Description
DS3800NCSA1A1B Product Overview
The DS3800NCSA1A1B is an auxiliary I/O printed-wiring board used inside GE Mark IV turbine and EX2000 exciter control racks. It plugs into the 6BA Euro-card file and acts as a signal-expansion node: it lands additional field contacts, scales analog feedback, and isolates the 5 V CPU from the 480 V class power electronics. Because the copper traces are fully encapsulated in high-temperature epoxy, the board is treated as a non-repairable module—any internal fault requires a complete card swap rather than component-level rework. The module is fully hot-swappable when the rack is powered down, and its 0.06 lb weight allows adjacent-slot population without additional support brackets.
The DS3800NCSA1A1B is an auxiliary I/O printed-wiring board used inside GE Mark IV turbine and EX2000 exciter control racks. It plugs into the 6BA Euro-card file and acts as a signal-expansion node: it lands additional field contacts, scales analog feedback, and isolates the 5 V CPU from the 480 V class power electronics. Because the copper traces are fully encapsulated in high-temperature epoxy, the board is treated as a non-repairable module—any internal fault requires a complete card swap rather than component-level rework. The module is fully hot-swappable when the rack is powered down, and its 0.06 lb weight allows adjacent-slot population without additional support brackets.
DS3800NCSA1A1B Technical Specifications
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Model Number: DS3800NCSA1A1B
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Manufacturer: General Electric
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Product Type: Auxiliary I/O / Add-On PLC Board
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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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Field Interface: 20 single-pin headers for sensor/actuator wiring
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Isolation: 500 V channel-to-ground; opto-coupled digital lines
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Power Demand: +5 V @ 0.6 A, +15 V @ 0.2 A from rack 2PL bus
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Operating Temperature: 0 – 60 °C (board rating)
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Weight: 0.06 lb (≈ 27 g)
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Construction: Epoxy-sealed copper traces—non-repairable
DS3800NCSA1A1B
Core Features & Customer Value
Lightweight Euro-Card Footprint: At 27 g the board adds negligible weight to the card file, eliminating mechanical stress on the 40-pin back-plane connectors and allowing full-slot population without additional card guides.
Epoxy-Sealed Construction: All internal copper is encapsulated in high-temperature epoxy. In environments with high humidity, dust, or conductive contamination the seal prevents trace-to-trace shorting that would otherwise cause random “AUX I/O FAIL” alarms after ten-plus years of service. The trade-off is non-repairability—any internal fault requires a whole-card exchange—but this is offset by reduced troubleshooting time and the fact that plants stock one spare instead of maintaining a repair bench.
Plug-and-Play Expansion: The dual 40-pin header mates directly with the Mark IV back-plane—no mounting brackets, jumpers, or external cabling required. For maintenance crews this translates to a three-minute replacement instead of a half-shift re-wiring job.
Typical Applications
In combined-cycle power plants the board is installed in the Mark IV turbine control core where it lands additional exhaust-temperature thermocouples and compressor discharge pressure switches. The on-board opto-isolators keep 480 V switching transients from walking into the 5 V CPU data bus.
On utility-scale EX2000 static exciters the same card is used to buffer the brushless-exciter diode-fail contacts and the field ground-detector relay. Because the inputs are group-isolated, a shorted contactor coil will not drag down the entire digital I/O rack.
Frequently the same part number is used on mechanical-drive gas compressors to expand the count of inlet-guide-vane limit switches beyond the base CPU capacity. Its ability to mix dry contacts and analog millivolt signals on one card makes it a universal “I/O extender” for any Mark IV loop that needs more field points.
