The GE IS200VCRCH1BBB Discrete Input/Output Board is a discrete I/O processor board used within GE Industrial Control Systems. As a member of the VCCC/VCRC board family, the IS200VCRCH1BBB Discrete Input/Output Board accepts 48 discrete inputs and controls 24 relay outputs from four terminal boards, providing the input isolation, high-speed scanning, sequence-of-events recording, and relay output control required for discrete process signal acquisition and control in Mark VI control architectures. The board communicates over the VME backplane to the VCMI board, which sends the signals to the controller.
The IS200VCRCH1BBB Discrete Input/Output 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 "VCRC" acronym identifies the board's functional designation as a Discrete Input/Output Board in the single-slot VCRC configuration. The "H1" designation identifies the hardware group, while the "BBB" 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 IS200VCRCH1BBB Discrete Input/Output Board is the VCRC version of the VCCC/VCRC family. The VCRC is a narrower, single-slot board that can be used instead of the double-width VCCC, providing the same functionality but taking up only one VME slot because no daughter board is required. Two front panel connectors, J33 and J44, accept the contact inputs from the TBCI terminal boards, while the relay outputs on the TRLY boards use the J3 and J4 ports on the VME rack, the same as for the VCCC. The VCRC is the preferred choice when locating the contact input cables on the front panel is acceptable, while the VCCC can be used if locating cables on the front panel is undesirable. The VCRC does not support the TICI contact voltage sensing board.
This product introduction provides detailed technical information, functional descriptions, connector assignments, configuration guidance, and comprehensive specifications for the GE IS200VCRCH1BBB Discrete Input/Output 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 IS200VCRCH1BBB Discrete Input/Output Board is built around a robust discrete signal processing architecture that supports 48 discrete inputs and 24 relay outputs, with the input signals passed through optical isolators and sampled at the frame rate for control functions and at 1 ms for sequence-of-events reporting.
The 48 dry contact inputs of the IS200VCRCH1BBB Discrete Input/Output Board are wired to two contact input terminal boards, with the first 24 inputs wired to the first terminal board and the second terminal board required for inputs 25 through 48. The dry contact inputs are powered from a floating 125 V DC supply (100–145 V DC) with the TBCIH1 board, or from a floating 24 V DC supply (18.5–32 V DC) with the TBCIH2 board. Filters reduce high-frequency noise and suppress surge on each input near the point of signal exit, and noise and contact bounce are filtered with a 4 ms filter. The AC voltage rejection is 60 V RMS at 50/60 Hz with 125 V DC excitation.
High-speed scanning and recording at a 1 ms rate is available for inputs monitoring important turbine variables, and the sequence-of-events recorder reports all contact openings and closures with a time resolution of 1 ms. Contact chatter and pulse widths down to 6 ms are reported, providing the detailed event timing required for fault analysis and sequence-of-events reconstruction.
For triple modular redundant (TMR) applications, the contact input voltages are fanned out to three VME board racks R, S, and T through plugs JR1, JS1, and JT1. The signals are processed by the three VCCCs and the results voted by the VCMI board in each controller rack, providing the fault tolerance and high availability required for critical control applications.
Relay Outputs
The relay outputs of the IS200VCRCH1BBB Discrete Input/Output Board are driven through the TRLYH1B terminal boards, which hold 12 plug-in magnetic relays each, providing a total of 24 relay outputs with two terminal boards. The first six relay circuits can be jumper-configured for either dry Form-C contact outputs or to drive external solenoids, and a standard 125 V DC or 115 V AC source, or an optional 24 V DC source, with individual jumper-selectable fuses and on-board suppression can be provided for field solenoid power. The next five relays (7–11) are unpowered isolated Form-C contacts, and output 12 is an isolated Form-C contact used for special applications such as ignition transformers.
Cables carry the relay control signals and monitor feedback voltages between the VCRC and the TRLY boards, with the relay drivers, fuses, and jumpers mounted on the relay board. Several types of relay boards can be driven, including the TRLY, DRLY, and SRLY boards, providing flexibility in the relay output configuration. The relay outputs have fail-safe features so that when a cable is unplugged, the inputs vote to de-energize the corresponding relays, and similarly, if communication with the associated VME board is lost, the relays de-energize, ensuring that the field outputs assume a safe state in the event of a communication failure.
The relay contact ratings include a nominal 125 V DC or 24 V DC rating and a nominal 120 V AC or 240 V AC rating, with a maximum load current of 0.6 A for 125 V DC operation, 3.0 A for 24 V DC operation, and 3.0 A for 120/240 V AC operation at 50/60 Hz. The relay contact material is silver cadmium oxide, and the contact life is 100,000 electrical operations and 10,000,000 mechanical operations. The maximum response time is 25 ms on and 25 ms off.
Installation and Wiring
The IS200VCRCH1BBB Discrete Input/Output Board is designed for straightforward installation in the VME I/O processor rack. To install the board, power down the VME I/O processor rack, slide in the board, and push the top and bottom levers in with your hands to seat its edge connectors, then tighten the captive screws at the top and bottom of the front panel. After powering up the VME rack, check the diagnostic lights at the top of the front panel.
Cable connections to the terminal boards are made at the J3 and J4 connectors (right-hand set) on the lower portion of the VME rack, and these are latching type connectors to secure the cables. Cable connections to the TRLY terminal boards are made to the left-hand set of J3 and J4 connectors. With the VCRC, both TBCI cables connect to J33 and J44 on the front panel, not to connectors under the rack, providing a convenient front-panel access for the contact input cables.
The board size is 26.04 cm high by 1.99 cm wide by 18.73 cm deep (10.25 in x 0.782 in x 7.375 in) for the VCRC, compared to 26.04 cm high by 3.98 cm wide by 18.73 cm deep (10.25 in x 1.564 in x 7.375 in) for the double-width VCCC. The operating temperature range is 0 to 60 °C (32 to 140 °F), making the board suitable for installation in standard industrial control cabinets.
Diagnostics and Fault Detection
The IS200VCRCH1BBB Discrete Input/Output Board provides comprehensive diagnostic capabilities that assist with system verification and fault isolation. Three LEDs at the top of the I/O board front panel provide status information, with the normal RUN condition being a flashing green, FAIL being a solid red, and STATUS being normally off but displaying a steady orange if a diagnostic alarm condition exists in the board.
Each output is monitored by diagnostics, with the voltage drops across the local and outer loop current sense resistors, the D/A outputs, and the shutdown relay contacts sampled and digitized. Standard diagnostic information is available on the outputs, including high and low limit checks and configurable high and low system limit checks, and if any one of the outputs goes unhealthy a composite diagnostic alarm occurs. The diagnostic signals can be individually latched and then reset with the RESET_DIA signal if they go healthy.
Each cable connector on the terminal board has its own ID device that is interrogated by the I/O processor. The ID device is a read-only chip coded with the terminal board serial number, board type, revision number, and the JR, JS, and JT connector location. When the ID chip is read by the I/O processor 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 IS200VCRCH1BBB Discrete Input/Output Board include loss of contact input excitation voltage, non-responding contact input in test mode, loss of user solenoid power due to a blown fuse, coil current disagreement with command, relay contact voltage monitoring indicating a problem, and unplugged cable or loss of communication with the I/O board, in which case the relays de-energize if communication with the associated I/O board is lost. A failed ID chip also generates a fault, providing comprehensive coverage of the most common failure modes in discrete input and output circuits.
Configuration
The IS200VCRCH1BBB Discrete Input/Output Board is configured through the system software, with the configuration information extracted from the toolbox and covering the system limits, the terminal board connections, the relay outputs, the contact inputs, and the signal inversion and filtering options.
The configuration parameters include the system limit enable or disable function, the terminal board connections for the TRLY and TBCI boards through J3, J4, J3A, and J4A, the relay output used or unused selection, the fuse diagnostic enable or disable function, the relay feedback point edit, the contact input used or unused selection, the signal inversion normal or invert selection, the sequence-of-events scanning enable or disable function, and the contact input filter in milliseconds (0, 10, 20, or 50 ms). These configuration options allow the board to be tailored to the specific application requirements and the connected field devices.
Application Suitability and System Integration
The IS200VCRCH1BBB Discrete Input/Output Board is a versatile discrete interface that can be used in a wide variety of GE Industrial Control System applications. Its 48 discrete inputs, supporting floating 125 V DC or 24 V DC excitation, and its 24 relay outputs, supporting dry Form-C contacts, external solenoid driving, and isolated Form-C contacts, allow the board to interface with limit switches, pressure switches, level switches, temperature switches, relay contacts, pushbuttons, pilot relays, interposing relays, contactors, solenoid valves, indicator lamps, and ignition transformers.
The board's support for both simplex 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 contact inputs and voted results provide the fault tolerance and reliability required for the most demanding control applications.
The board's high-speed scanning and sequence-of-events recording at a 1 ms rate, with contact chatter and pulse widths down to 6 ms reported, provide the detailed event timing required for fault analysis and sequence-of-events reconstruction, making the board suitable for applications where the precise timing of discrete events is important.
The VCRC single-slot configuration, with the contact input cables connected to the front panel J33 and J44 connectors, provides a space-efficient solution for applications where VME slot availability is limited, while the VCCC double-width configuration remains available for applications where locating the cables on the front panel is undesirable.
Maintenance and Lifecycle
The IS200VCRCH1BBB Discrete Input/Output Board is designed for long service life with minimal maintenance. The board contains the relays as its only moving parts, and its robust construction ensures high reliability in continuous industrial operation. Routine maintenance consists of periodic visual inspection of the board, connectors, and LEDs, verification that the discrete input and output signals are within specification, and confirmation that the diagnostic LEDs indicate normal operation.
The board's diagnostic features, including the output monitoring, the limit checks, the ID chip interrogation, and the comprehensive fault detection, simplify troubleshooting and ensure that the correct board is installed in each location. If a diagnostic alarm condition exists, the STATUS LED displays a steady orange, alerting the maintenance technician to a problem with the board or the field wiring.
If the board requires replacement, the process is straightforward. After powering down the VME I/O processor rack and verifying that no power exists, the cables should be disconnected from the J33 and J44 front panel connectors and the J3 and J4 VME rack connectors, the captive screws loosened, and the board removed from the rack using the top and bottom levers. The replacement board should be installed in the same position, the cables reconnected as labeled, and the diagnostic LEDs checked 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 IS200VCRCH1BBB Discrete Input/Output 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 IS200VCRCH1BBB Discrete Input/Output Board is a reliable, robust, and versatile discrete interface for GE Industrial Control Systems. Its 48 discrete inputs, supporting floating 125 V DC or 24 V DC excitation, its 24 relay outputs, supporting dry Form-C contacts, external solenoid driving, and isolated Form-C contacts, its high-speed scanning and sequence-of-events recording at a 1 ms rate, its fail-safe features, and its support for both simplex and TMR applications provide the flexibility, accuracy, and reliability required for a wide range of industrial discrete input and output applications.
With its single-slot VCRC configuration, front-panel J33 and J44 connectors for contact inputs, VME rack J3 and J4 connectors for relay outputs, clearly labeled connectors, and comprehensive diagnostics, the IS200VCRCH1BBB Discrete Input/Output Board is designed for easy installation, verification, and maintenance. Backed by GE's quality manufacturing, global support network, and commitment to backward compatibility, the IS200VCRCH1BBB Discrete Input/Output 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 IS200VCRCH1BBB Discrete Input/Output Board provides the discrete input and output functionality required for reliable and efficient control system operation.
