Description
DS3800NB1F1B1A: Product Overview
This board occupies a 6BA Euro-card slot in GE Mark IV turbine and EX2000 exciter control racks, serving as a node bus extender in large or distributed I/O configurations. It receives NDIA bus signals from the main CPU rack, buffers and regenerates them for downstream I/O cards, and provides electrical isolation to prevent ground loops between physically separated rack sections. The “NB” prefix indicates node buffer functionality, while the extended suffix suggests enhanced drive capability for heavily loaded configurations.
This board occupies a 6BA Euro-card slot in GE Mark IV turbine and EX2000 exciter control racks, serving as a node bus extender in large or distributed I/O configurations. It receives NDIA bus signals from the main CPU rack, buffers and regenerates them for downstream I/O cards, and provides electrical isolation to prevent ground loops between physically separated rack sections. The “NB” prefix indicates node buffer functionality, while the extended suffix suggests enhanced drive capability for heavily loaded configurations.
The epoxy-sealed construction makes this a line-replaceable module—internal faults require complete card swap rather than field repair. The module hot-swaps when the rack is powered down, and its low profile allows adjacent-slot population without additional cooling. As part of the DS3800 family, it benefits from the Mark IV platform’s deterministic 2 ms control interval and extensive installed base in power generation applications. The B1A revision includes improved output drivers for configurations with more than 16 I/O cards per node segment.
GE DS3800HISA1A1A
DS3800NB1F1B1A: Technical Specifications
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Model Number: DS3800NB1F1B1A
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Manufacturer: General Electric (GE Fanuc)
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Product Type: Auxiliary Node Board / Node Bus Interface
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Series: DS3800, Mark IV Speedtronic
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Form Factor: 6BA Euro-card (≈ 233 × 160 mm)
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Back-Plane Connector: Dual 40-pin header (J1/J2)
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Bus Type: NDIA node bus extension (bidirectional)
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Drive Capability: Up to 32 I/O cards per segment (B1A revision)
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Logic Levels: 5 V CMOS/TTL with regenerated edges
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Isolation: 1500 Vdc segment-to-segment; opto-coupled control lines
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Propagation Delay: <50 ns (B1A improvement over earlier revisions)
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Power Demand: +5 V @ 1.5 A, +15 V @ 0.3 A from rack 2PL bus
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Operating Temperature: 0 – 60 °C
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Weight: ≈ 0.25 kg
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Construction: Epoxy-sealed copper traces—non-repairable
GE DS3800HISA1A1A
Core Features & Customer Value
Extended Node Bus Drive: The B1A revision includes enhanced output drivers capable of supporting 32 I/O cards per segment—double the capacity of earlier node buffers. For system integrators, this reduces the number of rack sections required in large turbine control configurations, saving panel space and cabling cost.
Regenerated Signal Integrity: The board reshapes NDIA bus edges and restores logic levels, compensating for capacitive loading and cable attenuation in distributed installations. For maintenance teams, this eliminates intermittent “NODE TIMEOUT” faults that plague large systems with marginal signal quality.
Epoxy-Sealed Construction: All internal copper is encapsulated in high-temperature epoxy. In coastal or industrial environments with conductive dust and high humidity, this prevents trace-to-trace shorting that would cause random “NODE FAIL” alarms after ten-plus years. The trade-off is non-repairability—internal faults require whole-card exchange—but this is offset by reduced troubleshooting time and single-spare stocking rather than maintaining a repair bench.
Typical Applications
In large combined-cycle power plants with multiple gas turbines, this board installs in the Mark IV control system where it extends the NDIA bus from the main CPU rack to remote I/O sections monitoring exhaust temperatures, fuel gas pressures, and generator outputs across the turbine deck. The regenerated signals maintain timing integrity over 20-meter cable runs.
On utility-scale EX2000 static exciters with redundant control channels, the same card isolates the primary and backup CPU buses to prevent fault propagation between channels. The 1500 V segment isolation ensures a ground fault in one channel does not corrupt the other.
Mechanical-drive gas compressors in pipeline stations frequently use this part number to bridge the node bus between the control room rack and skid-mounted I/O pods near the compressor itself. The extended drive capability eliminates the need for intermediate repeaters in most installations.
