Description
Product Introduction
In turbine valve-control systems, an apparent valve-position deviation can occur even when the valve has not physically moved. LVDT excitation distortion, feedback wiring issues, and servo-interface faults can all contribute to misleading position readings. The GE IS200TSVOH2B is a Mark VI servo terminal board that connects field servo valves and position-feedback circuits to compatible VSVO control hardware.
The H2B version is significant because its revised LVDT excitation transformer addresses DC-offset-related saturation that can distort feedback waveforms in certain applications. When replacing an existing board, verify the complete part number, connected VSVO hardware, LVDT arrangement, and turbine-specific wiring configuration.
Key Technical Specifications
| Parameter | Specification |
|---|---|
| Model | IS200TSVOH2B |
| Manufacturer | General Electric |
| Product family | Mark VI Speedtronic |
| Functional acronym | TSVO |
| Product type | Servo terminal board |
| Primary interface | Compatible VSVO servo control board |
| Servo-valve circuits | 2 per terminal board |
| Position feedback | LVDT inputs |
| LVDT winding inputs | Up to 6 |
| Pulse-rate inputs | 2 |
| LVDT excitation frequency | 3.2 ± 0.2 kHz, reported for the TSVO/VSVO system |
| LVDT excitation voltage | 7.00 ± 0.14 VAC RMS, reported for the TSVO/VSVO system |
| Magnetic pickup signal | Up to approximately 150 V peak-to-peak into 60 kΩ, as documented for the associated interface |
| Active pickup signal | 5–27 V peak-to-peak, as documented for the associated interface |
| H2B design distinction | Revised excitation transformer intended to reduce DC-offset-related saturation |
| Board connections | Multiple backplane and field-interface connectors; verify the installed wiring drawings |
| Supply voltage | Confirm the applicable Mark VI hardware documentation and system configuration |
| Dimensions | Approximately 17.8 × 33.0 cm reported for this board family |
| Operating temperature | Confirm from the applicable GE installation manual |
Specification note: Some electrical values above are documented for the associated TSVO/VSVO interface rather than independently guaranteed for every H2B assembly. Confirm the exact ratings and wiring against the applicable GE Mark VI system guide before installation.
IS200TSVOH2B
Application Scenarios and Pain Points
A servo-control problem can appear as unstable valve positioning, a position-spread alarm, or inconsistent feedback between redundant measurement channels. Replacing a terminal board without checking the excitation and feedback circuits may leave the underlying issue unresolved.
- Gas turbine valve control: Interface compatible electrohydraulic servo valves and their LVDT position sensors.
- Steam turbine control: Support servo and valve-position signal paths within a compatible Mark VI configuration.
- LVDT feedback troubleshooting: Investigate excitation waveform distortion, abnormal position readings, and feedback discrepancies.
- Scheduled maintenance: Replace a defective servo terminal board while preserving the approved controller and field-wiring architecture.
Field note: The H2B transformer revision is particularly relevant in applications where DC offset can distort LVDT excitation. A position discrepancy should still be investigated across the complete circuit, including the sensor, wiring, terminal board, and VSVO controller.
Related Products
These models are related to GE Mark VI servo-control hardware, but they are not automatically interchangeable.
| Model | Functional distinction |
|---|---|
| IS200TSVOH1B | Earlier TSVO revision. The H2B revision was developed to address DC-offset-related LVDT excitation transformer saturation in certain applications. |
| IS200TSVOH1C | TSVO variant with enhanced open-wire detection through DC injection on LVDT feedback connections. Its electrical behavior differs from earlier revisions. |
| IS200VSVOH1B | Servo control board that processes feedback and controls servo-valve outputs when used with compatible TSVO hardware. |
| IS200DSVOH2B | Simplex DIN-rail-mounted servo terminal board with a different board designation and mounting arrangement. Do not confuse it with the IS200TSVOH2B. |
Engineer’s Guide: Three Checks Before Replacement
- Confirm the H2B revision requirement. Record the complete part number and existing revision. If the installation was upgraded to address LVDT excitation distortion, do not substitute an earlier revision without engineering approval.
- Verify the field wiring and feedback configuration. Identify the servo-valve channels, LVDT windings, pulse-rate connections, and associated VSVO board. Preserve connector assignments and cable routing according to the system drawings.
- Validate position feedback and servo operation after installation. Follow turbine-specific isolation procedures, check the LVDT excitation waveform, compare position feedback against the expected valve position, and verify alarm behavior and servo response during controlled commissioning.
Frequently Asked Questions
Q1. What is the GE IS200TSVOH2B?
It is a servo terminal board in the GE Mark VI turbine control system. It interfaces compatible servo-valve circuits and LVDT position-feedback signals with the servo control hardware.
Q2. What is the main difference between the H2B and H1B versions?
The H2B version uses a revised LVDT excitation transformer designed to reduce saturation caused by DC offset in certain applications. This can help prevent excitation waveform distortion and apparent valve-position errors.
Q3. How many servo valves can the board support?
The documented TSVO arrangement supports two servo valves per terminal board. The actual control configuration depends on the associated VSVO hardware and turbine application.
Q4. Can IS200TSVOH1B replace IS200TSVOH2B?
Do not assume that it can. The transformer revision addresses a specific feedback-signal issue. Any substitution should follow the approved GE documentation and the turbine’s engineering requirements.
Q5. What symptoms might indicate a TSVO-related problem?
Possible symptoms include abnormal LVDT feedback, position-spread alarms, excitation waveform distortion, or servo-interface faults. These symptoms are not conclusive proof that the terminal board has failed; inspect the sensor, wiring, and controller as well.
Q6. What should I request when purchasing a refurbished unit?
Request photographs of the full nameplate, board revision, connectors, and transformer area. Ask for inspection records and functional test evidence, including which feedback and servo-interface functions were tested.
Q7. What information is needed to verify compatibility?
Provide the complete board number, associated VSVO model, turbine control configuration, LVDT arrangement, and relevant wiring-drawing reference. This information helps determine whether the replacement matches the installed system.
Procurement recommendation: For GE IS200TSVOH2B, prioritize exact revision verification and documented LVDT/servo-interface compatibility. Because the H2B transformer design addresses a specific signal-integrity concern, selecting a board by physical appearance alone is not sufficient.
