Cabling Solutions for Foundation Fieldbus Systems

By Raman KalraBelden India

Technology Event

Fieldbus Foundation– Changing the Playing Field "

Date : 21st June, 2008 (Saturday)Venue : TROPICANA Conference Room. Hotel : Taj Residency,

Akota Gardens, Vadodara - 390 020 INDIA

Agenda

Foundation Fieldbus Cable Standard

Beyond the Standard- Multi Pair Solutions- Field Barrier and Long Distance Applications

Cost Comparison

Jacket & Armouring Options

FF standard

Colour code orange / blue Jacket colour Orange or Blue (for IS applications)Optional armouring to meet e.g. Atex requirements

IEC 61158/ISA-SP 50 Standards Type AFF SpecificationH1 Cable Test specifications FF844

Conductor Size 18AWG(0.8 sq.mm)Impedance 100ohms +/-20Capacitance Unbalance 4nF/KmConductor DC resistance 24ohms/KmAttenuation@39kHz 3dB/KmMax. Propagation Delay 1.7µS/KmMinimum Shield Coverage 90%Max Network Length 1900m

Key Cable Parameters

Impedance 100 Ω @ 31.25 kHzCapacitance Unbalance < 4 ηF/km (capacitance between one wire and screen to other wire and shield)

Conductor DC Resistance < 24 Ω/kmCable Shielding > 90% coverage

CcS

Ccc

Insulation

Drain wire

Shield Inductance & resistance

Centricity

CcS

Conductor

When twisted pair is exposed to a noise source such as runningmachinery or fluorescent lights, each conductor of the pair isexposed equally.

Capacitance UnbalanceA Twisted Pair Exposed to a Noise Source

Key Cable Parameters

Noise and Signal at the Receiving End of a Typical Pair

Ideal Capacitance Unbalance

When the capacitance of conductors within a pair are not equal, eachconductor will react differently to noise.Total subtraction of noise is virtually impossible.

Key Cable Parameters

When the capacitance of conductors within a pair are different, signals may travel atdifferent rates (velocity).Signal interpretation issues may occur as signals arrive at different times.Lower levels of capacitance unbalance equates to higher noise cancellation.

Key Cable Parameters

FF vs Standard Instrument Cable

FF cable has lower CapacitanceFF cable is designed to a specific impedance to reduce signal reflections and maximize network lengthFF cables are tested during production to meet specific requirements:– Capacitance Unbalance– Impedance– Conductor D.C. resistance

FF Wiring

Control Strategy

Agenda

Foundation Fieldbus Cable StandardBeyond the Standard- Multi Pair Solutions- Field Barrier and Long Distance ApplicationsCost Comparison

Jacket & Armouring Options

Multi Pair Solutions

Multi Pair Fieldbus cables:

2 to 24 pair configurationsEach individual pair meets the FF Type A requirementsOrange or Blue (IS) outer jacketArmouring optionallyOther jacket materials optionally

Agenda

Foundation Fieldbus Cable Standard

Beyond the Standard- Multi Pair Solutions- Field Barrier and Long Distance Applications

Cost Comparison

Jacket & Armouring Options

Fieldbarrier Concept

Fieldbarriers in Zone 1Instrument Spurs in Zone 0Bus trunklinealso used to power the Fieldbarriers

Maximize nr. of instruments on the bus in the zone.

R

PowerPowerSupplySupply

Fieldbus Fieldbus CardCard

Field Field ControlControl StationStation

HumanHuman Interface StationInterface Station

VV--networknetwork

Zone 1Zone 1

Zone 0Zone 0EexEex ia IICia IIC

EExEEx(e)(e) EExEEx(e)(e)

Agenda

Foundation Fieldbus Cable Standard

Beyond the Standard- Multi Pair Solutions- Field Barrier and Long Distance Applications

Cost Comparison

Jacket & Armouring Options

Reduction in hardware costs

4-20 mA

ISISIS ISIS Fieldbus

Less cable

Less installation time

Less I/O Less Interfacing

Reduced footprint in CR

Cost Comparison Vs Instr. Cable

Cost ComparisonWhy is Fieldbus cabling more expensive than standard

instrumentation cable?PP instead of PVC or XLPE on the coresMore insulation material required More complicated process = slower process = higher costs

0

20

40

60

80

100

120

140

160

PLTC ISOS FF Multi Pair BS5308 RE 2X(St)Y

Pric

e In

dex

-

200

400

600

800

1,000

1,200

1,400

Volu

me

in k

m

Agenda

Foundation Fieldbus Cable Standard

Beyond the Standard- Multi Pair Solutions- Field Barrier and Long Distance Applications

Cost Comparison

Jacket & Armouring Options

Jacket options

$$Limited Smoke, Low Acid Gas GenerationHalogen Free

$$$$High & Low Temp, Chemical ExposureTPE

$$$Chemical Wash Downs, Exposure to ChlorinesCPE

$General ApplicationsPVC

CostApplicationsJacket Material

Jacket options

• PVC meeting UL 13 (for physical requirements) (UL 1685 for flame requirements)

• LSNH meeting IEC 60332-3-24 (c)

• CPE (for improved chemical resistance) meeting UL 13 (for physical requirements) (UL 1685 for flame requirements)

• Oil Resistant PVC meeting UL 13(for physical requirements) (UL1685 for flame requirements)

• TPE jacket for improved flexibility meeting UL 13(for physical requirements) (UL 1685 for flame requirements)

Armouring options

Interlock– Aluminum– Steel

Protective Metal Tapes– Smooth or Corrugated (longitudinal or spiral

wrapped)• Copper• Aluminum• Steel

SWA (Steel Wire Armour)– Steel

Why use armour

Physical protectionMaintain signal integrityProvides additional shieldingReduces cost of conduitDirect BurialEasy to install and re-routeRodent ProtectionHazardous Locations – Class 1, DIV. 1 in Canada– Class 1, Div. 2 or Class 2, Div. 2 in USA– Zone 0, 1 or 2 IEC 60079 and Cenelec

FOUNDATION Fieldbus Features

PlantDiagnostics

process orequipment

Level 4

actuators, elementsvalves, connections

Field PerformanceDiagnostics

Level 3

Fisher

DeviceDiagnostics

Level 2

electronics

CommunicationsDiagnostics

Level 1

communicationsFisher

More information from field devices.

•Reduced maintenance –

Diagnostics/Adv diagnostics/ Asset Management

• Pro-active maintenance –

Fact based maintenance, avoid “no action” work

In order to achieve this all passive and active components have to be optimized

for a flawless data-transmission

Questions?