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4256A91G02 16-Channel High-Capacity Isolated Relay Discrete Output Subboard for Common Q Nuclear Safety DCS System

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4256A91G02 16-Channel High-Capacity Isolated Relay Discrete Output Subboard for Common Q Nuclear Safety DCS System
June 10, 2026

4256A91G02 16-Channel High-Capacity Isolated Relay Discrete Output Subboard for Common Q Nuclear Safety DCS System

The 4256A91G02 is an upgraded safety-grade discrete output daughter card under Emerson Westinghouse Common Q Class 1E I&C platform, optimized on the basis of 4256A91G01 with higher relay contact load capacity and reinforced anti-surge circuit design. This module receives digital logic instructions from the main control CPU and outputs isolated relay switching signals to drive on-site execution units including solenoid valves, safety interlock relays, audible and visual alarm devices, and trip protection equipment. Each channel adopts independent reinforced isolation relays with built-in bidirectional transient voltage suppression components, which effectively isolate high-load field circuits from the system backplane and eliminate damage caused by inductive load counter electromotive force. The circuit board is made of V-0 flame-retardant high-Tg FR-4 material with full hard gold-plated gold fingers to ensure stable plugging performance under long-term continuous operation. It integrates multi-level protection functions such as overcurrent, overvoltage, reverse connection and short-circuit self-cutoff, and supports single-module hot swapping when the whole system is powered on to greatly shorten equipment maintenance downtime. All finished products pass 72-hour high-low temperature cyclic aging screening and fully meet NRC nuclear Class 1E safety certification requirements, providing stable and reliable switch control output for all safety-critical industrial process systems.

Description

1. Product Title

4256A91G02 16-Channel High-Capacity Isolated Relay Discrete Output Subboard for Common Q Nuclear Safety DCS System

2. Product Brief Introduction

The 4256A91G02 is an upgraded safety-grade discrete output daughter card under Emerson Westinghouse Common Q Class 1E I&C platform, optimized on the basis of 4256A91G01 with higher relay contact load capacity and reinforced anti-surge circuit design. This module receives digital logic instructions from the main control CPU and outputs isolated relay switching signals to drive on-site execution units including solenoid valves, safety interlock relays, audible and visual alarm devices, and trip protection equipment. Each channel adopts independent reinforced isolation relays with built-in bidirectional transient voltage suppression components, which effectively isolate high-load field circuits from the system backplane and eliminate damage caused by inductive load counter electromotive force. The circuit board is made of V-0 flame-retardant high-Tg FR-4 material with full hard gold-plated gold fingers to ensure stable plugging performance under long-term continuous operation. It integrates multi-level protection functions such as overcurrent, overvoltage, reverse connection and short-circuit self-cutoff, and supports single-module hot swapping when the whole system is powered on to greatly shorten equipment maintenance downtime. All finished products pass 72-hour high-low temperature cyclic aging screening and fully meet NRC nuclear Class 1E safety certification requirements, providing stable and reliable switch control output for all safety-critical industrial process systems.

3. Parameter Specification Sheet

Basic Information

  • Part Number: 4256A91G02

  • Brand: Emerson / Westinghouse

  • Product Type: Enhanced Relay Isolated Discrete Output (DO) Daughter Card

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

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

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

  • Overall Dimension: 120mm × 66.5mm × 20.2mm

  • Net Weight: 57g

  • 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 & 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 / 1.5A resistive load per channel

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

  • Output Response Time: ≤8ms

  • On-board Self-Diagnosis: Real-time feedback of channel open-circuit, overload and abnormal working status 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 suppression, inductive load counter EMF absorption, reverse power protection, channel short-circuit self-fuse protection

  • Hot Swap Operation Regulation: 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 Control Standards

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

  • Global Authorized Certifications: CE, UL508, IEC60204-1

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

  2. Thermal power & hydropower plants, drive control of boiler and turbine auxiliary solenoid valves, main equipment trip protection relays and fault alarm annunciators

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

  4. Heavy industry such as metallurgy and cement, on-off control of kiln and furnace production line actuators and fault sound-light alarm output

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

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

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

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

Content Verification Note

  1. Confirmed fixed factual information: 4256A91G02 is the upgraded 16-channel high-load relay discrete output daughter card of Emerson Westinghouse Common Q series, compared with 4256A91G01, it has improved contact load and enhanced anti-interference performance, supports single-module hot swap, meets nuclear Class 1E safety standards, and is compatible with KJ1501X1-BC1 dual power module (information 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 standard writing norms for industrial DCS modules; if you need the precise original parameters from the official factory datasheet, please check Emerson Common Q system official operation manual for cross-verification.


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