PROFINET implementation and testing - Dave Tomlin, Hitex and Andy Morse, AJM

The process of certifying a new PROFINET
network and Diagnostics
Dave Tomlin – Hitex UK Ltd
Andy Morse – AJM Engineering

2PIUK 2PROFIBUS, PROFINET and IO-Link Seminar – March 2019
Introduction1
Designers Responsibilities2
Industrial Network Installation and Commissioning Guidelines3
Test Types4
Qualification and Verification5
Network Acceptance Tests6
Troubleshooting7
© 2017

3PIUKPROFIBUS, PROFINET and IO-Link Seminar – March 2019
Introduction
Profinet : - Highest availability requires tailor made validation
Growing popularity.
Open standard, manufacturer-independent automation solutions.
PROFINET applications requires individually tailored procedures when commissioning new and
expanded systems.
Serial Fieldbus: - still with us and will remain so for a long time
PROFIBUS, DeviceNet/ Can bus or Modbus RTU:
Backbone of automation technology.
Reliable, resilient and flexible. Commissioning is straightforward - quality of the cable installation
and the signal quality.
Industrial Ethernet, different approach during commissioning. focus is less on cable
measurements, signal levels or signal shapes.
© 2017

Introduction
PROFINET, optimisation and the greatest possible availability of the networks.
Open Standard, Different Protocols
The advantage of open and vendor-independent networks can also be the disadvantage, in that
many different transmission protocols have to come together and need to be reconciled.
Testing of transmission protocols. Evaluate the function of the individual components and adjust
them if necessary.
Optimisation :- how fast? Why?
Very often, operators of PROFINET installations do not have the necessary experience to detect
and correct weaknesses at the protocol level.
Reducing the update rate can significantly reduce the cyclic network load to improve the
communication performance and network stability."
© 2017

Introduction
Control and data flow:- use in a targeted manner
The desire for big data. Organisations collect more and more data from your automation network
This can often lead to network load problems and high error rates.
Use "managed Profinet switches" in PROFINET installations.
Names for Profinet communications, IP address for TCP/IP traffic.
Managed switches provide information, status, error rate and network load of their ports, thus
enabling targeted monitoring of data flow in the network and efficient use of existing resources.
Functional testing :- Self testing through managed switches
Functional test of the installed connection cables becomes easier with the use of managed
switches. The error rates at the individual ports quickly reveal physical problems.
For example, the wiring causes problems with data transmission, the CRC error rate on
the affected port increases, and a defective cable connection can then be targeted and
quickly located. "
© 2017

Introduction
If the wiring causes problems with data transmission, the CRC error rate on the affected
port increases, and a defective cable connection can then be targeted and quickly
located. "
© 2017

7PIUK 7PROFIBUS, PROFINET and IO-Link Seminar – March 2019 © 2017
Designers Responsibilities

Installation & Commissioning Guidelines
© 2017

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

Cable Verification in Practice
Qualification and Verification – PROFINET
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

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

Test Report – Verification and
Qualification
Clear details of each
cable
Report for end
customer or
management
© 2017

Certification (acceptance test)*
Some of the Classical network
acceptance tests
Full System Inventory
Network Topology
Packet loss rate
Network Load
© 2017

Inventory List – Firmware Check
PROFINET
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.
© 2017

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

Lost Packets – PROFINET
There should be no lost
packets/retries on fiber or
Copper connections, if there
are then this suggests there
may be trouble ahead.
© 2017

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

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

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

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

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

Free Tools (not exhaustive)
PRONETA – useful diagnostic and configuration tool
Wireshark – useful but complex packet analysis tool
IP Scanner – useful for finding devices
© 2017

Paid for Tools (not exhaustive)
Softing, PROCENTEC, Indu-SOL are the
major players represented today. Others
like Fluke etc are available but not
PROFINET Specific.
Tools for Monitoring, Analysis, Cable
testing, Acceptance testing & topology
viewing.
© 2017

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 02476 692066
dtomlin@Hitex.co.uk
www.hitex.co.uk
UK Technical distributor for Softing
Industrial Automation Tools.
Andy Morse
AJM Engineering Management Ltd
amorse@ajm-engineering.co.uk
www.ajm-engineering.co.uk
© 2017

PROFINET implementation and testing - Dave Tomlin, Hitex and Andy Morse, AJM

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