Description
DS3800DEPB1A1A: Product Overview
This board occupies a 6BA Euro-card slot in GE Mark IV turbine and EX2000 exciter control racks, serving as the final protection layer for safety-critical events. It accepts high-integrity digital inputs from overspeed bolts, vibration trip switches, emergency stop buttons, and fire detection systems, executes hardware-level trip logic in <5 ms independent of the main CPU, and drives dedicated trip outputs to fuel valves and breaker coils. The “DEPB” designation indicates digital/event/protection buffer functionality, while the A1A revision represents the initial production release with full C-ESS essential-service qualification.
This board occupies a 6BA Euro-card slot in GE Mark IV turbine and EX2000 exciter control racks, serving as the final protection layer for safety-critical events. It accepts high-integrity digital inputs from overspeed bolts, vibration trip switches, emergency stop buttons, and fire detection systems, executes hardware-level trip logic in <5 ms independent of the main CPU, and drives dedicated trip outputs to fuel valves and breaker coils. The “DEPB” designation indicates digital/event/protection buffer functionality, while the A1A revision represents the initial production release with full C-ESS essential-service qualification.
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.
DS3800NFDB1A1A
DS3800DEPB1A1A: Technical Specifications
-
Model Number: DS3800DEPB1A1A
-
Manufacturer: General Electric (GE Fanuc)
-
Product Type: Digital Event Protection Buffer / Critical Input Board
-
Series: DS3800, Mark IV Speedtronic
-
Form Factor: 6BA Euro-card (≈ 233 × 160 mm)
-
Qualification: C-ESS (essential-service qualified)
-
Back-Plane Connector: Dual 40-pin header (J1/J2)
-
Input Channels: 8 high-integrity (2-out-of-3 voting per channel)
-
Input Type: Dry contact or 24 Vdc (redundant sensing)
-
Hardware Trip Logic: <5 ms response (independent of CPU)
-
Trip Outputs: 4 Form-C relays, 10 A @ 250 Vac/Vdc
-
Isolation: 2500 Vdc field-to-logic; 1500 Vdc between channels
-
Self-Test: Automatic channel health monitoring
-
Power Demand: +5 V @ 1.0 A, +24 V @ 0.8 A from rack 2PL bus
-
Operating Temperature: 0 – 60 °C
-
Weight: ≈ 0.32 kg
-
Construction: Epoxy-sealed copper traces—non-repairable
Core Features & Customer Value
Hardware-Independent Trip Logic: The on-board FPGA executes trip decisions in <5 ms without CPU involvement. For protection engineers, this provides deterministic response even during CPU overload or communication loss—meeting SIL 2/3 requirements for overspeed and vibration protection that software-only solutions cannot guarantee.
2-out-of-3 Voting Architecture: Each channel uses triple-redundant sensing with majority voting. For safety-critical applications, this eliminates single-point failures from sensor wiring or contact degradation—a spurious trip requires two simultaneous channel failures, while a missed trip requires two simultaneous sensor failures.
C-ESS Essential-Service Qualification: The A1A carries full extended testing for thermal cycling, surge withstand, and seismic qualification. For plant owners, this satisfies insurance and regulatory requirements for primary protection systems, avoiding costly third-party safety certification for custom solutions.
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 compromise protection integrity 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.
DS3800NFDB1A1A
Typical Applications
In combined-cycle power plants, this board installs in the Mark IV turbine control core as the final overspeed protection layer. It monitors three independent magnetic pickups and two mechanical overspeed bolts, voting the inputs to trip main and reheat fuel valves within 50 ms of detected overspeed—faster than software-based protection can respond.
On utility-scale EX2000 static exciters, the same card provides emergency field suppression on detection of diode-fail cascade or field ground fault. The hardware trip bypasses normal control sequencing, forcing immediate de-excitation to prevent generator damage.
Mechanical-drive gas compressors use this part number for emergency shutdown on high vibration or surge detection. The <5 ms response time is critical here—compressor rotors can traverse damaging speeds in 100 ms during surge events, making software-only protection inadequate.
