Key Technical Specifications
| Parameter | Specification |
|---|---|
| Order Number | IS200TSVOH1BCC |
| Product Family | GE Speedtronic Mark VIe — TSVO series |
| Board Type | Servo Valve I/O Terminal Board |
| Associated Processor Pack | IS200VSVOH1B (Mark VI/VIe) or PSVO variants (Mark VIe) |
| LVDT Inputs | Up to 6 LVDT/LVDR position feedback channels |
| Servo Outputs | 2 servo valve coil drive outputs (to VSVO/PSVO pack) |
| Pulse-Rate Input | 2–14 kHz flow meter input (application-dependent) |
| Excitation Voltage | 24 V DC (internal, for LVDT excitation) |
| Redundancy Support | Simplex, Dual, and TMR (Triple Modular Redundant) |
| Connector Style | Barrier-style terminal blocks + ribbon/fan-out cable to processor pack |
| TMR Connectors | JR1 (Simplex), JR1/JS1/JT1 (TMR fan-out to R/S/T racks) |
| External Trip Input | JD1 or JD2 connector for protective module trip signals |
| Mounting | DIN rail or panel-mount bracket (rack-dependent) |
| Documentation | GEH-6421 (TSVO family reference) |
Product Introduction
If you’ve ever had a gas turbine trip on a servo valve LVDT fault during a load test, you know the TSVO board is not a component you want to discover is bad at 2 AM. The IS200TSVOH1BCC is GE’s servo valve terminal board for the Mark VIe platform — it’s the physical interface between your electro-hydraulic servo valves (which drive the fuel or steam control valves) and the VSVO or PSVO servo processor pack that runs the closed-loop position control.The TSVOH1 handles up to six LVDT position feedback channels, which means each servo valve can have redundant LVDTs for voting. In a TMR configuration, the same LVDT signals fan out to three independent processor packs across the R, S, and T racks — a single failed LVDT or a single bad input channel doesn’t trip the turbine. The board also carries the pulse-rate flow input for fuel flow measurement and provides the external trip interface (JD1/JD2) for the protective module. The “BCC” suffix is a specific manufacturing revision. GE changes component populations and connector options between revisions, so always verify the suffix matches your existing board before ordering.
Quality SOP & Tech Pitfalls
The Lab Report (SOP): Visual inspection first — I’m checking the barrier terminal blocks for heat discoloration or corrosion, the ribbon cable connector for bent pins, and the PCB for moisture ingress. I verify the LVDT excitation voltage at the terminal block with a Fluke 115 — should be approximately 24 V DC for the H1 variant. I simulate an LVDT signal on one channel and confirm the corresponding output at the ribbon cable connector. The fan-out ribbon cable gets a continuity check end-to-end. The revision suffix (BCC) gets photographed and cross-referenced against the GEH-6421 manual. Anti-static bag, silica gel, sealed.The Engineer’s Warning: Three things will burn you. First, revision mismatch. The “H1” tells you the base electrical configuration, but the trailing letters (BCC, BAA, BDC, etc.) can change jumper settings, filter component values, or connector populations. I’ve seen a BCC substituted for a BAA cause an LVDT channel to read erratically because the input filter network had changed. Second, and this is the big one: in TMR systems, the TSVO connects to three processor packs via JR1, JS1, and JT1. If you only reconnect JR1, you’ve lost two-thirds of your voting logic. The turbine may run, but you have no redundancy. Third, the suicide relay. Each servo output channel has a firmware-controlled relay that shorts the output to common on power loss. If this relay is stuck open, the servo valve won’t de-energize on a trip — that’s a safety-critical failure. Test it during commissioning.
Installation & Configuration Guide
1. Pre-Installation ⚠️
Follow your plant’s lockout/tagout procedure for the Mark VIe rack. If the turbine is running, coordinate with operations — this is a live control system. Photograph all cable connections (JR1, JS1, JT1, JD1/JD2), terminal block wiring, jumper positions, and the board label with revision letters. Note which LVDT channels are wired and which are spare.2. Removal
Label every wire at the terminal block — LVDT leads, servo valve coil wires, pulse-rate input, trip signals. Disconnect the ribbon/fan-out cable(s) from the rear connector(s) first — these are fragile. In TMR systems, there may be three cables (JR1, JS1, JT1). Remove the mounting screws or release the DIN rail clips. Slide the board out carefully.3. Installation
Verify the revision suffix matches your original board. Seat the new IS200TSVOH1BCC into the mounting location. Reconnect the ribbon cable(s) — in TMR, all three (JR1, JS1, JT1) must be connected. Reconnect all labeled field wires to the correct terminal positions. Verify jumper settings match the original board. Double-check the LVDT wiring polarity — reversed LVDT leads cause negative feedback and the servo valve will drive full open or full closed.4. Power-On & Testing
Apply rack power. Verify the 24 V DC LVDT excitation is present at the terminal block. In ToolboxST/ControlST, go online with the controller and monitor the LVDT position feedback for each channel. Verify all LVDTs on a given valve report consistent position. In TMR mode, confirm all three processor packs report consistent input status. Test the external trip circuit (JD1/JD2) and verify the suicide relay de-energizes the servo output. Perform a slow valve stroke test before returning to automatic control.
Compatible Replacement Models
| Compatibility | Model | Notes |
|---|---|---|
| ✅ Drop-in Replacement | IS200TSVOH1BCC | Exact match. Verify revision suffix before installation. |
| ✅ Drop-in Replacement | IS200TSVOH1BCx (same revision family) | Same electrical specs, minor manufacturing revision. Confirm jumper map and connector population match. |
| ⚠️ Software Compatible | IS200TSVOH1 (different trailing letters) | Same base board, different revision. May require verification of LVDT excitation levels and filter characteristics. Plan 1–2 hours for commissioning checks. |
| ⚠️ Hardware Mod Required | IS200TSVCH2 series | Different TSVO variant designed for PSVO/WSVO processor packs, not VSVO. Connector pinout and excitation may differ. Not a direct swap. |
| ❌ Hardware Mod Required | IS200DSVO series | Different mechanical form factor and connector layout. Requires rack and wiring changes. Not recommended for emergency replacement. |
Frequently Asked Questions (FAQ)
Can I hot-swap this board while the turbine is running?
In a TMR configuration, yes — the remaining two racks maintain control while you replace the board in the third rack. Follow GE’s hot-swap procedure: remove and replace one rack at a time, never two simultaneously. In a Simplex system, pulling the TSVO kills all servo valve feedback and output for that controller. Plan an outage.What’s the difference between TSVO, DSVO, and TSVCH2?
TSVO (IS200TSVOH1) is the barrier-style terminal board for the VSVO processor pack in Mark VI/VIe systems. DSVO is a similar board with a different connector style (DIN-style terminals). TSVCH2 is a different TSVO variant designed for the PSVO/WSVO processor packs in newer Mark VIe configurations — it is not directly interchangeable with the TSVOH1 without verifying processor pack compatibility.How do I know if my system is Simplex or TMR?
Look at the rear connectors. Simplex has one ribbon cable (JR1). TMR has three (JR1, JS1, JT1), each going to a different processor pack in a different rack. If you see three cables, you’re in TMR — and you need to reconnect all three.Does this board need firmware downloaded?
The TSVO is a terminal board — it’s mostly passive hardware. The intelligence lives in the VSVO or PSVO processor pack. However, GE documents note that some TSVO revisions may require firmware verification on the associated processor pack. Check the GEH-6421 manual for your specific revision.What does the “suicide relay” do?
Each servo output channel has a firmware-controlled relay that shorts the servo valve coil output to common when power is lost or a trip is commanded. This ensures the servo valve fails to a safe position (typically closed) on loss of control power. If this relay is stuck or failed, the valve may not trip — a critical safety issue.Is the IS200TSVOH1BCC still in production?
The Mark VIe platform remains active, but specific revision suffixes like “BCC” may be superseded by newer revisions. Market availability is primarily New Surplus or tested used stock. Confirm the revision and manufacturing date when purchasing.
