Description
DS3800HARA1B1C Product Overview
The DS3800HARA1B1C is a high-speed analog reference board that plugs into GE Mark IV turbine and EX2000 exciter control racks. Occupying a 6BA Euro-card slot, it acts as a precision analog “front end”: it buffers set-point commands from the CPU, scales feedback signals from field transducers, and provides 1500 Vdc isolation between the 5 V logic and the 480 V class power electronics. Because all copper traces are fully encapsulated in high-temperature epoxy, the unit is treated as a line-replaceable 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 low-profile epoxy package allows adjacent-slot population without additional cooling.
The DS3800HARA1B1C is a high-speed analog reference board that plugs into GE Mark IV turbine and EX2000 exciter control racks. Occupying a 6BA Euro-card slot, it acts as a precision analog “front end”: it buffers set-point commands from the CPU, scales feedback signals from field transducers, and provides 1500 Vdc isolation between the 5 V logic and the 480 V class power electronics. Because all copper traces are fully encapsulated in high-temperature epoxy, the unit is treated as a line-replaceable 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 low-profile epoxy package allows adjacent-slot population without additional cooling.
GE DS3800HARA1B1C
DS3800HARA1B1C Technical Specifications
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Model Number: DS3800HARA1B1C
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Manufacturer: General Electric (GE Fanuc)
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Product Type: High-Speed Analog Reference / Auxiliary Buffer 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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Analog Range: ±10 V or 4–20 mA (jumper-selectable input/output)
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Isolation: 1500 Vdc channel-to-ground; group-isolated
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Update Rate: 2 ms (synchronized to CPU scan)
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Accuracy: ±0.1 % of full-scale (typical)
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Power Demand: +5 V @ 0.8 A, ±15 V @ 0.2 A from rack 2PL bus
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Operating Temperature: 0 – 60 °C
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Weight: ≈ 0.22 kg
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Construction: Epoxy-sealed copper traces—non-repairable
Core Features & Customer Value
Precision Analog Buffering: The on-board instrumentation amplifiers maintain ±0.1 % accuracy across the full temperature range, ensuring the fuel-valve set-point or exciter voltage reference remains stable even during rapid load changes. For the control engineer this means tighter regulation and reduced overshoot that would otherwise stress mechanical components.
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 “ANALOG REF 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.
High-Speed Update Synchronization: The 2 ms update rate is phase-locked to the CPU scan, eliminating beat-frequency errors that would otherwise occur with free-running sample rates. This guarantees the analog output changes smoothly between control intervals, preventing step-discontinuities in valve position or exciter field current.
GE DS3800HARA1B1C
Typical Applications
In combined-cycle power plants the board is installed in the Mark IV turbine control core where it buffers the fuel-valve position set-point and scales the LVDT feedback signal. During load changes the card provides a smooth, continuous analog reference that prevents valve dither and extends actuator life.
On utility-scale EX2000 static exciters the same card is used to buffer the generator voltage set-point and scale the field-current feedback. Because the isolation is group-based, a shorted field rheostat will not corrupt the CPU’s analog reference bus.
Frequently the same part number is used on mechanical-drive gas compressors to buffer the inlet-guide-vane position command and scale the vane-angle LVDT. Its ability to mix set-point buffering with feedback scaling on one card makes it a universal “analog front-end” for any Mark IV loop that needs precision, ground-loop-free operation.
