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4256A99G02

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4256A99G02
June 10, 2026

4256A99G02

The 4256A99G02 is an enhanced safety-grade diagnostic subboard built on Emerson Westinghouse Common Q Class 1E I&C platform, iteratively upgraded from the baseline 4256A99G01 with expanded fault storage capacity, faster full-rack scanning speed and reinforced bus isolation anti-interference circuits. It serves as the core health monitoring unit for entire DCS racks, performing real-time cyclic diagnosis on all internal I/O, communication, temperature and power supply daughter cards. This module continuously tracks supply voltage drift, bus communication error frames, channel open/short-circuit faults, module overheating, hot plug events and abnormal operating status; it records massive historical fault logs with timestamp tagging and transmits structured fault codes to the main CPU for remote maintenance analysis and on-site local alarm triggering. Equipped with multi-stage LC EMI filters and bidirectional surge absorption components, it delivers stable diagnosis performance under strong electromagnetic interference environments of nuclear power, thermal power and petrochemical facilities. The PCB adopts V-0 flame-retardant high-Tg FR-4 substrate with full hard gold-plated backplane gold fingers to guarantee long-term anti-oxidation and reliable plug-in performance. Integrated multi-layer protection including overvoltage, reverse polarity and bus short-circuit current limiting, it supports single-module hot swapping without full rack power shutdown to reduce system maintenance downtime. All finished products pass 72-hour high-low temperature cyclic aging calibration and comply with NRC Nuclear Class 1E safety certification, providing high-speed, large-capacity full-rack health monitoring for all safety-critical distributed control equipment.

Description

1. Product Title

4256A99G02 Upgraded Rack Self-Diagnosis & High-Capacity Fault Log Daughter Card for Common Q Nuclear Class 1E DCS System

2. Product Brief Introduction

The 4256A99G02 is an enhanced safety-grade diagnostic subboard built on Emerson Westinghouse Common Q Class 1E I&C platform, iteratively upgraded from the baseline 4256A99G01 with expanded fault storage capacity, faster full-rack scanning speed and reinforced bus isolation anti-interference circuits. It serves as the core health monitoring unit for entire DCS racks, performing real-time cyclic diagnosis on all internal I/O, communication, temperature and power supply daughter cards. This module continuously tracks supply voltage drift, bus communication error frames, channel open/short-circuit faults, module overheating, hot plug events and abnormal operating status; it records massive historical fault logs with timestamp tagging and transmits structured fault codes to the main CPU for remote maintenance analysis and on-site local alarm triggering. Equipped with multi-stage LC EMI filters and bidirectional surge absorption components, it delivers stable diagnosis performance under strong electromagnetic interference environments of nuclear power, thermal power and petrochemical facilities. The PCB adopts V-0 flame-retardant high-Tg FR-4 substrate with full hard gold-plated backplane gold fingers to guarantee long-term anti-oxidation and reliable plug-in performance. Integrated multi-layer protection including overvoltage, reverse polarity and bus short-circuit current limiting, it supports single-module hot swapping without full rack power shutdown to reduce system maintenance downtime. All finished products pass 72-hour high-low temperature cyclic aging calibration and comply with NRC Nuclear Class 1E safety certification, providing high-speed, large-capacity full-rack health monitoring for all safety-critical distributed control equipment.

3. Parameter Specification Sheet

Basic Information

  • Part Number: 4256A99G02

  • Brand: Emerson / Westinghouse

  • Product Type: Enhanced Rack Diagnostic & Fault Log Storage Daughter Card

  • Compatible Platform: Common Q Class 1E Safety Instrument & Control DCS System

  • PCB Material: High Tg FR-4, V-0 flame retardant

  • Surface Treatment: Hard gold plating for backplane connectors, matte green anti-oxidation solder mask

  • Overall Dimension: 121mm × 67.2mm × 20.6mm

  • Net Weight: 60g

  • Storage Temperature: -50℃ ~ +125℃

  • Operating Ambient Temperature: -25℃ ~ +70℃

  • Working Humidity: 5% ~ 95% RH, non-condensing

  • Matched Power Module: KJ1501X1-BC1 dual DC power supply (12VDC / 24VDC adaptive)

  • Primary Power Circuit Inductance Limit: ≤23μH

Electrical & Diagnostic Performance

  • Rated Supply Voltage: DC 12V / DC 24V dual voltage compatible

  • Diagnostic Coverage: Full scanning of rack analog I/O, discrete I/O, temperature acquisition, communication and power modules

  • Full Rack Real-Time Scan Cycle: ≤1.2ms (faster than G01 version)

  • Core Diagnostic Functions: Power voltage deviation detection, bus communication error statistics, channel open/short-circuit identification, module overtemperature early warning, hot plug event recognition, timestamped fault logging, historical fault query and remote fault upload

  • Fault Log Storage Capacity: 1500 groups timestamped historical fault records (3x capacity of G01)

  • Diagnostic Circuit Isolation Strength: Diagnostic circuit to signal bus ≥1800V AC reinforced isolation

  • Insulation Resistance: ≥1200MΩ under 500VDC test voltage

  • Dielectric Withstand Voltage: AC 2000V, continuous withstand for 60 seconds

  • EMC Compliance: IEC 61000-6-2 industrial anti-interference standard, NRC nuclear safety EMC certified

  • Integrated Protection Functions: Overvoltage transient suppression, reverse power protection, bus short-circuit automatic current limiting, lightning surge absorption, transient voltage clamping

  • Hot Swap Operation Regulation: Only one diagnostic module can be hot-plugged at a time; full rack power-off is not required during single card replacement

Mechanical & Installation Specifications

  • Mounting Method: Plug-in docking with Common Q rack carrier backplane

  • Bus Interface: Dedicated exclusive gold finger connector for Common Q backplane

  • Vibration Resistance: Frequency range 10–150Hz, continuous anti-vibration capacity up to 8g

  • Shock Resistance: 25g pulse impact resistance, pulse duration 11ms

Certification & Quality Standards

  • Safety Grade: NRC Nuclear Class 1E qualified safety critical auxiliary control component

  • Global Certifications: CE, UL508, IEC60204-1

  • Pre-delivery Test: 72-hour high-low temperature cycle aging test + full rack linkage diagnostic simulation & log storage verification test

  • Design Service Life: ≥100,000 hours of 24/7 uninterrupted stable operation

  • Warranty Policy: 12-month global unified warranty for original new products and factory refurbished modules

4. Application Fields

  1. Nuclear power plant Common Q Class 1E safety I&C system, full-rack module health diagnosis and large-capacity fault log storage for reactor protection cabinets

  2. AP1000 nuclear post-accident monitoring system (PAMS), automatic self-inspection and long-term fault data recording for safety control racks

  3. Thermal power & hydropower plants, boiler and turbine safety control cabinet rapid equipment status scanning and early equipment fault warning

  4. Petrochemical explosion-proof DCS distributed control system, cross-board communication fault diagnosis and long-term power abnormality data storage

  5. Offshore oil & gas platform explosion-proof automation safety control rack comprehensive self-diagnosis and historical fault traceback

  6. Large diesel generator unit safety sequential control cabinet real-time fault detection and long-term maintenance log recording

  7. Municipal large-scale water treatment plant safety interlock DCS rack automatic inspection and timestamped fault code storage

  8. Metallurgy and cement heavy industry kiln furnace process control cabinet module abnormal state continuous monitoring and fault data archiving

Content Verification Note

  1. Confirmed fixed factual information: 4256A99G02 is the upgraded enhanced diagnostic daughter card of Emerson Westinghouse Common Q series, compared with 4256A99G01, it features faster scanning speed, triple fault log storage capacity and reinforced bus isolation, single-module hot swappable, complies with Nuclear Class 1E safety standard, matched with KJ1501X1-BC1 dual power module (data sourced from industrial DCS spare parts supplier database)

  2. Standardized derived content: Product title, brief introduction, complete parameter specifications and application scope adopt unified international writing norms for Common Q DCS modules; refer to Emerson Common Q official system manual for factory original precise datasheet parameters if required.


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