Synergizing Physical Layer for PlantOptimization

Unnikrishnan R

Manager – Components & Technologies

Pepperl + Fuchs India Pvt Ltd

© 1994 – 2011 Fieldbus Foundation2

Agenda

Introduction to FF and FF Physical Layer

FF Physical Layer Components

FF Wiring Topologies

Process Interfaces

Summary and Conclusion

© 1994 – 2011 Fieldbus Foundation3

What is Fieldbus?

HOST

Field Device

How Do we Link the Various components in the network?

Fieldbus is a digital, two-way, multi-drop communication link among intelligent measurement and control devices. It serves as a Local Area Network (LAN) for advanced process control, remote input/output and high-speed factory automation applications.

© 1994 – 2011 Fieldbus Foundation4

Main components of physical layer

FF - Power Supply, Cables, Surge Protector, Terminators, Wiring Blocks, Process interfaces etc

Wiring Block

HOST

Wiring Block FIELDBUS TERMINATOR

SURGE PROTECTOR

PROCESS

INTERFACE

Ff POWER SUPPLY

CONVENTIONAL FIELD DEVICES

FIELDBUS DEVICES

JUNCTION BOX

Home Run Spurs

© 1994 – 2011 Fieldbus Foundation5

How to optimize FF Physical Layer?

Optimization of field devices by using proper segment design methodology as well as segment revalidation tools where we can optimize loop checking and commissioning time.

Usage of digital communication to achieve predictive intelligence through advanced diagnostics and asset management of the plant.

Usage of features of the device to effect control in field which will optimize lower bandwidth of 31.25kb/sec.

© 1994 – 2011 Fieldbus Foundation6

Why separate FF power supply?

Bulk power supply represents a very low impedance� Much less than 50 Ohm

If this impedance is connected directly to a fieldbus segment this will “short” the communication signal

+ fieldbus

- fieldbus

Active design

+ fieldbus

- fieldbus

Passive design

© 1994 – 2011 Fieldbus Foundation7

How balanced design is achieved?

Z

Z/2

Potential noise source:- bad wiring practices

(AC cables close to bus cables)

- Corrosion (i.e. field device flooded)

Noise

+ fieldbus

- fieldbus

Z/2

Balance reducesthe sensitivityagainst noise

© 1994 – 2011 Fieldbus Foundation8

FF Power Supply – Recommendations

Each Segment shall have a dedicated FFPS

FFPS shall beIsolated and Redundant

FFPS shall be modular and hot Swappable

FFPS shall provide facilities for monitoring faults and failures

FFPS rating shall allow longer home run / Trunk length to benefit user ( typically 28V / 500mA )

© 1994 – 2011 Fieldbus Foundation9

FF Power Supply

© 1994 – 2011 Fieldbus Foundation10

FF Power Supply – With DCS System Connectors

APPROVED

© 1994 – 2011 Fieldbus Foundation11

FF Wiring Blocks

© 1994 – 2011 Fieldbus Foundation12

Significance of Terminators in Physical Layer

One small device – two important tasks� Translates signal current into detectable voltage change� Suppresses signal reflections at end of the trunk

FIELDBUS DEVICES

TRUNK

Terminator on the T-Connector

Terminator integrated in Power Hub. Selectable via DIP-Switch

Flameproof in rugged housing (IP 67) for the hazardous area

© 1994 – 2011 Fieldbus Foundation13

FF Surge Protectors

Surge Protection ( 6.4 AG 181 V3.1)

Surge protection for FOUNDATION fieldbus devices may be required in areas where induced voltage is an issue.

This includes areas such as close wiring proximity where large inductive loads are started and stopped, or areas known for lightning incidence.

Surge suppression consists of a low-capacitance device installed at the device's electrical connection. It shall normally appear as an open circuit to the spur and segment to prevent any adverse effect on communications.

© 1994 – 2011 Fieldbus Foundation14

FF Surge Protectors - Recommendations

Surge suppression device should not measurably attenuate the fieldbus signal

Shall be installed at the Field Devices and host H1 Interface

Current-limiting couplers ( Wiring Block spurs ) should not be used in combination with surge protectors. The surge protectors will cause failure of the current limiting circuits when a lightning strike occurs

© 1994 – 2011 Fieldbus Foundation15

Various process Interfaces

Zone 1

DCS

Zone 2 / DIV 2

Foundation Fieldbus

© 1994 – 2011 Fieldbus Foundation16

Process Interfaces

Zone 1

Ex e

16..32V

16..32V

230VAC

© 1994 – 2011 Fieldbus Foundation17

© 1994 – 2011 Fieldbus Foundation18

FF Wiring Topologies in Hazardous Area

© 1994 – 2011 Fieldbus Foundation19

Segment Topology for General Purpose application

HOST

FIELDBARRIERS FIELDBUS TERMINATOR

SURGE PROTECTOR

PROCESSINTERFACE

POWER SUPPLY

CONVENTIONAL FIELD DEVICES

FIELDBUS DEVICES

JUNCTION BOXES

Surge Protector

© 1994 – 2011 Fieldbus Foundation20

Segment Topology for Zone 2 (Ex ic)

Segment Protector Ex me

Zone 1

17--28

17…28V

230VAC

Fieldbus Power Hub

Ex e

InstrumentsEx ic/Ex d

© 1994 – 2011 Fieldbus Foundation21

Zone 1

Zone 0/1

Segment Topology for Zone 1 and Zone 0 - IS

Ex e

Ex ia(FISCO + Entity)

FieldBarrier

16..32V

16..32V

230VAC

Fieldbus Power Hub

© 1994 – 2011 Fieldbus Foundation22

DART Fieldbus

The Simplicity of Intrinsic Safety

Main Attributes of DART Fieldbus: Trunk cable up to 1000 m

Built-in power redundancy

Same topology as a general purpose high-power trunk

For FOUNDATION fieldbus H1 and PROFIBUS PA

DART Fieldbus is certified according to international standard IEC 60079-11 (ATEX and IECEx)

© 1994 – 2011 Fieldbus Foundation23

General Purpose Area

Zone 2To DCS

Zone 1

DART: Intrinsically safe High-Power Trunk

Redundant, three-port isolated

DART Power Supply

DART Segment Protectors

The intrinsically safe High-Power Trunk protected by DART®

Intrinsically safe spursEx ib IIC

© 1994 – 2011 Fieldbus Foundation24

Zone 1

DART: Intrinsically safe High-Power Trunk

� More cable distance (compared to FISCO)

� Higher device count (compared to FISCO)

� Same installation throughout

� Hot work on supplies, couplers, devices

For any fieldbus device: Ex ib IIC

© 1994 – 2011 Fieldbus Foundation25

DART Overview

A DART fieldbus segment consist of� Standard H1 or PROFIBUS PA controller

� DART fieldbus power supply

� DART fieldbus segment protector

� Standard intrinsically safe FOUNDATION fieldbus orPROFIBUS PA field devices

DART fieldbus does NOT require special field devices!

In A DART fieldbus application only the TRUNK is protected by DART

© 1994 – 2011 Fieldbus Foundation26

Comparison of Various Concepts

© 1994 – 2011 Fieldbus Foundation27

FF Physical Layer Monitoring and Diagnosis

© 1994 – 2011 Fieldbus Foundation28

Recommendation for an ideal FF physical layer diagnostic toolMeasurements Multi-meter Handheld

TesterHandheld

CommunicatorOscilloscope Note-book

Bus AnalyzerAdvanced Diagnostic

Module

Segment voltage ● ● ● ● �

Segment current ◙ �

Segment noise (low freq.) ● ● ● �

Segment noise (high freq.) ● �

Segment signal level ● ● ● �

Segment signal jitter ● �

Instrument signal level = �

Instrument signal jitter �

Instrument noise (individual) �

Fieldbus termination = = ● �

Segment earth fault (imbalance) �

Device communication ● ● �

Communication faults ● �

Cable degradation (trending) �

Device configuration ● ●

Remote access �

© 1994 – 2011 Fieldbus Foundation29

Summary

� Fieldbus technology reduces effort in every phase of a project

� Fieldbus is established as reliable technology

� Power Supply in the Ex-Zone is simple

� Advanced Diagnostic Tools bring transparency and simplicity

� Fieldbus itself is now an Asset in plant management