Power Supplies & Barriers

Power Supplies & Barriers

Power supplies and barriers are DIN-rail system components that energize transmitters and condition signals so they remain reliable, isolated, and compliant - especially where intrinsic safety is required. Endress+Hauser describes these modules as supplying transmitters with power (including in Ex areas where required) and transmitting galvanically isolated signals; optional HART monitoring can track transmitter status so even brief, intermittent errors can be detected and localized.

The portfolio includes supplies for 2- or 4-wire transmitters, active barriers that combine power supply and safe separation of 4…20 mA circuits, and units supporting bidirectional HART transmission with configuration conveniences such as communication sockets and integrated HART resistors. Benefits include galvanic isolation, flexible power sourcing, international Ex approvals and marine approvals, and sensor monitoring with early-warning behavior.

Application patterns are well-established. For example, an active barrier can power a 4…20 mA HART head transmitter (including in Ex areas) and pass the galvanically isolated signal onward; with optional HART monitoring, a relay can provide an alarm on detected faults. Where a sensor in the Ex area must be supplied from a PLC, a passive barrier can transmit supply into the Ex area and return the 4…20 mA signal without requiring its own power supply, drawing power from the loop.

Typical applications include intrinsic-safety interfaces, isolation of analog loops to reduce ground-loop and noise issues, HART-transparent marshalling for configuration access, protection of PLC/DCS I/O from field faults, and conditioning of NAMUR or switching-contact signals. They also support structured cabinet design by standardizing loop powering, separation, and fault annunciation functions across instrument types.

Engineering considerations include power budgeting, allowable loop resistance and voltage drop, HART transparency requirements, SIL/Ex compliance needs, thermal management in dense marshalling, and grounding/shielding practices to preserve signal integrity. Aligning barrier selection with maintenance strategy (diagnostics, alarm outputs, spare philosophy) improves long-term operability and reduces troubleshooting time.

At Eastern Controls, We are proud to be the exclusive authorized sales and service representative for Endress+Hauser.