I. Basic Information

Product Positioning: Redundant rack-mounted switching power supply module for ABB Symphony Plus DCS systems, a matched power supply unit for upgrading legacy Bailey Infi90 systems. It provides centralized power for DCS master controllers and I/O modules with 24/7 non-stop operation inside DCS cabinets of thermal power plants, hydropower stations and captive power plants. All PS203-series power supplies share identical rack slot dimensions, enabling direct drop-in replacement of legacy PS201/PS202 modules.

• Brand: ABB Automation | Origin: Switzerland
• Category: 24VDC Redundant Rack Power Supply Module for Symphony Plus
• Compatibility: Symphony Plus SDe/SD/SR racks, BRC410/BRC300 master controllers, GMKP-series DI/AI acquisition modules and full S800 remote I/O cabinet power feeding.
• Mounting: Plug-in installation into standard DCS rack slots; Dimensions: 60×125×120mm (H×W×D); Net weight: approx.1.2kg; Metal enclosure plus full three-proof insulated coating on PCB; Ingress Protection: IP20 (for installation inside sealed control cabinets).
• Onboard Configuration: Backplane gold-finger power bus connector, AC input terminal block, 24VDC output terminals, dual-color PWR/FAULT LED indicators for power status, synchronization pins for parallel redundant operation.

II. Technical Specifications

(1) Electrical Parameters

• Input: Wide-range single-phase AC 85~264V (50/60Hz), full-range universal input without external voltage stabilizer; Active PFC with power factor＞0.95.
• Output: Rated 24VDC/10A, total rated output power 240W; Voltage regulation accuracy ±1% across full load and entire input voltage range; Output ripple noise＜150mVpp; Hold-up time under full load＞20ms.
• Protection: Built-in protection including adjustable overvoltage shutdown (28~35V), automatic foldback recovery for 105%~150% overload, latch-type short-circuit protection, input surge suppression and reverse polarity hardware lockout. Supports parallel redundant current sharing among multiple identical units; faulty module shuts down seamlessly without power interruption to cabinet loads.
• Cooling: Natural convection cooling without cooling fan; full rated output available at 100% loading.

(2) Environmental Parameters

• Operating Temperature: -25℃～+70℃ for continuous long-term operation; Storage Temperature: -40℃～+85℃.
• Humidity: 5%~95% RH non-condensing; Compliant with IEC61000 industrial EMC immunity standards to withstand VFD harmonics, dust and condensed moisture corrosion in power plant environments; Certified to safety standards EN60950, UL508, CE & cULus.

III. Key Features

1. Parallel Redundancy with Automatic Current Sharing

   Two or more PS203PRESPMCPS units run in parallel with automatic load sharing. A faulty unit disconnects automatically while remaining units carry 100% of total load to ensure uninterrupted DCS cabinet power supply and satisfy SIL2 power requirements for critical thermal power facilities.
2. Wide Input Voltage Range with Active PFC

   Maintains stable 24VDC output under severe grid fluctuations including phase loss and voltage drop, suppresses input-side harmonic distortion; ideal for captive power plants with unstable auxiliary power and legacy unit retrofit projects.
3. Local Fault Indication & Remote Fault Reporting

   FAULT LED illuminates upon abnormal power, overcurrent or overvoltage conditions; fault signals are transmitted to DCS HMI via backplane bus for rapid faulty unit localization.
4. Drop-in Retrofit Replacement Without Field Rewiring

   Backward compatible with legacy PS201 and PS202 power supplies; direct plug-and-play swap during Bailey Infi90-to-Symphony Plus upgrade without modifying rack bases or field wiring.
5. Robust Three-proof Construction for All Operating Conditions

   Metal housing plus three-proof coated PCB delivers excellent high-temperature and dust resistance for long-term service inside harsh field-mounted boiler and turbine control cabinets.

IV. Working Principle

• Power-on Self-test: After AC mains energization, the unit runs diagnostics on input circuit, PFC converter and DC output circuit; steady green PWR LED lights up upon successful self-check.
• Power Conversion: AC input passes PFC correction, high-frequency switching conversion and regulated filtering to produce stable 24VDC, which feeds rack master controllers and I/O modules via backplane bus.
• Redundant Current Sharing: Synchronization pins enable automatic load balancing among paralleled power supplies.
• Fault Handling: Output short-circuit or overvoltage triggers immediate internal shutdown with red FAULT LED alarm; remaining parallel units automatically assume full load and fault information is uploaded to DCS monitoring system.

V. Application Scenarios

1. DCS Master Cabinets for Thermal Power Generators: Standard factory-fit power supply for Symphony Plus master & I/O racks on 30MW~660MW power generation units.
2. Automation Control Cabinets for Medium & Large Hydropower Plants: Centralized power feeding for unit central control and governor DCS cabinets of hydro-generator sets.
3. Captive Power Plants in Steel, Refining & Coking Industries: Replacement spare for upgrading outdated Bailey Infi90 DCS systems.

4. Combined-cycle Gas Turbine & Biomass Power Plants: Supporting power supply for plant-wide auxiliary control DCS racks.

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Version Differentiation

• PS203PRESPMCPS (Current Standard Version): Supports redundant parallel operation and PFC wide-range input, mainstream model for new unit construction and legacy system retrofits.
• PS203STD: Cost-effective standalone model without parallel current-sharing function, used for ordinary small cabinets inside clean control rooms.