Profibus Troubleshooting & Maintenance

PROFIBUS Troubleshooting & Maintenance V8.1.0 14 January 2011

Copyright (c) 1999-2011 PROCENTEC. All rights reserved. 1

Title slideTitle slide

Copyright © 1999-2011 PROCENTEC. All rights reserved. www.procentec.com

1Troubleshooting and Maintenance

PROCENTEC PROCENTEC –– www.procentec.comwww.procentec.com

Is a completely independent company(offices and local support in The Netherlands, Germany and Singapore).

Concentrates products and services on PROFIBUS and PROFINET technology.

Operational areas: Europe, Asia, Middle-East and North America.

Core activities:

Fi ld k ( it t bl h ti d t)


2

Field work (on-site troubleshooting and support)

Manufacturing of network components and tools

Certification (products and installations)

Training

3.3



Subjects (1)Subjects (1)

Introduction

Basic principles OSI model Topology Addressing Communication relations Token passing Baudrates

RS 485 and PROFIBUS DP The technology of RS 485 Signaling Cable specification, construction and variants Topology (cable lengths, spur lines) DB9 and M12 connector


3

DB9 and M12 connector Termination Repeaters

Grounding and shielding External influences on the bus cable IEC 61000-5-2 Grounding and shielding between cabinets Distances between high voltage cable

Subjects (2)Subjects (2)

Basic principles of data communication technology Impedance, delays Attenuation, skin effectReflections

Test- and measurement tools Handheld tools Oscilloscopes Busmonitors

Busparameters

PROFIBUS PA DP/PA couplers and links Topology Cable specifications


4

Cable specifications Terminators and connectors Parameters and profiles

Strategy of fault finding



A few words of some inexperienced engineers and marketeers:

‘The cabling is the easiestpart of bus systems…..’

‘Yeah right!!!!!’


5

The engineers and maintenance technicians who have just stepped out of the 4-20 mA technology had to understand a lot of new terms which makes the step to field busses very hard……

A change in working and thinking for the entire organizationA change in working and thinking for the entire organization

y


6

Not understanding these topics is not good for the ‘Bus business!’



Change in technology means change in tools!Change in technology means change in tools!

AD

DA

ADCPU CPU4..20 mA

Process Controlconventionalanalog

A D A

AD

DA

ADCPU CPU

HART4..20 mA

smart signal

smart

digital

analog + digital (hybrid)


7

AD CPU CPU

A multi-meter can not be used with digital technology.

digitaldigital

Fieldbus 0 1 0 1 0

What can happen in a running installation?What can happen in a running installation?

InternetInternet

OS OS

Programming faultsProgramming faults

PROFIBUS DP/PA

PROFINET / Ethernet / TCP-IP

PLC

RS 485-IS or MBP-ISRS 485 or FO

ManufacturingManufacturing ProcessProcess

PROFIBUS DP

IPC

Programming faultsProgramming faults

Connection faults, reflections, wire breaks, short circuitsConnection faults, reflections, wire breaks, short circuits


8

AS-Interface

Instrument or I/O failureInstrument or I/O failureInstrument removalInstrument removal

?Faulty addressFaulty address



Confusion about the LEDs!Confusion about the LEDs!

Problems can be very difficult to diagnose without the correct tools and a systematic approach. Intermittent faults can be particularly difficult.

The main problem is that the devices that are most affected are often at the

Cause of reflection, e.g. spur line

T T

The main problem is that the devices that are most affected are often at the opposite end of the segment from the source of the reflection!


Bus fault

9

1.0

This page has been intentionally left blank.


10



Basic principles

Basic principlesBasic principles


11

1.0

Overview of the PROFIBUS application layersOverview of the PROFIBUS application layers

PROFIsafePROFIBUS PA

PROFIBUSDP

PROFIdriveMarket name

Basic principles

Profile

PA

FDL + DP

DP

“PROFIsafe” “PROFIdrive”“PA Devices”Nothing

Communicationtechnology

FDL + DP FDL + DP FDL + DP


12

Transmissiontechnology

MBP-ISRS 485 RS 485 RS 485

2.0



Fiber OpticFiber Optic

RS 485RS 4852-wire CU-cable for general purposes

PROFIBUS supports 3 transmission mediaPROFIBUS supports 3 transmission media

Basic principles

Fiber OpticFiber OpticFor highest EMC protection

and wide distances

Fiber optic cable

Coupler CouplerMBPMBP--ISIS2-wire CU-cable with the option for

power over the bus and Ex-protection


13

Fiber optic cable

1.0

PROFIBUS is a PROFIBUS is a master/slave master/slave networknetwork

To create hierarchy in the network, PROFIBUS defines 2 types of devices: active (masters) and passive (slaves) devices.

Basic principles

master

commands

responses

network

slave

0 1 0 1 00 1 0 1 0

0 1 0 1 00 1 0 1 0


14

At least 1 master is mandatory.

PROFIBUS networks allow multiple masters.

In total 127 devices can be addressed (masters + slaves).

3.1



MasterMaster

Basic principles

This station is permanently responsible for the control of the network. The station can generate messages, send these to slaves and interpret responses of slaves.

Examples


15

p PLC’s DCS systems PC’s

2.0

SlaveSlave

Basic principles

This station can interpret messages of a master and dependent on the interpretation, generate responses and send them to the specific master.

Slaves are NOT able to send messages on its own initiative.

Examples: Remote I/O


16

Sensors and actuators

There are also PLC systems available which have slave functionality. They are slave on DP, but can control I/O locally.

2.0



TopologyTopology

PROFIBUS communicates over a two wire bus structure.

sendinglisten,

taking over and

Basic principles

1

taking over andanswering

9

5 43

listen

1170 1 0 1 0


17

Devices are addressed through a network address (0..126).

Devices are coupled in parallel to the bus.

Devices have no fixed position on the bus.

Devices can be removed and inserted during operation.

listen listen

2.0

Assigning the address by dipswitchesAssigning the address by dipswitches

Significance 1 2 4 8 16 32 64

Basic principles

OFF

ON

1 2 3 4 5 6 7 8

Software

Hardware

Address = 1 + 0 + 4 + 0 + 0 + 0 + 0 = 5


18

After changing the hardware address, most of the time the device has to be powered down/up.

2.0



When devices do not have dipswitches, the address can be assigned with the PROFIBUS “Set Slave Address” command. A number of tools are available to fulfil this function.

Assigning the address by softwareAssigning the address by software

Basic principles


19

With PROFIBUS PA considerably more devices do not have dipswitches.

With PROFIBUS PA considerably more devices do not have dipswitches.

1.0

PROFIBUS address mapPROFIBUS address map

0

1..2

Service-, diagnosis- and programming tool

Masters (class 1)

Basic principles

Most configuration tools block address 0 and 126 for slaves. Address 126 is a default address for slaves with software address settings. Add 127 i b d t dd ( l i ibl ith b it )

3..125

126

Slaves (total 123 or 124)

Address for: “Set Slave Address”

127 Broadcast address


20

Address 127 is a broadcast address (only visible with a busmonitor).

Maximum 124 DP slaves per bus!!!!!!!

2.0



Medium access by token passingMedium access by token passing

Active stations, master devices

Basic principles

PROFIBUS protocol

,

PLC DCSPC


21

Polling of passive stations (slave devices)

1.0

PROFIBUS offers the user the possibility to choose from 10 transmission speeds (RS 485).

Transmission speed (baudrate)Transmission speed (baudrate)

Basic principles

Remarks: The transmission speed determines the maximum cable length and vice versa.

The transmission speed has to be set identically at all the masters on the same bus.

Most slaves detect the baudrate automatically.

Because of economic and technical reasons some products do not support all

9,6 19,2 45,45 93,75 187,5 500 1500 3000 6000 12000 kbps


22

Because of economic and technical reasons some products do not support all transmission speeds.

Some older products do not support 45,45 kbps.

2.1



Application layersApplication layers


23

1.0

At this moment the application layer of the PROFIBUS family consists out of 2 standards + profiles: DP (DP-V0, DP-V1, DP-V2) PA

Application layersApplication layers

PA

IEC 61158

e P

rofi

les

atio

n P

rofi

les

Process Automation

PROFIBUS PA

Factory Automation

PROFIBUS DP

General PurposeAutomation

PROFIBUS FMS


24

Dev

ice

Ap

plic

aPROFIBUS PAMBP-IS

- Power over the bus - Intrinsic safety

PROFIBUS DPRS 485 / FO

- Plug and play- Efficient and cost effective

Speed

PROFIBUS FMSRS 485 / FO

- Large variety of applications- Multi-master communication

Universal Application oriented

3.1



PROFIBUS DP

PROFIBUS DPPROFIBUS DP


25

1.0

Decentralized Peripherals (DP)Decentralized Peripherals (DP)

Based on high speed data exchange between a central controller (master) and a number of slaves. The data transfer is cyclic.

PROFIBUS DP

The slaves are polled every cycle with the same priority.

Maximum 244 bytes input and 244 bytes output per slave.

Maximum baudrate: 12 Mbps.

Slave configuration and parameters are set from the master side.

Extended diagnostic possibilities.


26

124 slaves can be put in Data Exchange.

32 stations on one copper segment (RS 485).

2.3



PROFIBUS DP systems consist out of:- multiple masters (Class 1 or 2)- 1 to max. 124 DP Slaves

PROFIBUS DP Multimaster systemPROFIBUS DP Multimaster system

DP master

PROFIBUS DP

DP master(class 2)

DP master(class 1)

DP master(class 1)

PLC

PROFIBUS DP

PC

CNC


27

distributed inputs and outputs distributed inputs and outputs

DP slaves

1.0

Example of a DP master configuration toolExample of a DP master configuration tool

PROFIBUS DP


28

2.0



Request FrameRequest Frame

2

Request Frame

3

Request Frame

. x

Principle of data exchange with DP (cyclic)Principle of data exchange with DP (cyclic)

PROFIBUS DP

DP

sla

ve 1

DP

mas

ter

imm

edia

tere

spo

nse

trailer Output data header

Response Frame

trailerInput dataheader

imm

edia

tere

spo

nse


Response Frame


DP

sla

ve 2

imm

edia

tere

spo

nse


Response Frame


DP

sla

ve 3

imm

edia

tere

spo

nse


Response Frame


DP

sla

ve n

r.


29

Per slave:Max. 244 bytes output dataMax. 244 bytes input data

Per slave:Max. 244 bytes output dataMax. 244 bytes input data

1.1

The handling of all the slaves is called a cycle. The required time is dependent of:- the baudrate;- the number of slaves; - the net data;

The handling of all the slaves is called a cycle. The required time is dependent of:- the baudrate;- the number of slaves; - the net data;

Rules for PROFIBUS message transactionsRules for PROFIBUS message transactions

Correct transaction, the slave replies within the Slot Time.

Correct transaction, the slave replies within the Slot Time.

Master Slave(s)Output data

Input dataIn this example the retries of the master have been set to 3!

In this example the retries of the master have been set to 3!

PROFIBUS DP

the Slot Time.the Slot Time.

Because of no / illegal / corrupted replies, 2 retries but eventually OK (recovery).

Because of no / illegal / corrupted replies, 2 retries but eventually OK (recovery).

3-Retries ns ccessf l

3-Retries ns ccessf l

Output data

Output data - RetryOutput data - Retry

Input data

Output dataOutput data - RetryOutput data - Retry

ProfiTrace Statistics- Worst case sequence = 2- Total retries = 2

ProfiTrace Statistics- Worst case sequence = 2- Total retries = 2

ProfiTrace StatisticsProfiTrace Statistics

have been set to 3!have been set to 3!


30

unsuccessful.The slave is lost!unsuccessful.The slave is lost!

Every cycle a SYNC to establish contact with the lost slave.

Every cycle a SYNC to establish contact with the lost slave.

p yOutput data - Retry

Output data - Next slave

Get diagnostics or Output data - SYNC

Get diagnostics or Output data - SYNC

- Worst case sequence = 3- Total retries = 5- Worst case sequence = 3- Total retries = 5

ProfiTrace Statistics- Syncs are incrementedProfiTrace Statistics- Syncs are incremented



PROFIBUS PAPROFIBUS PAPROFIBUS PAPROFIBUS PA(part 1)(part 1)


31

1.0

Process Automation (PA)Process Automation (PA)

Communication, according to the intrinsic safe standard MBP-IS. The protocol is based on PROFIBUS DP + DP-V1, but the electrical characteristics are changed. This standard is used in the (petro)chemical and nutrition industry.g (p ) y

Replacement for 4..20 mA installations.

Suitable for chemical industry and process control.

Power supply and communication over two wires (31,25 kbps).

Profiles define parameters which are accessible by engineering tools (DP-V1


32

Profiles define parameters which are accessible by engineering tools (DP V1

communication).

The profile allows instrument exchange.

Certification according to the FISCO model.

2.3



PROFIBUS PA

=PROFIBUS DP/DP-V1

The principle of PROFIBUS PAThe principle of PROFIBUS PA

x+PROFIBUS DP

PROFIBUS DP/DP-V1

+Intrinsic safe communication properties


33

PROFIBUS PA

J

1.0

Overview of the PROFIBUS familyOverview of the PROFIBUS family

InternetInternet

OS OS

PROFIBUS DP/PA

Ethernet / TCP-IP / PROFINET

PLC

RS 485-IS or MBP-ISRS 485 or FO

ManufacturingManufacturing ProcessProcess

PROFIBUS DP

IPC


34

AS-Interface

2.1



RS 485 and PROFIBUS DP

RS 485 and PROFIBUS DPRS 485 and PROFIBUS DP


35

1.1

RS 485RS 485 Baudrates from 9.6 kbit/s to 12 Mbit/s

Shielded twisted pair cable

32 devices per segment


Distance: 12 Mbit/s = 100 m; 1.5 Mbit/s = 200 m; < 187.5 kbit/s = 1,000 m

Distance extendable with repeaters

MBPMBP--ISIS Fixed baudrate of 31.25 kbit/s

Intrinsic safety (option) and power over the bus


Distance up to 1,900 m per segment dep. on Ex-class and power consumption

10 32 devices per segment dep on Ex class and power consumption


36

10-32 devices per segment, dep. on Ex-class and power consumption

Fiber opticsFiber optics Baudrates from 9.6 kbit/s up to 12 Mbit/s

Monomode, Multimode, plastic or PCS/HCS fibers are available

Distance extendable with repeaters up to 100 km

1.0



Design specificationsDesign specifications

What are the critical points when designing RS 485 segments?

Spur lines


Shielding & Grounding

Spur lines

Powered Termination

Cable length


37

Max. 32 devices

2.2

The technology of The technology of RS 485RS 485

TTL/CMOSR T

DeviceTTL/

CMOSR T

DeviceTTL/

CMOSR T

Device

Maximum 32


Z Z Z

220E

+5V

390E

220E

+5V

390E i

A

B

Maximum 32devices.

+/-U

R = 30k..200kC < 35pF


38

6. Pull-up/down resistors are essential for the basic current.

GND

390E

GND

390E

1. Sending data by means of current and polarity change.

2. The receivers read the current flow by input impedance (Z).

A

4. The differential voltage should be +/-200mV or more. In reality in the range 4 to 5V.

3. Because of the parallel resistors, a maximum of 32 devices is allowed on a segment.

5. Termination on the end of the cable.

1.1



RS 485 SignalsRS 485 Signals


Line A (2 x Volt)Line A (2,x Volt)

Line B (2,x Volt)

Differential VoltageB A (4 x Volt)


39

B – A (4,x Volt)

1.0

More examples of signalsMore examples of signals


Acceptable signals(Good communication)


40

( )

Heavy noise interference(Communication errors)

Partial noise interference(Good communication)

1.0



TopologyTopology

1. Cable to next device. Spurs have to be as short as possible.

3. When the baudrate is 1500 kbps or higher, minimum 1 meter cable between 2 devices.

4. Termination (powered) at both ends.


Master SlaveSlave Slave Slave Slave Slave

Maximum 32 devices


41

power power power power power power power

2. The devices have their own power supply.

2.1

Plug with termination OFF.

Plug with termination ON.

1 meter rule with 1,5 Mbps or higher 1 meter rule with 1,5 Mbps or higher baudratesbaudrates

30 pF 30 pF

Each certified device has a small connection capacitance (typically 30 pF) and causes a minimal reflection because of the small short circuit that appears


30 pF p ppwhen bits change to another level. This is absolutely normal!

However when connected closely together the capacitances ADD and can produce a reflection that alters the bit level and corrupts messages.

‘Scope trace:-


42

Separating devices with at least 1 m cable, introduces a small signal delay between the devices, so the reflections don’t add!

1.0



These two cables could cause data communication problems (the 1 meter rule).

These two cables could cause data communication problems (the 1 meter rule).

Example Example –– Problems with the 1 meter ruleProblems with the 1 meter rule



43

1.1

Example Example –– Solution for the 1 meter ruleSolution for the 1 meter rule



44

A strategic placement automatically takes care of the 1 meter rule.

3.0



Baudrate (kbit/s)

Segment length ( )

9.6

1200 1200

19.2 1500 6000 120003000500187.593.7545.45

100100100200400100012001200

Cable length versus BaudrateCable length versus Baudrate


(m)

Segment length (feet)

3940 3940 3283283286561310328039403940

3 baudrate transitions in which the cable length reduces with more than 50 %.

3 baudrate transitions in which the cable length reduces with more than 50 %.


45

2.1

These lengths are defined for 1 segment with 32 bus loads!These lengths are defined for 1 segment with 32 bus loads!

Cable T-splice orjunction box

SSpurspurs


Device

Total length of allstubs max. 6,6 mwith 1500 kbps.

junction box

Try to avoid spurs with RS 485.Capacitance of connectors and

junction boxes is not well defined!

Try to avoid spurs with RS 485.Capacitance of connectors and

junction boxes is not well defined!


46

Device

Total 6,6 m with 1500 kbps (capacity of spurs = 0,2 nF) Total 20 m with 500 kbps (capacity of spurs = 0,6 nF) Total 33 m with 187,5 kbps (capacity of spurs = 1,0 nF) Total 100 m with 93,75 kbps (capacity of spurs = 3,0 nF) Total 500 m with 9,6 and 19,2 kbps (capacity of spurs = 15 nF)

2.2

The length is a sum of all the spurs in the segment!

The length is a sum of all the spurs in the segment!



Example Example -- Spur linesSpur lines


70 cm


47

More than 17 devices

1.0

Cable specificationsCable specifications

Standard PROFIBUS DP cables must comply to the following specifications:


Parameter Value

System specification

Low

Low

High?

System specificationWires 2 (twisted)

Impedance 150 Ohm (3 to 20 MHz)

Capacity ≤ 30 pF/m

Loop resistance ≤ 110 Ohm/km

Wire diameter ≥ 0.64 mm


48

g

High?

Lower shielding resistance -> better EMC quality.

4.0

Wire area ≥ 0.32 mm2

Shielding resistance ≤ 9.5 Ohm/km Low



The A and B line are green and red:

Cable construction and wire colorsCable construction and wire colors


A-line

B-line

TXD-N

TXD-P

1

2

-

+

green

red

4. Foil for frequencies above 50 MHz.

1. A-line (green) andB-line (red).


49

2.0

3. Braid for frequencies up to 50 MHz.

2. “Tubes” for a round cable.

All kinds of cables are available for areas in which the standard PROFIBUS cable cannot be used.

Cable typesCable types


Robust cableFlexible cable

Trailing cable

Robust cable

Food cable

Ground cable

Trailing cable

Festoon cable

Fire and heat cable

Flexible cable


50

FRNC cable

Shipboard cableFestoon cable Food cable

Robust cableHybrid cable

2.0

Flexible cable

Shipboard cable

Hybrid cable

Rodent protection cable



ConnectorConnectorss

The connector technology is NOT defined.

Manufacturers determine the implementation of the connector


Manufacturers determine the implementation of the connector.

The PROFIBUS standard describes some recommended implementations: DB9 and M12.

If a manufacturer selects a connector which is described in the standard, then it has to be implemented according to the standard.


51

1.0

For devices with a DB9 connector, standardized plugs are available for chaining the bus.

DB9 connectorDB9 connector -- StructureStructure


Versions are available on which an extrapiggy back connector is implemented. It’s

recommended to put one on every segment

Versions are available on which an extrapiggy back connector is implemented. It’s

recommended to put one on every segment


52

recommended to put one on every segment for maintenance purposes.

recommended to put one on every segment for maintenance purposes.

2.2



DB9 connector DB9 connector –– Pin layoutPin layout

The pin-layout of the DB9 connector is defined as follows:

Pin nr. Signal Description


1

2

3

4

5

6

7

8

M24

B-Line

CNTR-P

DGND

VP

P24

A Line

Shield <NOT USED ANYMORE>

Ground for +24 V output voltage

RxD/TxD-P Receive/Transmit data - plus

Repeater control signal (direction control), RTS signal

Digital ground

Supply voltage (+5 V)

Output voltage +24 V

RxD/TxD N Receive/Transmit data minus


53

8

9

A-Line

CNTR-N

RxD/TxD-N Receive/Transmit data - minus

Repeater control signal (direction control)

2.1

: This signal is mandatory.

Shield (Metal casing of the connector)Shield(10)

DB9 connector DB9 connector –– Connection methodConnection method

The method of connecting the cable is very important. When termination is enabled, the second channel is disconnected.


Shield

T = on T = off


54

Cable Insulation

1.3

The left plug has the termination ON, the second channel can not be used. The right plug has the termination OFF.



DB9 connector DB9 connector –– ExampleExample of the termination switchof the termination switch

Termination only at the end (normal situation)



Termination also in the middle

2. Branch is disconnected!


55

1. Termination somewhere on the cable.

2.0

Plug with termination OFF.

Plug with termination ON.


DB9 connector DB9 connector –– Fast ConnectFast Connect

Only use cables with solid core wires.

Cables must be suitable for Fast Connect (wire and cable thickness)


cable thickness).

It is recommended NOT to use the plug for the 2nd time.

If a new plug is assembled on an already used cable, then prepare the cable again (new clean wires).


56



Checklist 9Checklist 9--pin plug selectionpin plug selection

Angle of the plug?

Maximum baudrate?

Piggy back connector?


ggy

Can the termination be switched ON/OFF?

When termination is switched ON, is the outgoing channel disconnected?

Which one is the outgoing channel?

If Fast Connect, is the cable suitable?


57

Grounding and shielding system?

IP class?

Is the plug reusable?

Value of the series resistance?

2.0

M12 connectorM12 connector -- StructureStructure

With IP65 applications, the M12 system is often used.


Tee for chaining

Terminator


58

Tee for chaining

1.1

Instrument with2 connectors

(male and female)



M12 connector M12 connector –– Pin layoutPin layout

The pin layout of the M12 connector has been defined as follows:


12

34

5

Ref. point

Pin no. Signal Function

1 VP +5V supply for termination


59

2.0

2 RxD/TxD-N Data line minus (A-line)

3 DGND Data ground

4 RxD/TxD-P Data line plus (B-line)

5 Shield Ground <NOT USED ANYMORE>

Thread Shield Ground

M12 requires accurate assemblyM12 requires accurate assembly



60

Twisted and broken wires during assembly of the M12 connector.

1.0



FerrulesFerrules

Ferrules are NOT mandatory.

Choose ferrules that are suited for data communication.


OK

For example: galvanised copper. Do NOT use aluminium!

Make sure you use the correct ferrule size.


61

Not OK

Make sure the wires are pressed in deep enough.

Use correct tools.

1.0

The bus is terminated on both ends with terminating resistors.

5 Volt

TerminaTerminattionion -- StructureStructure


B

A

390 Ohm

220 Ohm

The termination consists out of 3 resistors.

The power supply takes care of a valid logic level when non of the devices are active on the bus.


62

A

GND

390 Ohm Without the power supply the

terminating resistor is not equal to the cable impedance!

1.2



First station Last station

Termination Termination -- ApplicationApplication

VP (6) VP (6)


B (3)

A (8)

DG (5)

390

220

390

B (3)

A (8)

DG (5)

B line

A line

390

220

390


63

B BA A

Station 2 Station 3

1.1

Termination must always be present and powered at all times.….If the user wants more guarantee, then an active termination is the best solution.Termination must always be present and powered at all times.….If the user wants more guarantee, then an active termination is the best solution.

Oractive termination

Oractive termination

He was correct! The termination is switched ON.He was correct! The termination is switched ON.



64

1.0

Sometimes the laptop was connected at this place!But, there is NO powered terminated here.Sometimes the laptop was connected at this place!But, there is NO powered terminated here.



Active TerminationActive Termination

Master


Power

“Last”Sl

Slave Slave Slave

Power

Power

Slave“Last” Slave

Slave Slave

Power


65

4.0

Slave Slave Slave Slave

In this segment every station can be removed or powered down without disrupting the network.

TerminationTermination -- ExampleExample

The use of active termination for higherreliability and simplification of

maintenance activities.

The use of active termination for higherreliability and simplification of

maintenance activities.


- 5 segments end in this cabinet. - 5 segments end in this cabinet.


66

1.0



Termination Termination –– Coupling componentsCoupling components



67

Termination is often forgotten when coupling components are involved.

Termination is often forgotten when coupling components are involved.

1.0

VP (6)

First station Second station

VP (6)

Termination Termination –– Only 2 devicesOnly 2 devices


At least 2 meters cable

VP (6)

B (3)

A (8)

DG (5)

390

220

390

VP (6)

B (3)

A (8)

DG (5)

B line

A line

390

220

390


68

1.0

When a segment only has 2 devices, it is recommended to install a cable length of at least 2 meters!When a segment only has 2 devices, it is recommended to install a cable length of at least 2 meters!



Repeaters are network components to enlarge the cable length and to increase the number of stations (more than 32).

RepeatersRepeaters


TTMax. 1200 m

Max. 31 stations

Max. 31 stations

Max. 29 stations

Max. 31 stations

TT

TT

TT

TT

Max. 1200 m


69

3.0

Repeaters are also bus loads and terminatingresistors need to be placed again.

Repeaters are also bus loads and terminatingresistors need to be placed again.

TTTT

TTMax. 1200 mMax. 1200 m

TT

Questions about repeaters ???Questions about repeaters ???


Max. 31 stations Max. 29 stations

T

T

T

Max. 1200m

What is the highest baudrate that is allowed in this installation?

Max. 31 stations Max. 31 stationsT

TT

T

Max. 1200m

Max. 1200mMax. 1200m

T


70

g

Why does the top-right segment have 29 stations?

Where in this installation can we hook up a laptop with a PROFIBUS card?

What is special about the termination on the top-left and bottom-right?

What happens when a segment has a short circuit?

2.0



Repeaters Repeaters -- StructureStructure

Segment 1 Segment 1


Isolation

Segment 11. The shielding can still be 1 on 1.

2. A tap point can be isolated or directly connected with a

3. Termination can be activated when the bus ends/starts at the repeater.


71

Segment 2Segment 2

segment.p

2.0

Wrong wiring of repeatersWrong wiring of repeaters



72

Now they have 41 devices on the same segment!Now they have 41 devices on the same segment!



Example Example –– Repeater backboneRepeater backbone

A DP backbone on which 4 repeaters are connected. At the other side of the

t t t t

A DP backbone on which 4 repeaters are connected. At the other side of the

t t t t


repeaters a new segments starts.repeaters a new segments starts.


73

The terminators are only activated at the ‘left side’.The terminators are only activated at the ‘left side’.

Beware of the ‘1 meter rule’!Beware of the ‘1 meter rule’!

2.0

ProfiHubs are more efficient for repeater backbonesProfiHubs are more efficient for repeater backbones

Long spur lines to instruments and the possibility to remove/insert them during operation. Short circuit protection on each spur line is automatically provided.


DP backbone

Each spur line

Wiring problemsdo not spread to


74

Each spur line can be 200 m at 1,5 Mbps.

do not spread to other spur lines.

1.0



For testing it is recommended to set the baudrate to the lowest possible speed (9,6 kbps). Most networks operate ‘correctly’ on this speed even when they have installation, cabling and termination faults. You can now check your

ti d dd i

TestingTesting


connections and addressing.

Low Baudrate

High Baudrate

Low % of Overall Bit Transmission Time

High % of Overall Bit Transmission Time


75

2.0

High % of Overall Bit Transmission Time

At higher baudrates there is more chance of bus faults!



76



Aarding en afscherming

Grounding and shielding

Grounding and shieldingGrounding and shielding


77

1.1

External influences on data communicationExternal influences on data communication


Sender Receiver

EMI


78

Currents



Interference by external sourcesInterference by external sources

High Voltage

Electrostatic injection:Capacitive coupling caused by nearby power lines.


g g

Interference sourcee.g. Power cable Capacitive coupling between cables

Pickup

Electromagnetic injection:Magnetic fields caused by high currents in nearby cables.


79

High Current

Inductive coupling between cables

Pickup

Interference sourcee.g. Power cable

Magnetic fields caused by high currents in nearby cables.

Reduction of electromagnetic injectionReduction of electromagnetic injection

The twist in the wires eliminates magnetic fields.

Try to keep the twist in the wires when the sheath has been removed.


Pickup

This theory is valid for al signal cariers!


80

Induced currents in adjacent loops tends to cancel



Reduction of electrostatic injectionReduction of electrostatic injection

The shielding of the cable reduces electrostatic injection!

Ground on multiple points (resistance reduction).


High VoltageInterference sourcee g Power cable k d

As thick possible.

Non grounded shielding has no effect!


81

e.g. Power cable

Pickup

Pickup passes to groundRs Rs Rs

Rs = Shield resistance

What does IEC61000What does IEC61000--55--2 say about grounding?2 say about grounding?

Ground as many points as possible. This reduces the resistance (less noise).


Be careful of the amount of current flowing through the shield. When the current gets too high, use;- fiber optic- extra ground cable- repeaters with isolation

Avoid the use of ‘pigtails’


82

Avoid the use of ‘pigtails’.

Avoid connection with the ‘minus’ of power supplies.

3.1



Grounding and shielding between cabinetsGrounding and shielding between cabinets

Slave Slave

Master


ground rail ground rail ground rail


83

PROFIBUS cable

Ground cable

PROFIBUS cable

1.0

Additional grounding pointsAdditional grounding points



84

2.0



ExampleExample -- ShieldingShielding notnot connectedconnected



85

1.0

Policy of separationPolicy of separation


As far away as possible!

Power line

As close as possible!Ground potential


86

2.0



The voltage levels and applications of cable needs to be classified into categories.

Category I:Fieldbus and LAN cables (PROFIBUS, PROFINET, ASi, etc.).Shi ld d bl f di it l d t ( i t RS 232 t )

Air gaps (1)Air gaps (1)


Shielded cables for digital data (printer, RS 232, etc.).Shielded cables for analog and digital signals (25 V).Low voltage cables (60 V).Coax cables

Category II:Cable with DC voltage >60 V and 400 V.Cable with AC voltage >25 V and 400 V.

Category III:


87

Category III:Cables with DC and AC voltage >400 V.Telephone cables.

Category IV:All cables from group I to III with the direct danger of lightning strikes (connections between

buildings or open air applications).

2.0

Air gaps (2)Air gaps (2)

20 cm

When cables are placed side by side, they have to comply to the following air gaps:


Cablecategory

I

Cablecategory

II

Cablecategory

III

Cable

10 cm 10 cm

50 cm

50 cm 50 cm


88

categoryIV

50 cm 50 cm

The air gaps are based on air space. In case of grounded metal plates, the distances can be reduced.

Cables of different categories may cross each other.

2.0



Air gaps (3)Air gaps (3)A measurement of a packing machine in which the PROFIBUS cables are placed too close to power lines.



89

Power lines are removed.

Power lines are too close.

3.0

Example Example -- Air gapsAir gaps

Power cablesExample: 230 V

Compressed air cables

Data communication cablesExample: PROFIBUS



90

The data communication cables have been placed more than 10 cm distance from the 230 V cables.The data communication cables have been placed more than 10 cm distance from the 230 V cables.

2.0



Separation of cables in metal cable traysSeparation of cables in metal cable trays

B di


Cat I Cat II Cat III

Channel lid Bonding

Bonding

Channel


91

Bonding

Channel

1.0

Creating a more reliable installationCreating a more reliable installation

Repeater backbones with repeaters/ProfiHubs (isolation of problems)

External powered termination (removing/adding devices)

Summary

Reduce the baudrate (improves signal quality)

Increase the repeats/retries (increases success rate)

Reduce the spur/stub lines or use repeaters/ProfiHubs (improves signal quality)

Cable as close as possible to ground (decr. EMC sensitivity)

Additional grounding points (decr. EMC sensitivity)

Activate the watchdog on all devices (safety)


92

Activate the watchdog on all devices (safety)

Use fiber optic for long distances (isolation of problems)

It is assumed that the installation complies with the PROFIBUS rules!It is assumed that the installation complies with the PROFIBUS rules!

1.0



Making troubleshooting easyMaking troubleshooting easy

Measurement connectors on every segment (start of the cable)

Every segment has its own addressing range (10..19, 20..29, etc)

Summary

Individual repeaters/OLMs can be powered up/down

Individual devices can be powered up/down

PLC/DCS at the beginning of the cable

Diagnostics is enabled in the devices

Installation drawing in 1 or 2 pages (with cable lengths and addresses)

Addresses clearly marked on the devices


93

Addresses clearly marked on the devices

All GSD files are available in ProfiTrace

Access to the PLC/DCS configuration

1.0



94



B i i i l fB i i i l fBasic principles of Basic principles of transmission technologytransmission technology


95

1.0

Cable properties (4..20 mA)Cable properties (4..20 mA)

R/2 R/2

G

R /k ( l l )


96

R = /km (real value)G = S/km (real value)

In DC situations every cable complies to this specification. Losses and cable resistance can easily be determined.



Cable properties (PROFIBUS)Cable properties (PROFIBUS)

R/2 L/2 R/2L/2

R = /km

GCG = S/kmL = H/kmC = F/km

I d AC i t Zj L R


97

Impedance = AC resistance Zj C G

In DC and AC situations every cable complies to this specification. Losses are calculated with another formula.

LossesLosses

R L

R l G l Z R l

U2U1 GC


98

Example: Z = 100 l = 1000 m R = 0,1 /m -> losses = 40%

U U eR l

Z

G l Z

2 1 2 2

U U eR l

Z2 1 2 if G = 0 S



Skin effect (1)Skin effect (1)

The losses are also linked to the skin effect. When the frequencies increase, the electrons move to the outer layer of the cable. This causes an increase in the cable resistancecable resistance.

F (MHz) (um)

1

100

10.000

68

6.8

0.68


99

This becomes important at frequencies above 100 kHz. De resistance increases with . f

The frequency is the factor which determines the maximum cable length

Hz

Maximum cable lengthMaximum cable length

dB

Hz

U1 U2cable Rt

With PROFIBUS:


100

Transmissionspeed in kbit/s

9.6 19.2 45.45 93.75 187.5 500 1500 3000 6000 12000

Segment lengthin m

1200 1200 1200 1200 1000 400 200 100 100 100

With PROFIBUS:



Propagation delaysPropagation delays

Because of the inductance and capacitance, the cable is subject to propagation time. On typical twisted-pair cables this is:

With most PROFIBUS cables this is:

4.2 ns per meter or 420 ns per 100 m or

0.84 us per 200 m or

4.2 us per km


101

This is about 200.000 km/s -> 60% of the speed of light.

ReflectionsReflections

A physical characteristic of objects which have ‘speed’ is that they reflect whenever they are blocked in their path.

This characteristic can also be found in transmission lines. Solutions for the termination of reflections is the use of terminating resistors.

RtRt


102

Rt = ZoRt = Zo



Rt=Zo

Zo=150 ,L=100m

Correct terminated cableCorrect terminated cable

The signal amplitude has been The signal amplitude has been


103

The signal amplitude has been attenuated (dep. On the cable length and baudrate).

The propagation indicates 100m cable length (420 ns).

The signal amplitude has been attenuated (dep. On the cable length and baudrate).

The propagation indicates 100m cable length (420 ns).

Acceptable signalAcceptable signal

1 V idle level because of powered terminationtermination


104

Acceptable reflections

No noise during idle state



Zo=150 ,L=100m

Cable without terminationCable without termination

Start

t2

t1

t4

t3

t6

t5


105

Start End

Endt7

The “width” of a reflection indicates the distance! Example: 840 ns = 100 m (to the end and back).The “width” of a reflection indicates the distance! Example: 840 ns = 100 m (to the end and back).

Termination missing or wire break (nearby)Termination missing or wire break (nearby)Detected glitch in the signalling

Detected glitch in the signalling

The reflections are compressed in the bit because the cable is short or the

The reflections are compressed in the bit because the cable is short or the


106

g gdisturbance is nearby. But, some reflections have a high amplitude that affects the bit interpretation.

disturbance is nearby. But, some reflections have a high amplitude that affects the bit interpretation.



Test- and measurement tools

TestTest-- and measurement toolsand measurement tools


107

2.0

Fault topFault top--55

1) Termination.


2) Power lines.

3) Cabling rules.

4) Configuration faults.

5) Damaged or not-certified interfaces.


108

Statistics from 300 field trips worldwide.



Handheld toolsHandheld tools

• Siemens BT200

• ComSoft Nettest II

Functions:Wire breaks/short circuits


ComSoft Nettest II Voltage or shielding faults Localizing faults Measuring cable lengths Termination detection List of slaves Logging


109

Non active segments (masters have been removed)!

2.2

Test and evaluation Test and evaluation mastersmasters

PROFIBUS MasterBihl & Wiedeman


ProfiCaptainPROCENTEC

F ti

Maximum baudrate 19,2kand RS 232!


110

Functions: Configuration I/O Testing Diagnostics Live List and Network Scan Set Slave Address

4.0

USB



OscilloscopesOscilloscopes


Functions Amplitude Reflections

1st: Large + Difficult

2nd: Expensive

3rd: Difficult 4th: Small, Fast and Easy


111

Noise EMC

The oscilloscope is the only tool that can display the bus signals!The oscilloscope is the only tool that can display the bus signals!

6.0

BusmonitorsBusmonitors / Analyzers/ Analyzers

• ProfiTrace 2 - PROCENTEC

• Bus check - Softing


• PBScope - T+H

• IT-Monitor - ITM / ComSoft / TMG-itec

• Amprolyzer

Functions


112

Active network!

6.0

Functions Live List Messages Device diagnosis Cycle times Logging

USB



Tap ConnectorTap Connector

Oscilloscope


| | | | | | | | | | | | | | | | | | | |

0 cm 10 cm 20 cm

ProfiCore


113

2.0

Example Example –– No measurement connectorsNo measurement connectors



114

2.0

It is highly recommended to put a measurement connector on the PLC/DCS when the cable also starts here.It is highly recommended to put a measurement connector on the PLC/DCS when the cable also starts here.



Required tools to exactly pinpoint “the fault”Required tools to exactly pinpoint “the fault”

Faults on DP Passive cable Running installation

General communication faults Not possible ProfiTrace

Double address Not possible ProfiTrace


Double address Not possible ProfiTrace

Wrong address BT200 ProfiTrace

No termination BT200, Multi meter Oscilloscope

Too many termination BT200, Multi meter Oscilloscope

Missing device (power off, connector removed, etc)

BT200 ProfiTrace, Configuration tool

Device diagnostics Not possible ProfiTrace, Configuration tool


115

Shortcircuit, break, crossed wires, etc BT200, Multi meter Oscilloscope

EMC problems Oscilloscope Oscilloscope

1 Meter rule Not possible Oscilloscope

Configuration faults Not possible ProfiTrace

1.0

Facts and FictionFacts and FictionFacts and FictionFacts and FictionTh i l fTh i l fTh i l fTh i l fThe most important tools for The most important tools for troubleshooting a network troubleshooting a network

during operation are an during operation are an illill dd

The most important tools for The most important tools for troubleshooting a network troubleshooting a network

during operation are an during operation are an illill dd


oscilloscopeoscilloscope and a and a busmonitor/analyzerbusmonitor/analyzer..oscilloscopeoscilloscope and a and a

busmonitor/analyzerbusmonitor/analyzer..



Facts and FictionFacts and FictionFacts and FictionFacts and FictionA multiA multi--meter is not useable meter is not useable

for dynamic signal for dynamic signal measurement!measurement!

A multiA multi--meter is not useable meter is not useable for dynamic signal for dynamic signal

measurement!measurement!




118



Busparameters

BusparametersBusparameters


119

3.0

Introduction BusparametersIntroduction Busparameters

Busparameters are settings that define the timing behavior on the bus.

By means of a config tool the busparameters are set at every master.

The most part of the busparameters have to be the same on all masters.

Busparameters

p p

“Modern” config tools set the busparameters automatically.

What is the reason to set busparameters:

Extension to other media (DP to PA).

Use of many fibre optic couplers or repeaters (delay times).

Performance improvement (efficiency).

T k d di t b (k i th i t ll ti i )


120

1.2

To work around disturbances (keeping the installation running).



Standard BusparametersStandard Busparameters

Busparameters have to be set at every master (automatically or by the user):

Baudrate Transmission speed (Baudrate) (10 possibilities)

TS Master address (0 to 126)

Busparameters

TSET

TQUI

max TSDR

min TSDR

Setup Time

Quiet Time

Largest Station Delay Responder

Smallest Station Delay Responder

20 to 28-1 (bit times)




Baudrate Transmission speed (Baudrate) (10 possibilities)

TSL Slot Time 52 216-1 (bit times)


121

3.0

Max Retry Limit

HSA

TTR

Maximum Retries

Highest Station Address

Target Rotation Time

0 to 8

2 to 126


G GAP Update Factor 1 to 100

The Slot Time is the maximum time the master waits for the complete reception of the first byte of a response (11 bits).

TTSLSL (Slot Time)(Slot Time)

Busparameters

Within the Slot Time the first byte should be received, otherwise the master will attempt a retry (repeat), or continue with other actions.

23n 1


122

1 2 n

2.1



This is the maximum time the slave could need to send the first bit of a response back.

With PROFIBUS DP thi l i t d di d

maxTmaxTSDRSDR (Largest Station Delay Responder)(Largest Station Delay Responder)

Busparameters

With PROFIBUS DP this value is standardized.

minTSDR < Response < maxTSDR

maxTSDR < TSL

23n 1


123

1 2 n

2.0

This is a time the slave has to wait before it can send a response back.

With PROFIBUS DP this time is sent with the parameters to the slaves. This is

min Tmin TSDRSDR (Smallest Station Delay Responder)(Smallest Station Delay Responder)

Busparameters

pthe reason why this parameter is set in the master.

Standard value: 11 bit times (to calm the bus).

minTSDR < Response

23n 1


124

23n 1

1 2 n

2.0



The Quiet Time controls the time when the bus electronics or software of the sender are set to ‘receive mode’ after a message has been sent.

TTQUIQUI (Quiet Time)(Quiet Time)

Busparameters

This parameter has to be set when reflections or other negative elements are involved.

TQUI < minTSDR

Standard value: 0 bit times


125

2.0

The Setup Time is an extra waiting time which is started before a message is sent (offset).

TTSETSET (Setup Time)(Setup Time)

Busparameters

The Setup Time is often used when DP/PA couplers or other media ‘transitions’ are involved. It should be set to the device which needs the longest Setup Time (stated in the manual).


126

2.0



Busparameter timing diagramBusparameter timing diagram

Busparameters

Tid1Master Slave

Tim

e

Response

minTSDR (11..x Tbit)

TSDR (60 800 Tbit)

Request

Request

Tslot

Tqui


127

2.2

maxTSDR (60..800 Tbit)Response

Tid1

Tid1 = 33 Tbit + 2*Tset + internal master delayTid1 = 33 Tbit + 2*Tset + internal master delay

New transaction starts here…

G (GAP Update Factor)G (GAP Update Factor)

With this parameter the factor is set after how many token cycles the master will search for a new master (FDL_Status message – SD1).

Busparameters

TGUD = G * TTR

If the factor is high, the network will increase in bus cycle efficiency, but it will be slower for master insertions.

Standard value: 10


128

A couple of masters ignore this parameter and always operate according to G = 1.

2.1



HSA (Highest Station Address)HSA (Highest Station Address)

This parameter sets the highest address in the network. Above HSA the master does not ‘look’ anymore.

Busparameters

A decrease of HSA makes the insertion of new masters quicker. The overall network performance is not effected.

Masters which have a higher address number than the HSA value, will not be able to access the network.

Standard value: 126


129

1.0

Max Retry Limit (Maximum Retries)Max Retry Limit (Maximum Retries)

This parameter sets the number of retries which are taken when a receiver does not respond to a message (not for FDL_Status messages).

Busparameters

Max Retry Limit is increased by the user when the network is exposed to distortions. The overall cycle time will be damaged because the message is repeated.


130

2.0



Standard busparameters for PROFIBUS DPStandard busparameters for PROFIBUS DP

Busparameters

Busparameterversus Baudrate

9.6 k 19.2 k 45.45 k 93.75 k 187.5 k 500 k 1.5 M 3 M 6 M 12 M

TSL [bit times] 100 100 640 100 100 200 300 400 600 1000

Max_Tsdr [bit times] 60 60 400 60 60 100 150 250 450 800

Min_Tsdr [bit times] 11 11 11 11 11 11 11 11 11 11

TSET [bit times] 1 1 95 1 1 1 1 4 8 16

TQUI [bit times] 0 0 0 0 0 0 0 3 6 9

G f t 1 1 10 1 1 1 10 10 10 10


131

1.2

Gap factor 1 1 10 1 1 1 10 10 10 10

HSA 126 126 126 126 126 126 126 126 126 126

Max_Retry_Limit 1 1 1 1 1 1 1 2 3 4

WatchdogWatchdog

The watchdog is a supervision time which is set/calculated in the configuration tool of the master. The watchdog will be transferred to all configured slaves.

Busparameters

Within the watchdog time, the master has to “contact” the slave. If this is not the case, the slave leaves the Data Exchange state.

When the watchdog is calculated by the configuration tool, the value is in most cases 6x the “worst case” cycle time.

Range: 10 ms .. 650 s.


132

2.0

Cycle time << Watchdog (ideal is 6x)



Single Master Single Master -- 1 master with 24 slaves1 master with 24 slaves

Busparameters


133

1.1

Watchdog

Cycle time



134



PROFIBUS PA

MBP and PROFIBUS PAMBP and PROFIBUS PA


135

3.0

RS 485RS 485 Baudrates from 9,6 kbit/s to 12 Mbit/s


32 devices per segment

PROFIBUS PA

Distance: 12 Mbit/s = 100 m; 1,5 Mbit/s = 200 m; < 187,5 kbit/s = 1.000 m

Distance extendable with repeaters

MBPMBP--ISIS Fixed baudrate of 31,25 kbit/s

Intrinsic safety (option) and power over the bus


Distance up to 1.900 m per segment dep. on Ex-class and power consumption

10 32 devices per segment dep on Ex class and power consumption


136

10-32 devices per segment, dep. on Ex-class and power consumption

Fiber opticsFiber optics Baudrates from 9,6 kbit/s up to 12 Mbit/s

Monomode, Multimode, plastic or PCS/HCS fibers are available

Distance extendable with repeaters up to 100 km

2.0



PROFIBUS PAPROFIBUS DP

DP/PA segment couplerDP/PA segment coupler

PROFIBUS PA

MBP-ISRS 485

AsynchronousNRZ coding

1 character = 11 bits(8 user bits + 1 start + 1 stop + 1 parity)

Variable baudrates

Synchronous Manchester coding

1 character = 8 bits

Fixed baudrate = 31 25 kbps

DP/PA coupler


137

Variable baudrates Fixed baudrate = 31,25 kbps

2.2

PROFIBUS PA

=PROFIBUS DP/DP-V1

The principle of PROFIBUS PAThe principle of PROFIBUS PA

PROFIBUS PA

x+PROFIBUS DP

PROFIBUS DP/DP-V1

+Intrinsic safe communication properties


138

PROFIBUS PA

J

1.0



MBP SignalingMBP Signaling

The instrument power supply (2-wire) is generated by the DP/PA coupler. It is normally between 12 to 24 V with a current of 90 to 400 mA, dependant

The instrument power supply (2-wire) is generated by the DP/PA coupler. It is normally between 12 to 24 V with a current of 90 to 400 mA, dependant

PROFIBUS PA

current of 90 to 400 mA, dependant on the Ex zone.current of 90 to 400 mA, dependant on the Ex zone.

Fig. 1 DC measurement


139

The data (31,25 kbit/s) is modulated on the power supply with an amplitude of 750 mV to 1 V (peak-to-peak).

The data (31,25 kbit/s) is modulated on the power supply with an amplitude of 750 mV to 1 V (peak-to-peak).

2.3

Fig. 2 AC measurement

MBP MBP SignalingSignaling

Transm it level characteristics Lim its

O utput leve l (peak-to-peak) 0.75 V to 1 V

PROFIBUS PA

M axim um positive and negative am plitude d ifference (s ignaling b ias)

± 50 m V

M axim um output level; open c ircuit (peak-to-peak)

35 V

R eceive c ircu it characteris tics Lim its

Input im pedance, m easured over the freq uency range 0.25 fr to 1.25 fr

3 kΩ

Sensitiv ity; m in . peak-to-peak s ig na l req u ired to be accepted

150 m V

N oise re jection ; m ax peak-to-peak


140

N oise re jection ; m ax. peak to peak no ise requ ired to be re jec ted

75 m V

1.0



PROFIBUS PA

DP/PA couplersDP/PA couplersand linksand links

DP/PA couplersDP/PA couplersand linksand links


141

1.0

11

Siemens segment coupler Siemens segment coupler -- AddressingAddressing

PROFIBUS PA

PROFIBUS DP

PROFIBUS PA

55 4433


142

1.1



DP/PA segment coupler from SiemensDP/PA segment coupler from Siemens

StandardPA current: 400 mA

PROFIBUS PA

[EEx ia] II C

[EEx ib] II CPA current: 110 mAPA voltage: 12,5 V

PA voltage: 19 V


143

[EEx ia] II CPA current: 90 mAPA voltage: 12,5 V

DP baudrate: 45,45 kbpsDP connector: DB9DP termination: NoPA connector: ScrewPA termination: Switchable

(Non-Ex only)

DP baudrate: 45,45 kbpsDP connector: DB9DP termination: NoPA connector: ScrewPA termination: Switchable

(Non-Ex only)

2.3

StandardPA current: 400 mA

DP/PA segment couplers from PDP/PA segment couplers from P++FF

PROFIBUS PA

[EEx ia] II CPA current: 100 mAPA voltage: 13 V

PA voltage: 25 V


144

DP baudrate: 93,75 kbpsDP connector: ScrewsDP termination: Yes

PA connector: ScrewsPA termination: Integrated

DP baudrate: 93,75 kbpsDP connector: ScrewsDP termination: Yes

PA connector: ScrewsPA termination: Integrated

3.1



PROFIBUS PA

DP/PA linkDP/PA linkssDP/PA linkDP/PA linkss


145

PROFIBUS DP

DP/PA link from SiemensDP/PA link from Siemens

PROFIBUS PA

9,6 kbit/s to12 Mbit/s

PROFIBUS PA

Link Coupler


146

DPSLAVE

DPMASTER 45,45 kbit/s

31,25 kbit/s

2.0



slave 105 Q bytes


PROFIBUS PA

DPMASTER

slave 155 I bytes

slave 125 I bytes

DPSLAVE


147

slave 10slave 15slave 12

I

O5 bytes 5 bytes

5 bytes

I

O10 bytes

5 bytes

Max. 5 standard Siemens DP/PA


PROFIBUS PA

couplers (Ex and Non-Ex)

Standard Siemenssegment coupler Ex and Non-Ex

Standard Siemenssegment coupler Ex and Non-Ex


148

DP baudrate: 9,6 kbps to 12 MbpsGateway is DP slave: YesNumber of bytes: 244 bytes Input/Output for the complete PA networkField instruments: Max. 31 slaves in Data Exchange

DP baudrate: 9,6 kbps to 12 MbpsGateway is DP slave: YesNumber of bytes: 244 bytes Input/Output for the complete PA networkField instruments: Max. 31 slaves in Data Exchange

Gateway, DP slave, PA masterGateway, DP slave, PA master

3.0



1 ms

Cycle time with a DP/PA link from SiemensCycle time with a DP/PA link from Siemens

PROFIBUS PA

DP/PA link

up to 12 Mbit/sPROFIBUS DP

PROFIBUS PA


149

15,5 ms15,5 ms

15,5 ms

11

Addressing with a DP/PA link from SiemensAddressing with a DP/PA link from Siemens

PROFIBUS PA

PROFIBUS PALink

PROFIBUS DP

PROFIBUS PALink44 33


150

33 44 55 44 5533

The lowest address behind the link is 3.The lowest address behind the link is 3.



Siemens DP/PA link Siemens DP/PA link –– Measuring the 45,45 kbps sideMeasuring the 45,45 kbps side

Connect the A line to pin 8 on DB 9

PROFIBUS PA

Connect the A-line to pin 8 on DB-9Connect the B-line to pin 3 on DB-9

DB-9 (Female)


151

On the backplane, the 45,45 kbps side is available on the bottom 2 pins. When a DB9 connecter is attached it can directly be connected with an analyzer (RS 485).On the backplane, the 45,45 kbps side is available on the bottom 2 pins. When a DB9 connecter is attached it can directly be connected with an analyzer (RS 485).

2.2

A

B

PROFIBUS PA

DP/PA linkDP/PA linkfromfrom Pepperl+FuchsPepperl+Fuchs

DP/PA linkDP/PA linkfromfrom Pepperl+FuchsPepperl+Fuchs


152



DP/PA link from PDP/PA link from P++F F -- SpecificationsSpecifications

StandardPA current: 400 mAPA voltage: 24 V

PROFIBUS PA

[EEx ia] II CPA current: 100 mAPA voltage: 12,8 V

g

Power-Link Non-Ex(segment coupler)

Power-Link Non-Ex(segment coupler)

Transparantgateway

(redundant

Transparantgateway

(redundantPower-Link Ex

(segment coupler)Power-Link Ex

(segment coupler)


153

DP baudrate: 9,6 kbps to 12 MbpsGateway is DP slave: NoNumber of bytes: 244 bytes Input and 244 bytes Output per PA slaveField instruments: 124 slaves in Data Exchange

DP baudrate: 9,6 kbps to 12 MbpsGateway is DP slave: NoNumber of bytes: 244 bytes Input and 244 bytes Output per PA slaveField instruments: 124 slaves in Data Exchange

(segment coupler)(segment coupler)(redundantoption)

(redundantoption)

(segment coupler)(segment coupler)

3.1

11

DP/PA link from P+F DP/PA link from P+F -- AddressingAddressing

PROFIBUS PA

PROFIBUS DP

PROFIBUS PA

55 4433


154

Because of the semi-transparency, address 1 for DP and PA slaves is not allowed.Because of the semi-transparency, address 1 for DP and PA slaves is not allowed.

1.1



Star- and bus constructions can be realized.

Topology of MBPTopology of MBP--ISIS

PROFIBUS PA

PROFIBUS DP

DCS/PLC

DP/PA-Link

x+

Junction Box


155

24 VPROFIBUS PA “T“

Segment

Explosion zone restrictionsExplosion zone restrictions

Area Zone 0 Eex ia IIC

Zone 1 Eex ib IIB

Zone 2 Non EX

Voltage 13,5 V 13,5 V 24 V

PROFIBUS PA

g , ,

Maximum power 1,8 W 4,2 W 12 W

Maximum current draw 110 mA 250 mA 500 mA

Maximum segment length 1.000 m 1.900 m 1.900 m


156

Spur length per device (1 to 10 stations)

30 m 30 m 120 m

Number of stations 10 20 32

These are the maximum allowable values! DP/PA couplers could have specifications of ‘less’ quality.These are the maximum allowable values! DP/PA couplers could have specifications of ‘less’ quality.

2.0



25 32

Length of the spur(Ex)

Length of the spur(not Ex)

M i 1

Spurs/Stubs with MBPSpurs/Stubs with MBP--ISIS

M i 1

Number of Spurs

PROFIBUS PA

25 to 32

19 to 24

15 to 18

13 to 14

Maximum 1 m

30 m

60 m

90 m

Maximum 1 m

30 m

30 m

30 m


157

1 to 12 120 m30 m

Maximum 3 instruments on a spur. Spurs under 1 meter do not have to be calculated. Maximum 3 instruments on a spur. Spurs under 1 meter do not have to be calculated.

1.0

Cable design

Type A(Reference)

Twisted pair,

Type B Type DType C

Multiple twisted pairs total

Multiple twisted pairs not

Multiple non-twisted pairs

Cable specifications of MBPCable specifications of MBP--ISIS

PROFIBUS PA

Cable design

Maximum conductorcross section (nominal)

Loop resistance(direct current)

Impedance (31,25 kHz)

Attenuation (39 kHz)

shielded

0,8 mm²(AWG 18)

44 Ohm/km

100 Ohm +20%

3 dB/km

pairs, total shielded

pairs, not shielded

twisted pairs, not shielded

0,32 mm²(AWG 22)

0,13 mm²(AWG 26)

1,25 mm²(AWG 16)

112 Ohm/km 264 Ohm/km 40 Ohm/km

100 Ohm +30% ** **

5 dB/km 8 dB/km 8 dB/km


158

Capacitive asymmetry

Max. Propagation delaychange (7,9 to 39 kHz)

Max. shield coverage

Cable length

2 nF/km

1.7 usec/km

90%

1.900 m

2 nF/km ** **

** ** **

** - -

1.200 m 400 m 200 m

** Not specified

2.0



R =100 Ohm

Termination in a PA bus structureTermination in a PA bus structure

PROFIBUS PA

T

C =1 F

PROFIBUS PA

PROFIBUS DP

R =100 Ohm

C =1 F


159

1.0

Termination in a PA “ChickenTermination in a PA “Chicken--Foot” topologyFoot” topology

R =100 Ohm

PROFIBUS PA

300m

10m 30m 20m

JunctionBox

C =1 F

R =100 Ohm

C =1 F


160

2.0



MBP termination MBP termination –– Missing terminationMissing termination

PROFIBUS PA


161

When termination is missing, the peak-to-peak voltage will be 1,5 V or higher.When termination is missing, the peak-to-peak voltage will be 1,5 V or higher.

1.1

Interconnection technology for IP 65 or higher (PA)Interconnection technology for IP 65 or higher (PA)

PROFIBUS PA


162



M12 connectorM12 connector

PROFIBUS PA


163

Instrument side Junction box/ T-box side

1.0

Strategy of troubleshootingStrategy of troubleshooting


164



Classifications of most common PROFIBUS problemsClassifications of most common PROFIBUS problems

Physical level

Device is NOT communicating anymore

Periodically no communication with a device

Application level

Invalid data (calibration or bug)

Device diagnostics (I/O problems)

The worst one


165

What kind of fault finding methods are at hand?What kind of fault finding methods are at hand?

1) Analyzer most important!

2) Electrical measurement

3) Visual inspection


166

The sequence above is also the way of working for localizing and solving ‘problems’.



Indicators (LEDs)Indicators (LEDs)

Most devices have indicators, which clarify the status of the device. This is very important for the users, especially maintenance personnel. With 3 indicators a lot of situations can be cleared (ON, BF, SF).

ON BF SF Fault condition

X

X

X X / O

O O

O

O

X

Everything OK

No communication

Communication, but not in data exchange


167

X(blinking)

X X Configuration not OK

Remarks:Most PA instruments do not have LEDs due to power consumption and Ex restrictions.

Everything OKEverything OK

Only “ON” is lit up.Only “ON” is lit up.


168



No communicationNo communication

“BF” and “ON” are lit up.“BF” and “ON” are lit up.


169

No valid messages are detected on the bus.

Communication on the bus, but not in data exchangeCommunication on the bus, but not in data exchange

“BF” is blinking.“BF” is blinking.


170

The device is not configured yet.

2.0



Configuration not OKConfiguration not OK

“SF”, “BF” and “ON” are lit up.“SF”, “BF” and “ON” are lit up.


171

Wrong configuration or a local problem.

AnalyzerAnalyzer

This is a PC application which extracts

The most important tool for fault finding is an Analyzer!

ppmessages from the bus and saves it in a database.

The technician can analyze the messages and come to a conclusion about the status of the instruments.


172

The predictability of the PROFIBUS protocol makesthe use of a busmonitor very easy.....



InfrastructureInfrastructure

XOld generation – brand X

New generation – ProfiTrace


173

Facts and FictionFacts and FictionFacts and FictionFacts and FictionFacts and FictionFacts and FictionFacts and FictionFacts and FictionBusmonitors do not have a Busmonitors do not have a network address, but are anetwork address, but are aPhysical Physical bus loadbus load on the on the

Busmonitors do not have a Busmonitors do not have a network address, but are anetwork address, but are aPhysical Physical bus loadbus load on the on the


yycablecable!!

yycablecable!!



Active stations (masters) are RED passive stations (slaves) thatActive stations (masters) are RED passive stations (slaves) that


175

Active stations (masters) are RED, passive stations (slaves) that exchange data have a GREEN background.Active stations (masters) are RED, passive stations (slaves) that exchange data have a GREEN background.

3 repeats, but finally a response.3 repeats, but finally a response.


176



DP slave DP slave state state machinemachine

Power on/Reset

Configuration

Parameters

Diagnostics The master constantly polls the diagnostics of every slave which is not available.

When the slave gives a reaction to a diagnostic request, the parameters are transmitted.

After the parameters, the configuration is transmitted.


177

Diagnostics

Data exchange

After configuration, the master requests diagnostics to check if everything has been accepted.

When the slave has accepted all the information, the master will constantly exchange data with the device.

2.1

PROFIBUS DP functions with appropriate SAPsPROFIBUS DP functions with appropriate SAPs

Functions

Data exchange

DSAP

---

SSAP

---

Check Config

Set Parameters

Get Diagnostics

Get Config

Set Global Control

Read Outputs

62 (3E)

61 (3D)

60 (3C)

59 (3B)

58 (3A)

57 (39)

62 (3E)

62 (3E)

62 (3E)

62 (3E)

62 (3E)

62 (3E)


178

Read Inputs

Set Slave Address

Master-Master Commands

56 (38)

55 (37)

54 (36)

62 (3E)

62 (3E)

54 (36)

2.0



DP slave state machine (2)DP slave state machine (2)Attention Service Sd Adr Sap Fc Len Data

(hex) (hex) (hex) | request data | SRD_HIGH | SD2 | 01 -> 22 | 3E -> 3C | 6D | | | | DL | SD2 | 01 <- 22 | 3E <- 3C | 08 | 016 | 02 05 00 FF A4 00 0A| | token | SD4 | 01 -> 01 | | | | | send data ack | SRD HIGH | SD2 | 01 -> 22 | 3E -> 3D | 5D | 017 | B8 14 01 0B A4 00 00

1. Diagnostics

| send data ack. | SRD_HIGH | SD2 | 01 > 22 | 3E > 3D | 5D | 017 | B8 14 01 0B A4 00 00| | OK | SC | | | | | | | fdl_status | SD1 | 01 -> 00 | | 49 | | | send data ack. | SRD_HIGH | SD2 | 01 -> 22 | 3E -> 3E | 7D | 002 | 13 23| | OK | SC | | | | | | | token | SD4 | 01 -> 01 | | | | | request data | SRD_HIGH | SD2 | 01 -> 22 | 3E -> 3C | 5D | | | | DL | SD2 | 01 <- 22 | 3E <- 3C | 08 | 016 | 00 0C 00 01 A4 00 0A| | token | SD4 | 01 -> 01 | | | | | request data | SRD_HIGH | SD2 | 01 -> 22 | () -> () | 7D | 004 | 00 44 67 33 | | DL | SD2 | 01 <- 22 | () <- () | 08 | 004 | 8A 08 FF DD| | fdl_status | SD1 | 01 -> 02 | | 49 | || | token | SD4 | 01 -> 01 | | | |

2. Parameters

3. Configuration 4. Diagnostics


179

| request data | SRD_HIGH | SD2 | 01 -> 22 | () -> () | 7D | 004 | 00 44 67 33 | | DL | SD2 | 01 <- 22 | () <- () | 08 | 004 | 8A 08 FF DD| | fdl_status | SD1 | 01 -> 03 | | 49 | || | token | SD4 | 01 -> 01 | | | | | request data | SRD_HIGH | SD2 | 01 -> 22 | () -> () | 7D | 004 | 00 44 67 33 | | DL | SD2 | 01 <- 22 | () <- () | 08 | 004 | 8A 08 FF DD

1.2

5. Data exchange

The EndThe End


180

1.0

Ing. Dennis van Booma, PROCENTEC Netherlands, [email protected]




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Documents

Profibus Troubleshooting & Maintenance