Key Features
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Multi-Channel Input Capability – Supports 8 independent vibration channels, 4 position channels, and 1 Keyphasor/reference probe circuit
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Broad Sensor Compatibility – Direct interface with eddy-current proximity probes (Bently Nevada 3300/3500 series), Velomitors, seismic velocity sensors, accelerometers, and 4–20 mA loop-powered transmitters
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On-Board -24V DC Sensor Excitation – Provides isolated -24V DC excitation for proximity probe preamplifiers, up to 12 mA per channel
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Buffered Outputs – BNC buffered test outputs per channel plus DB9 and DB25 connectors for connecting external diagnostic equipment without disturbing the main signal path
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High Isolation Rating – 1500 V DC to 2500 Vrms galvanic isolation between field side and control rack side, rejecting plant ground loop interference
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EMI Protection & Diagnostics – Per-channel EMI/RFI suppression, surge protection, and sensor open/short detection with LED status indicators for board power and channel fault alarms
Technical Parameters
Core Advantages
1. Critical Signal Interface for Turbine Protection
The IS200TVBAH2ACC serves as the primary signal interface between field vibration sensors and the Mark VIe control system's VVIB/PVIB vibration monitoring I/O pack. It converts raw sensor signals into high-resolution vibration data, enabling the system to detect mechanical imbalance, shaft displacement, bearing wear, or misalignment in real time.
2. On-Board Sensor Excitation and Signal Conditioning
Unlike standard analog boards, the TVBA is specifically engineered to handle the high-frequency AC signals and negative voltage excitation (-24V DC) required by industrial vibration probes. It provides isolated -24V DC excitation for proximity probe preamplifiers and performs hardware filtering and signal conditioning, converting weak field vibration signals into standardized analog values before transmission to the processor pack.
3. Conformal Coating (ACC) for Harsh Environments
The "ACC" suffix indicates the board is treated with conformal coating, providing extra protection against moisture, dust, chemicals, and industrial contaminants. In condensing or corrosive environments such as steam turbine enclosures, uncoated boards can develop creepage faults on high-voltage inputs within months.
4. Support for Redundant Architectures
The board is designed for use in simplex, dual-redundant, and TMR (Triple Modular Redundant) configurations. In TMR applications, vibration signals are distributed to three redundant I/O packs (R, S, and T) for voting protection logic, improving system availability and fault tolerance.
5. Comprehensive Diagnostics and External Test Capability
On-board diagnostics continuously monitor for sensor open/short circuits, excitation supply anomalies, and ribbon cable link faults, reporting them through LED indications and alarms to the turbine main controller. Per-channel BNC buffered outputs allow connection of external vibration analyzers for offline signal verification without disconnecting field wiring.
Applications
The IS200TVBAH2ACC is deployed in critical rotating machinery condition monitoring and protection applications:
Primary Functions
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Signal Termination – Provides removable screw terminals for field wiring of proximity probes, accelerometers, seismic sensors, and 4–20 mA transmitters
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Sensor Excitation – Supplies isolated -24V DC power for proximity probe preamplifiers
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Signal Conditioning – Hardware filtering and conditioning of vibration analog signals for transmission to processor
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Buffered Outputs – Per-channel BNC outputs for external diagnostic equipment access
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Fault Detection – Sensor open/short and excitation supply anomaly detection with alarm reporting
Recommended Models & Related Products
Important Compatibility Note: The TVBA board cannot operate standalone—it must be paired with a Mark VI/Mark VIe PVBA or VVIB vibration monitoring processor pack. A full vibration loop simulated test is mandatory after replacement. In TMR configurations, all three racks must use the same version (H2ACC); mixing H1A and H2A boards causes "hardware mismatch" voting faults.
What's Included
Note: PVBA/VVIB processor pack, ribbon cables, field sensors, and configuration software are sold separately.
Why Buy From Us?
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In Stock – Ready to ship immediately
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Fully Tested – Each board verified for functionality
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Warranty Included – Purchase with confidence
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Technical Support – Compatibility assistance available
Frequently Asked Questions (FAQ)
Q1: What is the GE IS200TVBAH2ACC?
It is a Vibration Input Terminal Board (TVBA) for the GE Speedtronic Mark VI and Mark VIe turbine control systems. It serves as the signal interface between field vibration sensors and the vibration monitoring processor packs (PVBA/VVIB), providing signal conditioning, sensor excitation, and termination.
Q2: What sensor types does this board support?
It supports eddy-current proximity probes (such as Bently Nevada 3300/3500 series), Velomitors, seismic velocity sensors, accelerometers, and 4–20 mA loop-powered transmitters.
Q3: What does the ACC suffix stand for?
ACC indicates conformal coating. This protective layer provides additional resistance against moisture, dust, chemicals, and industrial contaminants, making it suitable for harsh environments in power plants and industrial facilities.
Q4: Can this board be hot-swapped?
No. The rack power must be de-energized before board replacement. Hot-swapping is strictly prohibited to prevent electrical transients from disturbing the monitoring signal path or damaging backplane communication circuits. ESD precautions must be observed when handling the PCB.
Q5: Does this board support TMR (Triple Modular Redundant) configurations?
Yes. It is designed for use in simplex, dual-redundant, and TMR configurations. In TMR applications, signals are distributed to three redundant I/O packs (R, S, and T) for voting protection logic. However, all three racks must use the same version (H2ACC).
Q6: What should be done if the Keyphasor input is not used?
The Keyphasor input circuit (circuit 13) should be terminated per system documentation when no probe is connected. Leaving the input floating can cause noise pickup on the backplane, potentially triggering spurious diagnostic flags.
Q7: What key items should be verified during installation?
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Confirm gap voltage is within the specified -10 VDC operating window (for proximity probes)
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Ensure board mounting screws are fully tightened (they serve as the primary chassis ground path)
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Use shielded twisted-pair wiring for field sensors, with shields terminated at the terminal board ground bus
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Verify ribbon cable connectors are fully locked with no loose pins
Q8: What is the country of origin?
United States (USA).
Q9: Can this board be used with only the GE processor?
Yes. The board cannot operate standalone—it must be paired with a Mark VI/Mark VIe PVBA or VVIB vibration monitoring processor pack. A full vibration loop simulated test is mandatory after replacement.
Q10: What should I verify before ordering?
Always verify the exact part number (IS200TVBAH2ACC), confirm your system configuration (simplex, dual, or TMR), and check the existing board version (H1A vs. H2A) for compatibility.
