The GE IS200TBCIH1BBD TBCI Terminal Board is a contact input terminal board used within GE Industrial Control Systems. As a member of the TBCI board family, the IS200TBCIH1BBD TBCI Terminal Board accepts 24 dry contact inputs wired to two barrier-type terminal blocks and provides the field-side termination, signal conditioning, and group isolation required for discrete contact input signals in Mark VI and Mark VIe control architectures. DC power is wired to the board for contact excitation, and the contact inputs include noise suppression circuitry to protect against surge and high-frequency noise.
The IS200TBCIH1BBD TBCI Terminal Board is identified by the GE part numbering convention used throughout the Industrial Control Systems product line. The "IS200" prefix identifies the board as a GE Industrial Control Systems product, with "200" specifically indicating that the board is a base-level assembly. The "TBCI" acronym identifies the board's functional designation as a contact input terminal board. The "H1" designation identifies the hardware group and the excitation voltage variant, while the "BBD" suffix identifies the artwork and functional revision combination. All digits are important when ordering or replacing any board, as boards of different revision levels may not contain identical hardware, and GE ensures backward compatibility of replacement boards while noting that different revision levels may not contain identical components.
The IS200TBCIH1BBD TBCI Terminal Board belongs to the H1 version of the TBCI family, which uses a nominal 125 V DC floating excitation voltage ranging from 100 to 145 V DC. The TBCI family also includes the H2 version with a nominal 24 V DC excitation voltage and the H3 version with a nominal 48 V DC excitation voltage, allowing the family to be matched to the specific voltage levels of different turbine control and I/O applications. The H1 version is widely used in applications that derive their contact excitation from the 125 V DC turbine control supply.
This product introduction provides detailed technical information, functional descriptions, connector assignments, configuration guidance, and comprehensive specifications for the GE IS200TBCIH1BBD TBCI Terminal Board, serving as an essential reference for control system engineers, maintenance technicians, and system integrators working with GE industrial control equipment.
Functional Architecture and Signal Processing
The IS200TBCIH1BBD TBCI Terminal Board is built around a robust contact input architecture that supports 24 dry contact inputs, each with noise suppression and group isolation. The board performs several distinct functions that ensure reliable and accurate acquisition of discrete contact signals in electrically noisy industrial environments.
The 24 dry contact inputs of the IS200TBCIH1BBD TBCI Terminal Board are wired to two barrier-type terminal blocks, with each block held down by two screws and unpluggable from the board for maintenance. Each block has 24 terminals accepting up to #12 AWG wires, and a shield terminal strip attached to chassis ground is located immediately to the left of each terminal block to ensure proper shielding and grounding of the contact input cables. The contact input circuitry is designed for NEMA Class G creepage and clearance, ensuring safe operation at the elevated excitation voltages used by the H1 version.
The dry contact inputs of the IS200TBCIH1BBD TBCI Terminal Board are powered from a floating 125 V DC supply from the turbine control, ranging from 100 to 145 V DC. The 125 V DC bus is current limited in the power distribution module prior to feeding each contact input, providing protection against short circuits and faults on the field wiring. Filters reduce high-frequency noise and suppress surge on each input near the point of signal entry, ensuring that only valid contact transitions are reported to the I/O processor.
The discrete input voltage signals pass to the I/O processor, which sends them through optical isolators providing group isolation and transfers the signals to the system controller. The reference voltage in the isolation circuits sets a transition threshold that is equal to 50% of the applied floating power supply voltage, providing a well-defined and noise-immune switching point. The tracking is clamped to go no less than 13% of the nominal rated supply voltage to force all contacts to indicate open when the voltage dips below this level, ensuring fail-safe operation during low-voltage conditions.
A pair of terminal points is provided for each input, with one point (screw) providing the positive DC source and the second point providing the return (input) to the board. The current loading is 2.5 mA per point for the first 21 inputs on each terminal board, and the last three inputs have a 10 mA load to support interface with remote solid-state output electronics. This differentiated current loading allows the board to accommodate a wide range of contact types, from standard dry contacts to solid-state output devices.
Mark VI and Mark VIe Compatibility
The IS200TBCIH1BBD TBCI Terminal Board is compatible with both Mark VI and Mark VIe control systems, providing flexibility across different GE control architectures.
In the Mark VI system, the TBCI works with the VTCC or VCRC processor and supports simplex and TMR applications. Cables with molded plugs connect the TBCI to the VME rack where the VCCC or VCRC processor board is located. Both board versions TBCIH_B and TBCIH_C work correctly with Mark VI and are functionally identical.
In the Mark VIe system, the TBCI works with the PDIA I/O pack and supports simplex, dual, and TMR applications. One, two, or three PDIAs can be plugged directly into the TBCI, and the I/O packs attach to side-mounting brackets. One or two Ethernet cables plug into the pack, and firmware may need to be downloaded using ToolboxST for Mark VIe Control. Mark VIe requires the C version of this board for correct mechanical alignment of connector JT1 with the I/O pack mechanical support, so the IS200TBCIH1BBD TBCI Terminal Board is intended for Mark VI applications and for Mark VIe applications where the B version is acceptable.
Installation and Wiring
The IS200TBCIH1BBD TBCI Terminal Board is designed for straightforward installation and field wiring. The wires for the 24 dry contact inputs connect 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, and a shield terminal strip attached to chassis ground is located immediately to the left of each terminal block.
The TBCI connects to the contact excitation voltage source using plugs JE1 and JE2, as shown in the wiring diagram. In a simplex system, the TBCI connects to the I/O processor using connector JR1, while in a TMR system, the TBCI connects to the I/O processors using connectors JR1, JS1, and JT1. Cables or I/O packs are plugged in depending on the type of Mark VI or Mark VIe system and the level of redundancy, and the number and location of the connectors depend on the level of redundancy required.
The board size is 33.02 cm high by 10.16 cm wide (13.0 in x 4.0 in), and the operating temperature range is −30 to 65 °C (−22 to 149 °F), with a temperature rating of 0 to 60 °C (32 to 140 °F) for the terminal board. The power consumption is 20.6 W on the terminal board.
Diagnostics and Fault Detection
The IS200TBCIH1BBD TBCI Terminal Board provides comprehensive diagnostic capabilities that assist with system verification and fault isolation. The excitation voltage is monitored, and if the excitation drops to below 40% of the nominal voltage, a diagnostic alarm is set and latched by the I/O pack or board. As a test, all inputs associated with the terminal board are forced to the open contact (fail-safe) state, and any input that fails the diagnostic test is forced to the fail-safe state and a fault is created.
If the input from the board does not match the TMR voted value from all three boards, a fault is created, ensuring that a discrepancy in one channel is detected and reported. Each terminal board connector has its own ID device that is interrogated by the I/O pack or board. The connector ID is coded into a read-only chip containing the board serial number, board type, revision number, and the JR1, JS1, or JT1 connector location. When the chip is read by the controller and a mismatch is encountered, a hardware incompatibility fault is created, preventing the system from operating with incorrect or mismatched hardware.
The fault detection capabilities of the IS200TBCIH1BBD TBCI Terminal Board include loss of contact input excitation voltage, non-responding contact input in test mode, and unplugged cable, providing comprehensive coverage of the most common failure modes in contact input circuits.
Configuration
The IS200TBCIH1BBD TBCI Terminal Board has no jumpers or hardware settings on the board. All configuration is performed through the system software and the I/O pack or processor, simplifying installation and reducing the potential for configuration errors. The board's excitation voltage variant (H1, H2, or H3) is determined by the board part number and cannot be changed in the field, so the correct variant must be selected for the application.
Application Suitability and System Integration
The IS200TBCIH1BBD TBCI Terminal Board is a versatile contact input interface that can be used in a wide variety of GE Industrial Control System applications. Its 24 dry contact inputs, floating 125 V DC excitation, noise suppression, and group isolation make it suitable for monitoring limit switches, pressure switches, level switches, temperature switches, relay contacts, pushbuttons, and other discrete field devices in turbine control and balance-of-plant applications.
The board's support for simplex, dual, and TMR applications makes it suitable for a wide range of system architectures, from cost-sensitive simplex installations to critical TMR installations where high availability is required. In TMR applications, the board's fanned inputs and TMR voting provide the fault tolerance and reliability required for the most demanding control applications.
In Mark VI systems, the IS200TBCIH1BBD TBCI Terminal Board works with the VTCC or VCRC processor, with cables connecting the TBCI to the VME rack where the processor board is located. In Mark VIe systems, the board works with the PDIA I/O pack, with one, two, or three PDIAs plugged directly into the TBCI depending on the redundancy level. The board's unpluggable terminal blocks and clearly labeled connectors simplify installation, verification, and maintenance.
Maintenance and Lifecycle
The IS200TBCIH1BBD TBCI Terminal Board is designed for long service life with minimal maintenance. The board contains no moving parts, and its robust construction ensures high reliability in continuous industrial operation. Routine maintenance consists of periodic visual inspection of the board, terminal blocks, and wiring, verification that the excitation voltage is present and within specification, and confirmation that the shield terminals are properly connected.
The board's diagnostic features, including the excitation voltage monitoring, the fail-safe action, the test mode, and the onboard ID chip, simplify troubleshooting and ensure that the correct board is installed in each location. If the excitation voltage drops below 40% of nominal, the board forces all inputs to the open contact state and latches a diagnostic alarm, protecting the system from incorrect operation.
If the board requires replacement, the process is straightforward. After de-energizing the associated equipment and verifying that no power exists, the pluggable terminal blocks should be labeled and removed, and the board should be removed from its mounting. The replacement board should be installed in the same position, and the terminal blocks reconnected as labeled before returning the system to service.
GE Industrial Control Systems ensures compatibility of its replacement boards, even though boards of different revision levels may not contain identical hardware. When ordering a replacement IS200TBCIH1BBD TBCI Terminal Board, provide the complete part number and description, the drive or system serial number, and the Material List (ML) number. The factory may substitute later versions based on availability and design enhancements, but backward compatibility of replacement boards is guaranteed.
Conclusion
The GE IS200TBCIH1BBD TBCI Terminal Board is a reliable, robust, and versatile contact input interface for GE Industrial Control Systems. Its 24 dry contact inputs, floating 125 V DC excitation, noise suppression, group isolation, and comprehensive diagnostics provide the flexibility and reliability required for a wide range of industrial discrete input applications.
With its unpluggable terminal blocks, clearly labeled connectors, comprehensive diagnostics, and compatibility with both Mark VI and Mark VIe architectures, the IS200TBCIH1BBD TBCI Terminal Board is designed for easy installation, verification, and maintenance. Backed by GE's quality manufacturing, global support network, and commitment to backward compatibility, the IS200TBCIH1BBD TBCI Terminal Board continues to deliver the performance, durability, and reliability that industrial users expect from GE. Whether used in a new installation or as a replacement for an existing board, the IS200TBCIH1BBD TBCI Terminal Board provides the contact input functionality required for reliable and efficient control system operation.
