Description

The FOXBORO P0961CA is an intrinsically safe (IS) fieldbus power conditioner designed by Schneider Electric (under the Foxboro brand) to deliver reliable, conditioned power to FOUNDATION Fieldbus H1 segments in hazardous industrial environments. As a critical infrastructure component in Foxboro I/A Series distributed control systems (DCS), the P0961CA ensures stable communication and device operation by providing isolated, low-noise DC power while meeting stringent safety standards for explosive atmospheres.

Application Scenarios

At a Gulf Coast ethylene cracker, frequent Fieldbus segment dropouts during thunderstorms caused cascading loop failures across 48 smart transmitters. Root-cause analysis revealed that non-IS power conditioners lacked adequate surge suppression and ground isolation. The plant replaced them with FOXBORO P0961CA units, which feature built-in transient protection and true galvanic isolation. Since installation, the Fieldbus network has operated without weather-related outages for over three years—even during direct lightning strikes within 500 meters. Operators now trust their digital field devices as much as hardwired analog signals, thanks to the silent reliability of the P0961CA.

 

Technical Principles and Innovative Values

Innovation Point 1: True Intrinsic Safety Without External Barriers

The P0961CA integrates safety components internally—eliminating the need for separate Zener barriers—simplifying wiring and reducing installation cost while maintaining compliance with IEC 60079-11 for Zone 0.

Innovation Point 2: Low-Noise Power for Signal Fidelity

With ripple under 20 mVpp, the P0961CA prevents distortion of the Fieldbus Manchester-encoded signal, ensuring reliable communication even at maximum cable length (1900 m).

Innovation Point 3: Built-In Fault Tolerance

Short-circuit on the Fieldbus segment triggers current limiting—not shutdown—allowing other devices to remain online while diagnostics pinpoint the faulted spur.

Innovation Point 4: Seamless I/A Series Ecosystem Integration

The P0961CA is natively recognized in Foxboro’s Fieldbus Configuration Tool, enabling automatic topology mapping and health monitoring from the DCS engineering station.

Application Cases and Industry Value

A North Sea offshore platform deployed FOXBORO P0961CA units across all 12 Fieldbus segments in its separator train. During a routine safety audit, regulators required proof of intrinsic safety compliance for all field instrumentation. The P0961CA’s IECEx and ATEX certificates—combined with its integrated design—allowed the operator to pass inspection without costly rewiring or barrier additions. In another case, a pharmaceutical plant used the P0961CA in a sterile cleanroom where space was limited; its compact DIN-rail form factor enabled dense mounting alongside I/O marshalling panels, reducing cabinet size by 30%. These examples show how the P0961CA delivers both regulatory assurance and engineering efficiency.

Related Product Combination Solutions

P0916ZM: Foxboro Fieldbus terminator with status LED, required at each end of P0961CA-powered segment

FBM242: Foxboro FOUNDATION Fieldbus interface module (connects H1 segment to I/A Series DCS)

P0961CB: Redundant version of P0961CA with dual-input capability for critical applications

I/A Series Workbench: Engineering software for configuring and diagnosing P0961CA-connected networks

Smart Switches (e.g., P0970 series): For segment protection and spur isolation in large FF topologies

FF-JB12: Foxboro-approved Fieldbus junction box compatible with P0961CA outputs

HART Multiplexer (e.g., HIM): Enables hybrid HART/FF monitoring on same infrastructure

Power Rail System (e.g., P0921 series): Centralized 24VDC distribution for multiple P0961CA units

Installation, Maintenance, and Full-Cycle Support

Install the FOXBORO P0961CA on a grounded DIN rail within the control panel, ensuring proper separation from high-voltage AC circuits. Connect the 24 VDC input from a dedicated, fused power source, and wire the Fieldbus trunk using twisted-pair, shielded cable (e.g., Belden 3105A). Always install terminators (P0916ZM) at both ends of the segment. The unit requires no configuration—power-on readiness is immediate.

For maintenance, monitor the green “Power OK” LED; a dark indicator suggests input failure or internal fault. While the P0961CA is solid-state with no consumables, periodic inspection of terminal torque and shield grounding is recommended in high-vibration areas. We provide full compatibility verification with legacy and modern I/A Series systems, including migration paths from older P091x power supplies. Every P0961CA we deliver is factory-tested for output stability, isolation resistance, and safety certification validity, backed by a 24-month warranty and expert technical support.