Power Supplies & Barriers

Power Supplies & Barriers

Power supplies and barriers are DIN-rail system components that condition and protect measurement loops by providing transmitter excitation and galvanic isolation. In addition to supplying devices with power - including, where required, installations in Ex areas - these modules pass the measurement signal across an isolation boundary so downstream systems receive a clean, safely separated 4…20 mA representation. Optional HART monitoring can supervise transmitter status so even briefly occurring faults are easier to localize.

The Endress+Hauser portfolio includes power supplies for 2‑wire and 4‑wire transmitters, as well as active barriers that combine loop power and safe separation of 4…20 mA circuits in a single device. Variants support bidirectional HART transmission and include practical features such as communication sockets for HART access and an integrated HART resistor to simplify sensor configuration without external wiring changes.

Application patterns typically follow the location of the safety boundary. For example, an active barrier can supply a 4…20 mA HART head transmitter installed in a thermometer, including in Ex areas, then transmit the galvanically isolated signal to the safe side; with HART monitoring enabled, an alarm relay can be triggered if a device status issue is detected. Where a controller in the non‑Ex area must supply a sensor located in the Ex area, a passive barrier can pass the supply into the hazardous zone and return the 4…20 mA signal, drawing its own operating power from the loop rather than a separate power feed.

Benefits include flexible wide‑range power options, galvanic isolation of 4…20 mA circuits, and availability of international approvals such as Ex and marine certifications. Early-warning style sensor monitoring supports proactive maintenance by identifying developing loop issues before they become outages. Combining supply, isolation, and HART transparency in a single module can simplify loop design, reduce wiring complexity, and standardize interface practices across projects. Typical use cases include intrinsic safety interfaces, isolation of analog loops to prevent ground loops and interference, structured HART access for configuration and diagnostics, and reliable loop power distribution in marshalling and interface cabinets across process units.

Miller Mechanical Specialties, an exclusive authorized representative of sales and service for Endress+Hauser.