Power Supplies & Barriers

Power Supplies & Barriers

Power supplies and barriers are DIN-rail system components that energize transmitters and provide safe, galvanically isolated signal transfer - particularly where hazardous (Ex) and non-hazardous zones must be separated. They condition the 4…20 mA loop by ensuring adequate loop power and by isolating the measurement circuit to reduce susceptibility to ground loops and electrical interference, while maintaining signal fidelity back to the control system.

This category includes power supplies for 2-wire and 4-wire transmitters, as well as active and passive barriers. Active barriers integrate a power supply and safe separation for 4…20 mA circuits in one device; passive barriers are used when a control system supplies loop power and only a barrier is required to pass power and signal between zones. These devices are often paired with HART-transparent designs so that digital overlays remain usable for configuration and diagnostics.

Enhanced functionality can include bidirectional HART transmission, built-in communication sockets, and integrated HART resistors for streamlined configuration. Optional HART monitoring can continuously watch transmitter status so that even intermittent faults are captured and flagged - improving troubleshooting speed and preventing “no fault found” maintenance cycles.

Benefits include flexible wide-range power inputs, international Ex approvals, optional marine approvals, and improved loop robustness through isolation. For critical measurement points, barrier-level monitoring with early-warning behavior can increase availability by detecting degraded device conditions before they become process-impacting failures. The net result is safer energy delivery to the field and cleaner signal return to the automation system.

Typical applications include powering head-mounted temperature transmitters in hazardous areas, isolating analog loops between skids and central I/O, and implementing safe separation at cabinet marshalling for mixed-area installations. Proper selection focuses on loop voltage budgets, transmitter load, 2‑wire vs 4‑wire topology, HART transparency requirements, alarm relay needs, and SIL/Ex documentation alignment with site standards.

Engineered Equipment Company, a leading supplier of specialized industrial equipment.