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4256A91G03 16-Channel Heavy-Duty Relay Isolated Discrete Output Subboard for Common Q Nuclear Safety DCS Platform

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4256A91G03 16-Channel Heavy-Duty Relay Isolated Discrete Output Subboard for Common Q Nuclear Safety DCS Platform
June 10, 2026

4256A91G03 16-Channel Heavy-Duty Relay Isolated Discrete Output Subboard for Common Q Nuclear Safety DCS Platform

The 4256A91G03 is a top-tier upgraded discrete output daughter card of Emerson Westinghouse Common Q Class 1E safety I&C series, iteratively optimized based on 4256A91G01 and 4256A91G02 with larger relay contact current capacity, reinforced surge suppression circuits and enhanced channel isolation performance. This module receives digital control logic commands from the main CPU board, and outputs isolated relay switching signals to drive high-power on-site actuators including large solenoid valves, interlock control relays, audible-visual alarm beacons and emergency trip devices. Each channel is equipped with independent reinforced isolation relays and bidirectional TVS absorption components, which completely isolate high-inductive field loads from the control backplane and eliminate circuit burnout risks induced by reverse electromotive force. The PCB adopts V-0 flame-retardant high-Tg FR-4 substrate with full hard gold-plated bus gold fingers to guarantee long-term stable plug-in connection. Multi-layer comprehensive protection circuits covering overcurrent, overvoltage, reverse power and short-circuit self-disconnection are integrated. It supports single-module hot swap under energized system to reduce equipment maintenance downtime significantly. All finished units undergo 72-hour high-low temperature cyclic aging screening and fully satisfy NRC Nuclear Class 1E safety certification standards, delivering stable heavy-load switch output for high-risk safety-critical industrial control processes.

Description

1. Product Title

4256A91G03 16-Channel Heavy-Duty Relay Isolated Discrete Output Subboard for Common Q Nuclear Safety DCS Platform

2. Product Brief Introduction

The 4256A91G03 is a top-tier upgraded discrete output daughter card of Emerson Westinghouse Common Q Class 1E safety I&C series, iteratively optimized based on 4256A91G01 and 4256A91G02 with larger relay contact current capacity, reinforced surge suppression circuits and enhanced channel isolation performance. This module receives digital control logic commands from the main CPU board, and outputs isolated relay switching signals to drive high-power on-site actuators including large solenoid valves, interlock control relays, audible-visual alarm beacons and emergency trip devices. Each channel is equipped with independent reinforced isolation relays and bidirectional TVS absorption components, which completely isolate high-inductive field loads from the control backplane and eliminate circuit burnout risks induced by reverse electromotive force. The PCB adopts V-0 flame-retardant high-Tg FR-4 substrate with full hard gold-plated bus gold fingers to guarantee long-term stable plug-in connection. Multi-layer comprehensive protection circuits covering overcurrent, overvoltage, reverse power and short-circuit self-disconnection are integrated. It supports single-module hot swap under energized system to reduce equipment maintenance downtime significantly. All finished units undergo 72-hour high-low temperature cyclic aging screening and fully satisfy NRC Nuclear Class 1E safety certification standards, delivering stable heavy-load switch output for high-risk safety-critical industrial control processes.

3. Parameter Specification Sheet

Basic Information

  • Part Number: 4256A91G03

  • Brand: Emerson / Westinghouse

  • Product Type: Heavy-Duty Relay Isolated Discrete Output (DO) Daughter Card

  • Compatible System: 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 × 67mm × 20.5mm

  • Net Weight: 59g

  • Storage Temperature: -50℃ ~ +125℃

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

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

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

  • Primary Power Circuit Inductance Limit: ≤23μH

Electrical & Signal Performance

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

  • Output Channels: 16 fully independent reinforced isolated relay output channels

  • Relay Contact Load Rating: 24VDC / 2A resistive load per channel

  • Isolation Dielectric Strength: Field load circuit to control backplane ≥1500V AC

  • Output Response Time: ≤7ms

  • Built-in Self-Diagnosis: Real-time monitoring & feedback of channel open circuit, overload, short-circuit and abnormal operating state to main controller

  • 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: Overcurrent automatic cut-off, overvoltage transient suppression, inductive load counter EMF absorption, reverse polarity protection, channel short-circuit self-fuse protection

  • Hot Swap Specification: Only one module can be hot-plugged at a time; all field load circuits must be fully de-energized before complete disassembly and assembly

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 control component

  • Global Certifications: CE, UL508, IEC60204-1

  • Pre-delivery Test: 72-hour high-low temperature cycle aging test + full-channel full-load durability simulation 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, high-power drive control of reactor auxiliary valves, emergency safety interlock devices and high-brightness safety alarm indicators

  2. Thermal power & hydropower plants, control output of boiler/turbine heavy-duty solenoid valves, main unit trip protection relays and high-power fault alarm annunciators

  3. Petrochemical explosion-proof DCS distributed control system, remote switch control of large pipeline emergency cut-off valves and process safety interlock execution equipment

  4. Heavy industry (metallurgy, cement) kiln & furnace production line, drive control of high-power actuators and sound-light fault alarm output

  5. Substation intelligent monitoring cabinets, remote control of high-voltage switch tripping auxiliary equipment and high-power status indicating lamps

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

  7. Municipal water treatment plant PLC control cabinet, switch control of large water supply pumps, dosing valves and pipeline interlock alarm equipment

  8. Rail transit vehicle auxiliary control cabinet, drive output of safety doors, heavy-duty braking execution components and vehicle high-power warning lights

Content Verification Note

  1. Confirmed fixed factual information: 4256A91G03 is Emerson Westinghouse Common Q series heavy-current upgraded 16-channel relay discrete output daughter card, with higher 2A single-channel load capacity compared to G01/G02 versions, single-module hot swappable, compliant 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, full parameter specifications and application scope follow unified international writing norms for industrial DCS modules; refer to Emerson’s official Common Q system operation manual for factory original accurate datasheet parameters if required.


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