DS200SHCAG1 | GE Mark V Servo Hydraulic Card

Description

Product Introduction

The DS200SHCAG1 is a servo hydraulic amplifier interface board for GE’s Mark V DS200 series, used in Speedtronic turbine control systems. It converts the ±10 VDC output from an SDCC servo controller into a 0–200 mA current output to drive electro-hydraulic servo valves directly.

This board sits between the servo controller (SDCC) and the hydraulic valve. Standard SDCC outputs are limited to ±10 VDC at 10 mA—insufficient for many torque motor valves that require 40–200 mA. The SHCAG1 amplifies the voltage signal to a proportional current, providing up to 200 mA into valve coils (20Ω minimum load). Use it for retrofits where the existing valve requires higher current than the SDCC can provide.

Key Technical Specifications

Key Selling Points & Differentiators

• 0–200 mA output – Drives torque motor valves requiring 40–200 mA directly. Standard SDCC outputs only 10 mA.
• Adjustable gain (5–200 mA per 10 V input) – Match valve sensitivity. No external signal conditioner needed.
• Adjustable offset (null) calibration – Zero valve drift at 0 V input. Potentiometer accessible with board installed.
• Built-in dither – Prevents valve stiction. Frequency and amplitude adjustable. Many older valves require dither for reliable operation.
• Short-circuit and thermal protection – Output folds back on short (<250 mA limit). Thermal shutdown at 85°C.
• Feedback monitor output – ±10 VDC proportional to output current. Connect to SDCC’s feedback input for closed-loop current control.
• Isolated input – 1500 VAC between SDCC input and valve output. Prevents ground loops.
• QC includes 200 mA burn-in for 24 hours – Verified into 20Ω load at +65°C ambient.
• 2-year warranty

Frequently Asked Questions (FAQ)

Q: What is the difference between SDCC (servo controller), SDCIG (interface), and SHCAG1 (hydraulic amplifier)?

Use SHCAG1 when your hydraulic valve requires >20 mA coil current.

Q: What type of servo valves does the SHCAG1 drive?
A: Torque motor valves (Moog, Vickers, Bosch-Rexroth) with coil resistance 20–100Ω and current requirement 40–200 mA. Examples: Moog D63x series (40–100 mA), Vickers SM4 series (50–150 mA), older GE valves (100–200 mA). Check valve datasheet for “coil current” or “drive current.”

Q: How do I set the dither frequency and amplitude?
A: Two potentiometers on the board. Frequency: 100–400 Hz (turn clockwise for higher frequency). Amplitude: 0–20% of output current (turn clockwise for higher dither). Default: 200 Hz, 10%. For valves with high stiction (old, worn), increase amplitude to 15–20%. For low-friction valves, reduce to 5%. Oscilloscope recommended for tuning.

Q: Does the SHCAG1 require an external 24 VDC power supply?
A: Yes—the board draws up to 2 A at 24 VDC (200 mA output into 20Ω = 4 V drop; rest dissipated as heat). Backplane 24 VDC is typically limited to 1 A in Mark V racks. Use external 24 VDC supply (2 A minimum, 5 A recommended). We sell power supply kit ACC-PS-24V-5A.

Q: What is the minimum load resistance?
A: 20Ω. Below 20Ω, output current will not reach 200 mA (voltage compliance limit). Example: 10Ω load at 200 mA requires 2 V output—the board supplies 24 V, so current will be limited by the load. Check your valve coil resistance. If R < 20Ω, add external series resistor.

Q: How do I calibrate the output?
A: Apply 0 V input. Adjust offset potentiometer until output current reads 0 mA (or midpoint if valve requires bias). Apply 10 V input. Adjust gain potentiometer until output reads desired full-scale current (e.g., 200 mA). Repeat. Procedure in included guide.

Q: What QC tests are specific to the SHCAG1?
A: Nine tests:

1. Input impedance: 10 kΩ ±5%
2. Output linearity: 0–200 mA in 20 mA steps, error <±0.5% of span
3. Offset adjustment range: ±5 mA
4. Gain adjustment range: 5–200 mA per 10 V input
5. Dither frequency: 100–400 Hz (adjustable)
6. Dither amplitude: 0–20% of output
7. Short-circuit test: Output folds back to <250 mA
8. Thermal shutdown: 85°C ±5°C
9. Burn-in: 72 hours at +65°C, output at 200 mA into 20Ω load

Q: What shipping protection?
A: Anti-static bag, ESD foam cradle, double-wall box with “ESD SENSITIVE,” “FRAGILE” labels. Each board ships individually. Potentiometer adjustment tool included. Configuration guide included. Spare fuses in separate bag. External power supply not included—order separately

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