungrounded or • The maximum cable length of a segment is exceeded The diagram above shows how several segments have been combined into a network by means of repeaters. The RS 485 repeaters support all transmission rates from 9.6 kbits/s to 12 Mbits/s.
Configuration
The following boundary conditions must be considered when configuring an electrical network with RS 485 repeaters: • The maximum segment length for the transmission rate must be observed • The maximum number of bus couplings (nodes, RS 485 repeaters, OLM) on a segment is limited to 32. Additional restrictions may apply if the transmission rate of 1.5 Mbit/s is used. • The maximum number of nodes on a network is limited to 127. • No more than 9 RS 485 repeaters may be installed between two nodes • Each repeater reduces the number of possible nodes in the network by one.
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Automation and Drives
Configuration options with repeaters terminating resistor at segment 1 is ON
Terminating resistor activated! Example 1
terminating resistor at segment 2 is ON terminating resistor at segment 1 is ON
Terminating resistor activated!
Example 2
terminating resistor at segment 2 is OFF
SITRAIN IK-PBSYS / Transmission Media
Examples
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The two configurations in the diagrams above show two examples of possible topologies with repeaters. Please note that the terminating resistance at the beginning and end of a bus segment is switched on i.e. the switch position must be set to ON. Transmission rate
Max. segment length
Max. network size with 9 repeaters
9.6 kbit/s
1,200 m
12,000 m
19.2 kbit/s
1,200 m
12,000 m
45.45 kbit/s
1,200 m
12,000 m
93.75 kbit/s
1,200 m
12,000 m
187.5 kbit/s
1,000 m
10,000 m
500 kbit/s
400 m
4,000 m
1,500 kbit/s
200 m
2,000 m
3,000 kbit/s
100 m
1,000 m
6,000 kbit/s
100 m
1,000 m
12,000 kbit/s
100 m
1,000 m
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DP/DP coupler
PROFIBUS DP (Net 1) 1,5 MBit/s possible bus addresses: 1-122
ET200 PB(1)=3 Slave
Drive PB(1)=4 Slave
PROFIBUS DP (Net 2) 12 MBit/s possible bus addresses: 1-122
ET200 PB(1)=5 Slave
SITRAIN IK-PBSYS / Transmission Media
ET200 PB(„)=3 Slave
Drive PB(2)=4 Slave
ET200 PB(2)=5 Slave
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Task of the DP/DP coupler The DP/DP coupler can be used to transfer data between two PROFIBUS DP networks by means of internal copying. Field of application The PROFIBUS DP/DP coupler is used to connect two PROFIBUS DP networks with each other. This is done by transmitting byte data (0–244 bytes) from the DP master of the first network to the DP master of another network and vice versa. The principle is the same as conventional hard-wiring of inputs and outputs. The coupler uses two independent DP interfaces with which it connects the two DP networks. The DP/DP coupler is a slave on each DP network. Data transmission between the two DP networks is implemented by internal copying in the coupler. Design:
The DP/DP coupler has a compact 40 mm housing and can be mounted on a standard rail. It is recommended that the couplers are installed vertically next to each other. The coupler is connected to the PROFIBUS DP networks via an integrated 9-pin Sub-D connector.
Functions:
The DP/DP coupler continuously copies the output data of one network to the input data of the other network (and vice versa).
Parameterization
The PROFIBUS DP addresses are set via two DIP switches on the top of the unit. The system is configured by means of the GSD file with the configuring tool of the connected PROFIBUS DP master.
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Diagnostic repeater S7-CPU
STEP7 COM PROFIBUS Segment 1 Start determining of topology
Diagnostic distance to slave
distance to disturbance
Segment 2
SITRAIN IK-PBSYS / Transmission Media
Introduction
Segment 3
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07/2007 © Siemens AG 2007 - All reights reserved
During operation, the bus cables are subjected to external influences which can result in damage. This is particularly apparent if they are stressed, e.g. due to trailing cables or strong vibrations. In this case, they should be checked continuously to reduce failures to a minimum.
Diagnostic repeater The diagnostic repeater is used for diagnostics during operation. It is integrated into the PROFIBUS DP network as an RS 485 repeater and also offers powerful functions for cable diagnostics. The diagnostic repeater recognizes the following cable faults: • Open circuit A or B • Line-to-shield short-circuit (signal cables) • Missing bus terminating resistors The diagnostic repeater is configured in STEP 7 as a standard slave with COM PROFIBUS or using a GSD file. Design
• • • • • • •
Connection of 3 segments, two of which have diagnostics capability Connection of up to 62 nodes (31 per segment with diagnostics capability) Installation of up to 9 diagnostic repeaters in series Mounting on an S7-300 DIN rail or standard mounting rail LEDs to indicate 24 V DC, bus activity and line faults per segment Terminal block for external 24 V DC supply voltage 9-pin Sub-D socket for connection to PG, electrically isolated
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BT200 test unit for bus cables to RS485 Testing the PROFIBUS cable: Cable break/shield break Short circuits between cables or cable and shield Fault localization in the event of data cable break/short-circuit Detection of reflections which cause faults Cable replacement Lengths of the installed cables Checking the accessibility of the slaves: List of accessible slaves Specific addressing of individual slaves Checking the RS 485 interfaces of the masters and slaves: RS 485 driver Supply voltage for cable termination RTS signal Display of the PROFIBUS DP address
SITRAIN IK-PBSYS / Transmission Media
Application
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07/2007 © Siemens AG 2007 - All reights reserved
The PROFIBUS cable can be tested with the BT 200 test unit during the installation phase. The wiring can even be checked when the nodes have been connected. Installation errors are detected quickly and easily. The person installing the system does not require specialist PROFIBUS knowledge. The RS 485 interface of the PROFIBUS DP slaves and masters can be tested with the BT 200 even before the system start-up phase. The slaves which can be addressed over the completely wired bus can also be listed without a master on PROFIBUS DP. In this way, the operating capability of individual bus segments can be checked beforehand. This reduces the start-up time. In the event of a fault, the two test functions mentioned above are very helpful for localizing the fault and therefore minimize plant downtimes.
Functions
Cable break/shield break • Short-circuits between cables or between the cable and the shield • Fault localization in the event of a break or short-circuit in the data cables • Detection of reflections which cause faults • Cable replacement • Lengths of the installed cables Checking the availability of the slaves: • List of available slaves • Specific addressing of individual slaves Checking the RS 485 interface of the master/slave: • RS 485 driver • Supply voltage for cable termination • RTS signal.
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Components of an optical bus system ET 200M with IM 153-2FO Field device without fiber-optic interface
OBT: Optical Bus Terminal 1: Fiber-optic cable 1 Fiber-optic cable 2 PROFIBUS cable 3 PROFIBUS connecting cable 830-1T 4 PROFIBUS connecting cable 830-2 (1) Terminating resistor switched on SITRAIN IK-PBSYS / Transmission Media
OLM: Optical Link Module
Up to 15 km
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Characteristics of an optical network • An optical line is permitted to have a maximum of 32 integral optical interfaces in series. • Several lines comprising up to 32 integral optical interfaces can be connected via OBTs (optical repeaters). • For optical networks (line, star, ring) which only consist of OLMs, the number of OLMs is limited to 122. • The number of optical components (integral interfaces, OBTs, OLMs) in the optical PROFIBUS network must be specified in the configuration tool under "Number of OLMs, OBTs”.
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Advantages of the optical bus system •
Electrical isolation of nodes and segments
•
No compensating currents
•
Transmission path is not affected by external electromagnetic interference
•
No lightning protection elements required
•
No noise radiation along the transmission path
•
Low weight
•
Depending on the fiber type, cable lengths of up to a few kilometers can be implemented even for high transmission rates
•
The max. cable length does not depend on the transmission rate
•
The PROFIBUS optical components can be used to implement line, star and ring structures. SITRAIN IK-PBSYS / Transmission Media
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Fiber-optic cables (FOC) In the case of fiber-optic cables (FOC), data is transmitted through modulation of electromagnetic waves in the visible and invisible light spectrum. High-quality plastic and glass fibers are used for this purpose. The different FOC types can be used to match the solution for interconnecting components to the prevailing operating and environmental conditions. The fiber-optic cables for PROFIBUS are available with plastic, PCF and glass fibers: • Glass fiber-optic cable, 2-fiber cable for optical PROFIBUS networks indoors and outdoors • Plastic fiber-optic cable, duplex or standard cable for indoor applications with cable lengths up to 80 m • Plastic fiber-optic cable, standard cable for indoor applications with cable lengths up to 400 m Type of connection Due to technical reasons, FOCs can only be used to implement point-to-point connections i.e. each sender is only connected to one receiver. Duplex transmission between two nodes therefore requires two fibers (one for each direction of transmission).
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Glass FOC: Fiber-optic cable
RS 485-Segment
Monomode Glass FOC >15km Multimode Glass FOC 2-3km
Glass FOC: Fiber-optic cable PCS/HCS FOC 500m
Plastic FOC <80m
RS 485-Segment
SITRAIN IK-PBSYS / Transmission Media
Glass FOC
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Glass FOCs are used to bridge distances in the km range. For these distances, it is often not possible to install an uninterrupted length of cable. In this case, the FOC path must comprise several segments. The connection points consisting of couplings or splicing components cannot be implemented without attenuation. Furthermore, if the transmission path uses glass FOCs, the following must be taken into consideration: • Attenuation of the splicing points • Attenuation of the coupling points • When calculating the transmission path, a system reserve of at least 3 dB (for a wave length of 860 nm) or of at least 2 dB (for a wave length of 1300 nm) must be maintained. There are different versions of SIMATIC NET glass fiber-optic cables (FOC) which allow optimal adaptation to different application areas.
Application
• The fiber-optic standard cable is a universal cable for use indoors and outdoors • The INDOOR Fiber-Optic cable is a halogen-free, trample-resistant, flameretardant FOC cable for use in buildings • The Flexible Fiber-Optic trailing cable is used for special motion control applications • The SIENOPYR marine duplex fiber-optic cable is a hybrid cable made of 2 fiber-optic cables and 2 additional copper cables for permanent installation on ships and offshore installations.
SIMATIC NET standard fibers For glass FOC, SIMATIC NET uses a fiber with a 62.5 micro millimeter core diameter as standard. Splicing points
Repair splicing points must also be taken into account. Depending on the cables and stresses they are exposed to, one or more repairs should be taken into consideration ( approx. 1 per 500 m). Two splicing points are necessary for each repair since a long cable segment often has to be inserted (depending on the accuracy of the fault localization device).
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Glass FOCs: Various types 1 Outer jacket black PVC 2 Inner jacket gray PVC 3 Support element (Impregnated glass yarn) 4 Kevlar yarn 5 Fiber
1 Outer jacket 2 Aramid yarn 3 Fleece/strands 4 Dummy Dummyelement element 5 Support element 6 Inner jacket 7 Aramid yarn 8 Fiber
Standard FO cable Flexible F= Trailing cable
Outer sheath Copolymer FRNC, bright orange Inner sheath Copolymer FRNC, gray Aramid strain relief elements
Standard INDOOR FO cable
FRNC core sleeve Glass fiber G62.5/125 μm
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Standard fiber-optic cable 6XV1820-5 The Standard fiber-optic cable comprises two multimode graded-index fibers of type 62.5/125 μm. The outer casing is printed with “SIEMENS SIMATIC NET FIBER OPTIC 6XV1 820-5AH10” at intervals of about 50 cm. Meter markings consisting of a vertical line and a 4-digit number make it easier to estimate the length of the installed cable. The cable is sold by the meter (up to 4000 m). It is preassembled with 4 BFOC connectors in lengths of up to 1000 m. It is used to connect optical interfaces which use wavelengths around 850 nm and around 1300 nm. INDOOR fiber-optic cable 6XV1820-7 The INDOOR fiber-optic cable comprises two multimode graded-index fibers of 62.5/125 micromilli meters. The outer shield is printed with “SIEMENS SIMATIC NET INDOOR FIBER OPTIC 6XV1 820- 7AH10 FRNC” at intervals of about 50 cm. Meter markings consisting of a vertical line and a 4-digit number make it easier to estimate the length of the installed cable. It is available preassembled with 4 BFOC connectors in lengths from to 0.5 m to 100 m. It is used to connect optical interfaces which use wavelengths around 850 nm and around 1300 nm. Flexible fiber-optic trailing cable 6XV1820-6 The Flexible fiber-optic trailing cable comprises two multimode graded-index fibers of 62.5/125 μm. Integrated dummy elements ensure that the cross-section of the cable is round. The outer shield is printed with “SIEMENS SIMATIC NET FLEXIBLE FIBER OPTIC 6XV1 820- 6AH10” at intervals of about 50 cm. Meter markings consisting of a vertical line and a 4-digit number make it easier to estimate the length of the installed cable. The cable is highly flexible (100,000 bending cycles with a 150 mm/min bending radius) and is sold by the meter (up to 2000 m). It is available preassembled with 4 BFOC connectors in fixed lengths of up to 650 m.
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Optical Link Modul (OLM/ S4)
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Description
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The SINEC L2 optical link modules OLM/P3, OLM/P4, OLM/S3, OLM/S4, OLM/S3-1300 and OLM/S4-1300 are intended for use in optical PROFIBUS fieldbus networks. They can be used to convert electrical PROFIBUS interfaces (RS 485 level) into optical PROFIBUS interfaces and vice versa. You can integrate the modules into the existing PROFIBUS fieldbus network by utilizing the advantages of optical transmission. It is also possible to construct complete PROFIBUS fieldbus networks using optical link modules with a line, star or ring topology. To increase the failure safety of the fieldbus network, the modules OLM/P4, OLM/S4 and OLM/S4-1300 permit redundant network configuration. Each module has three or four channels (ports) which are independent of each other. They in turn consist of one sender and receiver component. Tables 1 and 2 show the different connection options for the modules and the maximum ranges for the individual channels.
Operating voltage
The operating voltage is 24 V DC. To increase availability, a redundant operating voltage supply is possible.
Channels
Channel 1 is implemented as a 9-pin Sub-D socket (female), Channel 2 uses a 2pin terminal block with a shield clamp. The fiber-optic cables are connected using BFOC / 2.5 sockets.
Displays
Five multicolored LEDs signal the current operating status and possible faults.
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Line topology OP270 OP270
Terminating Resistor switched on bus connector 1 Fiber-Optic Cable 2 PROFIBUS Bus Cable 3 PROFIBUS connecting cable 830–1T 4 PROFIBUS connecting cable 830-2 SITRAIN IK-PBSYS / Transmission Media
Line topology
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The individual optical link modules are connected to each other in pairs by means of duplex FOCs. At the beginning and end of a line it is sufficient to use optical link modules that have one optical channel, in between it is necessary to use optical link modules with two optical channels. Individual data terminals or complete PROFIBUS segments with up to 31 nodes can be connected to each optical link module via electrical channels with RS 485 interfaces. The advantage of this topology is that it can be used to bridge large distances. Echo functions (operating mode 0) can be used to monitor the individual FOC paths by means of the two connected optical link modules. If an optical link module fails or if a fiber-optic cable breaks, the overall network breaks up into two subnets. Fault-free operation is still possible within these subnets. If individual point-to-point connections must be established, this can be done with two optical link modules with one optical channel each.
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Star topology
starpoint
OP270
Terminating Resistor switched on 1 Fiber Optic 2 PROFIBUS Cable 4 PROFIBUS connecting cable 830-2 SITRAIN IK-PBSYS / Transmission Media
Star topology
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Several optical link modules are combined into a single PROFIBUS star hub. Additional optical link modules are connected to this hub via duplex fiber-optic cables. The optical link modules of the star hub are connected to each other over one of the electrical channels. The other electrical channels in this network topology are available for connection of data terminals or RS 485 segments. To construct an active PROFIBUS star hub, optical link modules with one or two optical channels can be used. An optical link module with a single channel is sufficient to connect a data terminal or RS 485 bus segment to the active star hub. The echo function (operating mode 0) of the two connected optical link modules can be used to monitor the FOC path. Even if only one direction of transmission fails, the segmentation function coupled with the monitoring system will safely disconnect the whole connection from the network. In a star topology, only the data terminal on the faulty path is disconnected from the network. Fault-free operation is still possible for the rest of the network. To increase the availability of the whole network, a redundant operating voltage supply for the active PROFIBUS star hub is recommended.
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Bus cable and connections for PROFIBUS PA
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Overview
• Bus cable for fieldbus systems according to IEC 61158-2, e.g. PROFIBUS PA • High interference immunity thanks to double shielding • Different variants for different applications (hazardous areas, non-hazardous areas) • Easy length measurement thanks to printed meter markings
Application
Differently marked cables are available for constructing fieldbus networks to IEC 61 158-2 (e.g. PROFIBUS PA) for different applications (hazardous areas, nonhazardous areas).
Design
• Shielded, twisted-pair cable with circular cross-section • System-wide grounding concept can be implemented using the external shield of the bus cable and the grounding terminals of the SpliTConnect system • Printed meter markings.
Cable types
• FC process cable: Special bus cable to IEC 61158-2 for use in hazardous areas and nonhazardous areas. • Bus segments with the RS 485 and IEC 61158-2 transmission method are interconnected using the segment coupler/link.
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Basic PROFIBUS-PA components: Coupler and Link PROFIBUS DP up to 12 Mbit/s
PROFIBUS DP 45.45 kbit/s
DP/PA link (modular expansion capability, head module with up to 5 couplers)
DP/PA coupler
J J
J
J
PROFIBUS PA 31.25 kbit/s
PROFIBUS PA 31.25 kbit/s
Non-Ex variant: I < 400 mA, up to 31 field devices
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Core statement:
For the transition from PROFIBUS-DP (RS 485) to PROFIBUS-PA (IEC 1158-2), the two network components DP/PA coupler and DP/PA link are available. Their use depends on the demands put on the automation technology.
DP/PA coupler
The DP/PA coupler has the following tasks: • Conversion of the data format from non-isochrone (11 bits/character) to isochrone (8 bits/character) and conversion of the transmission rate from 45.45 kbit/s to 31.25 kbit/s and vice versa. The coupler functions like a "wire"; it is not configured and cannot be detected by the bus nodes. • Power supply for the field devices • Limitation of the supply current by means of barriers (for hazardous applications) There are 2 variants of the DP/PA coupler: A non-Ex variant with an output current of up to 400 mA for supplying up to 31 field devices and a certified Exvariant with an output current of up to 90 mA for supplying up to 8 field devices in Zones 0, 1 and 2.
DP/PA link
The DP/PA link comprises up to 5 DP/PA couplers (Ex-variant) or 2 DP/PA couplers (non-Ex-variant) which are connected as a node through a head module to PROFIBUS-DP. The head module is a slave on the higher-level PROFIBUS DP (up to 12 MBit/s) and a master on the lower-level PA lines. These PA lines together form a logical bus. The sum of all field devices on a DP/PA link is limited to 30. This limitation applies regardless of the DP/PA coupler variant used. Prerequisite: The DP master can consistently transmit up to 244 bytes per slave (e.g. CP 443-5 Extended or IM 467). That is, the sum of all cyclic data is limited to 244 bytes per DP/PA link. Example: 20 transmitters (pressure, temperature) with 5 bytes each plus 5 transmitters (flow) with 15 bytes each plus 5 position controllers with 10 bytes each require together 225 bytes. The DP/PA link is used when there are high demands on the cycle time and for large numbers of signals.
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IK-PBSYS Transmission Media
Transmission media for PROFIBUS Interface for the first station
Interface for the last station Bus termination
+5V
Bus termination
VP (6)
(6) VP + 5 V
390 >
390 >
Data line B
RxD/TxD-P (3)
220 >
(3) RxD/TxD-P
220 >
Data line A
RxD/TxD-N (8)
(8) RxD/TxD-N
390 >
390 > (5) DGND
DGND (5)
A
B
A
B
Station 1 .............. Station 32 SITRAIN IK-PBSYS / Transmission Media
Page 1
Contents
07/2007 © Siemens AG 2007 - All reights reserved
Page
Electrical network, introduction ......................................................................................................... Cables for the electrical PROFIBUS network .................................................................................... Structure of a segment in the electrical network ................................................................................ Use of “FastConnect - Technology“ ......................................................................................... Principal outlay for the interfaces used with RS 485 ......................................................................... Terminating resistor for the electrical PROFIBUS DP ....................................................................... Resistor for terminating PROFIBUS ................................................................................................. Topology of an electrical PROFIBUS system with repeaters ............................................................. Configuration options with repeaters ................................................................................................. DP/DP coupler ................................................................................................................................. Diagnostic repeater .......................................................................................................................... BT200 test unit for bus cables to RS485 ........................................................................................... Components of an optical bus system .............................................................................................. Advantages of the optical bus system ............................................................................................... Glass FOC: Fiber-optic cable ........................................................................................................... Glass FOCs: Various types .............................................................................................................. Optical Link Modul (OLM/ S4) .......................................................................................................... Line topology .................................................................................................................................... Star topology .................................................................................................................................... Bus cable and connections for PROFIBUS PA ................................................................................. Basic PROFIBUS-PA components: Coupler and Link .......................................................................
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2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
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Automation and Drives
Electrical network, introduction
Explosion proof area
Drive
PROFIBUS cable Connecting cable SITRAIN IK-PBSYS / Transmission Media
Electrical network
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07/2007 © Siemens AG 2007 - All reights reserved
The electrical network uses a shielded twisted-pair cable. The RS 485 interface uses voltage differences. It is therefore more insensitive to disturbances than a voltage or current interface. In PROFIBUS, the nodes are connected to the bus with a bus terminal or bus connector (up to 32 nodes per segment). The individual segments are connected through repeaters. The transmission rate can be adjusted in steps from 9.6 kbit/s to 1.5 Mbit/s. For extremely time-critical PROFIBUS DP applications, the transmission rates 3 and 6 as well as 12 Mbit/s to IEC 61158/ EN 50170 can also be used. The maximum segment length depends of the transmission rate. The electrical network can be configured as a line ( bus) or tree topology (see diagram above). For failsafe applications using PROFIBUS PA transmission technology to IEC 61158-2 is used. In this case, the transmission rate is 31.25 kbit/s.
Features
• High-quality bus cable • Transmission method to RS 485 (in acc. with EIA) • Bus topology with bus terminals and bus connector for connecting PROFIBUS nodes • Transmission procedure to IEC 61158/EN 50170 for universal automation (PROFIBUS FMS/DP) as well as IEC 61158-2 for intrinsically safe applications (PROFIBUS PA) • The network components (DP/PA coupler or DP/PA link) convert the DP transmission technique from RS 485 (bit coding by means of voltage difference signals) to IEC 61158-2 (bit coding by means of current signals) • Simple, system-wide installation and grounding concept • Easy installation.
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Cables for the electrical PROFIBUS network Data cable A: Green core Data cable B: Red core Structure
Shielded twisted-pair cable
Loop resistance
135 ... 165 ohms
Wave impedance
110 ohm / km
Core diameter
0.64 mm
Core cross-section
> 0.34 mm²
Capacitance per unit length
< 30 pF / m
SITRAIN IK-PBSYS / Transmission Media
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FC standard cable 6XV1 830-0EH10 The 6XV1 830 0EH10 bus cable is the standard FastConnect bus cable for PROFIBUS networks. It complies with the requirements of EN 50170, cable type A, with solid copper cores (AWG 22). The combination of twisted cores, foil shield and braided shield makes it especially suitable for installation in industrial environments subjected to electromagnetic interference. The design also guarantees additional stability of the electrical and mechanical data in the installed state. The cable design permits the use of the FastConnect (FC) stripping tool for fast connection of the cable. With the help of the FastConnect stripping tool it is possible to strip the outer shield and cable shield of the new FastConnect bus cables to the correct length in a single step. In this way, the new bus connectors ( except 6ES7 972-0BA30-0XA0) can be connected easily and quickly to the bus cable. Features
The shield material contains special substances which makes the bus cable: • • • •
Application
Non-flammable Self-extinguishing in the event of a fire Resistant to mineral oils and grease Made of non-halogen-free shield material.
The bus cable has been designed for permanent installation in buildings (in-house wiring).
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Structure of a segment in the electrical network Segment range 9.6-19.2-93.75 187.5 500 1500 12000
kbit/s kbit/s kbit/s kbit/s kbit/s
1200m 1000m 400m 200m 100m
without repeater : max. 1000 m on 9.6 kbit/s max. 32 nodes with repeaeter : max. 1000 m on 9.6 kbit/s max. 31 nodes per segment max. 9 repeater in line, max. 127 nodes
twisted, shielded pair
Busconnector SITRAIN IK-PBSYS / Transmission Media
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Twisted-pair cable
The electrical PROFIBUS network uses a shielded twisted-pair cable. The RS 485 interface uses voltage difference signals.
Noise immunity
This interface is especially insensitive to disturbances.
Connection method In PROFIBUS, the nodes are connected to the bus with a bus connector or bus terminal. 32 nodes
Up to 32 interfaces can be connected per bus segment.
Segment length
The maximum segment length depends on the transmission rate.
Transmission rate
The transmission rate can be adjusted in steps from 9.6 kbit/s to 1.5 Mbit/s. For extremely time-critical DP applications and short distances, the additional transmission rates of 3.6 and 12 Mbit/s can be used.
Repeaters
Individual segments are connected via repeaters. The 12 Mbit repeater permits cascading of 10 segments.
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Use of “FastConnect - Technology“ 1. Measure
2. Strip
3. Remove
4. Insert cores into the colored sockets of the connector
6. Tighten cable strain relief
5. Push sockets down
A: Green core B: Red core
SITRAIN IK-PBSYS / Transmission Media
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Preventing errors through FastConnect Correct physical installation of the bus system is a prerequisite for smooth operation of the system. Since badly assembled connectors often result in downtimes, it is important to take great care during installation. The FastConnect connection method for PROFIBUS supports and speeds up this work significantly. Easy-to-use tools, bus cables and connectors permit correct assembly within minutes: • FastConnect stripping tool (6GK1 905-6AA..) • FastConnect standard bus cable (6XV1 830-0E...) • FastConnect bus connector with insulation displacement (6ES7 972-0B .50) Procedure
1.Measure the cable length by comparing the cable with the measuring template. 2.Insert the measured cable end into the stripping tool. Use the index finger of the left hand to determine how deep to insert the cable. Insert the cable in the stripping tool as far as the stop. Turn the stripping tool four times in the clockwise direction to strip the cable. 3.Pull the stripping tool from the end of the cable while closed. Bits of the cable will remain in the tool. When the tool is opened, the bits can be removed. If the white filling was not removed during stripping, remove it with your hand. Pierce the protective foil between the cores with a screwdriver to remove it more easily. Remove the protective foil of the cores.
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Automation and Drives
Principal outlay for the interfaces used with RS 485 Interface for the first station
Interface for the last station Bus termination
+5V
Bus termination
VP (6)
(6) VP + 5 V
390 >
390 >
Data line B
RxD/TxD-P (3)
220 >
(3) RxD/TxD-P
220 >
Data line A
RxD/TxD-N (8)
(8) RxD/TxD-N
390 >
390 > (5) DGND
DGND (5)
A
B
A
B
Station 1 .............. Station 32
SITRAIN IK-PBSYS / Transmission Media
Bus termination
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07/2007 © Siemens AG 2007 - All reights reserved
This slide shows the wiring and bus termination for a PROFIBUS system with cable type A. This is the preferred installation and termination method for all PROFIBUS networks. The termination for the network is usually located at the beginning and end of the segment. It must be ensured that the terminating resistors are always supplied with power. It is recommended to connect one bus termination to the master and the other one to the last slave of the segment.
Note:
When using repeaters it is meaningful to install one bus termination at the output and the other one at the last station of the bus segment or at the input of the next repeater.
Note:
The stations to which the terminating resistor is connected must always be supplied with power since the bus connector draws power from the station to which it is connected.
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Terminating resistor for the electrical PROFIBUS DP CPU with PROFIBUS DP interface Terminating resistor required
N
N
N
N
N= PROFIBUS DP nodes
CPU with PROFIBUS DP interface Terminating resistor required
Terminating resistor required
N
N
SITRAIN IK-PBSYS / Transmission Media
N
N
Page 7
N
N= PROFIBUS DP nodes
07/2007 © Siemens AG 2007 - All reights reserved
Terminating resistor Switch on the terminating resistor of the first and last station of a segment. For bus connectors of the older type, this is done by opening the cover of the bus connector and setting the switch to ON (see diagram). For newer bus connectors, set the red toggle which is located outside the connector to the ON position. Termination principle PROFIBUS is only terminated correctly if the power supply of the node into which the terminating resistor has been inserted has been switched on. If this is not convenient, PROFIBUS can also be connected over an active RS485 terminating resistor (6ES7972-0DA00-0AA0). In this case, the terminating resistor is supplied permanently with a separate voltage from the other I/O components or a voltage that is connected up-circuit from the I/O. Termination of the bus system allows the nodes (e.g. ET 200L) to be connected or disconnected freely without causing errors.
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Automation and Drives
Resistor for terminating PROFIBUS
PROFIBUS connection
SITRAIN IK-PBSYS / Transmission Media
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Cable termination with/without PROFIBUS terminator All segments must be terminated at their ends regardless of the transmission rate. For this purpose, the existing cable termination consisting of a resistor combination must be switched on in the corresponding connection elements. Additional cable segments are not permitted following an activated resistor combination. A cable termination is only active if it is connected to a supply voltage. For this purpose, the corresponding data terminal or RS485 repeater must be supplied with power. Alternatively, the PROFIBUS terminator can be used as a permanent cable termination. PROFIBUS terminator The PROFIBUS terminator is an active bus termination. The main advantage is that nodes on the bus can be switched off, removed or replaced without negatively affecting the data communication. This applies especially to the nodes at the two ends of the bus cable where up to now the terminating resistors had to be connected and supplied. The PROFIBUS terminator can be mounted onto a standard mounting rail.
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Automation and Drives
Topology of an electrical PROFIBUS system with repeaters OP270
PG attached via tap line for maintenance purposes OP270
OP270
Terminating resistor activated
SITRAIN IK-PBSYS / Transmission Media
RS 485 repeater
Page 9
07/2007 © Siemens AG 2007 - All reights reserved
You will require an RS 485 repeater if: • More than 32 stations (including the repeater) are connected to the bus • Bus segments on the bus are to be operated ungrounded or • The maximum cable length of a segment is exceeded The diagram above shows how several segments have been combined into a network by means of repeaters. The RS 485 repeaters support all transmission rates from 9.6 kbits/s to 12 Mbits/s.
Configuration
The following boundary conditions must be considered when configuring an electrical network with RS 485 repeaters: • The maximum segment length for the transmission rate must be observed • The maximum number of bus couplings (nodes, RS 485 repeaters, OLM) on a segment is limited to 32. Additional restrictions may apply if the transmission rate of 1.5 Mbit/s is used. • The maximum number of nodes on a network is limited to 127. • No more than 9 RS 485 repeaters may be installed between two nodes • Each repeater reduces the number of possible nodes in the network by one.
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Automation and Drives
Configuration options with repeaters terminating resistor at segment 1 is ON
Terminating resistor activated! Example 1
terminating resistor at segment 2 is ON terminating resistor at segment 1 is ON
Terminating resistor activated!
Example 2
terminating resistor at segment 2 is OFF
SITRAIN IK-PBSYS / Transmission Media
Examples
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The two configurations in the diagrams above show two examples of possible topologies with repeaters. Please note that the terminating resistance at the beginning and end of a bus segment is switched on i.e. the switch position must be set to ON. Transmission rate
Max. segment length
Max. network size with 9 repeaters
9.6 kbit/s
1,200 m
12,000 m
19.2 kbit/s
1,200 m
12,000 m
45.45 kbit/s
1,200 m
12,000 m
93.75 kbit/s
1,200 m
12,000 m
187.5 kbit/s
1,000 m
10,000 m
500 kbit/s
400 m
4,000 m
1,500 kbit/s
200 m
2,000 m
3,000 kbit/s
100 m
1,000 m
6,000 kbit/s
100 m
1,000 m
12,000 kbit/s
100 m
1,000 m
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DP/DP coupler
PROFIBUS DP (Net 1) 1,5 MBit/s possible bus addresses: 1-122
ET200 PB(1)=3 Slave
Drive PB(1)=4 Slave
PROFIBUS DP (Net 2) 12 MBit/s possible bus addresses: 1-122
ET200 PB(1)=5 Slave
SITRAIN IK-PBSYS / Transmission Media
ET200 PB(„)=3 Slave
Drive PB(2)=4 Slave
ET200 PB(2)=5 Slave
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07/2007 © Siemens AG 2007 - All reights reserved
Task of the DP/DP coupler The DP/DP coupler can be used to transfer data between two PROFIBUS DP networks by means of internal copying. Field of application The PROFIBUS DP/DP coupler is used to connect two PROFIBUS DP networks with each other. This is done by transmitting byte data (0–244 bytes) from the DP master of the first network to the DP master of another network and vice versa. The principle is the same as conventional hard-wiring of inputs and outputs. The coupler uses two independent DP interfaces with which it connects the two DP networks. The DP/DP coupler is a slave on each DP network. Data transmission between the two DP networks is implemented by internal copying in the coupler. Design:
The DP/DP coupler has a compact 40 mm housing and can be mounted on a standard rail. It is recommended that the couplers are installed vertically next to each other. The coupler is connected to the PROFIBUS DP networks via an integrated 9-pin Sub-D connector.
Functions:
The DP/DP coupler continuously copies the output data of one network to the input data of the other network (and vice versa).
Parameterization
The PROFIBUS DP addresses are set via two DIP switches on the top of the unit. The system is configured by means of the GSD file with the configuring tool of the connected PROFIBUS DP master.
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Diagnostic repeater S7-CPU
STEP7 COM PROFIBUS Segment 1 Start determining of topology
Diagnostic distance to slave
distance to disturbance
Segment 2
SITRAIN IK-PBSYS / Transmission Media
Introduction
Segment 3
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07/2007 © Siemens AG 2007 - All reights reserved
During operation, the bus cables are subjected to external influences which can result in damage. This is particularly apparent if they are stressed, e.g. due to trailing cables or strong vibrations. In this case, they should be checked continuously to reduce failures to a minimum.
Diagnostic repeater The diagnostic repeater is used for diagnostics during operation. It is integrated into the PROFIBUS DP network as an RS 485 repeater and also offers powerful functions for cable diagnostics. The diagnostic repeater recognizes the following cable faults: • Open circuit A or B • Line-to-shield short-circuit (signal cables) • Missing bus terminating resistors The diagnostic repeater is configured in STEP 7 as a standard slave with COM PROFIBUS or using a GSD file. Design
• • • • • • •
Connection of 3 segments, two of which have diagnostics capability Connection of up to 62 nodes (31 per segment with diagnostics capability) Installation of up to 9 diagnostic repeaters in series Mounting on an S7-300 DIN rail or standard mounting rail LEDs to indicate 24 V DC, bus activity and line faults per segment Terminal block for external 24 V DC supply voltage 9-pin Sub-D socket for connection to PG, electrically isolated
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BT200 test unit for bus cables to RS485 Testing the PROFIBUS cable: Cable break/shield break Short circuits between cables or cable and shield Fault localization in the event of data cable break/short-circuit Detection of reflections which cause faults Cable replacement Lengths of the installed cables Checking the accessibility of the slaves: List of accessible slaves Specific addressing of individual slaves Checking the RS 485 interfaces of the masters and slaves: RS 485 driver Supply voltage for cable termination RTS signal Display of the PROFIBUS DP address
SITRAIN IK-PBSYS / Transmission Media
Application
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07/2007 © Siemens AG 2007 - All reights reserved
The PROFIBUS cable can be tested with the BT 200 test unit during the installation phase. The wiring can even be checked when the nodes have been connected. Installation errors are detected quickly and easily. The person installing the system does not require specialist PROFIBUS knowledge. The RS 485 interface of the PROFIBUS DP slaves and masters can be tested with the BT 200 even before the system start-up phase. The slaves which can be addressed over the completely wired bus can also be listed without a master on PROFIBUS DP. In this way, the operating capability of individual bus segments can be checked beforehand. This reduces the start-up time. In the event of a fault, the two test functions mentioned above are very helpful for localizing the fault and therefore minimize plant downtimes.
Functions
Cable break/shield break • Short-circuits between cables or between the cable and the shield • Fault localization in the event of a break or short-circuit in the data cables • Detection of reflections which cause faults • Cable replacement • Lengths of the installed cables Checking the availability of the slaves: • List of available slaves • Specific addressing of individual slaves Checking the RS 485 interface of the master/slave: • RS 485 driver • Supply voltage for cable termination • RTS signal.
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Components of an optical bus system ET 200M with IM 153-2FO Field device without fiber-optic interface
OBT: Optical Bus Terminal 1: Fiber-optic cable 1 Fiber-optic cable 2 PROFIBUS cable 3 PROFIBUS connecting cable 830-1T 4 PROFIBUS connecting cable 830-2 (1) Terminating resistor switched on SITRAIN IK-PBSYS / Transmission Media
OLM: Optical Link Module
Up to 15 km
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Characteristics of an optical network • An optical line is permitted to have a maximum of 32 integral optical interfaces in series. • Several lines comprising up to 32 integral optical interfaces can be connected via OBTs (optical repeaters). • For optical networks (line, star, ring) which only consist of OLMs, the number of OLMs is limited to 122. • The number of optical components (integral interfaces, OBTs, OLMs) in the optical PROFIBUS network must be specified in the configuration tool under "Number of OLMs, OBTs”.
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Advantages of the optical bus system •
Electrical isolation of nodes and segments
•
No compensating currents
•
Transmission path is not affected by external electromagnetic interference
•
No lightning protection elements required
•
No noise radiation along the transmission path
•
Low weight
•
Depending on the fiber type, cable lengths of up to a few kilometers can be implemented even for high transmission rates
•
The max. cable length does not depend on the transmission rate
•
The PROFIBUS optical components can be used to implement line, star and ring structures. SITRAIN IK-PBSYS / Transmission Media
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Fiber-optic cables (FOC) In the case of fiber-optic cables (FOC), data is transmitted through modulation of electromagnetic waves in the visible and invisible light spectrum. High-quality plastic and glass fibers are used for this purpose. The different FOC types can be used to match the solution for interconnecting components to the prevailing operating and environmental conditions. The fiber-optic cables for PROFIBUS are available with plastic, PCF and glass fibers: • Glass fiber-optic cable, 2-fiber cable for optical PROFIBUS networks indoors and outdoors • Plastic fiber-optic cable, duplex or standard cable for indoor applications with cable lengths up to 80 m • Plastic fiber-optic cable, standard cable for indoor applications with cable lengths up to 400 m Type of connection Due to technical reasons, FOCs can only be used to implement point-to-point connections i.e. each sender is only connected to one receiver. Duplex transmission between two nodes therefore requires two fibers (one for each direction of transmission).
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Glass FOC: Fiber-optic cable
RS 485-Segment
Monomode Glass FOC >15km Multimode Glass FOC 2-3km
Glass FOC: Fiber-optic cable PCS/HCS FOC 500m
Plastic FOC <80m
RS 485-Segment
SITRAIN IK-PBSYS / Transmission Media
Glass FOC
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07/2007 © Siemens AG 2007 - All reights reserved
Glass FOCs are used to bridge distances in the km range. For these distances, it is often not possible to install an uninterrupted length of cable. In this case, the FOC path must comprise several segments. The connection points consisting of couplings or splicing components cannot be implemented without attenuation. Furthermore, if the transmission path uses glass FOCs, the following must be taken into consideration: • Attenuation of the splicing points • Attenuation of the coupling points • When calculating the transmission path, a system reserve of at least 3 dB (for a wave length of 860 nm) or of at least 2 dB (for a wave length of 1300 nm) must be maintained. There are different versions of SIMATIC NET glass fiber-optic cables (FOC) which allow optimal adaptation to different application areas.
Application
• The fiber-optic standard cable is a universal cable for use indoors and outdoors • The INDOOR Fiber-Optic cable is a halogen-free, trample-resistant, flameretardant FOC cable for use in buildings • The Flexible Fiber-Optic trailing cable is used for special motion control applications • The SIENOPYR marine duplex fiber-optic cable is a hybrid cable made of 2 fiber-optic cables and 2 additional copper cables for permanent installation on ships and offshore installations.
SIMATIC NET standard fibers For glass FOC, SIMATIC NET uses a fiber with a 62.5 micro millimeter core diameter as standard. Splicing points
Repair splicing points must also be taken into account. Depending on the cables and stresses they are exposed to, one or more repairs should be taken into consideration ( approx. 1 per 500 m). Two splicing points are necessary for each repair since a long cable segment often has to be inserted (depending on the accuracy of the fault localization device).
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Glass FOCs: Various types 1 Outer jacket black PVC 2 Inner jacket gray PVC 3 Support element (Impregnated glass yarn) 4 Kevlar yarn 5 Fiber
1 Outer jacket 2 Aramid yarn 3 Fleece/strands 4 Dummy Dummyelement element 5 Support element 6 Inner jacket 7 Aramid yarn 8 Fiber
Standard FO cable Flexible F= Trailing cable
Outer sheath Copolymer FRNC, bright orange Inner sheath Copolymer FRNC, gray Aramid strain relief elements
Standard INDOOR FO cable
FRNC core sleeve Glass fiber G62.5/125 μm
SITRAIN IK-PBSYS / Transmission Media
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Standard fiber-optic cable 6XV1820-5 The Standard fiber-optic cable comprises two multimode graded-index fibers of type 62.5/125 μm. The outer casing is printed with “SIEMENS SIMATIC NET FIBER OPTIC 6XV1 820-5AH10” at intervals of about 50 cm. Meter markings consisting of a vertical line and a 4-digit number make it easier to estimate the length of the installed cable. The cable is sold by the meter (up to 4000 m). It is preassembled with 4 BFOC connectors in lengths of up to 1000 m. It is used to connect optical interfaces which use wavelengths around 850 nm and around 1300 nm. INDOOR fiber-optic cable 6XV1820-7 The INDOOR fiber-optic cable comprises two multimode graded-index fibers of 62.5/125 micromilli meters. The outer shield is printed with “SIEMENS SIMATIC NET INDOOR FIBER OPTIC 6XV1 820- 7AH10 FRNC” at intervals of about 50 cm. Meter markings consisting of a vertical line and a 4-digit number make it easier to estimate the length of the installed cable. It is available preassembled with 4 BFOC connectors in lengths from to 0.5 m to 100 m. It is used to connect optical interfaces which use wavelengths around 850 nm and around 1300 nm. Flexible fiber-optic trailing cable 6XV1820-6 The Flexible fiber-optic trailing cable comprises two multimode graded-index fibers of 62.5/125 μm. Integrated dummy elements ensure that the cross-section of the cable is round. The outer shield is printed with “SIEMENS SIMATIC NET FLEXIBLE FIBER OPTIC 6XV1 820- 6AH10” at intervals of about 50 cm. Meter markings consisting of a vertical line and a 4-digit number make it easier to estimate the length of the installed cable. The cable is highly flexible (100,000 bending cycles with a 150 mm/min bending radius) and is sold by the meter (up to 2000 m). It is available preassembled with 4 BFOC connectors in fixed lengths of up to 650 m.
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IK-PBSYS Transmission Media
Automation and Drives
Optical Link Modul (OLM/ S4)
SITRAIN IK-PBSYS / Transmission Media
Description
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07/2007 © Siemens AG 2007 - All reights reserved
The SINEC L2 optical link modules OLM/P3, OLM/P4, OLM/S3, OLM/S4, OLM/S3-1300 and OLM/S4-1300 are intended for use in optical PROFIBUS fieldbus networks. They can be used to convert electrical PROFIBUS interfaces (RS 485 level) into optical PROFIBUS interfaces and vice versa. You can integrate the modules into the existing PROFIBUS fieldbus network by utilizing the advantages of optical transmission. It is also possible to construct complete PROFIBUS fieldbus networks using optical link modules with a line, star or ring topology. To increase the failure safety of the fieldbus network, the modules OLM/P4, OLM/S4 and OLM/S4-1300 permit redundant network configuration. Each module has three or four channels (ports) which are independent of each other. They in turn consist of one sender and receiver component. Tables 1 and 2 show the different connection options for the modules and the maximum ranges for the individual channels.
Operating voltage
The operating voltage is 24 V DC. To increase availability, a redundant operating voltage supply is possible.
Channels
Channel 1 is implemented as a 9-pin Sub-D socket (female), Channel 2 uses a 2pin terminal block with a shield clamp. The fiber-optic cables are connected using BFOC / 2.5 sockets.
Displays
Five multicolored LEDs signal the current operating status and possible faults.
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IK-PBSYS Transmission Media
Automation and Drives
Line topology OP270 OP270
Terminating Resistor switched on bus connector 1 Fiber-Optic Cable 2 PROFIBUS Bus Cable 3 PROFIBUS connecting cable 830–1T 4 PROFIBUS connecting cable 830-2 SITRAIN IK-PBSYS / Transmission Media
Line topology
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07/2007 © Siemens AG 2007 - All reights reserved
The individual optical link modules are connected to each other in pairs by means of duplex FOCs. At the beginning and end of a line it is sufficient to use optical link modules that have one optical channel, in between it is necessary to use optical link modules with two optical channels. Individual data terminals or complete PROFIBUS segments with up to 31 nodes can be connected to each optical link module via electrical channels with RS 485 interfaces. The advantage of this topology is that it can be used to bridge large distances. Echo functions (operating mode 0) can be used to monitor the individual FOC paths by means of the two connected optical link modules. If an optical link module fails or if a fiber-optic cable breaks, the overall network breaks up into two subnets. Fault-free operation is still possible within these subnets. If individual point-to-point connections must be established, this can be done with two optical link modules with one optical channel each.
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IK-PBSYS Transmission Media
Automation and Drives
Star topology
starpoint
OP270
Terminating Resistor switched on 1 Fiber Optic 2 PROFIBUS Cable 4 PROFIBUS connecting cable 830-2 SITRAIN IK-PBSYS / Transmission Media
Star topology
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Several optical link modules are combined into a single PROFIBUS star hub. Additional optical link modules are connected to this hub via duplex fiber-optic cables. The optical link modules of the star hub are connected to each other over one of the electrical channels. The other electrical channels in this network topology are available for connection of data terminals or RS 485 segments. To construct an active PROFIBUS star hub, optical link modules with one or two optical channels can be used. An optical link module with a single channel is sufficient to connect a data terminal or RS 485 bus segment to the active star hub. The echo function (operating mode 0) of the two connected optical link modules can be used to monitor the FOC path. Even if only one direction of transmission fails, the segmentation function coupled with the monitoring system will safely disconnect the whole connection from the network. In a star topology, only the data terminal on the faulty path is disconnected from the network. Fault-free operation is still possible for the rest of the network. To increase the availability of the whole network, a redundant operating voltage supply for the active PROFIBUS star hub is recommended.
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IK-PBSYS Transmission Media
Automation and Drives
Bus cable and connections for PROFIBUS PA
SITRAIN IK-PBSYS / Transmission Media
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07/2007 © Siemens AG 2007 - All reights reserved
Overview
• Bus cable for fieldbus systems according to IEC 61158-2, e.g. PROFIBUS PA • High interference immunity thanks to double shielding • Different variants for different applications (hazardous areas, non-hazardous areas) • Easy length measurement thanks to printed meter markings
Application
Differently marked cables are available for constructing fieldbus networks to IEC 61 158-2 (e.g. PROFIBUS PA) for different applications (hazardous areas, nonhazardous areas).
Design
• Shielded, twisted-pair cable with circular cross-section • System-wide grounding concept can be implemented using the external shield of the bus cable and the grounding terminals of the SpliTConnect system • Printed meter markings.
Cable types
• FC process cable: Special bus cable to IEC 61158-2 for use in hazardous areas and nonhazardous areas. • Bus segments with the RS 485 and IEC 61158-2 transmission method are interconnected using the segment coupler/link.
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IK-PBSYS Transmission Media
Automation and Drives
Basic PROFIBUS-PA components: Coupler and Link PROFIBUS DP up to 12 Mbit/s
PROFIBUS DP 45.45 kbit/s
DP/PA link (modular expansion capability, head module with up to 5 couplers)
DP/PA coupler
J J
J
J
PROFIBUS PA 31.25 kbit/s
PROFIBUS PA 31.25 kbit/s
Non-Ex variant: I < 400 mA, up to 31 field devices
SITRAIN IK-PBSYS / Transmission Media
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07/2007 © Siemens AG 2007 - All reights reserved
Core statement:
For the transition from PROFIBUS-DP (RS 485) to PROFIBUS-PA (IEC 1158-2), the two network components DP/PA coupler and DP/PA link are available. Their use depends on the demands put on the automation technology.
DP/PA coupler
The DP/PA coupler has the following tasks: • Conversion of the data format from non-isochrone (11 bits/character) to isochrone (8 bits/character) and conversion of the transmission rate from 45.45 kbit/s to 31.25 kbit/s and vice versa. The coupler functions like a "wire"; it is not configured and cannot be detected by the bus nodes. • Power supply for the field devices • Limitation of the supply current by means of barriers (for hazardous applications) There are 2 variants of the DP/PA coupler: A non-Ex variant with an output current of up to 400 mA for supplying up to 31 field devices and a certified Exvariant with an output current of up to 90 mA for supplying up to 8 field devices in Zones 0, 1 and 2.
DP/PA link
The DP/PA link comprises up to 5 DP/PA couplers (Ex-variant) or 2 DP/PA couplers (non-Ex-variant) which are connected as a node through a head module to PROFIBUS-DP. The head module is a slave on the higher-level PROFIBUS DP (up to 12 MBit/s) and a master on the lower-level PA lines. These PA lines together form a logical bus. The sum of all field devices on a DP/PA link is limited to 30. This limitation applies regardless of the DP/PA coupler variant used. Prerequisite: The DP master can consistently transmit up to 244 bytes per slave (e.g. CP 443-5 Extended or IM 467). That is, the sum of all cyclic data is limited to 244 bytes per DP/PA link. Example: 20 transmitters (pressure, temperature) with 5 bytes each plus 5 transmitters (flow) with 15 bytes each plus 5 position controllers with 10 bytes each require together 225 bytes. The DP/PA link is used when there are high demands on the cycle time and for large numbers of signals.
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IK-PBSYS Transmission Media
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