PROFINET network diagnostics and support - May 2020 - Peter Thomas

Diagnostics and Support
Webinar
Peter Thomas
Control Specialists Ltd
May 2020
www.controlspecialists.co.uk

PROFINET Diagnostics © Control Specialists Ltd – May 2020 Page 2
Established in 1989, we are an organisation
with ongoing experience in the design,
commissioning and support of programmable
industrial automation systems and the
communication networks used by them.
Our experience includes utilities (water and
gas), pharmaceutical, logistics, waste disposal
to name but a few.
We also provide training courses on several
areas of industrial automation.
We are a PROFIBUS and PROFINET International
Training Centre (PITC) and a member of PI UK.

PI UK Webinars - 2020
This webinar the second of a series of webinars being delivered
on behalf of PI UK.
11th May 2020 – EMC Awareness for Industrial Automation
20th May 2020 – PROFINET Network Design
27th May 2020 – PROFINET Diagnostics
3rd June 2020 – PROFINET Gateways
10th June 2020 – PROFIBUS Lightning Surge Protection
All webinars are being recorded and will be uploaded to our
YouTube Channel.
You will receive a .pdf copy of any presentation you attend.

What is PROFINET ?
PROFINET is an example of a real-time / deterministic Industrial
Ethernet communications protocol that is based on 100 Mbps, Fast
Ethernet as defined in IEEE802.3 and uses copper, fibre or wireless.
It is primarily associated with communications between PLC’s (IO
controllers) and plant-based devices (IO Devices) in an industrial
environment.
Source: PROFIBUS and PROFINET International – May 2020

5
PROFINET
HTTP SNMP Socket
IP
TCP / UDP
Sensor system
PC
SNMP/OPC server
PROFINET
IRT Field devicesPC
Internet Explorer
Real-Time
RT IRT
Ethernet
PROFINET
RT Field devices
PROFINET in Operation
Source: PROFIBUS and PROFINET International – May 2020

PROFINET Network
Components
PROFINET Networks consist of several discrete items
of apparatus:-
IO Controllers (IOC’s) – The devices actually
controlling the communications – these are
usually PLC’s.
IO Devices (IOD’s) – These are the plant-based
devices that the IOC is communicating with.
They may be remote IO, Invertor drives,
encoders etc.
Switches – These are used to connect the IOC’s
with the IOD’s.
Gateways – These are used to connect to other
network types, e.g. PROFIBUS, AS-I, CAN or IOT
(OPC-UA/MQTT)
Monitoring Tools – Essential for the qualification
and support of your network

PROFINET Network Design
The ease in which PROFINET networks can be configured
can lead to a false sense of security in terms of robustness,
support and future expansion.
Poorly designed networks present the risk of underlying
network-related issues that may only become apparent
after several months or even years
A PLC absent of bus faults does not indicate a healthy
network.
This presentation concentrates on the need to ensure that
your network can be qualified during the commissioning
stage and supported during normal operation.

PROFINET Diagnostics
IO Controller
Diagnostics
TAPS and
Network Access
Points
Passive
Diagnostic
Devices
Quality Criteria
Active
Diagnostic
Devices
Ethernet Frame
Analysers
Switch
Diagnostics
IIoT Logging

Quality Criteria
Drop-outs = 0
Network Load <=20%
Missing Frames = 0
Frame Discards = 0
Jitter < 50%
Frame Errors = 0

IO Controller Diagnostics
IO Controllers (PLC’s) are the obvious starting point when
wanting to diagnose faults on a network.
Network issues are generally shown by illuminating the Bus
Fault (BF) LED.
Accessing details of the diagnostics assumes one or more of
the following:
They are displayed on an operator panel (HMI)
The IO Controller has a built-in web server configured to
display the diagnostics.
The IO Controller has a built-in display to show the
diagnostics.
You have a copy of the software and are conversant with it.
Whilst IO Controllers can provide useful and detailed
diagnostics about themselves and the devices they
communicate with, they are generally limited to high level
diagnostics when it comes to network diagnostics.

Switch Diagnostics
The number of switches in a network is usually a function of
the chosen topology.
The more there are, the more segmented a network
becomes and localised issues can be difficult to determine
unless a switch has the ability to detect them.
Unmanaged switches can be used in a PROFINET network as
long as they are rated for use in the environment they will
operate in and support the ‘Quality of Service’ protocol.
However, the diagnostic capability of unmanaged switches
are usually limed to port LED’s flashing / not flashing.
PI recommend the use of Conformance Class B Managed
Switches to overcome this limitation.

Conformance Class B
switches
Conformance Class B Switches are switches that have been
certified by a PI Test Lab (PITL) and incorporate the following:
They will have a web interface
They are supplied with a GSDML file for incorporation into the
Hardware Configuration of the IO Controller (PLC).
They will have a device name and an IP address.
As well as supporting the “Quality of Service” protocol, they will
support important diagnostic-related protocols such as SNMP
(Simple Network Management Protocol) and LLDP (Link Layer
Discovery Protocol)
They have diagnostics specific to the traffic entering or leaving
their ports, i.e. localised.
They support port mirroring – more later.

PROFINET Diagnostic Tools
These are hardware or software applications
designed specifically to monitor the low-level
network performance of a PROFINET network.
They can be used for the initial qualification of your
network and for ongoing support.
Ideally they will be permanently connected to the
network to provide 24-hour monitoring.
PROFINET analysers come in two forms, Active and
Passive – both are equally important but very
different from each other. Ideally you will have
both.

Active Diagnostic Tools
Active Analysers “actively” poll the network devices for
diagnostic information.
Amongst other things they will transmit SNMP telegrams
to all network switches and devices to ask for their
diagnostics.
However, this will only work if the switches and devices
support SNMP !
An active analyser connects to the network via a spare
switch port.
You will generally only need one active analyser per
network.
Some active analysers can also display PROFIBUS
diagnostics.
Active analysers are completely transparent to the IO
Controller.

Passive Diagnostic Tools
Passive Analysers “passively” monitor the network traffic.
By definition they do not transmit anything but simply monitor
the telegrams in the PROFINET cable.
To do this, they need to be physically connected inline (series)
at the busiest point in the network, usually between the IO
Controller and first switch.
Once inserted, they are transparent to the PLC and failure of
them will not prevent communications between the controller
and the rest of the network.
Some passive analysers require the use of a TAP to facilitate
the physical connection to the network.
A tap is a passive device with a USB interface that is physically
inserted into the network

Ethernet Frame Analysers
A popular Ethernet frame analyser is Wireshark.
This is a free-to-download, software-based
application that captures Ethernet frames and
displays them on a frame-by-frame basis.
Wireshark is not specific to PROFINET but can,
and is, used to diagnose faults.
Wireshark will require a Mirror Port or a TAP to
allow it to connect to the network.
Unfortunately, Wireshark cannot capture on
event so the files can be very large.
Some Passive Analysers have the capacity of
doing this and save the file as PCAP file for
further offline interrogation by Wireshark.

Port Mirroring
Port Mirroring is a facility provided by most managed
switches.
It allows the switch to copy incoming and outgoing
packets from a chosen switch port to one designed as a
monitor port.
Port mirroring is configured via the web interface of the
switch.
PC’s / Laptops running frame analysis software can
them capture the frames via the monitor port.
Note however there are several issues regarding the use
of port mirroring, not least of which is the fact that the
mirroring process is a low priority task from a switch
point of view which may result in some packets not
being mirrored under heavy network loading.

Ethernet TAPS
TAPS are physical devices used in conjunction
with packet analysing software or, in the case
of PROIFINDT, passive analysing tools.
They typically have two RJ45 ports and a
single USB port.
They are completely passive, have no IP
address and do not require any configuration.
Although TAPS can be inserted anywhere in the
network, from a PROFINET point of view, they
are best installed at the busiest point in the
network, i.e. between the IO Controller and
the first switch.
The EtherTap from Procentec is an example of
an aggregating tap which merges frames in
and out of each RJ45 port into a single stream
for capturing purposes.

Ethernet Access Points
Although a TAP can be inserted
permanently, many choose to
keep it with them and insert on an
as-need basis.
This will always require the
network to be interrupted during
connection / disconnection which
can be an problem.
A solution is to purchase a
measurement access point that is
a lower cost than a TAP.
The access point is permanently
connected to the network and the
TAP connects to the measurement
access point as-needed without
disrupting the network.

IIoT Logging
Many organisations are starting to
become aware of the potential
benefits that the Industrial Internet
of Things (IIoT) offers.
These benefits can be operational
as well as commercial.
The two most popular IIoT protocols
are OPC-UA (Unified Architecture)
and MQTT (Message Queuing
Telemetry Transport)
Many PROFINET analysers have the
ability to publish their diagnostic
data in one or both formats.
This provides the end user with
greater flexibility in terms of how
and when to make use of the data.

Qualification
Qualification is the performing of a
series of pre-written tests to
establish the installation and
operational aspects of a PROFINET
network.
They will be completely separate
from the usual application-specific
testing.
PROFINET Diagnostic tools are an
essential part of this and very often
produce reports of their own to
assist in providing evidence.
A PLC with no bus faults is no
guarantee that there aren’t
underlying network issues.

VSD
(0.70)
(FIBRE)
IOC.1
RACK 2
0.20-
0.23
IOC.2
RACK 4
0.40-
0.43
IOC.2
RACK 5
0.50-
0.53
IOC.2
RACK 6
0.60-
0.63
IOC.1
RACK 3
0.30-
0.33
IOC.1
RACK 1
0.10-
0.13
4 4 9
8 8 9
PHOENIX
factory.s
w3(0.6)
PHOENIX
factory.s
w2
(0.5)
RC
RC
1 5
5
(0.5)
(0.6)
IOC.1 FACTORY
SWITCH RACK
6
2
1
8
8
2
(0.101) (0.102) (0.103)
(0.104 (0.105) (0.106)
(16.3)
PROFIBUS
TRAINING
NETWORK
CANOPEN
TRAINING
NETWORK
(0.212)
PN / CAN
(HELMHOLZ)
ROUTER
(HELMHOLZ)
(0.214)(0.213)
DP/PN
(HELMHOLZ)
(0.201)
PN / PA
(SOFTING)
(0.211)
LOCAL PA
TRANSMITTERS
PN / OPC UA
(ADFWEB)
(0.215)
(80)
MQTT
RASP PI
(0.216)
(NAT 16.15)
DOMAIN
‘CSL PN TRAINING’
192.168.16.2
FIXED: 16.2 – 16.10
NAT: 16.11 – 16.30
DHCP: 16.31 – 16.49
REMOTE ACCESS
IO LINK
MASTER
MODULE
4 * IOL
DEVICES
PROCENTEC
office.sw1
5
6
7
8
5
6
8
(M)
(0.7)
(0.2)
IOC.1
IOC.2
SIEMENS
KTP700
HMI.1
1
2
3
4
IOC.1
SIEMENS
factory.sw1
(0.3)
1
4
2
7
MIRROR PORTX
3
(0.1)
ETHERTAP
PROCENTEC
PROCENTEC
ATLAS
(0.4)
ETHERMIRROR
(MRP)
(MRP)
RM
Demonstrations

Training
Control Specialists provide the following PROFINET-related
training:
Face-to Face
Certified PROFINET Installer (1-day)
Certified PROFINET Engineer (3 ½ days)
Online / Instructor-Led (Half-day)
PROFINET Commissioning and Maintenance (½ day or 1 day)
EMC Awareness for Industrial Automation Systems (1 day)

Peter Thomas
Chairman of PI Training Centres and Technical Officer – PI UK
www.linkedin.com/in/petermthomas
peter.thomas@controlspecialists.co.uk
www.controlspecialists.co.uk
Tel +44(0)1925 824003

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