GE DS3800NASB Mark V | New Surplus

Description

Product Introduction

The data sheet says 0 to +60 °C. The turbine control room says 65 °C and rising, because the A/C failed at 3 PM on a July afternoon in Texas. That’s when you need the GE DS3800NASB—the analog I/O board that keeps monitoring and controlling when standard boards start throwing errors from thermal drift, with built-in signal conditioning for specialized sensors and actuators.

This isn’t a standard analog I/O board. The “NAS” means high-speed analog I/O with signal conditioning and extended temperature range, and the “B” indicates a specific signal conditioning configuration. That’s a game-changer for applications where you need to interface with specialized sensors that require excitation, bridge completion, or custom filtering—or actuators that need specialized drive characteristics. You get 8 analog inputs with 16-bit resolution, 8 analog outputs with 16-bit resolution, field-configurable for 0–10 V or 4–20 mA, with ±0.1% accuracy and a 1 ms settling time, all rated for -40 to +85 °C ambient. The signal conditioning includes programmable excitation (5 V or 10 V), bridge completion, and programmable filtering for noise rejection. Each channel is optically isolated and rated for 2500 VAC, with built-in short-circuit protection and thermal shutdown. We tested one on a recent project in a Texas gas plant, monitoring a strain gauge pressure sensor and controlling a proportional valve in a cabinet that hit 72 °C—the signal conditioning kept the readings stable, and the valve responded precisely, surviving a lightning strike that fried the plant’s network switch.

Key Technical Specifications

Quality Inspection Process (SOP Transparency)

We treat these NASB boards like field artillery. They’re sensitive, expensive, and the plant stops when they fail. Here’s our full procedure.

Incoming Verification: First, we match the serial number against GE’s OEM packing slip. We run the anti-counterfeit check—GE’s hologram is iridescent, not flat; a UV light reveals a hidden “G.” We verify the “NASB” marking against the packing list. No match? Rejected immediately. We check for corrosion, repair marks (mismatched solder or flux residue), and yellowing around the ADC, DAC, and signal conditioning circuits. We photograph the board’s condition on arrival.

Live Functional Test: The board goes into our GE Mark V simulator rack, but we don’t stop at room temperature. We perform the functional test at three temperature points: -40 °C (in a thermal chamber), +25 °C (ambient), and +85 °C (thermal chamber). We test all 8 inputs and 8 outputs in voltage and current modes. For inputs: we connect a precision voltage/current calibrator (Fluke 754) to each input and sweep the full range in 10% steps—measuring the digital reading and calculating the error at each step and each temperature. We test the signal conditioning by programming excitation voltages and verifying the output on the excitation pins, and by applying signals through the bridge completion circuits and verifying the readings. We test the programmable filter by injecting noise at various frequencies and verifying the attenuation. For outputs: we connect a precision voltmeter/ammeter (Fluke 8846A) to each output and sweep the digital input from 0 to 100% in 10% steps—measuring the output and calculating the error. We test the settling time by step-changing the output and measuring the 0.1% settling time. We test the short-circuit protection by shorting each output and verifying the board trips and recovers correctly. Finally, a 24-hour thermal cycle: -40 °C to +85 °C ramp over 8 hours, running all inputs and outputs at 50% of range, logging temperature and accuracy every 15 minutes.

Electrical Parameters: We check insulation resistance between the backplane connector and chassis ground using a Fluke 1587 at 500 VDC. Must read >10 MΩ. Ground continuity: <0.1 Ω. We skip hi-pot—every time we’ve tried it on a Mark V board, the CMOS logic ended up with phantom latch-ups.

Firmware Verification: We read the firmware version via the serial port. Must match v.11.04 or v.11.05—we record it and photograph the DIP switches on SW1, SW2, and SW4. We keep a photo log of all jumper positions.

Final QC & Packaging: The board passes only if it meets all specs at all three temperature points. We bag it in an anti-static bag, seal it with a dated QC label, wrap it in 2-inch foam, and pack it into a double-wall carton. The QC Passed label includes the inspector’s initials, test date, and a QR code linking to test videos. Test photos available on request.

Field Replacement Pitfalls

This board has caught more than a few engineers off guard. Here’s what I’ve learned the hard way.

Signal Conditioning—Don’t Assume Defaults: The NASB has programmable excitation, bridge completion, and filtering—but you must configure them per channel. One plant replaced a failed NASB with a new one, assuming the signal conditioning would be downloaded from the CPU. The problem? The signal conditioning is stored on the board itself, not in the CPU. The new board had default settings (no excitation, no filtering), but the old board was configured for 10 V excitation and 100 Hz filtering. The strain gauge read zero, and the turbine tripped. ❗ Before installation, record the signal conditioning settings (excitation, bridge completion, filter cutoff) for each channel from the old board. These are not stored in the CPU—they must be re-entered on the new board.

Excitation Loading—Don’t Overload the Excitation Source: The NASB’s excitation outputs are rated for 50 mA max per channel. One plant connected a bridge that drew 80 mA—the excitation source overheated and shut down, and the sensor read zero. ❗ Check the excitation current draw of your sensor before connecting it. If it exceeds 50 mA, you need an external excitation source.

Input Mode vs. Output Mode—Don’t Confuse Them: The NASB has both inputs and outputs, but the mode (voltage/current) is configured per channel via jumpers—and inputs and outputs have different jumper settings. One plant replaced a failed NASB with a new one, assuming the mode settings would be downloaded from the CPU. The problem? The modes are set by jumpers on the board, not in the CPU. ❗ Before installation, verify the input and output mode jumpers match your application.

Output Load—Don’t Overload the Outputs: The NASB’s analog outputs are rated for 2 kΩ (voltage) and 0–500 Ω (current). One plant connected a 100 Ω load to a voltage output—the driver overheated and failed. ❗ Check the output load impedance before you power up.

Filter Cutoff—Don’t Filter Out Your Signal: The NASB has programmable filter cutoff (10 Hz, 100 Hz, 1 kHz). One plant set the filter to 10 Hz to reject noise, but the sensor signal was 50 Hz—the filter attenuated the signal by 90%. ❗ Set the filter cutoff to at least 2× the maximum signal frequency. Don’t filter out your actual signal.

Firmware Rev Mismatch—Calibration Lives in the EPROM: The DS3800NASB has a firmware chip (U22) that differs between revisions. One plant ordered a board with v.11.02 to replace a v.11.05 unit. The result? The ADC, DAC, and signal conditioning calibration constants were different. ❗ Always read the version label on the metal can before you order.

The DIP Switch Gauntlet: SW1 sets the board address. SW2 sets the input mode (voltage/current). SW3 sets the output mode (voltage/current). SW4 sets the signal conditioning mode (excitation/filtering). Take photos of the old board’s switches before you disconnect a single wire. ❗ And check those backplane termination resistors—120 Ω on the ends only, not every slot.

Connector Snag: That 96-pin DIN backplane connector is fragile. Hold it straight, push firmly. If you hear a crunch, stop.

Power Budget Creep: The DS3800NASB pulls about 18 W—the signal conditioning circuits draw extra current from the +15 V rail. Add 6 of these boards and you’re at 108 W. Calculate the total at your operating temperature.

ESD is Real: Wear the wrist strap and connect the board’s chassis ground to earth before you touch the backplane.

Get these five right and you’ll cut rework time by 90%.

New Original vs. Refurbished: Why It Matters

I’m not here to scare you. I’m here to save you a phone call at 3 AM.

“New Original (New Surplus)” means GE made this board for a specific batch. The gold on the backplane contacts is untouched. The ADCs and DACs have never seen a signal or a load. The signal conditioning circuits are factory-verified. The calibration constants are factory-set. The extended-temperature components are factory-verified.

Refurbished Risk—Signal Conditioning Calibration and Temperature Compensation Are Compromised: Refurbishers often don’t test the NASB’s signal conditioning circuits under load or at temperature extremes—they’ll check a static input and output at room temperature, see a reading, and call it good. But the excitation regulation, bridge completion accuracy, filter response, and temperature compensation are rarely tested. The failure rate on refurbished signal conditioning analog I/O boards is typically 3–5x higher than new.

Our Proof: We include a photo of the OEM packing slip, the serial number traceable to GE’s production lot, and a 4-page test report (including full-scale input and output accuracy verification at -40 °C, +25 °C, and +85 °C, signal conditioning testing, excitation load testing, filter response testing, settling time measurement, output load testing, short-circuit protection testing, and thermal cycle data).

Performance Benchmarks & Test Results

We ran a DS3800NASB through our full test cycle. Conditions: three temperature points (-40 °C, +25 °C, +85 °C), +5.01 VDC supply, firmware v.11.05.

• Input Accuracy (Voltage) (-40 °C): Swept 0–10 V. Max error: ±0.1% of full scale.
• Input Accuracy (Voltage) (+25 °C): Max error: ±0.05% of full scale.
• Input Accuracy (Voltage) (+85 °C): Max error: ±0.1% of full scale.
• Output Accuracy (Voltage) (-40 °C): Swept 0–10 V. Max error: ±0.1% of full scale.
• Output Accuracy (Voltage) (+25 °C): Max error: ±0.05% of full scale.
• Output Accuracy (Voltage) (+85 °C): Max error: ±0.1% of full scale.
• Excitation Accuracy: Programmed 5 V and 10 V—measured voltage within ±0.1% of programmed value.
• Excitation Load Test: Loaded each excitation output to 50 mA—voltage regulation held within ±0.2%.
• Filter Response: Programmed 10 Hz, 100 Hz, and 1 kHz filters—measured cutoff frequency within ±5% of programmed value.
• Bridge Completion Test: Completed bridge circuits accurately—readings matched expected values within ±0.1%.
• Settling Time: Step change—settled to 0.1% of final value in 0.8 ms typical.
• Short-Circuit Protection: Shorted each output—board tripped within 10 ms and recovered.
• Thermal Cycle: 24-hour cycle from -40 °C to +85 °C. Input and output error remained within ±0.1% at all points. Excitation and filter response remained stable.
• Estimated MTBF: Based on MIL-HDBK-217F (ground benign, 40 °C), we calculate approximately 26,000 hours—about 3.0 years. The signal conditioning circuits, ADCs, DACs, and extended-temperature components are the limiting factors.

ABB XVC517AE02 3BHB004744R0002
TRICONEX 3625A
MOOG D136-001-007