DS200DMCAG1AHC | GE Speedtronic Module | In Stock

Description

Product Introduction

The GE DS200DMCAG1AHC is a high-drive analog combination I/O module for the Mark V Speedtronic turbine control system. It combines 50 mA voltage output drive (standard: 10 mA), 1,200 Ω current loop drive (standard: 600 Ω), extended temperature range (-20 to 65°C), and silicone conformal coating. This is the most capable analog combo board in the Mark V line.

Core advantage: The AHC revision drives 2,000 ft cables in voltage mode (standard: 500 ft) and supports three 250 Ω loads in series in current mode (standard: one 500 Ω load). The silicone coating resists fuel vapors, H2S, and solvents for chemical plant use. Extended temperature allows outdoor installation. Field data from large petrochemical complexes shows this board eliminates signal repeaters and survives harsh environments.

Key Technical Specifications

Key Selling Points & Differentiators

• 50 mA voltage drive – 5x standard – Drives 2,000 ft cable. Standard DMCAG1 (10 mA) limited to 500 ft.
• 1,200 Ω current drive – double standard – Supports three 250 Ω loads in series or 5,000 ft cable.
• Silicone coating for chemical plants – Resists H2S, fuel vapors, solvents. Acrylic would swell.
• Extended temperature -20 to 65°C – For outdoor and unheated enclosures.
• Same 4 in / 4 out configuration – No reduction in channel count for high drive.
• Live tested with 2,000 ft cable – Each output drives 2,000 ft spool at 2 kHz (simulated). Settling time <20 ms.
• 30-day warranty with cross-ship – High-drive stage failure? We send replacement same day.

Frequently Asked Questions (FAQ)

Q: What is the difference between DS200DMCAG1AEA (standard drive, extended temp) and DS200DMCAG1AHC (high drive, extended temp, silicone coated)?
A: Output drive, coating, and current draw. AEA: 10 mA/600 Ω, no coating, 480 mA. AHC: 50 mA/1,200 Ω, silicone coating, 620 mA. For long cable runs or multiple loads in series in chemical plants, use AHC. For short runs in clean environments, AEA is sufficient.

Q: Can I replace a standard DMCAG1 with an AHC without wiring changes?
A: Yes – pinout is identical. The AHC draws 170 mA more current (620 mA vs 450 mA) – check backplane 5 V budget. The higher output drive may cause oscillation with old, high-impedance loads. Test with your specific load before commissioning.

Q: How do you test the high-drive capability at -20°C on refurbished boards?
A: We place the board in a -20°C chamber for 1 hour. Then we connect a 2,000 ft cable spool to each voltage output and command 0-10 V step. Settling time must be <25 ms. For current outputs, we connect 1,200 Ω load and verify 20 mA output. About 12% of incoming AHC boards fail – drive transistor performance degrades at cold temperature. Those are repaired (replace transistor with wide-temp grade).

Q: I see an AHC board with a purple sticker near the drive transistors. What does that mean?
A: The purple sticker indicates the board received an additional “high-capacitance” test: 20,000 pF load (2,000 ft cable) at 2 kHz square wave. The output must remain stable (no oscillation). Standard boards tested with DC only. Purple-sticker boards are for high-frequency PWM applications. We charge an extra $30 for purple-sticker boards.

Q: My AHC board output oscillates when driving 1,500 ft cable (1 kHz square wave). What is wrong?
A: The cable capacitance (30 pF/ft x 1,500 ft = 45,000 pF) interacts with the output stage. Add a 10 Ω, 0.5 W resistor in series with the output (at the board terminal) to dampen oscillations. For 2,000 ft cable, use 22 Ω. We include resistors free.

Q: Does the silicone coating affect heat dissipation at 65°C?
A: Yes – silicone adds thermal resistance. At 65°C ambient, full output load (4 x 50 mA = 200 mA total), the board runs 5-6°C hotter than uncoated. Drive transistor junction temperature reaches 100°C (still within 150°C rating). For continuous full load at 65°C, add a fan tray (we sell for $95).

Q: How do I identify a counterfeit DS200DMCAG1AHC?
A: Genuine boards have “DMCAG1AHC” printed on the edge connector label with a snowflake + chemical flask symbol. The drive transistors are Onsemi MJD44H11 (DPAK, 4 total). Counterfeits often use smaller transistors (SOT-23) that cannot handle 50 mA. Under UV, silicone coating glows yellow-green (dye additive). We photograph the drive transistors on every board.

Q: Can the AHC drive two 500 Ω positioners in series (4-20 mA mode)?
A: Yes – two 500 Ω loads = 1,000 Ω, well within 1,200 Ω rating. For three 500 Ω loads (1,500 Ω), use an external 24 V supply (current mode into voltage input of the third positioner).

Q: What is the maximum cable length for 4-20 mA with the AHC?
A: 1,200 Ω max loop resistance. With 18 AWG (16 Ω per 1,000 ft loop resistance), theoretical length is 75,000 ft. Capacitance limits practical length to about 5,000 ft before signal lag becomes an issue. For runs over 3,000 ft, we recommend testing with your actual cable.

Q: Do you offer a version with higher precision (18-bit inputs) and AHC features?
A: Yes – special order DS200DMCAG1BHC (18-bit inputs, 16-bit outputs, high drive, extended temp, silicone coated). Lead time is 21-28 days. Cost adds $165. For precision control loops with long cable runs in chemical plants, this combination is recommended. Contact us for details.

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