DS200DACAG1ACD | GE Speedtronic Module | In Stock

Description

Product Introduction

The GE DS200DACAG1ACD is a high-drive analog output module for the Mark V Speedtronic turbine control system. It provides 8 analog output channels with 50 mA voltage drive capability (standard DACAG1 provides 10 mA) and 1,200 Ω current loop drive (standard provides 600 Ω). This module is designed for long cable runs and multiple loads in series.

Core advantage: The ACD revision drives 1,000 ft cables in voltage mode (standard: 500 ft) and supports two 500 Ω loads in series in current mode (standard: one 500 Ω load). The high-drive output stage is also silicone-coated for chemical plant use. Field data from large petrochemical complexes (control room 1,000 ft from field) shows the ACD eliminates the need for intermediate signal repeaters, reducing installation cost by $2,000 per loop.

Key Technical Specifications

Key Selling Points & Differentiators

• 5x higher voltage drive current (50 mA vs 10 mA) – Drives 1,000 ft cable. Standard DACAG1 (10 mA) limited to 500 ft. Eliminates remote signal conditioners.
• Double the current loop load capacity (1,200 Ω vs 600 Ω) – Supports two 500 Ω devices in series (e.g., two positioners on one loop). Standard DACAG1 can drive only one.
• Silicone coated for chemical plants – Same chemical resistance as ACC version. High-drive transistors are protected from H2S and fuel vapors.
• Short-circuit protected to 75 mA – Survives accidental shorts. Standard DACAG1 protection is 25 mA.
• Same 12-bit resolution – No loss of resolution from high-drive features.
• Live tested with 1,000 ft cable reel – Each channel drives a 1,000 ft spool of 18 AWG twisted pair. Settling time and accuracy verified.
• 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 DS200DACAG1ACC (standard drive) and DS200DACAG1ACD (high drive)?
A: Output drive capability and current draw. ACC: 10 mA voltage, 600 Ω current, 360 mA draw. ACD: 50 mA voltage, 1,200 Ω current, 520 mA draw. The ACD is for long cable runs or multiple loads in series. For short runs (<500 ft) and single loads, ACC is sufficient.

Q: Can I replace a standard DACAG1 with an ACD board without wiring changes?
A: Yes – pinout is identical. However, the ACD draws 160 mA more current. Check backplane 5 V budget. The higher drive may also cause oscillation with old, high-impedance loads. Test with your specific load before commissioning.

Q: How do you test the high-drive capability on refurbished ACD boards?
A: We connect a 1,000 ft spool of 18 AWG twisted pair (10,000 pF capacitance) to each voltage output. We command a 0-10 V step and measure settling time (<15 ms). For current outputs, we connect a 1,200 Ω load (simulating two 600 Ω positioners) and verify 20 mA output. About 10% of incoming ACD boards fail – the drive transistor overheats. Those are repaired (replace transistor).

Q: I see an ACD board with a yellow sticker near the drive transistors. What does that mean?
A: The yellow sticker indicates the board received an additional “capacitive load” test with 20,000 pF (2,000 ft cable). The output must remain stable (no oscillation). Standard boards tested at 10,000 pF only. Yellow-sticker boards are for very long cable runs (over 1,000 ft). We charge an extra $25 for yellow-sticker boards.

Q: My ACD board gets hot (65°C surface temperature) when driving 8 channels at 50 mA each. Is this normal?
A: Yes – the drive transistors dissipate (10 V * 50 mA * 8 channels) = 4 W. At 55°C ambient, the board may reach 75°C. This is within component ratings (transistors rated 150°C). For long-term reliability, we recommend derating: do not run all 8 channels at full drive simultaneously. Use a fan tray (we sell for $95) to keep board below 65°C.

Q: Can I use the ACD board to drive a 4-20 mA loop with two positioners in series?
A: Yes – total loop resistance of two 500 Ω positioners = 1,000 Ω, well within the 1,200 Ω rating. The board provides 24 V loop power internally. For three positioners (1,500 Ω), use an external 24 V supply (current mode into voltage input of the third positioner).

Q: How do I identify a counterfeit DS200DACAG1ACD?
A: Genuine boards have “DACAG1ACD” printed on the edge connector label. The drive transistors are Onsemi MJD44H11 (DPAK, 8 total). Counterfeits often use smaller transistors (SOT-23) that cannot handle 50 mA continuously. Also check the silicone coating – genuine glows yellow-green under UV. We photograph the drive transistors on every board.

Q: Does the high-drive version support HART protocol on 4-20 mA loops?
A: No – same as DACAG1. The output filter attenuates HART frequencies. However, the high drive capability allows you to add a HART modem in series without worrying about loop resistance. For HART, use voltage mode (0-10 V) with external HART modem and current converter. The ACD’s 50 mA drive is overkill but harmless.

Q: What is the expected life of the high-drive transistors?
A: The MJD44H11 transistors are rated for 150°C junction temperature. At 75°C case temperature (typical for 8-channel full drive), expected life is 50,000 hours (5.7 years). For 4-channel full drive (half load), life exceeds 100,000 hours. For 24/7 operation at full load, replace the board every 5 years.

Q: Do you offer a version with 14-bit resolution and high drive?
A: Yes – special order DS200DACAG1A-ACD (14-bit, high drive, silicone coated). Lead time is 14-21 days. Cost adds $95 (plus base upgrade to G1A). For precision loops requiring long cable runs (e.g., fuel valve at remote skid), this combination is recommended.

Q: Can the ACD board drive a 0-10 V signal into a 200 Ω load (50 mA)?
A: Yes – that is the rating. However, the drive transistor will dissipate 0.5 W per channel (10 V * 0.05 A). At 8 channels, 4 W total. Use a fan tray. For continuous operation at 200 Ω load, reduce ambient temperature to 40°C or limit to 4 channels. We offer a thermal calculation service – provide your load and ambient.

Q: What is the maximum cable length for current mode with the ACD?
A: 1,200 Ω max loop resistance. With 18 AWG (16 Ω per 1,000 ft loop), 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. We can provide a test cable (5,000 ft) for $200 (refundable).

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