Home ยป What is a Active Barrier ?
Control Systems

What is a Active Barrier ?

An active barrier uses transformers, optoisolators or relays to provide isolation between the hazardous area and the non-hazardous area. It does not require an intrinsically safe ground connection. Either or both the hazardous area or the non-hazardous area signals may be grounded. This may be the most logical barrier choice if a high quality I.S. grounding point is not available.

The below Figure shows a diagram of an active barrier. The barrier requires a 24 VDC power supply, and can typically drive larger loads than a loop powered zener barrier.

Active Barrier

Intrinsically safe systems should satisfy these requirements:

  • Ensure that there is a positive separation of intrinsically safe and non-intrinsically safe circuits. This prevents the ignition capable energy from intruding into the intrinsically safe circuit.
  • Separate conduit, panduit, cable trays, etc. should be used for I.S. wiring to keep it separate from the non-I.S. wiring. If conduit is used, it must be sealed per the applicable code. This is to prevent the conduit from becoming a means of conducting flammable material from the hazardous to the non-hazardous location. I.S. wiring must always be identified. This can be performed by tagging the wires, labelling the junction boxes, and/or color-coding the I.S. wires light blue.
  • Ensure that the entity parameters, upon which approval of the system is based, match up correctly.

Similar Articles:

Related Articles

Runaway Processes

S Bharadwaj Reddy

Ziegler-Nichols Open Loop Tuning Procedure

S Bharadwaj Reddy

Difference between Fieldbus, Profibus and HART Protocols

S Bharadwaj Reddy

How to Analyze a Cascade Control Loop

S Bharadwaj Reddy

Integrating Processes – Liquid Level Control

S Bharadwaj Reddy

Direct Digital Control (DDC) Systems

S Bharadwaj Reddy

Leave a Comment

This website uses cookies to improve your experience. We'll assume you're ok with this, but you can opt-out if you wish. Accept Read More

WordPress Image Lightbox