Commissioning and test bus networks

1. How to implement a stable network
Industrial network commissioning and
testing
Dave Tomlin – Hitex UK Ltd

2. 2PROFIBUS UK 2PROFIBUS, PROFINET and IO-Link Seminar – Glasgow 2018
Industrial Network Installation and Commissioning Guidelines1
Test Types2
Qualification and Verification3
Network Acceptance Tests4
Troubleshooting5
© 2017

3. 3PROFIBUS UKPROFIBUS, PROFINET and IO-Link Seminar – Glasgow 2018
Installation & Commissioning Guidelines
© 2017

4. 4PROFIBUS UKPROFIBUS, PROFINET and IO-Link Seminar – Glasgow 2018
Examples of test results
Test types - definition of terms
Verification (simple line test)*
Basic cabling structure test
Check for correct wiring
Qualification (functional test)*
Identifying performance of data transmission
Certification (acceptance test)*
Classical network acceptance tests
Assessment according to defined standards (e.g.
IEC11801 or in our case PROFINET Commissioning
Guidelines)
Troubleshooting
Typical Ethernet problems
* PROFINET Commissioning Guideline V1.36 PNO Dec. 2014
© 2017

5. 5PROFIBUS UKPROFIBUS, PROFINET and IO-Link Seminar – Glasgow 2018
Cable Verification in Practice
Qualification and Verification – PROFI BUS & NET
Verification test – Wire test
Confirm accurate wiremap from plug to plug
Opens
Shorts
Crossed wires
Measure length of cable
Easy to use or cheap?
Manual or automatic?
© 2017

6. 6PROFIBUS UKPROFIBUS, PROFINET and IO-Link Seminar – Glasgow 2018
Qualification and Verification - PROFINET
Qualification test – Functional test
Determination of signal-noise-ratio (SNR)
Noise sources: NEXT *, FEXT *, echo noise, environment noise
BERT (Bit-Error-Rate-Test) or Packet-Error-Rate-Test
Sends Ethernet frames with 100Mbit/s; okay if 10s without losing frames
Evaluation based on Ethernet error tolerances according to IEEE 802.3.
Determination of runtime difference between wire pairs
Fastest pair is 0ns **
e.g. limit for 1000BASE-T: 50ns
© 2017
* NEXT: near end crosstalk
FEXT: far end crosstalk
** (PROFINET works with two wire pairs. In the ideal case both pairs should have the same runtime)
Test line

7. 7PROFIBUS UKPROFIBUS, PROFINET and IO-Link Seminar – Glasgow 2018
Test Report – Verification and Qualification
Clear details of each
cable
Report for end
customer or
management
© 2017

8. 8PROFIBUS UKPROFIBUS, PROFINET and IO-Link Seminar – Glasgow 2018
Certification (acceptance test)*
Some of the Classical network
acceptance tests
Full System Inventory
Network Topology
Packet loss rate
Network Load
Assessment according to PROFIBUS/NET
Commissioning Guidelines
© 2017

9. 9PROFIBUS UKPROFIBUS, PROFINET and IO-Link Seminar – Glasgow 2018
Inventory List – Firmware Check PROFIBUS & NET
4.3.4 of PROFINET Commissioning
Guideline V1.36
Check the firmware revision
levels of the PROFINET devices
and document them.
If the firmware revisions installed
in the plant deviate from the
planning, contact the person
responsible for the planning of
the system.
PROFINET Devices are usually
“hot Swappable” assuming
correct FW versions are available.
Profibus devices may be swapped
in some cases but only with
compatible devices
© 2017

10. 10PROFIBUS UKPROFIBUS, PROFINET and IO-Link Seminar – Glasgow 2018
5.4.1 of PROFINET Commissioning Guideline V1.36
Network Topology - PROFINET
Checking for Line Depth and Structure
for load calculation and update time.
© 2017
Maximum line depth with update time*
1ms 2ms 4ms 8ms
7 14 28 58
*Store and forward Switches
Designed Structure

11. 11PROFIBUS UKPROFIBUS, PROFINET and IO-Link Seminar – Glasgow 2018
Network Topology - PROFIBUS
Is what was designed what was
implemented?
Max stations & Distances per segment?
Device Numbering?
Piggyback connectors for Maintenance?
Spur Lines?
PA Segments?
Proximity to Noise?
© 2017
*Store and forward Switches

12. 12PROFIBUS UKPROFIBUS, PROFINET and IO-Link Seminar – Glasgow 2018
Lost Packets – PROFIBUS & NET
There should be no lost packets/retries on fiber
or Copper connections, if there are then this
suggests there may be trouble ahead.
© 2017

13. 13PROFIBUS UKPROFIBUS, PROFINET and IO-Link Seminar – Glasgow 2018
PROFINET and “IT” traffic sharing the
network
Network Load - PROFINET
5.4.3 of PROFINET Commissioning
Guideline V1.36
A small change of hardware
implementation can have a serious
effect on network load
© 2017
Network Load Recommendation
<20% No action required
20-50% Check planned network load
>50% Take measures to reduce network load

14. 14PROFIBUS UKPROFIBUS, PROFINET and IO-Link Seminar – Glasgow 2018
Example of network load evaluation
Checking the loading
for each device
Usually the highest
load will be from the
first link to PROFINET
Controller
Run your analysis at a
time and duration to
capture representative
results.
© 2017

15. 15PROFIBUS UKPROFIBUS, PROFINET and IO-Link Seminar – Glasgow 2018
PROFINET - typical failures
Troubleshooting of typical PROFINET failures
Poor segmentation/planning of network
Use of wrong / outdated device description files (GSDML files)
Configuration errors (wrong name)
Cable errors, EMC – See Peters Presentation
Device diagnostics
Decrease of communication quality (aging)
© 2017

16. 16PROFIBUS UKPROFIBUS, PROFINET and IO-Link Seminar – Glasgow 2018
PROFIBUS Typical Failures
Wiring Faults cause an estimated 90% of PROFIBUS
faults
Faulty/incorrect termination
Bad connections
non PROFIBUS Cable or Connectors
Bad layout (not following the Spec)
Natural/Nature causes, Rats, Moisture ingress, uv
degradation etc
The other 10% includes
Interference (electrical)
PSU failure
Device/Instrument failure
© 2017

17. 17PROFIBUS UKEditable name of event
For PROFIBUS or PROFINET
Troubleshooting in a Nutshell
Have a PLAN!
Who is going to deal with a problem?
What tools do they need?
Do they have the documentation?
Network Diagrams
Permit to work?
Plan for accessibility, can you access the network?
Can you physically get to the network while its running?
Have you got piggyback connectors PB, or Spare (mirror)
ports/fixed TAP PN?
© 2017
Breakdown Plan:
1. Maintenance team view
logs in the “network Monitor”
to see what has failed.
2. Collect network diagrams
and tester and go to
relevant area
3. Inspect the problem
4. Repair problem
5. Test repair
6. Schedule any further
maintenance required
7. Review breakdown to see if
it is possible to avoid in
future

18. 18PROFIBUS UKPROFIBUS, PROFINET and IO-Link Seminar – Glasgow 2018
Conclusion
Commissioning and Trouble Shooting
PROFIBUS/NET
Read and understand the guidelines before even designing the system
Ensure that the cabling is installed, TESTED and signed off by suitably experienced people
Ensure the Network Acceptance tests have been done based on PNO recommendations
Install monitoring devices that can alert you before a major breakdown occurs
There are cable testing tools and there are cable certification tools they are not the same
Network diagrams are still really handy, but they are a lot easier to produce
automatically than with PROFIBUS
Having a reference to last known good state can save hours of troubleshooting, “who
changed that device”, “why was that plugged into a different port” etc etc.
© 2017

19. 19PROFIBUS UKPROFIBUS, PROFINET and IO-Link Seminar – Glasgow 2018
Important Things
All of the Documents below are available
to download on the PI Website*
PROFINET Design Guidelines
Network Load Calculation Tool
Installation Guideline for Cabling and
Assembly
Commissioning Guidelines
PROFIBUS Design Guidelines
PROFIBUS Assembly Guidelines
* You may need to be a member to access some documents
Thanks for listening
Dave Tomlin
Hitex UK Ltd
dtomlin@Hitex.co.uk
02476 692066
www.hitex.co.uk
UK Technical distributor for Softing
Industrial Automation Tools.
© 2017