The GE IS200TBCIH1BBC (commonly designated as the TBCI board) is a Contact Input Terminal Board engineered for General Electric’s Speedtronic™ Mark VI and Mark VIe turbine control systems. Mounted within control cabinets, the TBCI acts as the primary physical termination interface, accepting discrete field contact inputs (such as limit switches, pushbuttons, and relay contacts) and routing them to digital I/O processing cards or I/O packs.
Key Specifications & Identification
| Attribute | Details |
| Manufacturer | General Electric (GE / GE Vernova / GE Fanuc) |
| Part Number | IS200TBCIH1BBC |
| Board Acronym / Family | TBCI (Contact Input Terminal Board) |
| Revision Level | H1B base revision with BC artwork/conformal coating designator |
| System Compatibility | GE Speedtronic™ Mark VI and Mark VIe Control Systems |
| Number of Inputs | 24 Discrete Contact Input Channels |
| Excitation Voltage | Supports 24 V DC, 48 V DC, or 125 V DC field excitation options |
| Connectors | Barrier-style or box terminal blocks; 37-pin D-sub connectors for I/O cables |
Primary System Functions
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Discrete Signal Termination: Provides secure screw-terminal connection points for 24 dry or wet contact inputs originating from field instruments across the power plant.
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Noise Suppression & Filtering: Integrates onboard RC filtering networks, metal oxide varistors (MOVs), and transient voltage suppressors (TVS) to shield control electronics against high-voltage surges and electromagnetic interference (EMI).
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Flexible Cabling Architecture: Uses 37-pin D-sub connectors to route contact signals simultaneously to Simplex, Dual, or Triple Modular Redundant (TMR) processor channels (
<R>,<S>, and<T>cores). -
Field Excitation Distribution: Distributes wet contact excitation power to field loops while isolating internal logic rails from external wiring faults.
Servicing & Installation Guidelines
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Voltage Isolation Warning: Contact input loops can carry external excitation voltages up to 125 V DC or AC mains potential. Always measure and verify zero potential across terminal points before touching wiring connections.
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ESD Precautions: Handle the terminal board assembly using a grounded anti-static wrist strap to prevent static discharge into onboard filtering components and cable interface transceivers.
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Wiring & Shield Grounding: Ensure field cable shields are properly landed on the designated ground bar near the terminal block to maintain noise immunity and prevent ground loop interference.
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Cable Seating Check: When connecting multi-pin cables from the TBCI board to the Mark VI rack or Mark VIe I/O packs (e.g., PDIA packs), verify that connector lock screws are fully engaged to prevent accidental disconnection during operation.
