Belden Phillips Brandon Cabling

8/13/2019 Belden Phillips Brandon Cabling

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2008 Fieldbus Foundation

2008 FFIMC- Automation 2008-Mumbai

Author: Brandon Phillips

Sr. Product Development Eng.Belden

Fieldbus Foundation India Marketing Committee

Cables & The New FF Cable Specif ications

Date : 26th of September, 2008 (Friday)

Time : from 09:00 am to 06:00 pm.

Venue : Automation 2008 Conference Hall .

: Conference Hall, Bombay Exhibit ion Centre (NSE),

Goregaon (East), Mumbai INDIA


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Agenda

Foundation Fieldbus Cable Standard IEC 61158-2

FF-844

Cable Selection Standard instrumentation cable vs- FF cable

AWG size, Shielding, Jacketing, Armor types

Cable Installation & Termination

Q & A


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IEC 61158-2 Type A Cable Specification

Impedance: 100 Ohms Attenuation: < 3 dB/km

Capacitance Unbalance:

4nF/km max.

Conductor DC Resistance:24 Ohms/km max.

Maximum Propagation

Delay Change: 1.7 s/km

Wire Size: .8mm sq. (18AWG) nominally

Shield Coverage > 90%

CcS

Ccc

Insulation

Drain wire

Shield

CcS

Conductor

Jacket


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FF-844 Cable Test Specification

Builds on IEC Requirements to further qualify cables

Addition to IEC requirements Expands on shielding requirements

Specifies 10 to 22 pair twists/meter

Jacket Resistance

Required and optional cable ratings

Recommended connector characteristics

Cable registration is in process

Lay Length


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Instrumentation vs- FF Cable

FF Cable

Polyolefin Insulation Electronic grade insulation

100 Ohm Impedance

66% Velocity of Propagation

Designed with tolerancesnecessary to meet FF

specifications

Instrumentation Cable

PVC or XLPE Insulation 35-65 Ohm Impedance

55 to 60% Velocity of

Propagation

Designed to meet generalminimum instrumentation

cable requirements


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Instrumentation vs- FF Cable

FF cable has lower Capacitance

FF cable is designed to a specific impedance toreduce signal reflections and maximize network

length

FF cables are tested during production to meet

specific requirements:

Capacitance Unbalance

Impedance

Conductor D.C. resistance


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Cable Selection

First consult with Local Authority Having Jurisdiction

to ensure regulatory compliance

Selection Guide

Conductor Size

Shielding

Armor

Jackets


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Cable Selection Conductor Size

Most common design is one pair 18 AWG

Larger AWG (16, 14) provide:

Reduced resistance = less voltage drop

Extended cable runs

Greater current carrying capacity

Improved pull strength


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Cable Selection Shielding

Most common design - foil

shield only ~ 35 dB of Shield

effectiveness

Most effective at highfrequencies (>10 MHz)

Drain wire for easytermination

Combination shields

Foil in addition to Braid

Shield effectiveness of ~ 80dB

Effective from 60 Hz to GHz


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Cable Selection Armoring

Interlock

Steel Aluminum

SWA (Steel Wire Armor)

Protective Metal Tapes:

Smooth or Corrugated (Steel, Copper, Aluminum)


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Cable Selection Armoring

Why use Armor?

Rodent protection Physical integrity

Direct burial

Reduces cost of conduit Hazardous Locations


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Cable Selection Jacketing

PVC most common jacketing material

CPE good chemical and abrasion resistance LSZH low smoke zero halogen applications

HDPE direct burial applications

FEP high or low temperature applications (-70 to200C)


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Cable Installation

Follow manufacturers recommendations

Bending radii: generally 10 to 12x cable diameter Maximum pulling tension

Installation temperature

Pulling lubricant selection


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Cable Termination

Ground shield at one end only The near or hostend

Use provided drain wire or pigtail the braid

Grounding both ends results in ground loops

Required to prevent noise ingress, which could distort thesignal

Shields should be trimmed back flush with jacket Isolate shield using heat shrink tubing or tape

This keeps the shield from being inadvertently shorted to the

(+) or (-) wires or grounding at the device end


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Post Installation Verif ication

Follow FF Engineering Guide AG-181

Procedure for installing and commissioning fieldbussegments

Use DMM for Resistance & Capacitance measurements

Fieldbus Monitor is also available


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Common Installation Issues

Cable shield shorted to (+) or (-) wires

Cable shield grounded at both ends, increasing noise

susceptibility

Routing of cables in parallel with AC power lines

Minimum of 6 separation per IEEE 518

Minimize parallel runs

Cross power lines perpendicularly, when possible


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Summary

FF-844 Created to clarify cable requirements & register products

FF Cable Requirements are Much More Stringent than

Instrumentation Cabling Requirements

Select cable that is compatible with application

Consult Manufacturer for Installation & Termination

Recommendations

Follow AG-181 guidelines for testing FF segments

Look for the Registered FF Checkmark for quality cabling


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Questions?

Documents

Belden Phillips Brandon Cabling