Foxboro FPS400-24 24V DC Field Power Supply

Description

Product Introduction

The Foxboro FPS400-24 (Part Number P0926JM) is a high-efficiency 400-Watt power supply module engineered for Foxboro I/A Series and EcoStruxure DCS platforms. Designed to sit directly in power supply slots on Foxboro 200 Series baseplates, the FPS400-24 converts utility AC or high-voltage DC input power into clean, tightly regulated 24V DC power required by Control Processors (FCP270/FCP280), Fieldbus Modules (FBMs), and field instruments.

Built for high-reliability industrial environments, the FPS400-24 features an internal diode OR-ing circuit that enables true N+1 redundant power topologies. When two FPS400-24 units are installed on a redundant power baseplate, they share field load currents evenly. Should one power module experience an AC utility drop or internal power stage failure, the partner module seamlessly assumes 100% of the system load without dropping system voltage or disturbing critical DCS control loops.

Key Technical Specifications

Application Scenarios & The “Trench” Experience

The Trench Story

It is 01:50 AM during a heavy thunderstorm at a continuous refinery crude unit. A lightning strike on an external feeder trips the primary 120V AC utility breaker feeding Power Supply Slot A on Control Cabinet 04. The “POWER SUPPLY A FAIL” alarm lights up across the operator console. Thanks to an N+1 redundant pair of FPS400-24 (P0926JM) modules installed on the rack, Module B seamlessly took over 100% of the 24V DC bus load with zero drop in system rail voltage. The duty technician reset the main breaker, swapped in a bench-tested spare module on the live baseplate, and restored dual-redundant power status in under 10 minutes without disrupting a single barrel of production.

Target Application Scenarios

• Main DCS Enclosure Powering: Provides primary 24V DC operating power to FCP280/FCP270 controllers, 200 Series FBM baseplates, and FCM couplers.
• Transmitter Field Powering: Delivers isolated 24V DC power loop excitation to 4-20mA smart transmitters, pressure cells, and valve positioners via Termination Assemblies.
• High-Availability Process Cabinets: Deployed in dual redundant pairs to guarantee continuous 24/7 uptime in critical oil & gas, chemical, and power generation facilities.

FPS400-24

FPS400-24

Transparency SOP: Quality Assurance & Testing

We don’t just ship boxes; we test them on actual Foxboro power baseplates under full load. Every / P0926JM module undergoes a strict 5-stage workbench validation process prior to dispatch:

1. Inbound Visual & Mechanical Inspection: High-magnification check of housing vents, mounting latches, heavy-duty busbar connectors, and internal filter capacitors for thermal stress or swelling.
2. Cold Component & Isolation Testing: Resistance and dielectric breakdown checks across AC/DC input terminals, transformer windings, and 24V DC output stages to rule out internal short circuits.
3. Full 400W Burn-In Load Testing: The module is placed on a test rack and brought to 100% rated load capacity (~16.6A at 24V DC) using active electronic load banks. Thermal stability, voltage ripple, and regulation limits are verified under continuous load.
4. N+1 Redundant Failover Simulation: Paired with a second module in a live redundant configuration. We drop primary input AC power to verify instantaneous load sharing shift, zero output rail voltage dips, and proper triggering of the internal power alarm contacts.
5. Anti-Static & Heavy Packaging: Cleared modules receive thorough terminal cleaning, drying, and are packaged in custom heavy-duty protective foam to ensure safe transit.

The Veteran’s Tech Trap Guide

• ⚠️ Do Not Confuse (24V DC Output) with FPS400-48 or 12V Variants!

  The outputs 24V DC. Verify your baseplate and field instrumentation voltage requirements before installation; plugging a 48V power supply into a 24V DC baseplate bus will cause severe damage to installed FBM cards.

• ❗ Verify Total Cabinet Current Consumption:

  While a single provides 400W (~16.6A @ 24V DC), always calculate the total power budget of all attached controllers, FBMs, and field transmitter loops. If total cabinet draw exceeds 16A, configure modules in non-redundant parallel or add secondary power baseplate segments.

• ⚠️ Ensure Proper Cabinet Airflow & Convection Clearance:

  Power supplies generate internal heat during full-load operation. Ensure cabinet cooling fans are operational and vent louvers above and below the rack are clear to prevent thermal tripping.

• ❗ Bypass Alarm Interlocks Prior to Hot-Swapping:

  While Foxboro power baseplates support Live Insertion and Removal (Hot Swap) of redundant modules, extracting a failed module will briefly trigger the power supply fault relay. Notify operators or temporarily bypass hardware alarm loops before removing the card.

Frequently Asked Questions (FAQ)

Q: Can I hot-swap an module while the system is powered?

A: Yes, if installed in an N+1 redundant power baseplate configuration with a second healthy power supply module running. You can extract and replace the failed without powering down the baseplate or interrupting connected controllers and I/O cards.

Q: What is the exact difference between part numbers , P0926JM, and RH926JM?

A: “” is the functional model designation, “P0926JM” is the standard Foxboro hardware part number, and “RH926JM” is Schneider Electric’s RoHS-compliant (lead-free) hardware equivalent. and RH926JM are 100% functionally and mechanically interchangeable.

Q: Can the run on direct current (DC) input power?

A: Yes. In addition to standard 100–240V AC grid power, the accepts a wide 125V DC nominal input range (108 to 145V DC), making it suitable for plant station battery and uninterruptible DC bus systems.

Q: What warranty covers these pre-tested power modules?

A: Every ( / RH926JM) power supply sold includes a full 12-Month Functional Warranty. If the unit experiences hardware failure under normal operating parameters within 365 days, we provide an immediate unit replacement or full credit.