IS200VSVAH1A | Mark VIe Servo Valve Controller | New Surplus

Description

Product Introduction

The GE IS200VSVAH1A is a VMEbus servo valve driver board from the Mark VIe Speedtronic series, purpose-built for direct control of electro-hydraulic servo valves in turbine applications. Unlike command-only servo boards, this module includes integral power drive stages that provide the current output directly to valve coils—eliminating the need for external servo amplifiers. It interfaces with standard proportional servo valves (such as Moog, Rexroth, and Parker models) to position steam inlet valves, extraction valves, and other critical control elements.

What sets the H1A revision apart is its integrated power driver stages with current feedback and short-circuit protection, combined with 12-bit resolution for smooth, precise valve positioning. The board features two independent channels, each capable of delivering up to 100 mA of current output (with configurable dither) to drive a wide range of servo valve types. Built-in diagnostics include coil open-circuit detection, short-circuit monitoring, and current limit protection. For system integrators requiring a compact, all-in-one valve driver solution without the cost and complexity of separate amplifiers, this board is the direct OEM solution.

Key Technical Specifications

Key Selling Points & Differentiators

• Integrated Power Drivers: Directly drives servo valve coils without external amplifiers—saves cabinet space, reduces wiring, and simplifies commissioning.
• Dual Independent Channels: Two channels with separate current outputs, feedback inputs, and characterization curves—ideal for redundant valve configurations or paired actuators.
• Built-In Current Feedback: Closed-loop current control ensures accurate, repeatable valve positioning regardless of coil temperature changes or cable resistance variations.
• Comprehensive Valve Characterization: 9-point user-programmable curve per channel allows precise matching to non-linear valve response characteristics.
• Robust Protection: Short-circuit, open-coil, and over-temperature detection with automatic shutdown and fault reporting prevents damage to valve coils and the board.
• Live Test Verified: Every board undergoes a 48-hour burn-in with both channels driving simulated valve coil loads across the full current range. We log output accuracy, dither response, diagnostic thresholds, and temperature rise.
• 90-Day Warranty: Covers functional defects. If it fails under normal operating conditions, we replace it. No restocking fee for verified returns.
• OEM Traceability: All units come from audited surplus channels with original GE anti-static bags and serialized labels. No clones, no pull-and-refurbish from unknown sources.
• Configuration Backup Service (Free): Upon request, we extract and archive your existing board’s firmware version, valve characterization curves, and configuration before shipment.

Frequently Asked Questions (FAQ)

Q: What is the difference between IS200VSVAH1A and IS200VSCAH2A?

A: The VSVA includes integral current drivers that directly power servo valve coils—no external amplifier required. The VSCA generates ±10 V or 4–20 mA command signals only, requiring an external servo amplifier. Choose VSVA for direct coil driving where cabinet space is limited; choose VSCA for applications where you need separate amplifiers (for higher power coils, redundancy, or when interfacing with existing amplifier cabinets).

Q: What is the difference between IS200VSPAH1A and IS200VSVAH1A?

A: The VSPA provides command signals only (voltage or current loop) and requires an external amplifier. The VSVA includes integrated power drivers and provides current output directly to the servo valve coil. The VSPA offers higher feedback resolution (16-bit) and faster loop rates (500 Hz); the VSVA offers simplified integration with direct coil driving capability. Choose VSVA for compact, all-in-one valve control where lower resolution is acceptable; choose VSPA for higher precision applications with separate amplifiers.

Q: What types of servo valves can this board drive?

A: The VSVAH1A is designed for proportional servo valves with coil resistances typically in the range of 10–100 Ω and current requirements up to ±100 mA. It is compatible with common servo valve models from Moog (e.g., 760, 790 series), Rexroth (4WR series), Parker, and Vickers. The output is current-regulated with a compliance voltage sufficient to maintain the set current under varying coil resistance.

Q: What is the dither feature and why is it important?

A: Dither is a small high-frequency current superimposed on the valve command that prevents the valve from sticking due to static friction (stiction). The VSVAH1A allows software configuration of dither frequency (0–300 Hz) and amplitude (0–100 mA). Proper dither tuning significantly improves valve response and extends service life. Unlike command-only boards, the VSVA generates dither at the current drive level for optimal effectiveness. We’ve seen field technicians disable dither because they didn’t understand it—resulting in valve oscillation and premature wear. Keep it enabled unless you have a specific reason not to.

Q: Does the board require an external power supply?

A: The VSVAH1A requires both 5 VDC (for logic) and 24 VDC (for coil drive) from the Mark VIe backplane. The 24 V rail supplies the current drivers; if this voltage dips below 22 V, the output current may not reach its full rated value. Ensure your backplane power supply has sufficient capacity for both voltages—we recommend calculating your total backplane load and maintaining at least 20% margin.

Q: Is this board hot-swappable?

A: No. The Mark VIe VME backplane does not support live insertion. You must de-energize the rack, ground yourself, and wait 30 seconds for bulk capacitors to discharge. We’ve seen field crews try to pull a VSVA while the cabinet was still on auxiliary power—it damaged the current drivers and output protection circuits. Don’t risk it.

Q: How does the short-circuit protection work?

A: The VSVAH1A continuously monitors the output current on each channel. If the current exceeds a configurable threshold (typically 120 mA), the channel automatically shuts down and reports a fault to the Mark VIe Toolkit. The channel remains disabled until manually reset via software or power cycle. This protects both the board and the valve coil from damage. We recommend setting the current limit to match your valve’s rated maximum.

Q: Can the board detect an open coil or broken cable?

A: Yes. The VSVAH1A performs open-coil detection by applying a small test current and measuring the resulting voltage. If the resistance is outside the expected range (typically 5–200 Ω), the board flags an open-coil fault. This is particularly useful for detecting broken wires or failed valve coils before they cause a turbine trip.

Q: What is the typical lead time for this part?

A: We stock these on the shelf—usually ship within 24 hours of order placement and payment confirmation. For international orders, add 3–5 days for customs. If you need expedited (overnight air), we can do that, but you’ll need to coordinate with our logistics team for the cut-off time.

Q: Does this board work with the newer Mark VIeS (SIL-rated) cabinets?

A: To be direct: no. The IS200VSVAH1A is not SIL-certified. It’s meant for standard Mark VIe industrial control. The SIL-rated systems use the IS220VSVA (with additional redundancy, diagnostic coverage, and a separate safety shutdown path). Mixing them violates your site’s safety integrity level. If you’re in a SIL environment, we can source the correct variant but it will have a different model number.

Q: What’s your return policy if this doesn’t solve my valve control issue?

A: If the board is electrically functional (passes our QC test) but doesn’t correct your fault, we’ll accept a return within 30 days provided the board shows no physical damage and the connectors are intact. We do charge a 15% restocking fee if the fault was due to valve wiring issues, configuration errors, or toolkit compatibility problems. We’ll work with you over the phone or email to diagnose the problem before we ship—our goal is to get you running, not to ship boxes back and forth.

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