The document provides an overview of commissioning and maintaining PROFIBUS networks. It discusses typical faults that may occur, such as devices failing to reply due to cable damage. It emphasizes the importance of having the proper tools, such as a PROFIBUS analyzer, and expertise to diagnose issues. The document uses examples from the ProfiTrace analyzer to demonstrate how it can be used to check network performance, device communication, and waveforms. It also discusses how the analyzer can be used for commissioning new networks or sections of networks before a PLC is connected.

1. PROFIBUS
Commissioning
and
Maintenance
Presented by :-
Richard
Neeham
Hi-Port Controls

2. Agenda
Topic 1
Topic 2
Topic 3
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PROFIBUS Commissioning and Maintenance : Richard Needham - Oct 2015
PROFIBUS Commissioning & Maintenance
Introduction
PROFIBUS DP essentials
Typical faults which may occur
Important preparations for fault-finding
Tools and expertise needed to tackle problems
Expected PROFIBUS network quality / performance
Examples of typical analyser screen images
Preventive maintenance
What to do when the fault alarm rings!
Commissioning issues
Use test Master in place of operational PLC
Check cable connections & waveforms
Confirm slave address settings
Get slaves into data exchange : run test data
Connect PLC and confirm overall performance

3. High speed serial network
Bi-directional digital communications
Multi-drop cable array linking Masters & Slaves
Transferring both plant values and control signals
What is a PROFIBUS DP Network?
Master
Slave
1
Slave
2
Slave
3
Slave
4
This is called a Network Segment
3
The Master shown above is usually a semi-autonomous network
controller within a PLC, using shared memory or similar for passing
data between the two. Each is likely to operate at different cycle times
PROFIBUS Commissioning and Maintenance : Richard Needham - Oct 2015
3

4. Bi-directional digital communications
……but with only one device transmitting at any time…
…as directed by the Master which separately addresses each
slave, one a time, then awaits reply from that device
PROFIBUS resilience is partly derived from the fact that the
Master can cope with occasionally illegal (corrupted) or missing
replies – then asking for a second or subsequent attempt
Only when a device totally fails to reply, will it be indicated as lost
to the PLC which may then stop the operational program, but
generally the Master will continue it’s cyclic scanning of all slaves,
using a special Sync message addressed to the known missing
device in the expectation that it may be able to come back online
later
What is a PROFIBUS DP Network?
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5. Typical faults which may occur
Failure to reply by one or more slaves is most common fault
And is most likely to be due to connection network damage
After seeing that a device or devices are no longer
communicating, one should look for simple cable breaks,
wiring damage and check for corrupted waveforms
To see which devices are still connected and waveform quality
one needs a PROFIBUS Analyser Tool
…..and test point(s) on the network to which it may be
attached!
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6. Preparations for fault-finding
Needless to say, one also needs to know how to use any
available tools effectively and have reasonable
appreciation of PROFIBUS wiring and protocol basics!
Accurate network ‘as built’ drawings will be useful – these
might also usefully include geographic information about
locations of each device within the site, where appropriate
(particularly in multi-level buildings or distributed networks)
And hopefully a historical bench mark report against which
you can compare currently measured performance
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7. Test Points for PROFIBUS Analyser connection
We need at least one test point in each network segment
This will allow electrical waveform, voltage and full
message analysis
With usual 9-pin PROFIBUS connectors you will need (at
least) one with a rear PG test socket, as in following slide
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Master
Slave
1
Slave
2
Slave
3
Slave
4
Test point here

8. 9-pin PROFIBUS DP network plug
Plug for network
cable
connection to
Slave or Master
Optional female
PG rear test
connector
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9. Test Points for PROFIBUS Analyser connection
M S S S s
Repeater
s s
Segment 1 – up to 32 devices
9
Test Point 1
Test Point 2
Segment 2 – up to 32 more
The left hand test point will allow a connected analyser to see messages to
and from all devices, but will only faithfully show waveforms and voltages for
devices on segment 1
Although waveforms from devices in segment 2 will be ‘visible’ at Test Point 1,
these can actually show only the waveforms and voltages from the repeater
circuits – hence Test Point 2 is needed to see true values from segment 2
devices!
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10. PROFIBUS Analyser Tools
PROFIBUS Analyser Tools are available from a number of
different suppliers
But for this presentation we will show use of the Procentec
ProfiTrace tool. Broadly similar features are provided in
tools from other manufacturers
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ProfiTrace is supplied as
a suite of computer
programs, with the test
computer connected to a
PROFIBUS network with
USB cable onto a small
ProfiCore Ultra adapter
and a short Tap Lead, as
in adjacent picture and
following slides

11. Connecting ProfiCore Ultra to test point
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12. ProfiCore Ultra connected to test point on PLC
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13. PROFIBUS Analyser connection issues
It is vital that any test equipment connected to an
operational PROFIBUS network does not interfere with
normal operations of that network
Hence use of very short connection links and high input
impedance to the attached test device
Some analysers include local front panel display to allow
performance inspection without need for separate
computer. This can be useful, but will add to the device
size and weight loading on the test point connector
ProfiTrace uses a very small, lightweight adapter, with
scope for long USB cable to computer location
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14. What do we want to see on the network?
Network operating speed : bit rate ?
Details of devices connected : their addresses and type ?
What do the waveforms look like : noise, spikes, ringing ?
Is the Idle Voltage correct for 2 terminators ?
Are all connected device driver voltages OK ?
Check failure statistics for lost, repeats and syncs ?
A good network should show 1 volt idle voltage, square
waveforms and no message repeats (or losts / syncs)
Following slides show typical ProfiTrace images
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15. Initial ProfiTrace Live List display
Typical Live List view after
connection to running
network
Network speed
displayed here
Slave with address 66
- here in normal data
exchange
Master with
address shown
as red number
15
Slave with extended
diagnostic errors
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16. Oscilloscope waveform and voltage display
Double-click on the
device legends to see
associated waveforms
from each
Horizontal Time
Scale
Vertical Voltage
Scale
Display cursors
Note bit interpretation shown
hereSelected device
address
confirmed here
Check important idle
voltage level is at 1
volt as set by
terminators
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17. 12 Mbps example waveform on large network
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18. More usual waveform shape, but with spikes
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19. Large network bar graph example
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This photo shows the individual driver voltages from all connected
devices as seen at test point

20. Topology Scan : Typical result report
Start the Topology
scan
Total cable
length
Cable length between
devices
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21. Preventive Maintenance
PROFIBUS Analysers, such a ProfiTrace, should be used on
a regular basis to check on continued performance of all
networks
This will not only help to identify any gradually degrading
network performance issues, but may also help to identify
increasing incidents of interference or device weaknesses
(as seen through increasing numbers of message repeats)
When weaknesses are identified, these may be addressed
immediately, or tracked over time to the point where they are
felt to threaten overall network reliability
Scans of this nature also help keep staff fluent and familiar
with the test tools (and network documentation) to ensure
optimal effectiveness when a major network failure occurs
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22. High availability network maintenance
Networks which must be kept running safely and securely,
including those with personal safety or very high failure
costs may be fitted with automatic 24/7 performance
monitoring and fault reporting kit
For this requirement Procentec provides it’s ComBricks
range of modular repeaters which can be programmed (by
maintainers) to check, log and alert on typical network
performance issues such as redundant power supply
failures, message repeats, lost devices etc. Such reports
are logged to local microSD memory cards, but may also
be sent as email alerts to maintenance staff, then allowing
dial-in access to see both current real-time network status
and recorded information, using a browser program
Broadly equivalent devices are provided by other firms
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23. Commissioning using ProfiTrace
ProfiTrace can be used in place of a PLC/Master on a new
network to confirm cable integrity, current device
addressing and operation of these devices
In this case the ProfiCaptain Master software is arranged
to drive the network, scanning and reporting connected
devices. Although connected devices will not here be
operating in the usual Data Exchange, normal waveforms,
bar graphs, topology scan (diagramming) and message
statistics features of ProfiTrace will all work – and the
addresses of any software settable devices may be
changed online
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ProfiCore
Ultra
Slave
1
Slave
2
Slave
3
Slave
4

24. Commissioning using ProfiTrace
If GSD files are available for the connected devices,
ProfiCaptain may be used to Scan the network for
identification of all devices, replacing the device addresses
with better details in the Live List (& printable) reports
One may then automatically filter the available GSD file list to
isolate only those for connected devices and so help to
quickly set-up and bring each into full Data Exchange. This
may then allow automatically changing test patterns or fixed
data values to be output to these
These procedures may be applied to individual cabinets or
sections of a network, without final PLC. This can be done
before shipping to site, as part of a factory acceptance test,
then again on-site once all other sections are connected
Once the final PLC is available ProfiTrace may be used to
confirm correct operation of the completed network!
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25. Review and wrap-up
In the above slides I have attempted to highlight some of
the most important issues that need to be considered for
successful PROFIBUS DP network commissioning and
maintenance
This has been a very rapid review of a complex topic and
in no way claims to have covered all aspects. For
example, I have made no reference to PROFIBUS PA
networks, which Andy Verwer will be addressing later
For more comprehensive introduction to PROFIBUS you
should look into joining a one day Certified PROFIBUS
Installer Course, which is not only intended for installers,
but also for managers, designers, bidding teams etc –
thereafter a 1 day Commissioning and Maintenance
Course is also available
For further discussions and ProfiTrace demo see our
exhibition stand here today!
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26. Speaker contact details
For further information contact :-
Richard Needham -- Hi-Port Controls
Tel : 02392 552855 Mob : 07739 847277
richard@hiport.co.uk
Website : www.hiport.co.uk
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