profibus system engineering and monitoring - andy verwer and peter thomas

System

Engineering &

Network

Monitoring

Andy Verwer,

Verwer Training

& Consultancy,

Peter Thomas,

Control

Specialists Ltd

United Kingdom

Practical Aspects

of PROFIBUS,

PROFINET and

IO-Link,

Manchester,

29th March 2017

System Engineering & Network Monitoring, Andy Verwer, page 2Practical Aspects of PROFIBUS/NET, March 2017

Overview

This presentation will look at PROFIBUS and PROFINET systems

and examine the types of problems and failures that are

experienced.

We will examine how available devices can provide:

Network health monitoring, performance and diagnostics.

Engineering Access for device replacement, set-up, calibration

and diagnostics.

We will then demonstrate a couple of solutions that are

available for PROFIBUS and PROFINET monitoring.


PROFIBUS and PROFINET are very reliable and cost effective

technologies.

It is common to find extensive installations comprising

thousands of PROFIBUS devices operating on complex

networks.

The reliable operation of these networks is essential to

maintaining plant availability and productivity.

So, what can go wrong?

PROFIBUS and PROFINET


What can go wrong?

In our experience about 80% of problems are caused by

physical layer, cabling and connector problems:

Shorts and open-circuits;

Water and chemical ingress;

Termination problems (mainly PROFIBUS);

Poor network layout;

Etc.

The remaining 20% of problems are due to:

Interference pickup (EMC);

Power supply failure or overloading;

Software compatibility and security (mainly PROFINET);

Device failure (quite rare).


Quite often users are unaware that their system has errors

because the robustness of PROFIBUS and PROFINET can hide

developing faults.

Green light –

all must be ok!

But by then it is too late!

Communication faults

Only when the rate of data corruption reaches a critical

threshold will the fault become visible.


Permanent faults are relatively easy to fix.

Because the fault disappears when we've fixed it!

Intermittent faults can be a nightmare!

Because we cannot be sure that we have fixed it.

We may seem to have cured the problem, but then it comes

back again later!

Intermittent faults require long-term monitoring to check that

the fault is cured.

Statistical reporting over an extended period can be useful.

Intermittent Faults


Fault finding & health checking tools

A range of tools are available for PROFIBUS and PROFINET

system health checking and troubleshooting.

Analysers are useful for indicating protocol errors such as

repeated, missed or corrupted messages.

Waveform visualisation can help to diagnose physical layer

problems.

Advanced diagnostic tools can help to diagnose performance

degradation and network loading problems.

Unfortunately such tools are only of use when plugged in to

the network and operated by a competent engineer!


Health checking is an important part of the commissioning and

maintenance strategy for your plant.

The health check will help to find non-critical and intermittent

faults that are not obvious.

A health check should be carried out immediately after

commissioning. We also strongly recommend repeating the

health check at intervals.

How much better to integrate the health checking tools into the

network?

To give permanent monitoring of system health.

Automatically report failures.

Give pre-warning of impending failures and performance

degradation.

System Health Checking


Permanent monitoring tools

A number of tools have appeared on the market which are

designed to be permanently connected to the network to

provide 24/7 network monitoring.

For PROFIBUS systems:

PROCENTEC COMbricks

network monitor

(up to four networks,

20 DP or PA segments)

Indu-Sol’s PROFIBUS

INspektor

(one DP segment)

PROCENTEC

diagnostic hubs

(up to five DP

segments)

Siemens’ diagnostic

repeater

(two DP segments)

Softing’s TH LINK

PROFIBUS

(one DP segment)


Permanent monitoring tools

For PROFINET systems:

Indu-Sol’s

PROFINET

INspektorSofting’s

TH LINK

PROFINET

PROCENTEC’s

PROFINET monitor,

(to be announced at

the Hannover Fair,

next month)

Softing’s

PROFINET

monitor


Head Station

with ProfiTrace

built in

Repeater

modules with

optional

‘scope and

redundancy

PROFIBUS

DP slave

modules

IO modules

digital, relay,

analogue etc.

PROFINET IO

device

modules

Optical link

modules

(1 or 2

channel)

mix and match to produce the required functionality

PA module

Coupler

and/or MBP

monitor with

‘scope

COMbricks

COMbricks is a modular repeater and gateway system from

PROCENTEC with built-in PROFIBUS monitor and analyser

functionality accessible over Ethernet.

The modules available include:


Head

Station

Ethernet

Each of the four segments

can have up to 31 devices

connected.

But each channel can be

connected to a separate

network if desired, allowing

up to 4 separate networks to

be monitored

simultaneously.

2 channel

repeater

2 channel

repeater

E.g. 1 – DP Hub/Monitor

ProfiTrace - built into the

head station. Can monitor

all 4 segments

simultaneously. Accessible

remotely over Ethernet.


E.g. 2 – DP/PA coupler/monitor

1 channel

‘scope

repeater

Head

Station

PA coupler

moduleThis unit can be used as a

stand-alone DP/PA coupler

with both DP and PA

segments monitored by

the head station.

The unit acts like a

transparent link allowing

high-speed DP operation

(up to 1.5Mbit/s)

Ethernet

DP

(RS485)

PA

(MBP)

The same unit can also

simply be configured to

just monitor the signals on

an existing coupler or link.

These modules incorporate

an oscilloscope function

allowing waveform

visualisation and bar chart.


Simple web browser

27 March 2017

ProfiTrace streaming

FDT/DTM Tools

OPC / SCADA Alarm handling

All provided as standard

within the head station.

Remote monitoring via Ethernet


Demonstration

System Engineering & Network Monitoring, Peter Thomas, page 16Practical Aspects of PROFIBUS/NET, March 2017

PROFINET Diagnostics

The switched-based architecture of

a PROFINET network means that it is

very important to consider how

diagnostic tools will connect to the

network.

This is because switches learn the

MAC addresses of the devices to

ensure that traffic is only

transmitted to the relevant port on

the switch.

By default, an unused port will only

ever see broadcast traffic and will

therefore be useless for monitoring

purposes.

To PROFINET

IO Devices

Switch

IO Controller

Spare Port –

Sees broadcast

Traffic Only !



When using a Conformance Class B

PROFINET switch, one option is to

assign an unused port as a mirror

port.

This will “copy” all traffic from a

given port to the mirror port and

thereby allow diagnostic tools to

monitor the traffic in/out of the

monitored port.

Note that under periods of high

demand the transfer of traffic to the

mirrored port cannot be guaranteed.

To PROFINET

IO Devices

Switch

IO Controller

Set to “Mirror” Port,

connect diagnostic

tools here



A better solution is to include a

hardwired monitor and access

point.

This is completely transparent to

the PLC but allows permanent or

temporary tools to be connected

to the network without

disruption.

The monitoring function

operates even when tools are

disconnected.

It also has the advantage of

leaving unused switch ports

available for future use.

IO Controller

To PROFINET

IO Devices

Switch

Monitor

Monitoring and

diagnostic tools

connected here

Spare Port


Demo - PROFINET INspektor

24vPSU

IO Controller

PROFINETINSPEKTOR

PROFINETSWITCH

TOTRAININGRACKS VIA EXTERNALSWITCHES

PROFINETACCESS POINT

ETHERNET WIRELESS ROUTER


PROFINET – Quality Criteria


Demonstration