Inst ToolsInst ToolsInst Tools
  • Courses
  • Automation
    • PLC
    • Control System
    • Safety System
    • Communication
    • Fire & Gas System
  • Instrumentation
    • Design
    • Pressure
    • Temperature
    • Flow
    • Level
    • Vibration
    • Analyzer
    • Control Valve
    • Switch
    • Calibration
    • Erection & Commissioning
  • Interview
    • Instrumentation
    • Electrical
    • Electronics
    • Practical
  • Q&A
    • Instrumentation
    • Control System
    • Electrical
    • Electronics
    • Analog Electronics
    • Digital Electronics
    • Power Electronics
    • Microprocessor
  • Request
Search
  • Books
  • Software
  • Projects
  • Process
  • Tools
  • Basics
  • Formula
  • Power Plant
  • Root Cause Analysis
  • Electrical Basics
  • Animation
  • Standards
  • 4-20 mA Course
  • Siemens PLC Course
Reading: Fieldbus Coupling Devices
Share
Font ResizerAa
Inst ToolsInst Tools
Font ResizerAa
  • Courses
  • Design
  • PLC
  • Interview
  • Control System
Search
  • Courses
  • Automation
    • PLC
    • Control System
    • Safety System
    • Communication
    • Fire & Gas System
  • Instrumentation
    • Design
    • Pressure
    • Temperature
    • Flow
    • Level
    • Vibration
    • Analyzer
    • Control Valve
    • Switch
    • Calibration
    • Erection & Commissioning
  • Interview
    • Instrumentation
    • Electrical
    • Electronics
    • Practical
  • Q&A
    • Instrumentation
    • Control System
    • Electrical
    • Electronics
    • Analog Electronics
    • Digital Electronics
    • Power Electronics
    • Microprocessor
  • Request
Follow US
All rights reserved. Reproduction in whole or in part without written permission is prohibited.
Inst Tools > Blog > Communication > Fieldbus Coupling Devices

Fieldbus Coupling Devices

Last updated: March 26, 2018 9:36 am
Editorial Staff
Communication
No Comments
Share
4 Min Read
SHARE

In order to simplify the task of connecting Fieldbus devices to such a network segment, multiple manufacturers sell coupling devices (often informally referred to as bricks) with quick-disconnect electrical fittings so the end-user does not have to build and commission junction boxes using standard terminal blocks. A photograph of a Turck brand Fieldbus coupling device appears here, showing multiple spur cables plugged into it:

Fieldbus coupling devices

Coupling devices are highly recommended for all industrial fieldbus systems, FF or otherwise. Not only do these devices provide a convenient means of forming highly reliable connections between field instruments and the trunk cable, but many of them are equipped with features such as short circuit protection (so that a shorted spur cable or field instrument does not cause the entire segment to stop communicating) and LED indication of spur status.

Cables connecting to a coupling device must be equipped with special plugs matching the sockets on the coupler. This presents a bit of a problem when attempting to pull such a cable through electrical conduit: the bulky plug requires either over-sized conduit to accommodate the plug’s width, or requires the plug be installed on the cable after pulling through the conduit. Both approaches are expensive, the first in terms of capital cost and the second in terms of installation labor. For this reason, many installers abandon electrical conduit altogether in favor of ITC (“Instrument Tray Cable”).

A wider-angle photograph of the coupling device previously shown reveals many ITC cables and their routing through wire “basket” style trays among process instruments and vessels:

Instrument Tray Cables

As evident in this photograph, ITC is obviously rated for continuous exposure to direct sunlight and moisture, as well as a certain amount of physical distress (abrasion, high and low temperatures, etc.). Article 727 of the National Electrical Code (NEC) defines the acceptable uses and installations of ITC.

It should be noted that while a properly shielded and grounded FF cable is quite resistant to radio-frequency interference, coupling devices may present “weak spots” where radio interference may find its way onto the segment. Different styles of coupling devices offer differing levels of immunity to RF (Radio Frequency) noise. Those made of metal and properly bonded to ground will be well-shielded, while those made of plastic having exposed connection terminals offer little or no protection. In any case, it is a good practice to avoid “keying” any portable radio transmitter in the near vicinity of a Fieldbus coupling device.

Not all Fieldbus couplers are rated for outdoor installation. Some are intended for mounting inside electrical enclosures, such as this Pepperl+Fuchs model shown mounted on a DIN rail:

Fieldbus couplers

This Fieldbus coupling device is aptly labeled a segment protector, for it not only couples spurs to the main trunk of the Fieldbus segment, but it also guards against short-circuits in the spur cables and devices from interrupting communication on the rest of the segment. If you look closely at the upper-left of the coupling device, you will see a black plastic square with two leads inserted into screw terminals: this is one of two terminating resistors found in this Fieldbus segment, meaning this particular coupling device is at the “end of the line” of the network segment.

Not only do enclosure-protected coupling devices eliminate the need for special weather-proof connectors and instrument tray cable, but they also enjoy the radio interference immunity granted by being inside a metal cocoon.

Don't Miss Our Updates
Be the first to get exclusive content straight to your email.
We promise not to spam you. You can unsubscribe at any time.
Invalid email address
You've successfully subscribed !

Continue Reading

Serial Communication Interview Questions and Answers
Difference between Modbus and DNP3 Communication Protocols
Why is Ethernet IP Preferred in Large Networking Systems?
HART Communication Tutorial Part 1
Troubleshooting Fieldbus Devices
History of OPC Protocol
Share This Article
Facebook Whatsapp Whatsapp LinkedIn Copy Link
Share
Leave a Comment

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Stay Connected

128.3kFollowersLike
69.1kFollowersFollow
210kSubscribersSubscribe
38kFollowersFollow

Categories

Explore More

What is Rapid Spanning Tree Protocol? – RSTP Network
Top 10 Facts about HART Technology
Difference Between RS232 and RS485
Actuator Sensor Interface (ASi) Protocol in PLC
Latest ProfiBus Questions and Answers
Fiber Optic Cable Connectors, Routing, and Safety
Network Topologies Selection Factors and Comparison
Fieldbus Control

Keep Learning

WirelessHART Device Terminals

WirelessHART Network Gateway Device

Foundation Fieldbus Signal Conversion Formula

Foundation Fieldbus Signal Conversion Formula

Tree (chicken foot) topology

Fieldbus Device Capability

Things You Need to Know About DeviceNet

Things You Need to Know About DeviceNet

BACNet Protocol

What is the BACNet Protocol? BACNet IP vs. BACNet MS/TP

Patch Panel

What is a Patch Panel? Types and Uses in Networking

Introduction to Fieldbus Function Blocks

Fieldbus Wiring

Fieldbus vs 4-20mA

Learn More

Flanged Turbine Meter made flangeless for Bolting

Serious Constraints Prevent using an Available Turbine Flow Meter

Omron PLC Online Training Course

Omron PLC Online Training Course

Valve Software

Free Control Valve Software Download

simple latching motor control circuit

Motor Control Circuit Wiring

Types of Sensors Used in Automobiles

Types of Sensors Used in Automobiles

Control Systems Questions & Answers

Control Systems Objective Questions & Answers – Set 6

CNC Milling versus CNC Turning

CNC Milling versus CNC Turning – Which is the Best Option?

Synchronous Motor Is Not Self Starting?

Menu

  • About
  • Privacy Policy
  • Copyright

Quick Links

  • Learn PLC
  • Helping Hand
  • Part Time Job

YouTube Subscribe

Follow US
All rights reserved. Reproduction in whole or in part without written permission is prohibited.
Welcome Back!

Sign in to your account

Username or Email Address
Password

Lost your password?