General Electric DS200DTBAG1A Mark V Discrete Contact Input Board

General Electric DS200DTBAG1A Mark V Discrete Contact Input Terminal Board (DS200DTBAG1AAA)

The General Electric DS200DTBAG1A (functional revision DS200DTBAG1AAA) is a Contact Input Terminal Board engineered for the GE Speedtronic Mark V turbine control architecture. Designed to serve as the primary physical field-wiring interface for discrete contact signals, this board routes up to 72 dry contact inputs from field switches, pressure transducers, limit switches, and protection relays directly to the Mark V core processors.

The DS200DTBAG1A incorporates onboard transient suppression, current-limiting resistors, and optical isolation interfaces via downstream I/O conditioning boards. In dual-redundant and Triple Modular Redundant (TMR) configurations, the board distributes field signals seamlessly across the <R>, <S>, and <T> control cores without introducing single-point field wiring bottlenecks.

Model Details

• Manufacturer: General Electric (GE Energy / GE Industrial Systems)
• Series: Speedtronic Mark V
• Base Model Number: DS200DTBAG1A
• Full Assembly MPN: DS200DTBAG1AAA
• Board Type: Discrete Contact Input Terminal Board (DTBA)
• Functional Revision Code: G1A (Hardware Revision A, Firmware/Configuration Revision AA)
• Mounting Configuration: Vertical DIN/Panel Chassis Mount inside Mark V I/O Core Cabinet

Features

1. High-Density 72-Channel Termination: Accommodates 72 individual dry contact inputs across two heavy-duty Euro-style barrier terminal blocks (TB1 and TB2) rated for 14 AWG to 22 AWG stranded or solid copper field wiring.
2. Integrated Contact Wetting & Suppression: Equipped with factory-installed metal-oxide varistors (MOVs) and RC snubber networks on every input channel to suppress inductive kickback and electromagnetic interference (EMI) from heavy switchgear.
3. Redundant Ribbon Cable Distribution: Features dedicated 50-pin and 34-pin high-retention ribbon headers (J1, J2, J3, JR, JS, JT) that fan out discrete signals to <R>, <S>, and <T> I/O cores (via DS200DCFB or DS200TCEA/TCDA boards) for TMR voting.
4. Isolated Contact Excitation Supply: Supports external or internal 125 VDC (nominal) and 24/48 VDC floating wetting voltage buses with onboard jumper-selectable isolation (JP1 through JP6) to prevent ground loops across marine hulls and turbine skids.
5. Conformal Coated PCB Architecture: Manufactured on a flame-retardant FR-4 multi-layer substrate with protective acrylic conformal coating to resist salt-mist corrosion, moisture condensation, and conductive dust.

Compatible Equipment Models

• Turbine Control Systems: GE Speedtronic Mark V LM (Aeroderivative) and Mark V Heavy-Duty Gas/Steam Turbine Control Panels
• Supported Prime Movers: GE Frame 5, Frame 6B, Frame 6FA, Frame 7EA, Frame 7FA, Frame 9E, Frame 9FA Gas Turbines; LM2500 and LM6000 Marine & Industrial Gas Turbines
• Companion Mark V Boards:
  • DS200TCDAG1A / DS200TCDAG1B (Digital I/O Board)
  • DS200DCFBG1B (Main Power Supply & Control Board)
  • DS200DTBBG1A (Companion Discrete Contact Input Terminal Board for expanded I/O)
  • DS200PDIAG1A (Power Distribution Interface Board)

Part Number Cross-References

• Base Hardware ID: DS200DTBAG1A
• Complete Functional Assembly ID: DS200DTBAG1AAA
• Alternate / Backward-Compatible Revisions: DS200DTBAG1AAB, DS200DTBAG1AAC (Verify jumper parity prior to installation)
• Related Board Family: DS200DTBBG1A (Used in slots requiring secondary 72-channel expansion)

Frequently Asked Questions

What is the difference between DS200DTBAG1A and DS200DTBAG1AAA?

DS200DTBAG1A is the base hardware part number printed on the PCB silkscreen, while DS200DTBAG1AAA represents the complete assembled board including its specific factory functional revision (AA). Both numbers refer to the exact same physical Mark V Discrete Contact Input Terminal Board and are 100% interchangeable when ordered for maintenance replacement.

Can the DS200DTBAG1A be replaced while the turbine is running?

In a Triple Modular Redundant (TMR) Mark V system, individual core boards (<R>, <S>, or <T>) can be powered down and serviced online. However, because the DS200DTBAG1A serves as the common field terminal block that distributes contact signals to all three cores simultaneously, replacing the DTBA board itself requires a turbine shutdown and full isolation of the 125 VDC contact wetting power supply.

How many contact inputs does the DS200DTBAG1A support?

The board supports 72 discrete dry contact inputs, split evenly between terminal block TB1 (Inputs 1–36) and terminal block TB2 (Inputs 37–72). If a turbine application requires more than 72 discrete inputs, a companion DS200DTBBG1A board is installed to expand capacity up to 144 channels.

What voltage is used to wet the contacts on the DS200DTBAG1A?

By default, the board operates with a 125 VDC nominal floating contact excitation supply provided by the Mark V power distribution system. Through onboard jumper configurations (JP1–JP6), the board can also be adapted to accept external 24 VDC or 48 VDC customer-supplied wetting buses.

What causes a DC ground fault alarm on the DS200DTBAG1A?

A DC ground fault (GND FLT) associated with the DTBA board is typically caused by moisture ingress inside a field junction box, pinched field wiring grounding the 125 VDC wetting bus to the turbine skid or ship hull, or a shorted Metal-Oxide Varistor (MOV) on one of the 72 input channels following a severe inductive surge.