ABB NDBU-95 (64008366)
ABB NDBU-95 (64008366) - Image 2

ABB NDBU-95 (64008366)

Product Brief:​ The NDBU-95 is a DDCS bus distribution / repeater module used in ABB multi-drive systems (common DC link with several inverter modules) or in master-slave drive configurations. It receives the DDCS fiber-optic link from the RDCU (via AINT board or directly from NAMC-01’s fiber transmitter) and fans out / repeats the signal to multiple inverter units (up to N nodes per DDCS chain — typically 6–12 depending on fiber budget). It also can be used to interconnect a DDCS master (e.g., ACS800 with DDCS option) to a slave drive or to a DDCS-to-Profibus gateway. The board mounts inside the drive cabinet on a DIN clip or on the AINT interface board header.

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Category: SKU: ABB NDBU-95 (64008366)

Description

ABB NDBU-95 (64008366)

  • Technical Specifications:
    • Function: DDCS bus repeater / distributor — receives fiber-optic DDCS from master, regenerates & distributes to up to 5–7 slave nodes (per ABB DDCS fan-out rules)
    • Fiber Ports: Typically 1 × DDCS IN (from master), 3–5 × DDCS OUT (to slave inverters or next NDBU-95); ST-type connectors (820 nm or 1300 nm per DDCS version)
    • Max Fiber Length (per segment): 50 m multimode (830 nm) typical for DDCS; 300 m (1300 nm) on some versions — check drive manual
    • Power: 24 V DC from drive internal supply (or from AINT board header)
    • Indicators: Power LED, Link Active LED per port
    • Operating Temp.: –20 °C to +60 °C
    • Dimensions: ≈100 × 70 mm PCB; DIN-clip or header-mount
    • Conformal Coating: Present on “-C” version (NDBU-95C) per G3 ISA-S71.04
  • Functional Features:
    • Regenerates DDCS telegrams — allows longer multi-drop chains than direct fiber from RDCU
    • Provides electrical isolation between DDCS segments (via fiber)
    • Used in common-DC-link multi-inverter setups (e.g., paper machine sectional drive — one rectifier feeding 6 inverter modules, each with its own ACS800 + NDBU-95 tapped off DDCS bus)
  • Application Scenarios:
    • Sectional drive paper machine — master rectifier + DC link, 4–12 inverter drives each receiving DDCS reference via NDBU-95 distribution
    • Wind tunnel / dynamometer — master speed reference fanned out to multiple load absorbers
    • Retrofit / expansion of existing ABB multi-drive system — add NDBU-95 to increase DDCS node count
  • Material & Structure / Working Principle / Installation / Precautions:
    • Mount NDBU-95 inside drive cabinet; connect IN fiber from master (RDCU/AINT DDCS TX); connect OUT fibers to each slave drive’s DDCS RX port
    • Verify fiber polarity (Tx→Rx; some DDCS uses simplex — one fiber per direction; others use duplex — follow ACS800 fiber diagram)
    • In drive system, no configuration needed — DDCS is transparent; each slave drive is addressed via DIP switches on its AINT/NDCU board
    • Precautions:
      • Do NOT bend fiber beyond minimum bend radius (≈30 mm for 62.5/125 µm multimode)
      • Clean fiber end-faces before mating — contamination causes high attenuation / intermittent DDCS loss
      • Do NOT look into powered fiber — invisible IR (820/1300 nm) — though low power, good practice to avoid direct viewing
      • In multi-drop, ensure total number of nodes and fiber length stay within DDCS spec — exceeding causes timing violations

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