IS200DTBCG2A - Digital Terminal Board (DTBC

SPECIFICATIONS:

Part Number: IS200DTBCG2A
Manufacturer: General Electric (GE)
Series: Mark VI
Product Type: Digital Terminal Board (DTBC)
Functional Acronym: DTBC
Number of Inputs: 48 Contact Inputs (Dry Contact)
Excitation Voltage: 24 V dc or 125 V dc (Configuration dependent)
Input Filtering: Hardware-based RC filtering
Terminal Blocks: Two (2) High-Density Barrier Terminal Blocks
Board Type: TMR (Triple Modular Redundant) / Simplex Compatible
Operating Temperature: -30 °C to +65 °C
Availability: In Stock
Country of Origin: USA

FUNCTIONAL DESCRIPTION:

The IS200DTBCG2A is a specialized Digital Terminal Board (DTBC) engineered by General Electric for the Mark VI control platform. It serves as a high-density interface for discrete field signals, specifically designed to land and process up to 48 contact inputs. The DTBCG2A is a critical component in the I/O subsystem, acting as the physical termination point for dry contact sensors, limit switches, and pushbutton signals, facilitating their integration into the turbine control logic.

TMR ARCHITECTURE & SIGNAL FAN-OUT:

A defining feature of the DTBCG2A is its ability to support Triple Modular Redundancy (TMR). The board is designed to fan out the 48 field signals to three separate I/O processors (R, S, and T). This architecture ensures that a single processor failure does not result in the loss of critical diagnostic or control data. High-speed opto-isolators on the associated I/O packs ensure that the signals are processed independently, providing the fault tolerance required for utility-scale power generation.

EXCITATION & CONTACT SENSING:

The board provides the necessary excitation voltage to sense the state of the field contacts. Depending on the system configuration and the specific hardware group, the DTBC can manage:

• 24 V DC Excitation: Typically used for standard instrumentation and localized cabinet switches.

• 125 V DC Excitation: Utilized for long-distance field wiring to overcome voltage drops and penetrate oxidation on contact surfaces.

• RC Filtering: Each of the 48 channels includes integrated RC (Resistor-Capacitor) networks to filter out high-frequency electrical noise and contact bounce, ensuring that only valid state changes are reported to the controller.

WIRING & INTERCONNECTIVITY:

The hardware is equipped with two heavy-duty, high-density barrier terminal blocks. These blocks are designed for reliable termination of field conductors up to #12 AWG. The Digital Terminal Board interfaces with the Mark VI I/O rack via high-density cables (typically J-type connectors), which carry the fanned-out signals to the VCRC or VDRP boards. The physical layout is optimized to maintain clear separation between field wiring and internal logic traces, minimizing the risk of crosstalk and electromagnetic interference (EMI).

DIAGNOSTICS & FIELD MAINTENANCE:

The DTBCG2A facilitates efficient plant maintenance through its transparent design and software integration:

• Point-by-Point Monitoring: Operators can monitor the real-time status of each contact input through ControlST (ToolboxST).

• Fault Identification: The system can identify and alarm on "Contact Sequence of Events" (SOE), allowing for millisecond-precision post-trip analysis.

• Passive Reliability: As a terminal board, the DTBC focuses on rugged mechanical and electrical design, resulting in a high Mean Time Between Failures (MTBF) compared to active electronic modules.

WHY BUY FROM WOC:

WOC is a premier global supplier of GE Mark VI turbine control solutions. We maintain a large inventory of the IS200DTBCG2A, available in both UNUSED and professionally REBUILT conditions. Each board undergoes rigorous continuity, insulation, and fan-out verification testing to ensure it meets original OEM specifications. Backed by our standard warranty and 24/7 technical support, WOC is your trusted partner for maintaining the reliability of your discrete control loops.

FREQUENTLY ASKED QUESTIONS:

What is the IS200DTBCG2A?

It is a Digital Terminal Board (DTBC) for the GE Mark VI system. It is a termination module used to land 48 discrete contact inputs from the field and distribute those signals to the control processors.

How does the board support TMR (Triple Modular Redundancy)?

The DTBCG2A features internal circuitry that splits each of the 48 input signals into three paths. These paths lead to the R, S, and T I/O packs, allowing three independent controllers to see the same field data simultaneously for voting and fault tolerance.

What is the difference between the G1 and G2 versions of the DTBC?

The G2 (Group 2) designation typically refers to specific excitation voltage configurations or terminal block styles. The G2A version is designed for standard high-density applications and is the common replacement for most Mark VI discrete input requirements.

Does this board include onboard fuses?

While the DTBC handles contact excitation, primary circuit protection is usually managed at the power distribution level or on the associated I/O pack. However, the board's traces are designed to handle standard 125 V dc excitation currents without degradation.