Description
The GE IS200VSVOH1B is a VMEbus-based servo control board manufactured by General Electric for the Speedtronic Mark VI turbine control system. Operating as the primary execution hardware for high-precision electrohydraulic valve positioning, this board regulates up to four independent servo valve channels to position critical fuel and steam valves on gas and steam turbines. It integrates LVDT/LVDR sensor excitation and conditioning, bi-directional servo current output drivers, and high-speed pulse rate flow monitoring loops into a single centralized processing asset.
Technical Specifications
| Parameter | Value |
| Brand / Manufacturer | General Electric (GE Industrial Systems) |
| Part Number / MPN | IS200VSVOH1B |
| Functional Acronym | VSVO |
| System Platform | Speedtronic Mark VI Control Series |
| Mounting Style / Form Factor | Single-slot VME rack-mounted board |
| Servo Valve Channels | 4 bi-directional current driver channels |
| Coil Configurations Supported | 2-coil or 3-coil servos (3-coil utilized for TMR configurations) |
| LVDT Position Feedback | Up to 12 LVDT/LVDR inputs (via matching terminal boards) |
| LVDT Excitation Frequency | 3.2 kHz sinusoidal signal |
| Pulse Rate (Flow) Inputs | 3 channels, frequency range 2 Hz to 14 kHz (Active or Passive sensors) |
| Hardware Revision | Rev. B |
| Coating Type | Conformal PCB Coating |
| Front Panel Interfaces | J5 cable connector, 3 Status LEDs (RUN, FAIL, STATUS) |
Supply Status and Procurement Logic
- Condition: New Surplus (Never Used) / Pre-Owned Clean and Fully Bench Tested
- Warranty: 12-Month Comprehensive Technical Warranty
- Availability: In Stock
- Lead Time: Ships within 1 to 2 business days from order confirmation
- Pricing: Price subject to global turbine control component market conditions. Contact our industrial sales engineering group for a firm commercial quotation.
Architectural Context and Integration Constraints
In field deployments of Mark VI VME processor racks, the IS200VSVOH1B executes a cyclic control loop partitioned into software configurations (edited via Toolbox) and hardware conditioning. Integrators and plant maintenance engineers must align with specific system boundaries during deployment:
Redundancy Topologies (Simplex vs. TMR)
The VSVO board supports both Simplex and Triple Modular Redundant (TMR) architectures. In a TMR scheme, three identical IS200VSVOH1B boards are distributed across the R, S, and T VME racks. They interface with specialized terminal boards (such as the TSVO or DSVO) using the JR1, JS1, and JT1 connectors to handle 3-coil servo configurations. The system uses software-implemented fault tolerance (SIFT) to continuously vote sensor inputs and median-select servo output currents.
Hardware Compatibility Faults
The VSVO queries a read-only ID chip embedded within the associated terminal boards to verify data including serial numbers, board type, and revision levels. If you connect an incompatible or misaligned terminal revision variant to the lower J3 or J4 VME backplane connectors, the VSVO flags an immediate hardware incompatibility fault and prevents loop initialization.
Hardware Suicide Relays
To protect turbine assets from uncontrolled overspeed or fuel injection during a serious electronic failure, each of the four servo output circuits features an independent, dedicated hardware “suicide relay” (K1 through K4). Managed by onboard firmware and monitored via self-diagnostics, these relays instantly short-circuit the bi-directional servo outputs to a common reference line upon a fatal fault condition, dropping valve actuation current to zero.
Diagnostics and Field Troubleshooting
The front panel features three distinct diagnostic LEDs that establish initial plant-floor troubleshooting metrics:
- RUN (Flashing Green): Indicates regular cyclic board processing and normal communication across the VME backplane.
- FAIL (Solid Red): Indicates a fatal internal hardware failure or an interrupted boot sector.
- STATUS (Flashing Orange): Indicates an active diagnostic alarm condition (the composite
L#DIAG_VSVOsignal).
Common Alarm Vectors
- LVDT Out of Limits: Triggered if a feedback voltage drifts beyond the expected tracking parameters. The digital regulator software automatically discards the failed sensor from the active loop calculations and transfers positioning logic to the remaining operational LVDT.
- TMR Differential Limit Exceeded: Occurs when the variance between input readings across the R, S, and T channels exceeds the pre-configured software differential threshold, indicating a localized tracking or field-wiring fault.
- A/D Converter Out of Range: Indicates that internal analog-to-digital calibration reference voltages have drifted, forcing the board to fall back on default software safe values.
