Indu-Sol GmbH Specialist in Fieldbus Technology … GmbH – Specialist in Fieldbus Technology 4 |...

Indu-Sol GmbH – Specialist in Fieldbus Technology

1 | PROFIBUS & PROFINET User Conference 2015 | presented: Indu-Sol GmbH | 16.07.2015

PROFINET

The future of communication

Marco Freihöfer


2 | PROFIBUS & PROFINET User Conference 2015| presented: Indu-Sol GmbH | 16.07.2015

Common Points / Differences

1. Basics and quality parameters

1.1 Physical parameters

1.2 Logical parameters

2. Netload in PROFINET (Netload Class)

3. Metrological measurement and evaluation of quality parameters

PROFINET – The future of communication Abstract:



Common points with the classic fieldbus:

■ The physical basis, PROFIBUS / Interbus / CAN / SafetyBus p / AS-i

■ Balanced data transmission by means of differential voltage signal

■ Evaluation of communication quality over measuring/access points

Differences to classic fieldbus, e.g. PROFIBUS:

■ PROFIBUS has up to 32 devices in a segment, arranged linearly along a

passive line(max 125). PROFINET can be designed with up to 250 devices.

■ PROFIBUS logically functions according to the master/slave principle, using a

token passing procedure, only one telegram at a time – ‘male communication’

■ PROFINET uses the provider/consumer model, each device and the controller

send cyclic data without request at pre-set Update rate – ‘female communication’

■ PROFIBUS baudrate set once for all devices. In PN the updaterate for each

device can be set separately

■ Ethernet standard. Use of foreign protocols such as TCP/IP at the same line

(netload may spike).

Common points / differences



■ Communication over 2 pair of wires (1-2 and 3-6)

■ Line-, star, ring topology

■ 2 devices are connected over 1 line

■ Integrated repeater function (switch function)

Controller Switch Switch Switch Switch

1 2 3 6

IP

Mac

Name

IP

Mac

Name

IP

Mac

Name

IP

Mac

Name

1. Basics and Quality Parameters

PROFINET – The future of communication



1.1 Physical Parameters – CAT5 Certification


■ Line Length

■ Attenuation

■ Crosstalk

■ Specification after CAT5 Norm

■ 100 m max. Line length 24dB Attenuation

■ 1,5 m cable length also max 24dB Attenuation ???


Installed

cable length

Max. attenuation acc. to

standard Cat. 5e for 100

MHz

Length-dependent max.

attenuation, Indu-Sol

GmbH

Length-dependent

recommended

attenuation,

Indu-Sol GmbH

100 m 24 dB 24 dB 21 dB

50 m 24 dB 21 dB 18 dB

25 m 24 dB 18 dB 15 dB

12 m 24 dB 15 dB 12 dB

6 m 24 dB 12 dB 9 dB

3 m 24 dB 9 dB 6 dB

1.5 m 24 dB 6 dB 3 dB

Installed

cable length

Min. attenuation acc. to

standard Cat. 5e for 100

MHz

Length-dependent min.

attenuation Indu-Sol

GmbH

Length-dependent

min. attenuation Indu-

Sol GmbH

100 m 30 dB 30 dB 33 dB

50 m 30 dB 33 dB 36 dB

25 m 30 dB 36 dB 39 dB

12 m 30 dB 39 dB 42 dB

6 m 30 dB 42 dB 45 dB

3 m 30 dB 45 dB 48 dB

1.5 m 30 dB 48 dB 51 dB



1.1 Physical Parameters - Linedepth

Every switch placed between a controller and a

Device leads to latency

During the design of a network, linedepth have to

be taken into account



I/O-Devices Terminal-Device I/O-Devices Terminal-Device

I/O-Devices

Terminal-Device




Table for max linedepth at Store & Forward

Table for maximum linedepth at Cut Through



Max. linedepth at updaterate of

1 ms 2 ms 4 ms 8 ms

7 14 28 58


1 ms 2 ms 4 ms 8 ms

64 100 100 100



Caution: As it is unsure whether a device works in

Cut Through or Store & Forward modus, the design

of a network should be picked according to Store

& Forward (shorter line-depth) table.




1 ms 2 ms 4 ms 8 ms

7 14 28 58




Controller Switch

IP

The Jitter describes the time variance of PROFINET

packets (delay)

Raising Jitter could be evidence for a exceeded linedepth,

changed netload or device failure


1.2 Logical Parameters - Telegramjitter




Controller Switch

IP

4 ms

6 ms ∆ = 2ms = 50% Jitter

Examples of Error Patterns: Device falls of its own update rate To much TCP/IP traffic or disadvantageous topology Use of external, active diagnostic tools Recommendation Indu-Sol: 50%








The real bus traffic “Jitter” (delay)

Update rate (arrival times)






“Jitter” (delay)

Update rate (arrival times) Scheduled bus traffic




Controller Switch

IP

1.2 Logical Parameters – Telegram Gap

Missing telegram

Communication failures may happen within a network.

Failures need to be recognized fast enough to bring the

system in a defied safe state

PROFINET – The future of communication 1. Basics and Quality Parameters



Controller Switch

IP

Caution: PROFINET per default accepts only 3 missing

telegrams in a row

Recommendation Indu-Sol: 0


1.2 Logical Parameters – Telegram Gap




Controller Switch

IP

Telegram content defective

Communication failures may happen within a network.

Failures need to be recognized fast enough to bring the

system in a defied safe state


1.2 Logical Parameters – Error Telegram




Controller Switch

IP

1.2 Logical Parameters – Error Telegram

Caution: PROFINET per default accepts only 3 missing

telegrams in a row

Recommendation Indu-Sol: 0




Controller Switch

IP

The netload of a network should be measured during full

operation

Communication lines with additional TCP/IP traffic

become more relevant


1.2 Logical Parameters – Loading Ratio




Controller Switch

IP


Caution: to much TCP/IP traffic can lead into

communication failure

Recommendation Indu-Sol: 100:1


1.2 Logical Parameters – Loading Ratio



Controller Switch

IP

Controller Switch

IP


1.2 Logical Parameters – Netload



Controller Switch

IP

In order to leave enough reserve for network expansion and

or additional NRT traffic (TCP/IP) netload should not be

exceeded.




Netload Recommendation

<20%: no action necessary

20…50%: Check-up of planned netload is recommended

>50%: measures to decrease netload are demanded



Controller Switch

IP

Throughput per time unit (max. 100 MBit/s – Line

capacity)

Devices are specified after there throughput capacity

Recommendation Indu-Sol: 20%





Netload

Jitter

Telegram Gaps

Loding Ratio

Error Telegrams

< 50%

0

0

< 20%

100:1

Recommendations

1.2 Logical Parameters - Overview


Indu-Sol



Normal Operation Limited Operation Faulty Operation

Cyclic and acyclic

communication

Only cyclic communication No communication

function

Netload-Class 1 < 1% < 5% > 5%

Netload-Class 2 - - -

Netload-Class 3 < 5% < 30% > 30%

■ Normal Operation

cyclic und acyclic data is being processed without restrictions

■ Limited Operation

cyclic data is being processed, acyclic data may be discarded

■ Faulty Operation

device can shut down

■ Once the netload returned to normal the device must power up again automatically

PROFINET – The future of communication 2. Netload in PROFINET (Netload Classes)



2. Netload in PROFINET (Netload Classes)

Netload is to measure at nodes with concentrated

communication (Controller)

Multi controller networks need to be measured at each

controller separately




IP IP IP IP

Controller

Switch Switch Switch Switch

■ Evaluation of Communication quality with PROFINET-INspektor®

■ Performance measure with a PASSIVE and direct network access point

3. Metrological measurement and evaluation of Quality Parameters




■ Device matrix with status bar

Telegramjitter

Telegram Gap

Error Telegram

Loading Ratio

Netload

PROFINET – The future of communication 3. Metrological measurement and evaluation of Quality Parameters



■ Gather information about Topology, Device setup or

Linedepth with PROscan® Active




■ Documentation and Device List




■ Portstatistics

■ Errorcounter

■ Powerbudget

■ Connection Type

■ Discards



35 | PROFIBUS & PROFINET User Conference 2015 | presented: Indu-Sol GmbH | 16.07.2015

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