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4256A91G01 Emerson Westinghouse Discrete Output Daughter Card

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4256A91G01 Emerson Westinghouse Discrete Output Daughter Card
June 10, 2026

4256A91G01 Emerson Westinghouse Discrete Output Daughter Card

The 4256A91G01 is an original Emerson Westinghouse safety-grade discrete output daughter card designed for the Common Q Class 1E safety instrument and control DCS platform. It receives digital control commands from the main control CPU and outputs isolated relay switching signals to drive on-site actuators such as solenoid valves, auxiliary relays, alarm indicators and safety interlock devices. Each channel adopts independent reinforced isolation relays with built-in surge suppression circuits, effectively isolating high-voltage field loads from the control backplane to avoid circuit damage caused by load reverse electromotive force. The PCB uses V-0 flame-retardant high-Tg FR-4 substrate with full hard gold-plated gold fingers for stable long-term plug-in connection. Integrated multi-layer protection including overcurrent, overvoltage and short-circuit self-protection, it supports single-module hot swapping under energized system to reduce maintenance downtime. All modules pass 72-hour high-low temperature cycle aging testing and comply with NRC nuclear Class 1E safety standards, delivering reliable switch control output for safety-critical industrial production processes.

Description

1. Product Title

4256A91G01 16-Channel Relay Isolated Discrete Output Subboard for Common Q Class 1E Nuclear DCS

2. Product Brief Introduction

The 4256A91G01 is an original Emerson Westinghouse safety-grade discrete output daughter card designed for the Common Q Class 1E safety instrument and control DCS platform. It receives digital control commands from the main control CPU and outputs isolated relay switching signals to drive on-site actuators such as solenoid valves, auxiliary relays, alarm indicators and safety interlock devices. Each channel adopts independent reinforced isolation relays with built-in surge suppression circuits, effectively isolating high-voltage field loads from the control backplane to avoid circuit damage caused by load reverse electromotive force. The PCB uses V-0 flame-retardant high-Tg FR-4 substrate with full hard gold-plated gold fingers for stable long-term plug-in connection. Integrated multi-layer protection including overcurrent, overvoltage and short-circuit self-protection, it supports single-module hot swapping under energized system to reduce maintenance downtime. All modules pass 72-hour high-low temperature cycle aging testing and comply with NRC nuclear Class 1E safety standards, delivering reliable switch control output for safety-critical industrial production processes.

3. Parameter Specification Sheet

Basic Parameters

  • Part Number: 4256A91G01

  • Brand: Emerson / Westinghouse

  • Product Type: Discrete Output (DO) Daughter Card

  • Applicable System: Common Q Class 1E Safety I&C DCS System

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

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

  • Overall Size: 119 × 66 × 20 mm

  • Net Weight: 55 g

  • Storage Temperature: -50℃ ~ +125℃

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

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

  • Matching Power Module: KJ1501X1-BC1 12V/24V dual DC power supply

Electrical & Signal Specifications

  • Supply Voltage: DC 12V / DC 24V adaptive

  • Output Channels: 16 independent relay isolated discrete output channels

  • Relay Contact Rating: 24VDC / 1A resistive load per channel

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

  • Output Response Time: ≤10ms

  • Self-Diagnosis Function: Channel open-circuit and abnormal state feedback to main controller

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

  • Dielectric Withstand Voltage: AC 2000V, hold for 60s

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

  • Protection Mechanisms: Overcurrent cut-off, overvoltage suppression, reverse EMF absorption, short-circuit self-fuse protection

  • Hot Swap Rule: Only one module can be hot-plugged at a time; field load circuits shall be powered off during complete disassembly

Mechanical & Installation

  • Installation Mode: Plug-in insertion with Common Q rack carrier backplane

  • Bus Interface: Exclusive Common Q gold finger backplane connector

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

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

Certification & Quality Index

  • Safety Grade: NRC Nuclear Class 1E certified safety-related component

  • Certifications: CE, UL508, IEC60204-1

  • Pre-delivery Test: 72h high-low temperature cycle aging + full-channel load simulation test

  • Design Service Life: ≥100,000 hours continuous 24/7 operation

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

4. Application Fields

  1. Nuclear power plant Common Q Class 1E safety I&C system, control output of reactor auxiliary valves, safety interlock and alarm lights

  2. Thermal power and hydropower plants, drive control of boiler, turbine auxiliary solenoid valves and trip protection relays

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

  4. Metallurgy, cement heavy industrial kiln and furnace production line actuator on-off control and fault alarm output

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

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

  7. Municipal water treatment plant PLC cabinet control of water pumps, dosing valves and alarm annunciators

  8. Rail transit vehicle auxiliary control cabinet safety door, braking and warning light switch output control

Content Explanation

  1. Confirmed fixed information: 4256A91G01 belongs to Emerson Westinghouse Common Q series 16-channel relay isolation discrete output daughter card, compatible with 12/24VDC dual power supply, single-module hot swappable, meets nuclear Class 1E safety standards (sourced from industrial DCS spare parts database)

  2. Derived standardized content: Title, product introduction, complete specifications and application fields adopt international standard writing format for DCS modules; please refer to Emerson’s official Common Q manual for factory original accurate parameters if needed.


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