Isolated Powered Barriers

Published on 18 Mar 2017 by Lana Hajovsky


  • Input / Output galvanic separation, no need of an isopotential ground system
  • Allow use of not isolated field elements
  • High voltage available in the field, independently from the supply voltage
  • Protected against short circuits
  • Provide a high level isolated output signal (usually 4-20 mA) already and standardized
  • The plug-in card version can be substituted, within few seconds, without shutting down the power or removing the wiring
  • Suitable to all applications 


  • Higher cost than passive or loop powered barriers.

Isolated powered barriers are available in a broad range that practically includes all of the instrumentation applications.

They are available for DIN rail mounting or as plug-in cards for 19" Rack.

They can be powered by the mains or by auxiliary DC voltages always guaranteeing the galvanic separation between the Intrinsically Safe circuits connected to the hazardous location and the Non-Intrinsically Safe circuits located in safe area.

The barriers of this type do not require either isolated sensors or an isopotential ground system.

The Intrinsic Safety characteristics cannot be compromised by a fault in the isolation and do not depend on the integrity of the ground connection, since it is not even necessary.

They allow direct interlacing with thermocouples, resistance temperature detectors, transmitter potentiometers, signal transmitters, strain gauge bridges, pH or conductivity electrodes, contacts, proximity switches, electropneumatic converters, electropneumatic positioners, solenoid valves, magnetic pick-ups, and a variety of other sensors.

In the plug-in card version, they can be inserted or removed under power without compromising the Intrinsic Safety characteristics, therefore allowing on inter-venting on the plant within few seconds.

They are technically suitable to all of the Intrinsic Safety applications, without any exception.

Tags: barriers isolated

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