ABB NU8976A
ABB NU8976A - Image 2

ABB NU8976A

Product Brief:​ The NU8976A is an internal interface / communication adapter PCB used in ABB Symphony Plus (S+ / INFI 90 Evolution) or Harmony rack systems to bridge the legacy Control Way (C.W.) bus to the newer HN800 I/O bus, or to provide the high-speed processor-to-I/O link in a controller node. It may also appear as the processor-bus-to-I/O-backplane interface​ inside an AC 800M / CPM810-based node when interfacing legacy I/O. The exact role depends on system architecture — in many spare-part lists it is the HN800 C.W. Interface Board for S+ I/O nodes​ or the ICP (I/O Communication Processor) piggyback board.

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Category: SKU: ABB NU8976A

Description

ABB NU8976A

  • Technical Specifications (typical for C.W.↔HN800 bridge):
    • Function: Bidirectional protocol conversion / data marshalling between C.W. (INFI 92 side) and HN800 (S+ I/O side)
    • Ports: 1 × C.W. interface (to IEMMU21 backplane edge); 1–2 × HN800 ports (RJ45 or fiber ST for HN800 bus to SD I/O stations)
    • HN800 Capability: Supports up to N SD I/O stations per link; redundant HN800 A/B supported
    • Data Update: Cyclic I/O scan + acyclic parameter/diagnostic messages
    • Power: From controller backplane (5 V / 24 V DC)
    • Indicators: Run, C.W. Active, Link Active, Fault LEDs (visible when board is accessible)
    • Mounting: Plugs into dedicated slot/header on controller motherboard or on IEMMU21’s communication slot (depending on implementation)
    • Operating Temp.: 0 °C to +60 °C
  • Functional Features:
    • Transparent I/O mapping — S+ I/O modules (HAI805, HDO, HDI…) appear as legacy I/O blocks to INFI 92 application
    • Supports redundant bus with automatic switchover
    • Diagnostic upload to controller — reports node missing, I/O module fault, CRC errors
    • Time synchronization passed from C.W. master clock to I/O stations
  • Application Scenarios:
    • Hybrid system — INFI 92 controller with newer Symphony Plus S+I/O (HN800bus) via NU8976Abridge
    • Retrofit — keep existing INFI 92 application logic; replace old S100 I/O with S+ I/O for better diagnostics & HART
    • Spare for controller node — replacement requires firmware/configuration compatibility check
  • Material & Structure / Working Principle / Installation / Precautions:
    • Install in designated controller slot (often the comm slot adjacent to INNIS21 or on CPU motherboard header)
    • Connect bus cable to SD termination unit first I/O station; daisy-chain or star per design
    • In Engineering Workbench: define node type with + NU8976A bridge; assign I/O addresses per S+ I/O catalog
    • Verify link LED before downloading I/O config
    • Precaution:​ Firmware on NU8976A must match system release — mismatch causes node fail to boot. After replacement, confirm C.W. and links show active before loading I/O configuration. Handle with ESD precautions.

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