Description
DS3800NCIA1B1C Product Overview
The DS3800NCIA1B1C is a current-isolator interface board that plugs into GE Mark IV turbine and EX2000 exciter control racks. Occupying a 6BA05 Euro-card slot, it acts as the analog “front end” between field transducers and the 5 V CPU: it accepts 4–20 mA or ±10 mA current-loop signals, provides 1500 Vdc group isolation, buffers the result to the NDIA data bus, and clamps incoming surges with on-board MOVs. 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 DS3800NCIA1B1C is a current-isolator interface board that plugs into GE Mark IV turbine and EX2000 exciter control racks. Occupying a 6BA05 Euro-card slot, it acts as the analog “front end” between field transducers and the 5 V CPU: it accepts 4–20 mA or ±10 mA current-loop signals, provides 1500 Vdc group isolation, buffers the result to the NDIA data bus, and clamps incoming surges with on-board MOVs. 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 DS3800HMPJ1A1D
DS3800NCIA1B1C Technical Specifications
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Model Number: DS3800NCIA1B1C
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Manufacturer: General Electric (GE Fanuc)
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Product Type: Current Isolator / Analog I/O Interface Board
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Series: DS3800, Mark IV Speedtronic
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Form Factor: 6BA05 Euro-card (≈ 233 × 160 mm)
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Assembly Code: C-ESS (essential-service qualified)
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Input Range: 4–20 mA or ±10 mA current loop (jumper-selectable)
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Isolation: 1500 Vdc channel-to-ground; group-isolated
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Update Rate: 2 ms (scanned by CPU every control interval)
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Surge Protection: 40 mm MOVs, integral with board traces
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Operating Temperature: 0 – 60 °C
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Weight: ≈ 0.25 kg (0.55 lb)
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Construction: Epoxy-sealed copper traces—non-repairable
Core Features & Customer Value
Current-Loop Isolation: The on-board isolation amplifiers accept 4–20 mA or ±10 mA on the same terminal strip. For the control engineer this eliminates external signal conditioners and ground-loop errors, reducing wiring complexity and spare-part count.
Epoxy-Sealed Construction: All internal copper is encapsulated in high-temperature epoxy. In coastal or industrial sites with conductive dust and high humidity the seal prevents trace-to-trace shorting that would otherwise cause random “CURRENT LOOP 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.
C-ESS Assembly Qualification: The board carries the C-ESS code, indicating it is qualified for essential-service applications. For the owner this means the card has passed extended thermal-cycle and surge testing, giving confidence that it will survive decades of daily start/stop duty without degradation.
GE DS3800HMPJ1A1D
Typical Applications
In combined-cycle power plants the board is installed in the Mark IV exciter cubicle where it isolates the generator field-current transmitter (4–20 mA) and the brushless-exciter diode-fail monitor. During load changes the card presents an isolated current signal to the CPU so the voltage-regulation loop remains stable even when the utility grid experiences transients.
On utility-scale EX2000 static exciters the same card is used to isolate the exciter armature-current loop and the field ground-detector analog output. Because the inputs are group-isolated, a shorted transducer will not drag down the entire analog I/O rack.
Frequently the same part number is used on mechanical-drive gas compressors to land the 4–20 mA inlet-pressure transmitter and the ±10 mA guide-vane position feedback. Its ability to mix current-loop and low-level voltage signals on one card makes it a universal “current isolator” for any Mark IV loop that needs deterministic, ground-loop-free operation.
