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7/26/2019 Steps to a successful profibus project
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Practical Steps to a Successful
PROFIBUS Project
Slides by Dr. Xiu Ji - MMU
Presentation today by Richard Needham Hi-Port Controls
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 2
Outline of this presentation
Presentation objective
Introduction to PROFIBUS and associated benefits
Connection options and rules
Other cabling issues : grounding and interference
Design Considerations
Implementation issues
Essential training
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 3
Introduction to PROFIBUS
Fieldbus is widely used in many automation systems.
PROFIBUS solutions for Factory Automation (FA) andProcess Automation (PA)
Applications also involving drives, instruments, servos,robotics, functional safety, redundancy, and explosiveenvironments etc.
Extensive diagnostic functions available to operators andmaintenance engineers
Diagnostic tools available for engineering, commissioning,maintenance, and fault finding
Excellent support from PROFIBUS International, regionalevents and competence and training centres.
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 4
More Information
More adjustable settings and parameters (e.g. scaling,
linearization and calibration).Diagnostic data to inform if measurement is valid.
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 5
Extensive Diagnostics
Controller
Engineering
Station
PA Software
SCADA/HMI
1
2
2
3
Analyser
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 6
6PROFIBUS Applications
Vehicle
manufacture
Bottling plants
Warehousingsystems
Switchgear
Hollow glass
production
Vehicle
assembly
Machine tool
building
Chemical
industry
Petrochemical
industry
Paper and
textile industry
Foodstuffs
Power stations
Sewage plants
Machine tools
Packaging
machines
Pressing plants Paper production
Factory
automationProcess
automation
Drive
technology
Safety
applications
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 7
The PROFIBUS Family
PROFIBUS DP (Decentralised Periphery)Low cost, simple, fast for general automation applicationsWithin short distances, in large quantities, mainly in-door, in dryareas, in cabinetsParameters, options and capabilities can be defined using asimple, text GSD file.
Physical layer uses RS485 or fiber optic
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 8
The PROFIBUS Family
PROFIBUS PA (Process Automation)Developed specifically for the process industry to replace 4-20mAtransmissionTwo-wire connection carrying both power and dataSpread over long distances, in low quantities, mainly out-doors,in wet and exposed sites
Parameters, options and capabilities are defined in additional to aGSD file, in EDD or FDT/DTMLarge number of parameters, options and diagnostic eventsCyclic and acyclic communicationsPA equipment is often used in explosive environments
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 9
Transmission Technologies
Communicat ionTechnology
Transmiss ion
Technologies
PRO FIBUS DP (DP-V0, -V1, -V2)
WiredRS485 / RS485-IS
MBP / MBP-IS
E
ngi
neering
Techn
ologies
GSD
,EDD
,FDT/DTM,
TCI
OpticalGlass, PC F, Plastic
Wireless
P
ROFIdrive
P
ADev
ices
E
nco
der
Ident
Systems
W
eighing
&
D
osage
H
ARTon
P
ROFIBUS
L
abAutomation
SpecificAp plica ti onProfi les
CommonAp plica ti onProfi les
X
Y. . . .
PRO FIsafe, I&M, iPar-Server,Time Stamp, Redundancy,
Communicat ionTechnology
Transmiss ion
Technologies
PRO FIBUS DP (DP-V0, -V1, -V2)
WiredRS485 / RS485-IS
MBP / MBP-IS
E
ngi
neering
Techn
ologies
GSD
,EDD
,FDT/DTM,
TCI
OpticalGlass, PC F, Plastic
Wireless
P
ROFIdrive
P
ADev
ices
E
nco
der
Ident
Systems
W
eighing
&
D
osage
H
ARTon
P
ROFIBUS
L
abAutomation
SpecificAp plica ti onProfi les
CommonAp plica ti onProfi les
X
Y. . . .
PRO FIsafe, I&M, iPar-Server,Time Stamp, Redundancy,
PROFIBUS supports different transmission technologiesWired, Optical, and Wireless
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 10
Connection technologies
PROFIBUS DP uses 2-core shielded and twisted RS485 wiring.
9-pin sub-D or M12 connectors extensively used.
DP can also use plastic or glass fibre optic cabling.ST/BFOC connectors widely used
PROFIBUS PA uses Manchester Bus Powered (MBP) cabling
over 2 cores.Glanded screw or M12 connection normally used
1
0
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 11
Optical transmission
The implementation of a fibre optic cable network involves theuse of electro optical converters (OBT and OLM):
for long distance, between buildings, andto solve grounding problem (grounds with un-even earthpotential).
Fibre
to
Copper
OLM(OpticalLinkModule)
OBT(Optical
BusTerminal)
FO
CouplerFO
Coupler
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Control System Architecture
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 13
From DP (RS485) to PA (MBP)
0
-9mA
time
Current/mA
+9mA
1 1 0 0
PROFIBUS PA, MBP
10 mA
4
To
7
volts
PROFIBUS DP, RS485
0 0
1 1 1
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 14
DP & PA Segments
One PROFIBUS network can host up to 126 stations (masters and slaves)
capacity of a PROFIBUS DP master
Limitation of RS485 and MBP 32 loads and total cable length per segment
M
S
S S
S
S S
S
S
M
S
S
S
S
R O O
Segment
1 RS485
Segment 2
RS485
Segment 3
Fibre Optic
Segment 4
RS485
Segment 5
MBP
Repeater
Fibre optic
links
C
DP/PA
Coupler
SMBP segments can be laid out in a
more flexible manner using Tee
junctions to create spur lines.
Each RS485 segment are best laid
out as a linear bus daisy-chaining
from device to device.
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 15
DP Segment Cable Length
When using best quality PROFIBUS RS485 (Type-A) cables, the
segment cable length is limited according to the network speed.
Baud rate Maximum segment length
9.6 kbit/s 1 200m
19.2 kbit/s 1 200m45.45 kbit/s 1 200m
93.75 kbit/s 1 200m
187.5 kbit/s 1 000m
500.0 kbit/s 400m1.5 Mbit/s 200m
3.0 Mbit/s 100m
6.0 Mbit/s 100m
12.0 Mbit/s 100m
Low
speeds
High
speeds
Middlespeeds
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 16
PA Segment Cable Length
PA baud rate is fixed at 31.25 kbit/s.
The maximum segment cable length is 1900 meters for non-intrinsically safe applications, and.
1000 meters for intrinsically safe applications
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 17
Segmentation, PA
The maximum number of devices on a PA segment is the sameas the maximum on a DP segment, which is 32.
However, how many slaves can be connected to a PA segmentdepends primarily on the power supplied to the segment.
Segment CouplerV = 13.4 VDC, I = 100 mA
#13#14
#15
#16
#17T
14 mA 14 mA 14 mA 14 mA14 mA
Maximum number of
PA slaves = 100 / 14 = 7
I actual = 5 x 14 = 70 mA
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 18
Reflections
When electrical signals travel down a cable, any electricaldiscontinuity can cause reflections to occur
The end of the cable in particular is a major discontinuity, whichcan cause severe reflections, particularly with fast changes
Just like an echo, the reflected signal can cause multiple signalsor corrupted telegrams to appear on the line
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 19
Reflection caused bymissing terminator
Reflection caused by
missing terminator
Reflection caused bymissing terminator
Reflections
Analysis of PROFIBUS system behaviour is covered in PROFIBUS in
Practice system engineering, troubleshooting and maintenance.
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 20
Termination - Rules
To avoid reflections from ends of the cable it is essential
that each segment is terminated at both ends andnowhere else
Both terminators in each segment must be powered at alltimes
Terminator switches and resisters are normally include in9-pin PROFIBUS connectors for this purpose, with plug-interminators used for M12 schemes
+5 volt power is needed for these terminators to workproperly. This is normally supplied from the connected
device
T i ti
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 21
Termination
Standalone termination boxes are also available
for DPand for PA
Termination on Repeaters
Termination
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 22
Termination
1 network with 2
segments.
DP/PA
coupler
#1#0 #10 #11
#13#14
#15
#16#17
Power supply for PA segment
TT
T
T
C f R fl ti
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 23
Causes of Reflections
Missing terminatorUn-powered terminator
Terminator switch - faultyExtra terminatorReflection can also be caused by:
Un-certified devicesCable length between two devices is too shortSpurs are used in high speed networks
Wrong types of cables are usedCores are sharply bent
Allowance of RS485 Spurs
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 24
Allowance of RS485 Spurs
Bit rateTotal allowable spurcapacitance Total Spur cablelength/segment*
>1.5 Mbit/s None None
1.5 Mbit/s 0.2 nF 6.7 m
500 kbit/s 0.6 nF 20 m
187.5 kbit/s 1.0 nF 33 m
93.75 kbit/s 3.0 nF 100 m
19.2 kbit/s 15 nF 500 m
* Calculated for PROFIBUS cable type A at 30pF/m
One spur @ 6.7m or
6 spurs @ 1.1m each
It is much more flexible @ low speed.
Allowance of MBP Spurs
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 25
Allowance of MBP Spurs
The length of the individual spur-lines on a PA segment depends
upon the total number of spurs used:
Number of
spur-lines
Maximum spur length
non-intrinsically safe
Maximum spur length
intrinsically safe
25 to 32 1 m 1 m19 to 24 30 m 30 m
15 to 18 60 m 60 m
13 to 14 90 m 60 m
1 to 12 120 m 60 m
Note that the maximum cable length of 1900m includescable used for spurs. E.g. 18 x 60 = 1080m spurs + 810m trunk line.
Interference
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 26
Interference
Interference is picked up from adjacent equipment or
connected equipment with poor Electromagnetic Compatibility(EMC) rating.
Interference can be caused by:Inadequate earthing of equipment,Poor or incorrect earthing of cable shield,
Insufficient segregation of power and bus cables,Routing cables through electrically noisy areas, andHeavy earth currents on the cable screen.
2
6
Equipotential Bonding
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 27
Equipotential Bonding
Installation: Shielding and Grounding
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 28
Shielding and Grounding
The recommended grounding practices:
Connect all PROFIBUS interfaces and cable shields to ground.
Use a grounding cable to go from cabinet to cabinet
in the same segment equipotential bonding.
Types of grounding:
Direct grounding (at any connecting point)
Capacitive grounding
Installation: Shielding and Grounding2
8intern
Equipotential Bonding at a Device
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 29
Equipotential Bonding at a Device
Connect the PROFIBUS cable shield to the equipotential
bonding at every PROFIBUS station assuming local potentialsare equal!
Shielded, twisted-pair cable
Cable shield route
to groundRx
Tx Tx
Rx
Connector
Device Device
Red = +
Green = -
Connector wiring problems
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 30
Connector wiring problems
Which connectors are incorrectly wired?
A CBD
Cable Segregation
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 31
Cable Segregation
All channels and partitions must be properly earthed.
Use flexible bonding links are protected against corrosion. Braided straps are better than solid metal.
Cable Segregation Distance
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 32
g g
In general, the greater the spacing between the cables and the
shorter the paths run parallel, the lower the risks ofinterference.Recommended cable segregation distances:
Cable
Category II
20 cm
10 cm 10 cm
50 cm 50 cm 50 cm
Cable
Category I
Cable
Category III
Cable
Category IV
Cable Segregation ?
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 33
g g
An example: variable frequency drivesCan you spot the error here?
Power cable route
Spot the errors
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 34
p
Spot the errors
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 35
Spot the errors
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 36
Standard connections PROFIBUS DP3
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 37
3
7
Standard connections PROFIBUS PA3
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 38
3
8
Tink
oupler
TPROFIBUS DP PROFIBUS PA
Trunk
Spur lines
Devices
Link
oupler
TPROFIBUS DP PROFIBUS PA TJunction
Box
Junction
Box
Spur lines
Trunk
Devices
Spot the errors
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 39
Design considerations - details
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 40
Limitations of segment loads and total cable length
Standalone terminations for DP, redundant power supply toterminators
Network drawings node addresses, mark of terminationposition, cable routes, cable length between connectors andjunction boxes, trunk cable and drop cable length
Piggyback connectors spare connection into EVERY segmentfor voltage measurements and troubleshooting
Design considerations - architecture4
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 41
Which network to use PROFIBUS, PROFINET, DP, PA, AS-i?
Designation of safe and hazardous areas
Production and functional safety systems
Cable routes fibres, copper cables, earthing systems,equipotential bonding cable in place?
Cabinet or field assembly
Connection of devices via remote IO or integrated fieldbus?
Use of redundancy at difference levels
Network and device access for engineering, monitoring andmaintenance
4
1
Installation Checklists4
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 42
Checklist to determine network topology and obtain thenetwork drawing
Checklist for PROFIBUS DP (RS485) Grounding
Checklist for PROFIBUS PA (MBP) Grounding
Checklist for PROFIBUS DP (RS485) Cabling
All above are included in PROFIBUS in Practice installingPROFIBUS devices and cables as templates for a Factory
Acceptance Test document.
4
2
Practical steps to a successful PROFIBUS project4
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 43
The very first step to a successful project should be
Training
PROFIBUS training courses are available for:Installers,System Designers,
Commissioning Engineers, andMaintenance staff.
Many industry sectors specify that their staff, contractors andsub contractors must be appropriately trained.
Competence Centre - Manchester Metropolitan University
Training Centre Verwer Training and Consultancy
4
3
Certified PROFIBUS Installer Training4
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 44
This training is widely accepted as the minimum standard oftraining for anyone who is working in PROFIBUS systems at atechnical level.
Available as a one-day training course in house or on-site.
It teaches the basic principles of PROFIBUS and covers the basic
layout, installation and testing of DP and PA networks.
It is also essential basic training for system designers,maintenance and all engineering staff.
Background details are covered in the series of PROFIBUS in
Practice, the orange and blue textbook.
Extra days can be added to extend the training for maintenance,design and engineering staff.
4
4
PROFIBUS System Design Training4
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 45
Good overall design, with good documentation and clearspecifications of required wiring, installation, testing,commissioning and final setting-to-work practices arerecommended. Production of final as installed drawings arealso recommended (to assist with subsequent maintenance)
Designer training will allow companies to ensure that their
designers are aware of the common design pitfalls and able toproduce systems that are cost effective, efficient andmaintainable.
Designer course at MMU is 3 days covering installation,maintenance, and design.
4
5
Summary: Steps to a successfully project4
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Practical steps to a successful project, The PROFIBUS Group Seminars, Dr Xiu Ji Slide 46
1. Design staff should be trained before the design starts.
2. Everyone involved in the project at a technical level is trained toan adequate level, at the least to the designer or installer level
3. Make sure that designers are fully aware of the methods fordiagnosing and locating faults, before start of design
4. Ensure that health checking and performance monitoringfacilities are incorporated into the network
5. Follow the extensive guidance that is available from PI and fromcompetency and training centres, for example, incorporating
the checklists in to your installation acceptance tests
6