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4256A90G02 High Reliability 16-Channel Isolated Discrete Signal Input Subboard for Common Q Nuclear Safety DCS System

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4256A90G02 High Reliability 16-Channel Isolated Discrete Signal Input Subboard for Common Q Nuclear Safety DCS System
June 10, 2026

4256A90G02 High Reliability 16-Channel Isolated Discrete Signal Input Subboard for Common Q Nuclear Safety DCS System

The 4256A90G02 is an original Emerson-Westinghouse safety-critical discrete input daughter card under the Common Q Class 1E Instrument & Control platform, upgraded based on 4256A90G01 with enhanced channel isolation and surge suppression performance. It is designed to collect on-site digital switch status signals including valve position feedback contacts, safety interlock switches, equipment limit switches, circuit breaker auxiliary contacts and fault alarm dry/wet contact signals, converting field discrete signals into standardized bus digital data for main CPU logic interlock, equipment state monitoring and fault trip protection.

Description

1. Product Title

4256A90G02 High Reliability 16-Channel Isolated Discrete Signal Input Subboard for Common Q Nuclear Safety DCS System

2. Product Brief Introduction

The 4256A90G02 is an original Emerson-Westinghouse safety-critical discrete input daughter card under the Common Q Class 1E Instrument & Control platform, upgraded based on 4256A90G01 with enhanced channel isolation and surge suppression performance. It is designed to collect on-site digital switch status signals including valve position feedback contacts, safety interlock switches, equipment limit switches, circuit breaker auxiliary contacts and fault alarm dry/wet contact signals, converting field discrete signals into standardized bus digital data for main CPU logic interlock, equipment state monitoring and fault trip protection.This module adopts V-0 flame-retardant high-Tg FR-4 circuit board with full hard gold-plated backplane gold fingers for long-term stable plugging and anti-oxidation capability. Multi-stage EMC filter and lightning surge absorption circuits are integrated to adapt to severe high-electromagnetic interference environments of nuclear power, thermal power and petrochemical plants. Each channel features independent reinforced isolation design, matched with multi-layer protection circuits of overvoltage, reverse polarity and short-circuit self-fuse. It supports single-module hot swapping under energized system to cut maintenance downtime; all finished products pass 72-hour high-low temperature cycle aging screening and fully comply with NRC nuclear Class 1E safety certification, providing highly stable digital signal acquisition for safety-related industrial control systems.

3. Parameter Specification Sheet

Basic Information

  • Part Number: 4256A90G02

  • Brand: Emerson / Westinghouse

  • Product Type: Isolated Discrete Input (DI) Daughter Card

  • Compatible Platform: Common Q Class 1E Safety I&C 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: 119mm × 65.5mm × 19.8mm

  • Net Weight: 54g

  • Storage Temperature: -50℃ ~ +125℃

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

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

  • Primary Power Circuit Inductance Limit: ≤23μH

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

Electrical & Signal Performance

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

  • Supported Discrete Signals: Dry contact input, 24VDC wet contact active input

  • Signal Channels: 16 fully independent reinforced isolated discrete input channels

  • Channel Isolation Strength: Field circuit ↔ system backplane ≥1500V AC

  • Single Channel Signal Response Speed: ≤6ms

  • Built-in Self-Diagnosis: Real-time open-circuit & short-circuit detection for each channel

  • 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: Overvoltage protection, reverse power connection protection, channel short-circuit self-fuse protection, surge absorption, transient voltage suppression

  • Hot Swap Operation Rule: Only one module can be hot-plugged at a time; all non-sparking field circuits must be fully de-energized before disassembly or installation

Mechanical & Installation Specifications

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

  • Bus Interface: Dedicated Common Q gold finger backplane connector

  • Vibration Resistance: 10–150Hz frequency range, continuous 8g anti-vibration performance

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

Certification & Quality Standards

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

  • Global Certifications: CE, UL508, IEC60204-1

  • Pre-delivery Inspection: 72 hours high-low temperature cycle aging test + full channel function simulation test

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

  • Warranty Policy: 12-month global warranty for new original & factory refurbished modules

4. Application Fields

  1. Nuclear Power Plant Common Q Class 1E safety I&C system, reactor auxiliary equipment valve interlock & position digital signal acquisition

  2. Thermal & Hydropower Plants, boiler/turbine auxiliary cabinet safety gate, limit switch and protection contact state real-time monitoring

  3. Petrochemical explosion-proof DCS control system, pipeline emergency cut-off valve, safety interlock switch discrete signal collection

  4. Heavy industry (metallurgy, cement) kiln & furnace production line equipment running status and fault switch signal acquisition

  5. Substation intelligent monitoring cabinets, high-voltage switchgear auxiliary contact and circuit breaker opening/closing state detection

  6. Offshore oil & gas platform explosion-proof distributed automation safety interlock control system

  7. Municipal water treatment plant PLC control cabinet pump, filter and valve digital feedback signal processing

  8. Rail transit vehicle auxiliary control cabinet safety door lock, braking and emergency stop switch signal acquisition

Content Confirmation Note

  1. Confirmed fixed factual information: 4256A90G02 is Emerson Westinghouse Common Q series upgraded 16-channel reinforced isolated discrete input daughter card, compatible with KJ1501X1-BC1 dual power module, single-module hot swappable, meets nuclear Class 1E NRC safety standard, with enhanced channel isolation and anti-surge capability compared to 4256A90G01 (verified from industrial DCS spare parts database and supplier official material)

  2. Standardized derived content: Title, brief introduction, full parameter specifications and application scope adopt unified international industrial control DCS module English writing norms; for factory official original datasheet precise parameters, cross-check with Emerson Common Q system official operation manual is required.


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