GE IS200TSVOH1B GE Mark VI Servo Terminal Board

Description

Product Model: GE IS200TSVOH1B
Product Brand: GE (General Electric)
Product Series: Mark VI / IS200 family
Product Features:

• TSVO termination board for interfacing servo valves in turbine control
• Dual servo current channel inputs; supports LVDT feedback and pulse rate signals
• Barrier-type terminal block arrangement, accepts up to three LVDT windings per block
• Operating in harsh control equipment environments, part of the GE Speedtronic Mark VI system

Applications & Industry Context

In power plants, especially those running gas or steam turbines, precise actuation and feedback of valves (for steam, fuel, or oil) is critical to performance, stability, and safety. That’s where a terminal board like GE IS200TSVOH1B plays its role. It connects the control electronics (in a Mark VI control rack) to the physical servo valves and LVDT (Linear Variable Differential Transformer) sensors that measure valve position. Without reliable termination and interface hardware, the best software or controller logic is moot in the field.

In retrofit projects, plants often retain legacy Mark VI racks but require replacement boards when originals age or fail. The IS200TSVOH1B is a common replacement module due to its compatibility with existing TSVO loops. In new turbine control installations, it’s part of the broader Speedtronic ecosystem, working with modules such as VSVO, VCMI, and others.

This board often resides inside control cubicles or VME racks, not directly exposed to ambient environment, but still sees electrical stress, thermal cycling, and maintenance handling. In heavy-duty power stations or turbine enclosures, reliability matters: a single miswired connection or intermittent contact in the TSVO board can translate to a valve failure or turbine trip. Hence, engineers favor boards with robust terminal constructs (e.g. barrier terminal blocks), good physical layout, and proven performance.

Product Role & System Fit

The GE IS200TSVOH1B serves as a servo termination board in the Mark VI control architecture. “TSVO” is often taken to mean Turbine Servo Valve/Output or similar, signifying its interface to electrohydraulic valve actuators.

Electrically, it sits between the control rack (VSVO, I/O cards) and the field elements: servo valves, LVDTs, and sometimes pulse rate feedback sensors. It routes current, feedback signals, excitation, and trip signals. The board handles multiple feedback loops: each TSVO terminal block can accept up to three LVDT windings (for high/median/low select) per channel — meaning the IS200TSVOH1B supports flexible sensing architectures.

On the control side, signals are forwarded to modules such as VSVO or processor modules, with connectors (e.g. J5) carrying aggregate I/O. On the field side, electro-hydraulic servo valves may have one or multiple coils; the TSVO board provides the necessary current drive paths. It also carries excitation circuits for LVDTs used in valve position feedback.

In simplex or triple modular redundant (TMR) control schemes, the IS200TSVOH1B may route redundant wiring and trip signaling (JD1 / JD2 plugs) for external trips or protection interlocks.

Thus, while it is not a controller itself, IS200TSVOH1B is a critical interface component that ensures the logical commands and feedbacks in a turbine control system remain physically connected and reliable.

Technical Features & Benefits

One of the first distinguishing features of GE IS200TSVOH1B is its barrier-type terminal block design, all mounted along one side of the board. This design promotes clarity of wiring, better separation of signals, and easier field access.

The board’s architecture accepts two independent servo current channels, allowing it to drive two servo valves simultaneously. Each channel also supports LVDT feedback (position sensors) and pulse rate inputs (2–14 kHz) for additional feedback or sensor diagnostics.

One advantage: the IS200TSVOH1B can support up to six LVDT windings total (three per terminal block) enabling high/median/low sensing redundancy or sensor selection logic.

The board includes features for jumper-select coil current paths (JP1–JP6) to adapt to different coil configurations or multiple coil servo valves in TMR architectures.

It also provides external trip connectivity via JD1 and JD2 plugs — allowing the board to accept protection or shutdown commands external to the core control logic.

From the perspective of electrical compatibility, the TSVO supports typical field wiring resistances (maximum two-way cable resistance up to ~15 Ω) and can support servo cable lengths up to about 300 m (984 ft) — ideal for many turbine installations.

Regarding LVDT excitation, the board delivers a nominal AC excitation (often ≈ 7 V rms at ~3.2 kHz) to LVDT sensors, and measures the differential outputs for position sensing.

In field experience, these TSVO boards are appreciated for their clarity of layout, stable mounting, and maintainability. Because much wiring is concentrated on the terminal side, technician servicing or diagnosis is more straightforward.

One caution from field notes: ensure that the wiring is kept neat, use proper tagging, and avoid pulling or stressing terminals. Also ground shielding properly. A misplaced connection or loose wire is among the top causes of intermittent behavior in turbine control loops.

Technical Specifications Table

Here’s a summary table of known and typical specs for GE IS200TSVOH1B:

Installation & Maintenance Insights

Proper installation of IS200TSVOH1B is key to long-term reliability in turbine control systems. Begin by mounting the board in the control rack in an environment with controlled temperature, minimal vibration, and secure panel grounding.

When wiring, route servo valve current wires, LVDT feedback wires, and pulse/sensor cables separately to reduce coupling or noise. Use shielded twisted pairs for LVDT or pulse rate lines, and bond shielding carefully at a single point to avoid ground loops.

In TSVO boards, each barrier terminal block has 24 terminals (12 pairs) and accepts wiring up to AWG #12. Be cautious: overtightening or improper wire stripping can damage terminals. It’s good practice to retorque periodically during scheduled maintenance to guard against loosening over thermal cycles.

When connecting to external trip circuits (JD1/JD2), verify polarity and isolation. Always test external trip functionality before closing up. In TMR configurations, ensure that redundancy paths are intact and not inadvertently bridged.

Before powering, perform continuity checks: verify no shorts across channels, open circuits in sensors, and correct jumper settings (JP1–JP6) configured to your servo coil design. Also verify that the board’s supply is at nominal ~24 V DC and stable.

In commissioning, validate each servo loop: command small valve movements, monitor LVDT readings, inject known signals and verify the loop’s response. Check pulse rate inputs, if used, by simulating input frequencies between 2–14 kHz.

During periodic maintenance, inspect for signs of corrosion, discoloration, or heating near terminals. Inspect solder joints and any signs of movement or cracks. For boards with conformal coating, verify coating integrity in critical areas. Check that connectors (J plugs) remain firmly seated and that retention clips are intact.

Because these boards are critical, many plants keep a spare IS200TSVOH1B on hand; swapping is often a matter of minutes. After swap, log the event, revalidate wiring and re-run tests. Always retain original wiring layout or labeling to avoid errors.

Related Models

Here are some sibling or related modules (within GE Mark VI / TSVO / IS200 series) for comparison:

• IS200TSVOH1BAA — variant with alternate suffix, same functional board family
• IS200TSVOH1BBB — a TSVO version under a different revision
• IS200TSVOH1BCB — variant with alternate wiring or connector layout
• IS200TRTDH1C — a different termination board for TRTD functions
• IS200TPROH1B — module in the PRO (protection/relay) side of the system
• IS200TSVOH1A — earlier revision (A) version of the TSVO board
• IS200EAUXH1A — auxiliary I/O interface board in IS200 series