DS3800XTBA1B1B | New Surplus GE Speedtronic Part

Description

Product Introduction

The DS3800XTBA1B1B is the ruggedized variant of GE’s 2-wire RTD input board. That “B” at the end (not to be confused with the first “B” which indicates 2-wire) tells you this board has a thick epoxy conformal coating—not the standard acrylic “A” coating, but a heavier layer designed for salt spray, chemical vapor, and extreme humidity. The first “B” in the suffix (“1B1B”) confirms the 2-wire Pt100 configuration. Combined, this is the board you spec for coastal plants, offshore platforms, or chemical processing facilities where corrosion resistance is critical.

The board shares the same electrical architecture as the XTBA1B1A—8 channels of 2-wire Pt100 measurement, 1mA excitation current, 16-bit resolution. The difference is purely environmental: the epoxy coating covers both sides of the PCB with a thicker, more durable layer that stands up to salt fog and aggressive atmospheres. The trade-off is that the coating traps slightly more heat, so the board runs about 2-3°C warmer at full load—still within the 0-60°C operating range, but something to note if your cabinet is already marginal. Typical buyers are plant engineers in marine environments or heavy industrial settings where standard boards corrode within a few years.

Key Technical Specifications

Compatible Replacement Models

Frequently Asked Questions (FAQ)

Q: Can I hot-swap this board?

No. The Mark VIe backplane does not support live insertion for RTD input boards. Power down the entire I/O pack before removal. The thick coating doesn’t change this—it’s a backplane limitation. We’ve seen field engineers try and take out the excitation current source on the replacement board.

Q: How is the “B” coating different from the “A” coating?

On GE’s conformal coating scale for RTD boards:

• “A” (or no suffix): No coating or standard acrylic (depending on revision).
• “B”: Thick epoxy coating. More durable, better salt spray resistance, but runs slightly warmer.

The epoxy coating is applied to both sides of the PCB and is typically 75-100µm thick (versus 25-35µm for acrylic). It’s designed to meet MIL-I-46058C standards for salt fog and humidity resistance. If your cabinet is in a corrosive environment, this is the coating you want. In a clean, dry cabinet, it’s overkill.

Q: Can I use 3-wire RTDs with this board?

No. This board is 2-wire only. If you connect a 3-wire sensor, the third lead will be unused, and you’ll lose the lead resistance cancellation that 3-wire provides. You could wire it as 2-wire, but the lead resistance will add to the measurement. If you have 3-wire sensors, you need the standard XTBA (3-wire version).

Q: What’s the trade-off with 2-wire RTDs and the epoxy coating?

Two things to consider:

• Lead resistance error: The 2-wire configuration means lead resistance adds directly to the RTD reading. Keep cable runs short (<10 meters) or calibrate out the offset. Every 1Ω of lead resistance adds about 0.4°C of error.
• Heat trapping: The epoxy coating insulates the components, making them run about 2-3°C warmer at full load. If your cabinet is already near 60°C, this could push the board closer to its thermal limit.

If both of those trade-offs work for your installation, this board is a solid choice for harsh environments.

Q: How do you test this board before shipping?

We run a 7-step test with precision decade resistance boxes and extra attention to the coating:

• Visual inspection: Check for cracked connectors, burnt traces, swollen capacitors. Verify the epoxy coating is uniform, free of bubbles, and covers all components.
• ESD check: Insulation resistance between channels and chassis ground >10MΩ.
• Power-up: Apply +5V DC, measure current draw (1.2A ±10%).
• Communication handshake: Simulate backplane connection, verify board ID.
• Excitation verification: Measure the 1mA excitation current on each channel—must be within ±1%.
• RTD simulation: Connect a precision decade box to each channel and simulate 0°C (100Ω), 100°C (138.5Ω), and 200°C (175.8Ω). Verify accuracy within ±0.1% of reading ±0.5°C. The coating adds no electrical error, but we check thermal drift.
• 24-hour soak: Run at 50°C ambient with all channels at 100Ω. Log drift—failure threshold is ±0.5°C deviation. The epoxy coating means we also monitor temperature to ensure it doesn’t exceed 75°C.

We reject about 5% of these boards—typically due to coating defects (bubbles or voids) that can trap moisture over time.

Q: What’s the most common failure on this board?

Three things, with the coating adding a fourth:

• Excitation current drift: The 1mA current sources drift over time. We replace reference resistors on about 15% of refurbished units.
• Coating delamination: If the epoxy coating isn’t applied correctly, it can separate from the PCB over time, especially with thermal cycling. We check for this during visual inspection.
• Input protection diode burnout: Field wiring faults can short the protection diodes. The board still works but is unprotected.
• Connector corrosion: The 37-pin D-Sub pins can corrode on the field side, especially in salt spray environments. Clean them regularly.

Q: What’s the lead time?

We typically carry 2-3 units. Orders before 2 PM EST ship within 1-2 business days after testing. The 24-hour soak is mandatory—we won’t skip it.

Q: Are there counterfeit versions of this board?

Yes. Look for:

• Coating quality: Genuine epoxy coating is thick, uniform, and slightly yellowish. Fakes use thinner coatings that are clear or uneven.
• Reference resistors: Genuine boards use 0.1% precision resistors. Counterfeits use 1% resistors—the excitation current drifts with temperature.
• Label: Genuine—matte finish, greenish barcode. Fakes—glossy.

We trace stock to decommissioned assets. Demand photos of the component side and serial sticker.

Q: What’s your warranty?

1-year against functional defects. For coated boards, if the coating fails (delamination, cracking) within the warranty period and hasn’t been physically damaged, we’ll replace it.

GE IC698CPE030
ABB IMHSS03
ABB UNITROL 1010
SIEMENS 6DD1661-0AD1