IS200TBCIH1BCD - Contact Input Group Isolation Terminal Board

SPECIFICATIONS:

Part Number: IS200TBCIH1BCD
Manufacturer: General Electric
Series: Mark VIe
Product Type: Contact Input Group Isolation Terminal Board
Number of channels: 24
Excitation voltage: 125 V dc
Input current: 10 mA
Power consumption: 20.6 W
Physical size: 33.02 cm high × 10.16 cm wide
Repair: 3-5 Days
Product of Origin: United States
Availability: In Stock
Manual: GEH-6721_Vol_II

FUNCTIONAL DESCRIPTION:

IS200TBCIH1BCD is a Contact Input with Group Isolation Terminal Board manufactured and designed by General Electric as part of the Mark VIe Series used in GE distributed control systems. The Contact Input with Group Isolation (TBCI) terminal board is engineered to interface with 24 discrete dry-contact inputs, distributed across dual barrier-type terminal blocks for organized, secure field wiring. Each input channel is group-isolated, providing galvanic separation to mitigate cross-talk and ensure signal integrity. The board requires an external DC excitation voltage, which biases the dry contacts for accurate state detection, enabling reliable monitoring of relays, switches, and auxiliary devices within industrial control systems.
The input circuitry incorporates surge suppression and high-frequency noise filtering, utilizing components such as transient voltage suppressors (TVS) and RC snubbers to protect against electromagnetic interference (EMI) and voltage transients. This robust design enhances system reliability by preventing false triggering, minimizing signal degradation, and maintaining operational stability in electrically noisy environments. The TBCI board is optimized for critical automation and control applications, providing both electrical isolation and noise-hardened input monitoring in a compact terminal interface.

COMPATIBILITY:

The TBCI (Terminal Board with Contact Input and Group Isolation) is engineered for full interoperability with the PDIA I/O pack, supporting redundancy architectures including simplex, dual-redundant, and triple-modular-redundant (TMR) configurations. Up to three PDIA modules can be directly interfaced with a single TBCI board, providing scalable input expansion for high-availability and fault-tolerant control systems. The board’s modular design ensures deterministic signal routing and maintains signal integrity across all connected I/O modules, facilitating seamless integration into complex industrial control networks.

The C-version TBCI board is mandated to achieve precise mechanical alignment of the JTI connector with the I/O pack’s structural support interface. This ensures correct connector mating tolerance, prevents mechanical stress on the pins, and maintains reliable galvanic contact under operational vibration and thermal cycling. Consequently, the TBCI provides robust electrical interfacing, mechanical compliance, and modular compatibility essential for mission-critical automation and high-integrity process control applications.

INSTALLATION:

Connect the wires for the 24 dry contact inputs directly to two I/O terminal blocks on the terminal board. These blocks are held down with two screws and can be unplugged from the board for maintenance. Each block has 24 terminals accepting up to #12 AWG wires. A shield terminal strip attached to chassis ground is located immediately to the left of each terminal block.

In a simplex system, connect the TBCI to the PDIA I/O pack using connector JRI. In a TMR system, connect TBCI to the three PDIAS using connectors JR1, JS1, and JT1. The PDIAS plug into TBCI and attach to side-mounting brackets. One or two Ethernet cables plug into the I/O pack. Firmware may need to be downloaded. Connect TBCI to the contact excitation voltage source using plugs JE1 and JE2.

SIGNAL CONDITIONING AND INPUT POWER:

Each discrete input on the TBCI_1C terminal board is equipped with high-frequency filters and surge suppression circuitry located near the point of signal entry to minimize electromagnetic interference (EMI) and transient voltage effects. The dry contact inputs are energized from a floating 125 V dc supply (operating range 100–145 V dc) provided by the turbine control system. This 125 V dc bus is current-limited within the power distribution module prior to distribution to individual input channels, ensuring protection against overcurrent conditions. For the H2, H3, and H4 board variants, lower excitation voltages are used as specified in the Specifications section. Each input receives power through a dedicated pair of terminal points—one providing the positive dc source and the other serving as the return path to the board. The first 21 inputs are designed with a 2.5 mA nominal current load, while the final three inputs are rated for 10 mA to support integration with remote solid-state output devices. The contact input circuits comply with NEMA Class G creepage and clearance standards, ensuring electrical safety and insulation integrity in harsh industrial environments.

SIGNAL TRANSFER AND ISOLATION:

The discrete input voltage signals are routed to the PDIA I/O pack, where they pass through optical isolators providing group isolation before transmission to the Mark VIe controller. Within the isolation circuits, a reference voltage sets the input transition threshold at 50% of the applied floating supply voltage, providing reliable detection of contact state changes. The circuit design includes a tracking clamp that limits the threshold to no less than 13% of the nominal supply voltage, guaranteeing that all contacts indicate an open state when the supply voltage falls below this level. This design ensures consistent logic interpretation, even under voltage sags or fluctuations, and preserves the integrity of the turbine control input signals throughout the system.

WORLD OF CONTROLS maintains the largest inventory of GE Speedtronic Mark VIe OEM replacement parts, including both unused and expertly rebuilt components, all backed by a warranty for reliability and performance assurance. In addition to supplying parts, the team provides comprehensive repair services for faulty boards, ensuring minimal downtime and seamless integration into your automation systems. With 24/7 technical support, our specialists are ready to assist with troubleshooting, parts selection, and system optimization, delivering prompt and knowledgeable solutions for all your control and automation requirements. For pricing, availability, or service inquiries, contact the team directly via phone or email.

FREQUENTLY ASKED QUESTIONS:

What is IS200TBCIH1BCD?

The IS200TBCIH1BCD is a Contact Input with Group Isolation Terminal Board designed for GE Mark VIe control systems. It interfaces with 24 discrete dry contact inputs, providing galvanic isolation, surge suppression, and high-frequency noise filtering to maintain signal integrity.

How are the inputs powered and protected?

Inputs are energized from a floating 125 V dc supply (100–145 V dc), with current limiting applied in the power distribution module. Each input includes high-frequency filters, RC snubbers, and transient voltage suppressors (TVS) to protect against EMI, voltage transients, and surges.

What is the input current rating?

Channels 1-21 are rated at 2.5 mA, while channels 22-24 are rated at 10 mA. This allows the board to interface with both relay contacts and solid-state output devices. Each input is protected against overcurrent by the current-limited DC supply.